!

UNIVERSITY FARM

Minnesota Plant Life.

MINA IT

PL

JFK

by
v Mac Mil Ian

R e p u r t of the S u r v ey

Botanical Scries

III

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.id '{d rlqetsoloriq e moil .arnorl -liarlJ sdum

PLATE I. (Frontispiece.) A ravine near St. Paul, where shade-loving
plants make their home. From a photograph by Dr. Francis
Ramaley.

MI N N E SO

PLAINT LIFE

by
Con way Mac Mill an

Report of the Survey

Botanical Series

III

Saint Paul, Minnesota
October 30, \8gg

PUBLISHED BY AUTHORITY OF THE
BOARD OF REGENTS OF THE UNIVERSITY

FOR
THE PEOPLE OF MINNESOTA

Edition, 10, 000 copies

Preface*

|T has been well said that the main difficulties with the book on popular
science are that, if popular, it will not be scientific, and, if scientific, it
will not be popular. Yet, notwithstanding the truth thus epigrammatically
expressed, I am venturing to put forth Minnesota Plant Life as a book
certainly meriting the designation of popular, in so far as it is addressed to an
audience not composed of botanists, and at the same time scientific, to the extent at
least of choosing for its field one of the two great realms of living things the king-
dom of plants.

While to be out of fashion is to be out of the world, I have, nevertheless, resisted
the impulse to designate this volume as a suitable text-book for the "secondary
schools." On the contrary, such a use of it would be, in my opinion, distinctly un-
fortunate. It is not written in pedagogical vein, nor does it pre-suppose an acquaint-
ance with teachers and laboratories. It would, however, be disingenuous to deny
that the author has a definite educational purpose in view. Since this volume is to
be distributed in every county and perhaps in every school district in Minnesota, it
should, especially among the young, stimulate an interest in the study of plants.
With a minimum of technicalities, sentimentalities, unavoidable inaccuracies or cum-
bersome details, it seeks to accomplish the following ends:

1. The plant world is presented as an assemblage of living things.

2. The different kinds of plants in Minnesota, from the lowest to the highest,
are briefly reviewed in their natural order.

3. Some plant structures and behaviors are elementarily explained, as adapta-
tions to surrounding nature.

4. Certain plant individuals and societies are brought before the reader as hav-
ing life problems of their own, not as mere material for economic, anatomical or
classificatory industry.

In short, I have recognized that there are in Minnesota a number of intelligent
men and women, boys and girls, who wish to know more about plants, and in the
pages of this book I have sought to bring together what, from my own experience as
a student of plants, and as an instructor of the young, seems to me a sufficiently
adequate and compact presentation of the subject. Errors of judgment and of fact no
doubt exist, as in many works of mere human construction. I hope that they will
not prove harmful. In some matters, indeed, the point of view has shifted since cer-
tain chapters were in type. For example, experiments recently completed by the
United States Department of Agriculture tend to modify the German and Danish ex-

vi Minnesota Plant Life.

planations of bacterial relation to dairy industries and to the curing of tobacco. Other
new facts have been elicited by investigators studying the red and purple coloring
substances in plants, so that, if prepared to-dayt various chapters would undergo
slight alteration* In a subject developing so rapidly as is modern botany, it is diffi-
cult to be always absolutely abreast of the current.

A large number of the illustrations in the volume are from photographs of Min-
nesota vegetation, some of them made by myself, or under my direction, others
selected from the collections of friends, acquaintances and dealers. Many figures,
too, have been obtained in other ways. I have particularly to thank Dr. N, L.
Britton, of the New York Botanic Garden, for the cuts from his splendid Illustrated
Flora of North America, here credited to Britton and Brown. I am also much in-
debted to Professor G. F. Atkinson, of Cornell University, for permission to use nu-
merous engravings from his excellent text-book, Elementary ^Botany, and likewise
express my thanks to the United States Department of Agriculture, to Professor
Francis Ramaley, of the University of Colorado, Mr. C. G. Lloyd, of Cincinnati, the
Botanical Gazette, Meehan rs Monthly, Professor L. H. Bailey, of Cornell Univer-
sity, Professor B. D. Halsted, of Rutgers College, Professors Hall and Appleby and
Instructors Mackintosh, Mills and "Wheeler, of the University of Minnesota, Professor
Bruce Fink, of Fayette College, the late Warren W. Pendergast, and several others,
all of whom have assisted me in collecting illustrations. Tarn also greatly obliged to
my father, Dr. Geo. McMillan, for much valuable assistance with the proofs, and to
Miss Josephine E. Tilden for the preparation of the index.

I am particularly indebted to President Cyrus Northrop for suggestions and
assistance, without which, in all probability, this volume would have been neither
prepared nor published.

Among many books that I had occasion to consult during the preparation of
manuscript the Illustrated Flora of Britton and Brown, Sargent's magnificent Sileua,
Kerner's 'Plant Life, "Warming's Ecology, Schimper's 'Plant Geography, Lafar's
Technical Mycology and Upham's Catalogue of the Minnesota Flora, deserve
especial mention. Yet I should not give the impression that cMinnesota Plant Life
is wholly a product of the study; it is much more the offspring of the woods, the
prairies, the rivers and the lakes. In every part of the state, during the past twelve
years, I have visited them, and this book, with whatever merits and demerits it may
have, received an inspiration from such excursions among the plants themselves.

If, by the distribution of this volume a broader knowledge, a deeper interest, a
truer appreciation and a better understanding comes to those in whose hands its pages
open, the writer will feel well repaid for the labor of preparation. An intelligent
study of nature is one of the foundation stones of useful citizenship.

The University of Minnesota,
October 2, 1899.

Table of Contents*

PREFACE ............................................................ v

CHAPTER I ........... Plants in their Societies ...................... I

CHAPTER II .......... Plant Wanderings and Migrations ............. 18

CHAPTER III ......... Slime-moulds and Blue-green Algae ......... ; . 26

CHAPTER IV ......... Bright-green Algae ........................... 33

CHAPTER V .......... Brown Algae and Red Algae .................. 39

CHAPTER VI ......... The Lower Sorts of Fungi ................... 43

CHAPTER VII ........ Smuts and Rusts ............................. 48

CHAPTER VIII ....... Trembling Fungi, Club-fungi, Shelf-fungi and

Mushrooms ............................... 55

CHAPTER IX ......... Carrion-fungi and Puff-balls ................... 66

CHAPTER X .......... Yeasts, Morels, Cup-fungi and Truffles ...... ." . 72

CHAPTER XI .......... Blights, Black-fungi and Root-fungi ......... 80

CHAPTER XII ........ Lichens and Beetle-fungi ...................... 91

CHAPTER XIII ....... Various Kinds of Bacteria .................... 101

CHAPTER XIV ....... Mosses and Liverworts as Links between the

Algae and Higher Plants ................... 122

CHAPTER XV ........ Liverworts of Minnesota ...................... 132

CHAPTER XVI ....... Mosses of Minnesota ......................... 144

CHAPTER XVII ...... Christmas-green Plants or Club-mosses ....... 156

CHAPTER XVIII ..... Ferns and Water-ferns ........................ 161

CHAPTER XIX ....... Scouring-rushes and Horse-tails ............... 175

CHAPTER XX ........ What Seeds Are and how they are Produced. . . 180

CHAPTER XXI ....... Ground-hemlocks and Various Pines .......... 185

CHAPTER XXII ...... From Cat-tails to Eel-grasses ................. 197

CHAPTER XXIII ..... Grasses and Sedges ........................... 204

Vlll

Minnesota Plant Life.

CHAPTER XXIV From Callas to Water-star-grasses 217

CHAPTER XXV Rushes, Lilies, Blue Flags and Orchids 224

CHAPTER X XVI Poplars and Willows 233

CHAPTER XXVII From Bayberries to Oaks, Elms and Nettles.. . 243

CHAPTER XXVIII . . . From Sandalwoods to Buttercups 256

CHAPTER XXIX From Barberries to Witch-hazels 274

CHAPTER XXX Roses, Peas and the Relatives 286

CHAPTER XXXI From Geraniums to Maples and Touch-me-nots 305

CHAPTER XXXII From Buckthorns to Prickly Pears 319

CHAPTER XXXIII. .. From Leatherwoods to Dogwoods. 332

CHAPTER XXXIV ... High Types and Low Types of Flowers 343

CHAPTER XXXV .... From Wintergreens to Chaffweeds. 350

CHAPTER XXXVI . . . From Ash Trees to Verbenas 360

CHAPTER XXXVII . . From Peppermints to Plantains 375

CHAPTER XXXVIII . From Bedstraws to Lobelias 388

CHAPTER XXXIX. .. Dandelions, Ragweeds and Thistles

CHAPTER XL Adaptations of Plants to their Surroundings..

CHAPTER XLI Hydrophytic Plants

CHAPTER XLII Xerophytic Plants

CHAPTER XLHI Halophytes and Mesophytes 473

CHAPTER XLIV Maintenance of the Plant Individual 483

CHAPTER XLV Maintenance of the Plant Species 509

399
417

442

463

List of Plates.

PLATE I. A ravine near St. Paul, where shade-loving plants make
their home. From a photograph by Dr. Francis
Ramaley Frontispiece.

PLATE II. In the black oak country. Near the Chisago lakes. From

a photograph by Dr. Francis Ramaley 248

PLATE III. Pond with lilies. Ramsey county. Around it are growing
oaks, willows, sumacs and blue flags, milkweeds and
smartweeds. From a photograph by Williams 312

PLATE IV. Roadside vegetation near St. Paul. The most conspicu-
ous plants are hemp, wormwood, squirrel-tail grass and
daisies. From a photograph by Dr. Francis Ramaley. . . 456

Index to Illustrations*

FIG. i. In the forest district. Growth of white pines and spruces upon
a rocky island. Steamboat channel, Lake of the Woods.
After photograph by the author ............................ 7

FIG. 2. Prairie scene on the Coteau. Sunflowers line the roadway on

either side. After photograph by Mr. R. S. Mackintosh ..... 9

FIG. 3. Roadside vegetation. Grasses and pulses. An elm tree in

background. Cedar lake. After photograph by Williams... 10

FIG. 4. Spruces forming a zone around a peat-bog. Farther back are
tamaracks and pines. The shrub in the foreground is the
bog-willow, while the flowers are those of an orchid, — Pogo-
nia. Near Grand Rapids. After photograph by Mr. Warren
Pendergast ................................................ 1 1

FIG. 5. Zones of aquatic vegetation. In the center pond-lilies; at the
edge smartweed; farther back cat-tails, blue flags, sweet flags
and sedges; still farther back soft turf with grass, moss,
sedge and milkweed. After photograph by Williams ........ 12

FIG. 6. Island in the Mississippi above St. Paul. The center is occu-
pied by elms while the rim is fringed with willows. An ex-
ample of a "minor tension." After photograph by Professor
W. R. Appleby ............................................ 14

FIG. 7. Lake border vegetation of cat-tails, grasses, reeds and sedges.

Lake of the Isles. After photograph by Williams ........... 18

FIG. 8. Portion of a board which had been standing in the tank shown
in Fig. 10. It is encrusted with limestone deposited by a
colony of blue-green algae. After photograph by Miss Jos-
ephine E. Tilclen. From the Botanical Gazette ............... 31

xii Minnesota Plant Life.

FIG. 9. Portion of a pond-scum thread, showing how it is made up of
transparent-walled cells with a coiled green ribbon in each,
much magnified. After Atkinson 34

FIG. 10. Patches of pond-scum floating in a tank. A lime-encrusting
alga grows on the boards up to high-water mark. Near
Minneapolis. After photograph by Mr. R. W. Squires 35

FIG. ii. Patches of wheat-rust, natural size and enlarged. The red rust

stage. After Atkinson 51

FIG. 12. Patches of wheat-rust, natural size and enlarged. The black

rust stage. After Atkinson 51

FIG. 13. Wheat-rust in its barberry-leaf stage; to the left a barberry
leaf with diseased spots; in the middle, a single spot with
cups; to the right, two of the cups, in top view slightly mag-
nified. After Atkinson 52

FIG. 14. Magnified section through a cluster-cup of the wheat-rust in its
barberry-leaf stage. Shows chains of spore-cells. The large
cells at the sides are those of the barberry leaf much magni-
fied. After Atkinson 53

FIG. 15. Growth of club-fungi on decaying wood. After Lloyd 56

FIG. 16. Shelf-fungus growing on dead stump of oak tree. After pho-
tograph by Hibbard 57

FIG. 17. Upper and under sides of mushroom-like pore-fungus. After

Lloyd 59

FIG. 18. A pore-fungus lying flat upon a decaying branch. After Lloyd 60
FIG. 19. Deadly variety of mushroom. After Atkinson. Bulletin 138,

Cornell Ag. Exp. Station. This is sometimes known as the

"poison cup" 61

FIG. 20. Under side of two mushroom-fruits. After Atkinson. Bulletin

138, Cornell Ag. Exp. Station 62

FIG. 21. Common edible mushroom. After Atkinson. Bulletin 138,

Cornell Ag. Exp. Station 63

Minnesota Plant Life. xiii

FIG. 22. Development of mushroom-fruits on their underground vege-
tative tract. After Atkinson. Bulletin 138, Cornell Ag. Exp.

Station 64

FIG. 23. Warty puff-ball. After Lloyd 68

FIG. 24. Tufted puff-ball. After Lloyd 69

FIG. 25. Pocket-fungus on sand-cherry. After Bailey. Bulletin 70,

Cornell Ag. Exp. Station 74

FIG. 26. A morel fruit-body. After Lloyd 75

FIG. 27. Cup-fungi growing on decaying twig. After Lloyd 76

FIG. 28. Leaf-spot disease caused by fungus. After Halsted 82

FIG. 29. Leaf-spot fungus growing on pear leaves. After Duggar. Bul-
letin 145, Cornell Ag. Exp. Station 83

FIG. 30. Fungus spot-disease of strawberry leaf. After Bailey. Bulletin

79, Cornell Univ. Ag. Exp. Station 84

FIG. 31. Fungus spot-disease on leaf of false Solomon's seal. After

Halsted 85

FIG. 32. Fungus spot-disease on pear. After Duggar. Bulletin 145,

Cornell Ag. Exp. Station • 86

FIG. 33. Fungus spot-disease of bean pods. After Halsted 87

FIG. 34. Twig-fungus on currant canes. After Durand. Bulletin 125,

Cornell Exp. Station 88

FIG. 35. Rock-lichens growing profusely in a glacial pot-hole. Near

Taylor's Falls. After photograph by Mr. E. C. Mills 92

FIG. 36. "Old man's beard." A lichen growing attached to the twigs
of tamarack. Lake Superior, north shore. Natural size, six
inches in length. After photograph by Professor Bruce Fink 93,

FIG. 37. A lichen growing upon a rock, and covered with the charac-
teristic saucer-shaped fruits of its fungus component. After
Atkinson 95

xiv Minnesota Plant Life.

FIG. 38. A tuft of "reindeer moss." Natural size, 2.y2 feet in diameter.
Age, probably over one hundred years. North shore of Lake
Superior. After photograph by Professor Bruce Fink 97

FIG. 39. A male moss plant. The spermaries are produced in clusters

at the end of the stem. After Atkinson 125

FIG. 40. A female moss plant. The egg-organs are inclosed in the tuft

of leaves at the tip of the stem. After Atkinson 125

FIG. 41. The club-shaped spermary of a moss, much magnified, and two

sperni£tozoids, very highly magnified. After Atkinson 126

FIG. 42. Tip of a leafy moss plant, sectioned lengthwise and magnified.
The flask-shaped egg-organs, one with an egg in place, are
shown. These bodies are barely visible to the naked eye.
After Atkinson 127

FIG. 43. Mud-flat liverwort, showing method of growth and branch-
ing. After Atkinson 132

FIG. 44. The umbrella-liverwort; showing the prostrate vegetative
body, and the upright branches on which the egg-organs are
borne, and where later the capsular plants will be found
perching. After Atkinson ^5

FIG. 45. Stem of the umbrella-liverwort, showing the little cups with
bodies inside, which are employed by the plant for purposes
of propagation. After Atkinson j^g

FIG. 46. Road across a peat-bog; tamaracks and birches in background.
Near Grand Rapids. After photograph by Mr. Warren Pen-
dergast I45

FIG. 47. Peat-moss leafy-plants with capsular-plants imbedded at the

tips of short leafless erect branches. After Atkinson 147

FIG. 48. A moss leafy-plant, with prostrate propagative branch and
erect female reproductive branch. On the latter two egg-
organs have developed their eggs into capsular plants, one
of which is ejecting spores. The two round bodies are spores
much magnified. After Atkinson. . 153

Minnesota Plant Life. xv

Fir,. 49. Branch of a club-moss plant, hearing two cones; with a single
leaf of the cone, showing the spore case and one of the

spores, the latter much magnified. After Atkinson 156

FIG. 50. Flat-branched club-moss. After Britton and Brown 158

FIG. 51. Smaller club-moss. To the left a plant with three cones, next
a single cone dissected to show the spore cases, next a single
large-spore-case with four spores revealed, and on the right
a small- spore-case with the small spores sifting out. After

Atkinson 159

FIG. 52. Adder's-tongue fern. After E. N. Williams, in Meeharis

Monthly 162

FIG. 53. Virginia grape-fern. After Britton and Brown 163

FIG. 54. A quillwort plant. After Atkinson 164

FIG. 55. Clayton's, or interrupted fern. After Britton and Brown 164

FIG. 56. Bed of ferns. Sensitive fern in middle of foreground. After

photograph by Williams 165

FIG. 57. Cliff-brake. After Britton and Brown 166

FIG. 58. The interrupted fern (in background) and shield-ferns (in fore-
ground). After photograph by Williams 167

FIG. 59. Four-leaved water-fern. After Britton and Brown 168

FIG. 60. A sexual fern-plant somewhat magnified. Its natural size is
about a quarter of an inch across. The round bodies are
spermaries, the chimney-shaped ones are egg-organs, seen

from below. After Atkinson 168

FIG. 61. A fern-plant embryo imbedded in the enlarged egg-organ,
where it arose by segmentation of an egg. S, tip of rudi-
mentary stem ; L, tip of first leaf; R, tip of primitive rootlet;

F, nursing foot. Much magnified. After Atkinson 169

FIG. 62. Portion of maiden-hair fern leaf, showing marginal pockets,
which serve to protect the clusters of spore-cases under each
Map. After Atkinson 170

xvi Minnesota Plant Life.

FIG. 63. A patch of spore-cases on the back of a common polypody-
fern-leaf. Magnified. After Atkinson 170

FIG. 64. Spore-cases of the common fern, much magnified, showing
how the spring back reverts and then snaps shut again,
throwing the spores as from a sling. After Atkinson 171

FIG. 65. A walking-fern climbing down a hillside. Buds form at the
very tips of the slender leaves and grow into new plants.
After Atkinson 1 72

FIG. 66. Maiden-hair ferns and lady ferns. After photograph by Wil-
liams 173

FIG. 67. A fruiting stem of the horse-tail. The shield-shaped spore-
bearing leaves are aggregated in a cone. After Atkinson.. . . 176

FIG. 68. Scouring-rush spores; to the left a spore with appendages
curled up, in moist air; to the right a spore with appendages
extended, in dry air. After Atkinson 177

FIG. 69. Diagram of an ovary, with one seed-rudiment, in a higher
seed-plant, s, the stigma, where two pollen-spores have
germinated; o, wall of ovary; f, stalk of ovule; ai and ii,
rudimentary seed-coats; n, spore-case, with single large
spore, which has germinated to produce the reduced female
plant; k, the egg; e, the body which forms the albumen; b,
other cells of the female. The male plant is shown as a tubu-
lar thread growing towards the egg. After Atkinson 181

FIG. 70. White pines on the rocks at Taylor's Falls. After photograph

by Williams 187

FIG. 71. Jack pine. After Britton and Brown 188

FIG. 72. Rock-vegetation near Duluth. White pines, white cedars and

junipers. After photograph by Williams 189

FIG. 73. Tamarack swamp with sedge border. After photograph by

Williams 191

FIG. 74. Red cedars on the banks of a Minnesota lake. After photo-
graph by Williams 193

Minnesota Plant Life. xvii

FIG. 75. Rock on the St. Croix river, near Taylor's Falls. Shows zonal
distribution of trees. White pines stand on top of the rock,
and birches and poplars on the sides. After photograph by
Mr. H. C. Cutler 195

FIG. 76. Bur-reed. After Britton and Brown 198

FIG. 77. Lakeside vegetation. Just off shore is a growth of the floating
pondweed, then of arrowheads, while farther out are reeds

and rushes. After photograph by Williams 199

FIG. 78. Clasping-leaved pondweed. After Britton and Brown. ....... 200

FIG. 79. Evening scene in Minnesota. Arrowheads, bulrushes and wil-
lows in foreground. After photograph by Williams 201

FIG. 80. Arrowhead. After Britton and Brown 202

FIG. 81. Eel-grass. After Britton and Brown 202

FIG. 82. Wild rice and pond lilies. After photograph by Williams 204

FIG. 83. Beard-grass. After Britton and Brown 205

FIG. 84. Barnyard grass. After Britton and Brown 205

FIG. 85. Minnesota Muhlenberg grass. After Britton and Brown 206

FIG. 86. Beckman grass. After Britton and Brown 206

FIG. 87. Indian corn in the shock. After photograph by Williams 207

FIG. 88. Wild rice in a Minnesota lake. After photograph by Williams 208

FIG. 89. Wild rice. After Britton and Brown 209

FIG. 90. Kalm's brome-grass. After Britton and Brown 209

FIG. 91. A cluster of sedge-flowers (Carex-type), a single pistillate
flower with one fruit rudiment, and a staminate flower with

three stamens. After Atkinson 210

FIG. 92. Cyperus-sedge. After Britton and Brown 211

FIG. 93. Cotton-grasses growing in a bed of peat-moss. Near Grand

Rapids. After photograph by Mr. Warren Pendergast 212

FIG. 94. Lake border vegetation. Bulrushes and reed-grasses. After

photograph by Williams 213

xviii Minnesota Plant Life.

FIG. 95. Bulrush-sedge. After Britton and Brown 214

FIG. 96. Carex-sedge. After Britton and Brown 215

FIG. 97. A skunk-cabbage in early spring, before the leaves have un-
folded. The purple hood covering the flower cluster is

shown on one side. After Atkinson 218

FIG. 98. Sedges and rushes. After photograph by Williams 224

FIG. 99. Dog's-tooth violet in flower. After Atkinson 225

FIG. 100. Clintonia. After Britton and Brown 225

FIG. 101. Blue flags. After photograph by Williams 226

FIG. 102. Stream-side vegetation. Blue flags in foreground. After pho-
tograph by Williams 227

FIG. 103. Yellow lady-slipper. After photograph by Mr. R. S. Mackin-
tosh 229

FIG. 104. Wild orchis. After Britton and Brown 230

FIG. 105. Cottonwoods on the Minnesota. After photograph by Wil-
liams 235

FIG. 106. Poplar vegetation of burnt district. Near Rat Portage, Ont.

After photograph by the author 237

FIG. 107. Cottonwood. After Britton and Brown 238

FIG. 108. Peach-leafed willows on shore of stream. After photograph by

Williams 239

FIG. 109. Clusters of willow flowers; on the left the pistillate flowers
and on the right the staminate. Each pistillate flower con-
sists principally of a single fruit-rudiment, and each staminate
flower of two, or sometimes a larger number of stamens.

After Atkinson 240

FIG. no. Beach vegetation, Garden Island, Lake of the Woods. The
long-leafed willow forms the outer zone, and the black willow

the inner. After photograph by the author 241

FIG. in. Hickory trees. Lake Minnetonka. After photograph by Wil-
liams 244

Minnesota Plant Life. xix

FIG. 112. Ironwoods and oaks. The smaller trees are ironwoods and
hop-hornbeams. Lake Calhoun. After photograph by Hib-

bard 245

FIG. 113. The paper or canoe birch. After photograph by Williams. .. . 247
FIG. 114. An Indian encampment, Lake of the Woods. The vegetation
is principally the canoe birch, and the canoes and tepees illus-
trate the uses to which birch-bark is put by the aborigines.
After photograph by Wright. From Minnesota Botanical

Studies 248

FIG. 115. An oak twig with leaves and both sorts of flowers. The one
with three prongs is the pistillate flower; the other, with five
stamens, is the staminate. The staminate flowers grow in

drooping clusters. After Atkinson 249

FIG. 116. Oaks and blue flags. A marshy place in the oak-woods. After

photograph by Williams 250

FIG. 117. American elm. After Britton and Brown 251

FIG. 118. American elm. Lake Minnetonka. After photograph by Wil-
liams 252

FIG. 119. Roadside vegetation of nettles and vines. Winter aspect.

After photograph by Williams 254

FIG. 120. Glasswort. After Britton and Brown 259

FIG. 121. Pokeweed. After Chesnut. F. B. 86, U. S. Dept. Ag 260

FIG. 122. Carpetweed. After Britton and Brown 261

FIG. 123. Spring-beauty in flower. After Atkinson 262

FIG. 124. Water-shield. After Britton and Brown 264

FIG. 125. Water-lilies. After photograph by Williams 265

FIG. 126. Marsh-marigold or cowslip. After Britton and Brown 268

FIG. 127. False rue-anemone growing in pots. University plant house.
After photograph by Dr. D. T. MacDougal. From Minne-
sota Botanical Studies 270

FIG. 128. White water-buttercup. After Britton and Brown 271

xx Minnesota Plant Life.

FIG. 129. Early meadow-rue. After Britton and Brown 272

FIG. 130. May-apple, or mandrake, in flower. After Atkinson 275

FIG. 131. Clammy-weed. After Britton and Brown 276

FIG. 132. Blood-root. After Britton and Brown 276

FIG. 133. Water-cress. After Britton and Brown 277

FIG. 134. Pitcher-plant. After Britton and Brown 278

FIG. 135. Sundew. After Britton and Brown 280

FIG. 136. River-weed. After Britton and Brown 281

FIG. 137. American alum-root. After Britton and Brown 282

FIG. 138. Marsh Parnassia. After Britton and Brown 283

FIG. 139. Hawthorn. After Britton and Brown 287

FIG. 140. Apple-blossoms. After photograph by Williams 288

FIG. 141. Marsh fivefinger. After Britton and Brown 289

FIG. 142. Roses. After photograph by Williams 291

FIG. 143. Sand-cherry in fruit. After Bailey. Bulletin 70, Cornell Ag.

Exp. Station 292

FIG. 144. A cluster of choke-cherry flowers and a single flower dis-
sected. After Atkinson 293

FIG. 145. Kentucky coffee-tree. After Britton and Brown 296

FIG. 146. Wild lupine. After Britton and Brown 298

FIG. 147. Sweet-clover bushes. After photograph by Williams 299

FIG. 148. White clover. After photograph by Williams 300

FIG. 149. Tick-trefoil. After Britton and Brown 303

FIG. 150. Sumac bushes, with golden-rods in foreground and maples in

background. After photograph by Williams 309

FIG. 151. Poison-sumac. After Chesnut. F. B. 86, U. S. Dept. Ag 310

FIG. 152. Poison-ivy. After .Chesnut F. B. 86, U. S. Dept. Ag 311

FIG. 153. Leaves and flowers of the sugar-maple. After Atkinson 314

FIG. 154. A grove of sugar-maples. Near Lake Minnetonka. After

photograph by Mr. E. C. Mills 315

Minnesota Plant Life. xxi

FIG. 155. Moosewood maple. After Britton and Brown 316

FIG. 156. Touch-me-not. After Britton and Brown 317

FIG. 157. Tree covered by grape-vine. After photograph by Williams. . 320
FIG. 158. Virginia creeper on tree trunks. After Schneck in Meehan's

Monthly 322

FIG. 159. Basswood trees. Shore of Lake Calhoun. After photograph

by Hibbard 324

FIG. 160. Beach heather. After Britton and Brown 327

FIG. 161. Sweet white violet. After Britton and Brown 328

FIG. 162. Western prickly-pear cactus. After Britton and Brown 330

FIG. 163. Ginseng. After Britton and Brown 337

FIG. 164. Water-parsnip. After Britton and Brown 338

FIG. 165. Wild parsley. After photograph by Williams 339

FIG. 1 66. Water-hemlock. After Chesnut. F. B. 86, U. S. Dept. Ag.. . 340

FIG. 167. Dwarf cornel. After Britton and Brown 341

FIG. 168. Wintergreen plant in flower. After Atkinson 351

FIG. 169. Kalmia flowers. After Atkinson 354

FIG. 170. Moss-plant. After Britton and Brown 355

FIG. 171. Small cranberry. After Britton and Brown 357

FIG. 172. Yellow gentian. After Britton and Brown 362

FIG. 173. Swamp milkweed. After Britton and Brown 365

FIG. 174. Brookside vegetation. Milkweeds in foreground. After pho-
tograph by Williams 366

FIG. 175. Dodder in flower; the parasite is seen to be clutching tightly

the stem of its host plant. After Atkinson 368

FIG. 176. Virginia water-leaf. After Britton and Brown 37°

FIG. 177. Blue verbena. After Britton and Brown 373

FIG. 178. Wild mint. After Britton and Brown 375

FIG. 179. Clump of horse-mint (in middle of picture). After photo-
graph by Williams 376

xxii Minnesota Plant Life.

FIG. 180. Horse-mint. After Britton and Brown 377

FIG. 181. View in Minnesota lake district. Shows in center two mullein
plants in characteristic positions. After photograph by Wil-
liam s 380

FIG. 182. Monkey flower. After Britton and Brown 381

FIG. 183. Lousewort. After Britton and Brown 382

FIG. 184. Bladderwort. After Britton and Brown 383

FIG. 185. Cancerroot. After Jellett in Median's Monthly 385

FIG. 186. Rugel's plantain. After Britton and Brown 386

FIG. 187. Bedstraw. After Britton and Brown 389

FIG. 188. Partridgeberry. After Britton and Brown 389

FIG. 189. High bush cranberry. After Britton and Brown 390

FIG. 190. Snowberry. After Britton and Brown 392

FIG. 191. Blue-bells. After Britton and Brown 395

FIG. 192. Blue lobelia. After Britton and Brown 396

FIG. 193. Chrysanthemum in flower. After Miller. Bulletin 147, Cor-
nell Ag. Exp. Station 400

FIG. 194. Dandelions in flower. Lake Calhoun. After photograph by

Hibbard 401

FIG. 195. Dandelions in fruit. After photograph by Williams 402

FIG. 196. Wild lettuce, a compass-plant; the fruits stand in heads, and
each fruit is provided with a parachute of bristles. After

Atkinson 403

FIG. 197. Rattlesnake-root. After Britton and Brown 404

FIG. 198. Cocklebur. After Britton and Brown 404

FIG. 199. Ragweed. After Britton and Brown 405

FIG. 200. Autumnal vegetation of marsh border. Thoroughwort or joe-

pye weed. After photograph by Williams 406

FIG. 201. Boneset or thoroughwort. After Britton and Brown 407

FIG. 202. Blazing-star. After Britton and Brown 407

Minnesota Plant Life. xxiii

FIG. 203. Autumnal composite vegetation. In foreground golden-rods,
sunflowers and asters; in background, on brow of cliff,
wormwood or sage-brush. After photograph by Williams.. . 408

FIG. 204. Early golden-rod. After Britton and Brown 409

FIG. 205. Asters a'nd golden-rod. Banks of the Mississippi. After pho-
tograph by Williams 410

FIG. 206. Rosinweed compass-plant. After Britton and Brown 411

FIG. 207. Cone-flowers. After photograph by Williams 412

FIG. 208. Prairie cone-flower. After Britton and Brown 413

FIG. 209. Water bur-marigold. After Britton and Brown 414

FIG. 210. Corn-flower. After Britton and Brown 414

FIG. 211. Bur oak and bracken fern. Illustrates relation between strength
of stem and the weight to be borne. After photograph by

Hibbard 419

FIG. 212. Willows and bulrushes. The latter are typical surf-plants.

After photograph by Williams 421

FIG. 213. Elm tree growing in the open. Light is received on all sides.

After photograph by Williams 429

FIG. 214. Two-leafed wood-lilies. These plants have the broad leaves of
shade plants and the white, conspicuous flowers. After pho-
tograph by Hibbard 430

FIG. 215. Jack-in-the-pulpit. A shade plant. After photograph by Hib-
bard 431

FIG. 216. Leaves of the sensitive fern, a shade-loving variety. After

photograph by Hibbard 432

FIG. 217. The Virginia creeper on the walls of the old round tower,
Fort Snelling. This plant does not turn towards the sun, but
clings to the shaded wall. After photograph by Williams. . . . 433
FIG. 218. "Gallery woods," near Minnesota Falls, valley of the Minne-
sota, in the prairie district. Dependence of trees upon mois-
ture is illustrated by their grouping in declivities. After pho-
tograph by Professor R. D. Irving 434

xxiv Minnesota Plant Life.

FIG. 219. Dandelion fruiting in shady spot. Shows the slender stems
and erect root-leaves of the shady habitat, and fruits adapted
for wind distribution. After photograph by Hibbard 441

FIG. 220. Vegetation of ravine. The home of mosses and liverworts.
The plants in front are touch-me-nots. After photograph by
Williams 447

FIG. 221. Stream-side vegetation. Ironweeds, thoroughwort, mullein,
sedge, speedwell and shrubbery. Hydrophytic vegetation in
water's edge. After photograph by Williams 448

FIG. 222. Birch trees along a lake shore. Bar vegetation in background.

After photograph by Williams 449

FIG. 223. Trees along a river bank. Soft maple and cottonwood. Min-
nesota river. After photograph by Williams 452

FIG. 224. Marshy place at the edge of a wood. After photograph by

Murdock 454

FIG. 225. Ferns in tamarack swamp, Lake Calhoun. After photograph

by Hibbard 455

FIG. 226. Swamp saxifrages. The large root-leaves are adapted to the
shade of the swamp. The whole plant is hairy. Tamarack
swamp, Lake Harriet. After photograph by Hibbard 456

FIG. 227. A marsh-loving sedge, showing fruit clusters. After photo-
graph by Hibbard 458

FIG. 228. A pitcher plant in flower; tamarack swamp. The leaves are

converted into insect-traps. After photograph by Hibbard. . . 461

FIG. 229. Rock vegetation, Lake of the Woods, near Keewatin, Ontario.
Junipers, bellworts, pines, ferns, poplars and grasses predom-
inate. After photograph by Wright 466

FIG. 230. Growth of hardwood trees upon a rocky island. Northwest

angle, Lake of the Woods. After photograph by the author. . 468

FIG. 231. Vegetation of sand dunes, Isle aux Sables, Lake of the
Woods. In the foreground is the sand cherry and scrub
poplar, in the center a juniper bush and in the background
plums. After photograph by the author 470

Minnesota Plant Life. xxv

FIG. 232. The valley of the Minnesota river in the prairie district. Abun-
dant grass vegetation. After photograph by Professor R. D.
Irving 471

FIG. 233. Cottonwood trees on the Minnesota river. After photograph

by Williams 474

FIG. 234. A Minnesota meadow bordered by shrubbery and deciduous

forest. After photograph by Mr. W. A. Wheeler 475

FIG. 235. Roadside vegetation in summer. After photograph by Wil-
liams 477

FIG. 236. Roadside vegetation in winter, St. Anthony Park. Oaks, sun-
flowers and goldenrods. After photograph by Williams 477

FIG. 237. Autumnal underbrush, Mississippi river, between Minneapolis
and St. Paul. Golden rods, asters and sumac. After photo-
graph by Williams 478

FIG. 238. Neglected corner in the Minneapolis manufacturing district.

Weeds and shrubbery. After photograph by Williams 479

FIG. 239. Modern hardwood forest of the St. Croix valley, near Osceola.

After photograph by Professor W. R. Appleby 480

FIG. 240. View of Fort Snelling, showing midsummer vegetation. After

photograph by Williams 481

Chapter I.

Plants in their Societies*

Purpose of this book. In the pages of this book I hope
to give the reader an idea of the diversified plant life which
occupies the air, the soil and the waters of Minnesota. First
of all, it must be remembered that plants although passive
creatures are quite as truly living beings as are the more active
animals. Just as men and women, either themselves or their
ancestors, have entered the state from some other region, so
also have plants, according to the nature of each, found their
way and selected their abodes. It is no easy problem to de-
termine why some family has chosen one village rather than
another. This may have been from causes which are too subtle
or too remote for analysis, but it is recognized that people have
not come to make their homes without some reason which
seemed sufficient to them or to their forefathers. So, too,
there is always some reason for the appearance at a particular
spot of one kind of plant rather than another, and it is possible
ir i general way to explain the vegetation of the hills and
meadows of the state.

Minnesota geography. A glance at the map will show that
the State of Minnesota lies between the 43rd and 49th paral-
lels of north latitude and between the 8gth and 97th meri-
dians west, and that it is centrally located in the North Ameri-
can continent. Within its domain rises the Mississippi and
by this great river the surplus rain-fall of the state is in large
measure carried away to the Gulf of Mexico. The northwest-
ern portion, by the Red river and its tributaries, is drained
through Lake Winnipeg into Hudson bay, while a few streams
flow in the valley of the St. Lawrence to the Atlantic ocean.
Minnesota, therefore, is not only geographically but hydro-
graphically central. Hence it might be supposed that its plants

2 Minnesota Plant Life.

would have immigrated equally from all directions. Such, how-
ever, is bv no means the fact and it is needful to inquire further
into the conditions which regulate plant distribution before
the true situation can be understood.

Minnesota climate. Connected with the geographical posi-
tion of the state, and to a very great degree dependent upon
it, is that combination of average winds, average temperature,
average precipitation of moisture, and average illumination
by the sun to which is given the general name of climate. Min-
nesota enjoys what is known as a mid-continental climate,
characterized by warmth in the summer and cold in the winter.
There are no prevailing winds from years end to year's end
as there are at some places by the sea. The sun never shines
with equatorial directness, nor are there ever weeks or months
of twilight, or of darkness, as in the regions of the poles. There
are no great mountain ranges to cool the clouds as they move
across the sky and to force them to yield their moisture in the
eternal snows; and during the year there may always be ex-
pected an average rain-fall of about twenty-five inches. Through
the spring and summer there is always a rise in temperature to
stimulate growth, but there is never that fervent, damp heat
which favors the rank and luxuriant vegetation of the tropics.
Consequently there are to be found in Minnesota, plants adapted
to the rhythm of the seasons, to the oblique illumination of the
sun, to the average moisture of the air and of the soil, and to
the winds which sometimes sweep over the prairies with an
almost resistless force.

As an illustration of the adaptation of plants to seasonal
rhythm may be mentioned the autumnal habit of most trees in
Minnesota of shedding their leaves. Indeed, this is so common
a fact of experience that it is scarcely realized to be a definite
reaction of the plant to its environment. Yet leaves do not fall
merely because the nights are growing cold, but because there
is formed at the base of each leaf-stalk a little layer of cork
which, when complete, cuts the leaf from the twig as if by a pair
of shears. Certainly such is not everywhere a necessary habit,
for it is known that in the tropics many trees do not lose their
leaves each year, but retain them for varying periods of time
until their usefulness is past — a character shared also by some

Minnesota Plant Life. 3

trees of temperate regions. Apparently, then, the habit of
rejecting leaves that would be killed by the winter's cold and
would become burdensome another summer may be directly
connected with the geographical position of the state.

Again, trees with enormous, delicate leaves like those of many
palms or bananas, are not found upon the prairies of the Red
river, because, clearly, if trees with such thin, large leaves were
exposed to the wind they would be blown to pieces and their
life would be destroyed. Large delicate-leaved forms are more
characteristic of regions where the wind is slight or where it is
broken by masses of surrounding vegetation.

Furthermore, in a state so well watered as Minnesota there
is no development of those curious desert types which are seen
in Arizona, in the Sahara, or in the arid regions of South Africa
and Australia; for where it is arid those plants only can grow
that by structure and habits are fitted to utilize the relatively
small quantities of moisture. The strange columnar cacti of
the Gila, standing leafless and rigid — vegetable pillars of the
desert — would be out of place wherever the rain-fall permits the
production of ordinary leaves and branches. Thus in survey-
ing the vegetation of the world one is impressed with the influ-
ence of climate upon the plant population of every district.

The physical history of Minnesota. A knowledge of its
geography and climate does not, however, afford all the data
for comprehending the vegetation of any region, since it is not
alone the climate of to-day, but even more strongly the climate
and other conditions of the past, that are reflected in the forms
and structures of the plants. Therefore, a knowledge also of
the geological history of the state and of its various soils is
essential to an understanding of its vegetation. There is strong
reason to suppose that about ten thousand years ago much of
the surface of North America was covered by a thick sheet of
ice which advanced slowly from the north and later as slowly
retreated. The period of ice-advance is known to geologists as
the glacial period, and throughout Minnesota are to be found
the traces of glacial action. The clays, pebbles and bowlders so
abundant throughout the state are believed to have been depos-
ited either upon the front of a glacial mass, or underneath, or
from the waters caused by its melting. When such a move-

4 Minnesota Plant Life,

ment of ice took place there must have been a great modifica-
tion of drainage conditions over all the invaded district. Streams
were dammed, hills were levelled, valleys were filled, lake bot-
toms were hollowed out or covered with confused masses of
rocks and clay — ground into pow^der by the powerful action of
the ice, continuing, as it did, through more than a thousand
years. It is clear, too, that the ancient vegetation must have
been almost wholly swept away by this invasion from the Arctic
zone. It is true that plants are sometimes found growing close
to the edge of glaciers in the Alps, in Greenland and in Alaska.
Sometimes even masses of soil are so borne upon the surface of
the glacier that plants of hardy habit may continue their exist-
ence there. Yet, with a due regard to these well-known facts,
it is not conceivable that for so long a period of rigorous cold
the old pre-glacial plant-population of the state could have held
its ground. It must be supposed, rather, that as the glacier
steadily advanced from the north, year after year plants flung
their seeds into air-currents moving southward or attached them
to the fur of animals seeking a warmer clime and thus gradu-
ally season by season themselves migrated toward the south.
Evidently those plants provided with seeds, buoyant, winged,
barbed or hooked were best fitted by such contrivances to leave
the snows and ice of a thousand years, while the plants with
smooth and heavy seeds either migrated more leisurely and
more sparingly or were quite extinguished by the cold.

When the glacial period came finally to an end and the ice-
sheet moved north beyond the confines of the state, there
opened to the immigrants from the south a new Minnesota.
Great lakes formed by the waters of the melting ice now lay
where before there was land. Rivers were flowing in new direc-
tions and were carving for themselves new gorges through the
rocks. A fertile soil was deposited upon the hill-sides — not,
indeed, a rich leaf-mould, but capable of supporting many kinds
of plants. Into this land of promise the southern plants began
to come. Winds from the south, animals ranging toward the
north and water-fowl in their annual migrations, brought back
in some instances no doubt the very same varieties which hun-
dreds of years earlier had fled before the ice, and in others, new
kinds born and bred in the south and seeking new homes where

Minnesota Plant Life. 5

they might obtain a foothold for themselves and their descend-
ants. When one contemplates for a moment this epitome of
plant-wanderings he is impressed by its similarity to the history
of his own race. It is known how peoples have moved from
one country to another, not usually en masse but individually,
quite as did the plants and under very much the same impelling
forces. For it is those plants which were able to leave the region
of increasing cold that later continued their kind under more
favorable circumstances, as it is also the hardy race of men who
migrate from the worn out farm, or congested city to some
new country in which they may find prosperity and happiness
for themselves and for their children.

Laws of plant distribution. There are, then, three paths
along which to seek the general laws of plant distribution. First,
as regards an area, one must inquire what is its geographical
position? second, what is its climate? third, what is its soil
and physical history? The answers to these three questions ex-
plain in large degree what must be the plant population of that
area. With respect to the vegetation of Minnesota the most
impressive fact is that it is an immigrant vegetation. It mani-
fests the characters of a new community quite as truly as does
the American Republic, in its social and political organization,
the characters of a new country. This can be illustrated clearly
if one compare the Minnesota forest with the ancient forest of
the tropics in India, in Venezuela, or about the sources of the
Nile. When one enters the dark solitudes of an equatorial for-
est his first thought is, from the sounds that reach his ears, that
the life of the forest must be above his head. Few animals are
seen, almost no insects and scarcely a green leaf or plant upon
the forest-floor, but there, rather, are dead and decaying trunks
of trees which have fallen and massive columns of trees that are
standing, while arching overhead are interlaced branches that
intercept the light and make the scene like that in some dim
cathedral. But if from a balloon one could look down upon the
immemorial crowns he would see spread out beneath him a
world alive with birds and insects, brilliant with flowers and rich
with the verdure of vines and air-plants. It would be much as
if the tree-tops had taken the place of the turf and shrubbery of
more northern climes. Many orchids and other plants of that

6 Minnesota Plant Life.

nature would be seen perched upon the branches, dangling their
roots into the damp air below; climbing and twining plants
would be abundant and especially would there be observed a
much greater variety over a particular area than could be
expected in temperate regions. This peculiarity of the tropical
forest, this exuberant development of tree-top life is a natural
result of age. It is because the forest has been standing for
countless centuries, unmodified by changes of climate, unin-
vaded by glacial sheets, that it includes so many different kinds
of individuals. For the same reason there have arisen depen-
dencies between different varieties of plants, and some have
learned to perch themselves upon the branches of others or have
entwined themselves around the stems of their neighbors. Just
so, in an old societv like that of India or wherever there is not
the democracy and equality which exists under a newer social
order, is caste developed. People are born to be dependent and
it is fore-ordained in the social system that they and their de-
scendants shall not rise above this position.

In the forests of Minnesota all is very different. When one
enters the pine-woods of the north, or the elm and maple-woods
of the south, he is not impressed with the silence and solitude
of the forest-floor, nor does he discover that the tree-tops have
become a special soil for the development of peculiar plants.
Perching plants are rare ; vines and lianas do not form so large
a proportion of the total population. There is nearly always a
well-developed underbrush, and many sorts of little heaths,
asters, gentians and golden-rods display their flowers and ripen
their fruits under the shadow of the trees. They are not com-
pelled by the umbrageous growth of larger plants to climb the
trunks or hang themselves upon the topmost branches in order
to obtain their share of sunlight and of rain. Nor is the number
of kinds in an acre nearly so great as in the tropics, for there
has not yet ensued that long period of competition which, in the
tropical forest, has reduced what might once have been social
clumps of trees to the lone survivors of to-day.

Forest and prairie. There are two principal vegetation-
regions in Minnesota, the forest and the prairie. The forest
occupies the northern portion of the state extending south to

Minnesota Plant Life. j

the valley of the Minnesota river. The prairie comprises the
southern portion of the state and a strip along the western
boundary in the valley of the Red river of the North. These
two regions, so different in their appearance, are inhabited by
plants which are not altogether dissimilar to each other. Most
of the plants at home on the prairie are not entirely absent from
the forest, while the greater number of forest plants may be
encountered, possibly not so abundantly, but at least casually,
on the prairie. The difference between the two regions does

FIG. 1. — In the forest district. Growth of white pines and spruces upon a rocky island.
Steamboat channel, I,ake of the Woods. After photograph by the author.

not lie in differences in the kinds of plants so much as it does in
the different character of the dominant plants. Among the pines
and spruces of the forest occur many of the grasses, vetches
and asters of the prairie. Along the borders of prairie sloughs
and streams there will be growing the same varieties of arrow-
heads, milkweeds and willow-herbs that form a characteristic
vegetation in similar places in the forest. But the dominant
plants of the forest are trees, lifting up their erect, perennial
stems, struggling with each other for light and air and giving to
the whole formation an upright effect, while the prairies are

8 Minnesota Plant Life.

dominated by grasses with prostrate underground stems woven
together into a solid and matted turf, thrusting into the air only
their side-branches and thus giving to the whole a flat and level
character. It is not very well known precisely why the prairie
type of vegetation has established itself over such large areas of
the world. Some have attributed it to fires, others have thought
that climate and soil are responsible for the difference between
prairie and forest. Perhaps all that need be said is that there
are these two principal methods of developing plant-stems.
When the dominant plants of an area are such as have acquired
the habit of trying to avoid each other's shade by elongation of
their stems, that region is a forest. When, on the other hand,
an area is occupied by plants that have learned to elbow each
other beneath the surface of the soil, that region is a prairie.
It is a mistake to suppose that the lofty tree is in every sense
stronger than the modest grass, for the two have simply devised
different means of accomplishing the same result. A prime
necessity of most plants is sunlight, since without it they are
unable to construct their food from the gases of the atmosphere
and the water of their sap. Therefore, they must have light,
and to obtain it they adopt instinctively the methods of growth
which will enable them to do their own life-work regardless of
their neighbors. The pine tree may be described as a plant
which for ages has been solving the problem of better illumina-
tion by a progressive increase in height. The grass, by copious
ramification of a protected underground stem upon which lat-
eral leaf-bearing branches are produced, in its way strives to
obtain illumination, nutriment and persistence.

Another difference which exists between the forest and prairie
of Minnesota is in the direction from which the plants have
come. The forest is, in large part, composed, so far as its domi-
nant plants are concerned, of northern forms, while the prairie
is inhabited rather by immigrants from the south. So on a
map illustrating plant distribution in the northern hemisphere
it will be found that the prairies in Europe, in Asia and in
America lie south of a forest belt. It is true that in the tropics
around the world a forest region exists, broken only by deserts
like those of the Sahara, or northern Australia ; but in regions
beyond the tropics it would seem that in both hemispheres there

Minnesota Plant Life. g

are intermediate forest zones between the prairies of temperate
regions and the tundras about the poles.

Minnesota is situated between the forest and prairie regions
of the North American continent and includes a representation
of each. A careful study of the populations in these regions
will show that each is striving to extend itself; thus wherever a
stream flows from the forests of the north down through the
prairies of the south, forest plants advance along the banks and
reach more southern latitudes. In Minnesota the pine trees
that in the north form so characteristic a growth are found in
isolated patches, fewer in numbers, down the Mississippi — even

FIG. 2. — Prairie scene on the Coteau. Sunflowers line the roadway on either side. After
photograph by Mr. R. S. Macintosh.

beyond the confines of the state, for the white pine exists upon
the Mississippi bluffs in Iowa. Similarly, along the open which
a river produces, there is chance for southern winds to distribute
the seeds of prairie plants, and characteristic vegetation of the
prairie, such as sunflowers and golden-rods, has pushed its way
up into the forest, leaving the larger streams along their tribu-
taries, and finding a path even into depths of the pine-woods
where the soil is favorable. It would be a great mistake to
count plants quiet, unenterprising creatures, not alert to make
use of every opportunity for growth and development. The
forest must rather be regarded as composed of plants eager to
compete with those of the prairie upon their own ground, and
equally must the prairie plants be regarded as ambitious on their

10

Minnesota Plant Life.

part to try conclusions with those of the forest, if they obtain an
opportunity to penetrate between the interstices of the more
northern erect formation.

Plant populations, then, in the two great vegetation regions
of the state, are in a state of tension, and the line between them
is necessarily slowly shifting and irregular. Some little change
in the topography, some slight modification of the drainage,
the drying up of a lake or the erosion of a deeper gorge by a
stream, may give an opportunity for one formation or the other
to extend its limits at the expense of its neighbor. This gen-
eral state of tension exists not only between the forest and the

FIG. 3. — Roadside vegetation. Grasses and pulses. An elm tree in background.
Cedar lake. After photograph by Williams.

prairie, but also between plants on the tops of hills and those
at the base, between plants in the center of swamps and those
at the circumference, or between plants at the edge of a lake or
stream and those farther inland.

Plant zones. The result of such competition is seen in the
pretty general appearance of plant zones wherever the topog-
raphy permits them to be developed. A simple and well-known
example of this tendency of plants to grow in zones or lines
may be seen along any road, path, ditch or trail in the state.
It is well known that certain kinds of plants particularly select
the road-side as a favorite place for growth. Such are usually

Minnesota Plant Life.

1 1

robust, enterprising plants of modern structure, and the pick of
the whole world for growing ability — for nowhere is there so
great a proportion of what are called weeds and introduced
plants as beside a road. There one finds the knot-grasses, rag-
weeds, thistles, cockscomb-grasses and other imported species,
many of them belonging to types which by sheer vegetable
enterprise and ability have found their way with man around
the whole northern hemisphere, and some of them are common
even to Australia and Africa as well. As might be expected

FIG. 4. — Spruces forming a zone around a peat-bog. Farther back are tamaracks and pines.
The shrub in the foreground is the bog-willow, while the flowers are those of an orchid, —
Pogonia. Near Grand Rapids. After photograph by Mr. Warren Pendergast.

from their distribution along paths or other works made by
man, they have been assisted in their wanderings by human
agencies rather than by the ministrations of the winds, the
water-fowl or the beasts of the field. Such plants appear also
in door-yards, in neglected meadows, in pastures, along railway
lines and in short wherever man has gone.

Another kind of zonal distribution, not influenced by human
agencies, may be seen around the lakes of the state, especially
where beaches have been formed. Here special beach-rows of

12

Minnesota Plant Life.

plants will be found, consisting among others of certain sand-
loving grasses, cockleburrs, pinks and fumitories, and clearly
distinct from the plants farther back upon the shore. Nor will
these plants develop so vigorously under any other conditions.
Again in the swamp region of the north, where a peat-bog is
slowly filling with moss and encroaching upon the forest, beau-
tiful illustrations of this zonal arrangement can be observed
with the tamarack and spruce trees becoming gradually smaller
and smaller toward the center of the bog. In meadows, too,

FIG. 5. — Zones of aquatic vegetation. In the center pond-lilies; at the edge smartweed; far-
ther back cat-tails, blue flags, sweet flags, and sedges; still farther back soft turf with
grass, moss, sedge and milkweed. After photograph by Williams.

formed by the drying-up of lakes, are sometimes found en-
croachments of the meadow plants upon such knolls as were
originally islands surrounded by water. The meadow, as it
were, washes up upon the knoll and upon the banks of the old
lake, so that mingled with the dogwoods, willows and other
shrubs of the knoll or bank one will observe the grasses and
sedges of the meadow.

Zonal distribution is a characteristic arrangement not only of
land, but also of water plants, and as one pushes his canoe from
the shore of a Minnesota lake he will doubtless find that he

Minnesota Plant Life. i 3

passes over distinct zones of aquatic vegetation. First, there
will be the sedges at the water's edge, then the reed-grasses, or
wild rice in a little deeper water, then the bulrushes with their
cylindrical, leafless stems rising from submerged rootstocks
below, and exposing as small a surface as possible to the action
of the surf. Next will come the pond-lilies and water-lilies, the
water-shields, and sometimes the lotus with its circular leaves
rising from or floating upon the water and presenting every-
where their arched margins to the waves. Then come the pond-
weeds and milfoils with their stems and submerged leaves
ascending through the water but not reaching the surface, and
finally the bass-weeds with their lime-encrusted stems and
leaves lying upon the bottom at a depth of from ten to fifteen
feet. Whether one climbs a hill, rows out into a lake, walks
from the margin of a stream back to the prairie or the woods;
whether one steps from his house and across the road into a
field, or strolls from a meadow up to a wooded bank, he will
find that he is traversing zones of vegetation. The occasion for
such a distribution of plants in zones is to be sought generally
in the topography of the region, and where there is great irregu-
larity in the topography there is irregularity in the zones, while
sometimes over a level no zones appear. Sometimes, also,
where the topography is favorable to the development of plant
zones special conditions of distribution serve to obliterate them
or prevent their occurrence.

The same general causes which tend to separate the forest
from the prairie, defining their limits, are seen to mark also the
boundary between one portion of the forest and another. Just
as the great prairie group of plants strives as a whole to en-
croach upon the forest, so the plants at the base of a knoll strive
to climb it and establish themselves over its surface, and mean-
while quite as vigorously the plants on the knoll attempt to
make their way into the gullies and sloughs. The plant on
drier soil may be regarded as always endeavoring to accommo-
date itself to moister soil, and that on moist soil as always strug-
gling to gain a foothold where the moisture is not so great.
So there are often seen at the margin of ponds the pond-lilies
emerging as far as they are able upon the mud, exerting them-
selves to the full limit of their structural qualities to maintain

14 Minnesota Plant Life.

a terrestrial life, and in the same pond may be found land-plants
pushing down to the very water's edge or beyond it until they
can go no farther because of the limitations of their structure.

The tension between the forest and prairie, because it extends
so widely, may be called a continental tension. The other ten-
sions, between knolls and ravines, between banks and meadows,
between beaches and pond edges, may be called minor tensions,
but the law of the two cannot be very different. Indeed, there
may be gained a fair idea of the fundamental difference between
prairie and forest by observation of an area so limited as a road-

FIG. 6.— Island in the Mississippi above St. Paul. The center is occupied by elms while the
rim is fringed with willows. An example of a "minor tension." After photograph by
Professor W. R. Appleby.

side or path. The principal difference between the two is the
duration of the causes at work. Between the prairie and the
forest the tension has been in existence possibly for thousands
of years, while between the knoll and the ravine possibly for but
a few decades or centuries. As a result there have come to
exist in the old warring formations structural peculiarities char-
acteristic of each, so that, to the eye of the observer, they pre-
sent very different appearances. Where the struggle is of more
recent origin and of more limited extent the differences are not
so great and, therefore, not so evident.

Forests of Minnesota and of the world. We cannot well
consider forest as it exists in Minnesota apart from the general
forest which covers the northern part of the continent. From

Minnesota Plant Life. 15

the plant's point of view, Minnesota is not a province, for, to
the plant, political boundaries as established by man, have slight
significance. Nor does the prairie, which occupies the south-
ern part of the state, exist as a special Minnesota prairie.
Rather is it the northeastern extension of the great plains which
occupy the whole central area of the continent from the foothills
of the Rockies back to the forests of Kentucky, Tennessee, Indi-
ana and Wisconsin. The question then arises how did the for-
ests come to consist of the plants which dominate them, and
how did the prairie come to have its particular inhabitants
rather than others?

If a census be taken of all the kinds of plants in the forests
of North America and be compared with a similar census taken
in the forests of Europe and Siberia there will be perceived a
great similarity between the plants of the two regions. But if
in like manner the plants of the prairies of the United States
be compared with those growing upon the steppes of Russia
and Siberia it will be discovered that the similarity is not by any
means so great. A very much larger number of plants are
common to the forest districts of Europe, Asia and North
America than are common to the steppes and prairies of the two
hemispheres. Yet, in this latter instance, there are many
groups which are similar and not a few identical species. Sup-
pose, further, that the forests of the northern hemsiphere, of
which the Minnesota forest is but a portion, be compared with
the deciduous forests of the southern hemisphere, including
those of the Transvaal Republic, Chili and the Argentine, New
Zealand and Tasmania, it would be noticed that almost no com-
mon species, and but few common groups of species can be
found. Or if the pampas of the Argentine be compared with
the prairies of the United States, again would it be discovered
that the common species are exceedingly scarce.

It would seem, then, that the greatest differences which exist
between plant populations of the world are between those of
the north temperate and the south temperate regions. The
occasion of this will be understood if it be remembered for a
moment what are the opportunities for the expansion of plant-
life in the tropics and under the equator. There for countless
thousands of years plants have been developing and competing

1 6 Minnesota Plant Life.

with one another amid favorable conditions of temperature,
moisture and illumination. The equatorial region of the world
is at once the cradle and the crucible of plant-life. In that tre-
mendous struggle for existence many of the modern improve-
ments and refinements in plant structure began to originate.
During the centuries, forms unfavorable were eliminated and
destroyed, leaving the stronger in a condition to migrate north
or south as rapidly as they accommodated themselves to the
increasing obliqueness of the sun. Evidently, then, the great-
est differences should be expected not between the plants of
North America and Europe, both of them tenanted by north-
bound immigrants from the equatorial region, nor even between
the north temperate regions and the tropics, since the plants in
the former are but the traveled relatives of those at home in the
latter region. But the greatest difference should be expected
to exist, as it does, between those plants which have left the
tropics and have slowly made their way, changing their form
and habits as they wandered, some to the far north and others
to the south.

North American flora. If the North American continent
were quite flat, without differences in elevation above the sea,
and were connected with the tropics by a continuous stretch of
land, it could be imagined that the forest region might have
extended directly across the northern half of the continent.
It is, however, not such a level plain, for two great mountain
ranges run from north to south and the continent is connected
with the tropics by a narrow isthmus, so that there are factors
which prevent an even division of forest and prairie. Mountain
ranges extending from north to south are not, as mountain
ranges extending from east to west would be, barriers against
plant distribution from the tropics toward the poles. This is
the reason why North America has what the botanists call a
"richer flora" than Europe and Asia. In the Old World the
principal mountain ranges, such as the Pyrenees, the Alps, the
Appenines, the Carpathians, the Caucasus and the Himalayas
are transverse, extending in a generally east-and-west direction.
For this reason when the glacial period came on, unfortunate
European or Asiatic plants as they migrated south, found them-
selves compelled to climb some mountain range in order to

Minnesota Plant Life. 17

make their escape to the temperate climate beyond the influ-
ence of the ice, and under these conditions most of them must
have perished as wretchedly as did so many of the troops of
Hannibal when they crossed the Alps. Moreover, when the gla-
cial period came to an end in Europe and Asia it was difficult
for plants to return over the mountain-passes, and as a result,
these continents are tenanted by a less diversified vegetation
than that of North America.

The longitudinal mountain ranges of the New World have
rather aided the movements of plants than hindered them, for
they have assisted northern plants to find their way along high
altitudes to constantly lower latitudes, while at the various stages
of their journey such plants have enjoyed the opportunity of
climbing down the mountain sides and out upon the plains, if
they were able to accommodate themselves to the higher tem-
perature. This movement has taken place not only on the
western side of the continent, but also along the Alleghenies.
Yet owing to the greater height of the western range it is found
that northern genera of plants like some of the roses and willows
have developed more abundantly toward the southwest than
toward the southeast, simply because they have followed an
easier path along the cool high ridges of the Rockies than along
the warmer, lower Appalachian range. By these two mountain
ranges, lying one to the east and the other to the west of Minne-
sota, some slight influence has no doubt been exerted upon
plant migration, both in the prairie and in the forest region of
the state. But this effect must have been stronger in the prairie
region ; for the forest plants from the east and north could enter
as easily from the north and would not need to depend upon
any lateral movement. From the west, however, where the
plains rise gently to the mountains, many plants which had
found an asylum on the sides of peaks and escarpments must
have, in the last ten thousand years, slowly crept down into the
plains and there developed habits and structures which persist
to this day.

3

Chapter II.

Plant Wanderings and Migrations.

*T

Habits of birds and animals. The habits of birds and ani-
mals are of much importance in any study of plant distribu-
tion ; for the plant, but rarely provided with independent meth-
ods of locomotion, is forced to depend upon other agencies for
dissemination. To the waterfowl especially, with their well-

FIG. 7.— I^ake border vegetation of cat-tails, grasses, reeds and sedges,
After photograph by Williams.

the Isles.

known habit of flying south in the autumn and north in the
spring, do many plants owe the widening of their range. Their
seeds are ripened and fall upon the mud at the border of some
lake or pond where they are picked up on the feet or plumage
of migrant birds and are carried hundreds of miles north or
south of the point where they were produced. That is one rea-

Minnesota Plant Life. 19

son why throughout Minnesota the lake-shore vegetation is so
homogeneous. Every bay is visited at some time during the
year by wild fowl and in the mud on their feet they carry about
the seeds of a variety of plants. It is therefore, those water-
edge plants which have seeds not too large to be thus trans-
ported that are the more widely distributed. Especially if the
seed is of a kind attractive to the bird is it likely to be removed.
Thus ducks, though they eat hundreds of thousands of young
wild-rice plants encased in their seed-coats, nevertheless from
their very habit of using these plants for food distribute them
more widely than if they were not thus agreeable to their taste.

Migrating animals, like the bison which once roamed in enor-
mous herds over the whole prairie region, must have picked up
in their fur, as they wallowed in the sand or on the banks of
streams, countless seeds of a great variety of plants and carried
them to all parts of their range. In this way, plants having
seeds provided with attachment-prongs, like the tick-trefoils,
beggars'-lice, burdocks and cockleburrs must have obtained
through the agency of animals far greater opportunities for
travel than were enjoyed by species the seeds or fruits of which
were hard and smooth.

The fancy of animals and birds for certain sleeping places
has also influenced plant distribution, and their habits of wan-
dering in the woods and by the water have been utilized by cer-
tain kinds of plants, and some remarkable adaptations exist,
such as the curious explosive seed-pods of the touch-me-not.
This common plant, when brushed against, explodes its fruits,
throwing out the seeds where they may be caught in the fur of
a passing animal and carried away. Certain exotic gourd-plants
too, have explosive fruits which when agitated by a slight
touch shoot out the seeds and these, provided with a viscid
membrane, readily adhere to the passing bird or animal. Other
plants have their seeds enclosed in edible areas, as for example
the gooseberries, currants, apples, peaches, raspberries, junipers
and a host of others. In such fruits the seeds are themselves
protected by hard coats which resist the digestive processes of
the animal or bird and they can thus pass through its body with-
out injury. Sometimes the instincts of animals benefit the
plant, as when a squirrel carries off an acorn and buries it from

2o Minnesota Plant Life,

some dim notion of secretiveness or possibly of providence.
On account of the rhythm of the seasons in Minnesota the
principal migrations of birds and land animals have not been
from east to west but from north to south, and the principal
tension-line runs in general from east to west.

Insects and worms. A few seeds are peculiarly modified
for insect distribution, as for example, those of some spurges
and other small plants, which have little crests or grooves just
fitted to receive the jaws of ants, thus making them easily porta-
ble by these busy toilers. Others are assisted in their distribu-
tion by burrowing worms, but this always within narrow limits.

Inanimate agencies. Allusion has already been made to the
inanimate agencies which are employed by plants as aids in
distribution. Among these are currents of wind, currents of
water and in a slight degree translocations of soil. The latter,
best observed in mountainous regions where avalanches exert
a considerable influence, is of slight importance in Minnesota,
though upon the hillsides and cliffs along some of the northern
lakes, this method of distribution exists.

Wind currents. In plant distribution the most important
inanimate agency is doubtless the wind. The alertness with
which plants make use of it in seed-dissemination is well exem-
plified by the new population which appears after a fire and
covers burnt places in the forest. When the pines or spruces
are destroyed by fire it is a fact of common observation that
poplars, maples, elms, willow-herbs, milkweeds and other light-
seeded plants spring up. The well-known fire-weed with its
purple panicle of flowers ripens seeds that are provided with
tufts of delicate hairs, and when thrown out of the pods in which
they are produced the wind may catch them and whirl them
away over the tree-tops for many miles. The poplars, too, and
cottonwoods are famous for their winged seeds and succeed in
entering promptly a burnt tract, so that within a year or two
they have established themselves while there are yet to be found
probably none of the heavy-seeded plants, like hickories, wal-
nuts and oaks, and but few of the plants with adhesive seeds
or pulp-inclosed seeds fitted for animal distribution. It is not
the seeds alone but often the fruits of plants which are trans-
ported by the wind, as for example, the maple-fruits, the elm-

Minnesota Plant Life. 2 i

fruits and the fruits of a great variety of dandelion-like and sun-
flower-like plants. Sometimes the whole plant is distributed
by the wind and examples of this are especially striking upon
the prairie where the wind has free sweep. Thus, tumbling
plants like the Russian thistle, the tumbling mustard and the
tumbling grass, when their fruits are ripe separate all or the
greater part of the stem from its attachment and curve their
branches so that the whole takes the shape of a ball rolling
freely for miles over the level prairies before the wind. Some-
times the wind acts indirectly in the distribution of plants, as
for instance, when a portion of the boggy shore of some lake
breaks loose and is blown away to be anchored possibly under
new conditions across the lake.

Water currents. Though the agency of currents of water
in transporting seeds is scarcely so universally employed as that
of the wind, it should not be overlooked. This agency is par-
ticularly important for heavy-seeded plants as their seeds are
often borne along a stream in its currents and eddies to find a
lodgment possibly miles below the point where they were intro-
duced. Other seeds, to facilitate their floating, are provided
with buoyant apparatus which adapts them also for wind distri-
bution.

Man. One very important agent in plant distribution re-
mains to be considered, namely, man. Unlike the birds and
animals, man in his migrations is not so strongly regulated by
the changing rhythm of the seasons. On the contrary the prin-
cipal lines of migration of men since the advent of Caucasians
upon the continent have been from east to west, rather than
from north to south. Roads and trails have been beaten across
the plains and through the forests; railway lines have been
built, binding distant portions of the country together, and to
connect with them steamships cross the seas. Freights are car-
ried from one hemisphere to another, and along with that for
which there are invoices and bills of lading comes often a con-
signment of seeds of fruits, unrecorded yet none the less im-
portant. In this manner some harmful weeds as well as some
useful forage-plants have reached the fields of Minnesota. With
the immigration of men and women from Russia has come the
Russian thistle ; from France and England the cockles of the

22 Minnesota Plant Life.

wheat; from Italy some mustards; indeed, from all the coun-
tries of Europe plants have found their way in company with
man. Some of them are later immigrants than others. Those
which crossed with the pilgrim fathers are now as much at home
as those to the manner born. Others, the advent of which
dates from yesterday, have not yet shown all their capabilities,
and doubtless even now the dangerous new weeds of the next
decade are some of them precariously existing as little colonies
upon ballast-heaps or along the lines of eastern or western rail-
ways.

Associations between migrating plants. When plants travel
they do not always travel alone, but in company as man does,
who when he migrates brings with him his horses, oxen, sheep,
fowls, dogs, and other domestic animals which have become
attached to him. So the plant when it migrates often takes
with it other plants. Thus where the maples go, there go also
those curious fungi that grow upon the leaves, looking like little
drops of tar. With the willow as it is uprooted and floats down
a stream, perhaps finding a foothold for its twigs somewhere
below, go the lichens and mosses upon its bark.

There is something about the proximity of certain kinds of
plants which is very agreeable to other varieties, so that gen-
erally with pine trees one finds wintergreens associated, and
with peat-mosses, cranberries. The latter are not associations
like the associations between the maple and the fungus upon its
leaves, but are rather indications of kindred tastes in habita-
tions. The establishment of one kind of plant over an area
may be the natural and, perhaps, the necessary pre-requisite for
the development of another plant which has formed the habit
of attaching its fortunes to those of the first one in the field.
Plants, also, by their position and attitudes strongly influence
the distribution of other plants. If plants, which are accus-
tomed to depend upon winged seeds for their distribution, find
themselves gradually enclosed by the foliage of strong-growing
neighbors it will be difficult, perhaps, for them to extend farther
the range of their seeds. Or, possibly, the berries which were
attractive during a season when neighboring plants were not in
fruit may not be so attractive another year when the adjacent
forms are ripening their own larger, more highly colored, more
highly scented or sweeter fruit.

Minnesota Plant Life. 23

Where the story of plant migration is recorded. It is im-
possible to mention except in a more extended account the
many and various ways in which plants influence the distribu-
tion of each other or receive influence from outside sources, but
enough has been said to indicate the general laws under which
the State of Minnesota has received the plants which now
inhabit its territory. They have come from all points of the
compass, from all parts of the world, bringing with them habits
acquired through countless generations of struggle and adapta-
tion. To the enlightened eye, the form of a plant tells a story
of its life and of the experiences it must have undergone to
develop one type of structure rather than another. Just as in
the formidable defensive armor of an extinct armadillo may
be read somewhat of the story of its struggle with its enemies,
so in the three hundred feet of solid trunk and in the massive
girth of a living Big-tree in the Sierras one may read the story
of its struggle in the ancient forests when its allies and com-
petitors were perhaps more numerous and more vigorous in
their aspiration for light than are the neighbors of to-day.

In the Minnesota valley, not far from New Ulm, there are
found upon rocks exposed in the river-bed by the erosion of the
waters, some specimens of the little prickly-pear cactus, a desert
plant which has found its way from the plains of Arizona and
New Mexico. By all its characters it indicates how it must
have been trained in a school of life different from that in which
the plants around it receive their education. Its solid, leafless,
flattened stem with a resistent rind is fitted to withstand the
evaporation of moisture — a character much needed in the des-
ert, but less necessary in the valley of the Minnesota. Its
strong root system extending out a yard or more on every side
was indispensible to collect what little moisture there might
have been in the arid soil of the southwestern desert; with a
smaller root system it could do very well in its northern home.
The sharp thorns and spines with which it is covered were a
necessary protective armor where vegetation was sparse and
grazing animals hungry ; without this armor it could live very
well on the hills of New Ulm, for there dwell other plants, with-
out armor nor do the herds destroy them. Such a plant, evi-
dently a wanderer from another land, is like a man of mediaeval

24 Minnesota Plant Life.

times who should be reincarnated in a modern society and
should insist upon wearing the coat of mail and carrying the
rapier which were necessary in another age, but would be rec-
ognized as altogether out of place in the life of the present day.

The pine trees, with their needle-shaped leaves fitted to trans-
pire water but slowly and with their strong branches able to
carry the weight of the snow which is piled upon them in their
northern home, when they find their way down the river to the
comparatively genial climate of Iowa cannot at once abandon
the structures which they developed under the stern necessity
imposed by the severer climate of their native land. The mat-
plant, such as a purslane or carpet-weed, adapted to life on a
flat plane where it is not shaded by surrounding plants but
spreads out all its prostrate branches in a discoid body, cannot
erect itself into the slender wand of the aster, taught to assume
this shape by centuries of existence in the underbrush above
which it had to lift its leaves that they might catch the sun.
The aspiring spruce telling in its form a story of other spruce
trees close beside it crowding each other as they all reached
upward for the light, if it is planted in one's dooryard with noth-
ing near to shade it cannot abandon the character which it
developed of old. Plants when they migrate from place to
place must take with them those structures and habits which
are fitted best to the whole history of their species. In their
migrations they select places which resemble as closely as pos-
sible those to which they are accustomed. They allow them-
selves a certain freedom just as men do, but even as regards men
it is well-known that they prefer to migrate along the same
parallel of latitude, so that the inhabitants of Minnesota have
come rather from the forests of New England and New York,
from Canada, from Scotland, and from Scandinavia, than from
the highlands of Mexico, from Italy, Africa, or Brazil.

Struggles of migrating plants. It must be apparent from
all that has been said that the laws governing the migration of
plants are substantially the same as those that govern the migra-
tion of other living beings. It is an instinct with all living
creatures to maintain their own existence as long as they can
and to do this they wrest from others, weaker or less fortunate,
the right to food and sunshine which they in their turn demand

Minnesota Plant Life. 25

of nature. It is even so with men ; the dervishes of the Soudan
must give way before civilized England. Thus also must the
feeble plants of a meadow's edge yield before the onslaught of
trained roadside plants, brought in from other parts of the
world and fitted to cope with the conditions of existence in a
stronger and better way. As one looks at a placid meadow, its
grasses bending in the breeze, he should remember that under-
neath the calm serenity of the scene there is a bitter struggle,
a relentless internecine warfare between the plants that are
already in the meadow and those that are striving to enter
from without.

Comparison of plants with animals. Next to and even
stronger than the instinct to exist is the instinct to persist, and
plants sacrifice their own lives for their offspring just as readily
in their sphere of life as will a human mother give up her life
for her child. In dealing with plants the mind must be rid of
the mistaken notion that they are dull, stupid things which stay
where they are set without ability to better themselves and
their offspring. On the contrary the plant should be regarded
as a living organism with definite necessities and definite in-
stincts. Plants are quite as much alive as animals, and, indeed,
they are greater ground-gainers on the surface of the earth
than animals are, for if all the plants of the world should be
weighed in one scale pan of a gigantic balance with all the ani-
mals in the other it would be seen that as organizers of dead
matter into living substance the plants far outrank the animals.
In dynamic force, in the ability to apply energy in some definite
direction, the animal is indeed superior, but in those purely con-
structive vital powers no organisms are so skillfully adapted and
so perfectly organized as the plants. They are not altogether
of a lower type of life than animals, for they do their work in
the world after their fashion, and that is all that animals can do.
They are rather to be viewed as other kinds of living things,
and are to be regarded not as merely subservient to the needs of
animals, not solely as a food-supply for grazing cattle or roving
birds, but of interest for their own sake and possessing an indi-
viduality to be respected.

Chapter III.

Slime-Moulds and Blue-green Algae.

Number of plants in the world. In the whole world there
are now living about 300,000 different kinds of plants, and it is
possible that nearly as large a number of forms are extinct.
The relics of past plant life in Minnesota are not very abundant,
but in the older rocks there are a few fossil sea-weeds deposited
on the mud flats of an ancient ocean which covered the region
now occupied by the land, and in the red sandstone which oc-
curs in the Minnesota valley in limited quantities, there have
been found imprints of leaves belonging to by-gone genera.
For example, in those days palm trees flourished in the state
and have left their replicas along with the remains of red-woods,
big-trees, cycads, magnolias, tulip-trees and other varieties,
which are not now found within hundreds of miles of Minnesota.
From old peat deposits and from soil masses lying under the
glacial clays, fragments of charred wood and vegetable debris
are sometimes exhumed. Such fossils often show that the dis-
tribution of plants before the glacial period was quite different
from that of to-day.

Number and sorts of plants in Minnesota. At the present
time, of the 300,000 living species of plants, about 7,500 are
probably to be found growing without cultivation in Minnesota.
The figures are in the nature of an estimate, for by no means so
considerable a number has yet been discovered. But it must
be remembered that the larger proportion of these plants are
not the conspicuous objects which are usually in mind when the
word "plant" is used, but are rather the insignificant micro-
scopic forms, difficult to discover and often of such slight differ-
ence from each other that they would be recognized as distinct
varieties only by the most trained observers.

Minnesota Plant Life. 27

An estimate of the distribution of these 7,500 species of Min-
nesota plants among the different groups is approximately as
follows: slime-moulds 150; bacteria and algae 1,000; fungi and
lichens 3,250; liverworts and mosses 500; ferns and flowering
plants 2,600. It is evident then, that most plants of the state
belong to the lower orders of vegetation.

There may now be given a general account of the Minne-
sota vegetation, avoiding the use of technical terms and describ-
ing where it is possible certain common forms of each group, so
that the reader may have within small compass a comprehensive
view of the classes just named, as they are represented in the
state.

Slime-moulds. The plants (or more probably animals) known
as slime-moulds constitute a very peculiar group of organisms.
It is by no means certain that they are plants at all, although
they have some vegetable characters. In other respects
they resemble the lower animals, and botanists and zoolo-
gists have often debated to which of the two great realms of life
they really belong. One of them, which is known to occur in
Minnesota, may possibly have come under the observation of
some of the readers of this book. The roots of cabbages and
turnips, when pulled from the ground, are sometimes found to
be covered with a curious irregular growth of little spherical
tubers, about the size of hazel nuts, — sometimes larger, though
often very much smaller. The occasion of the appearance of
such tubers is the development of singular little slime-moulds
too small to be seen by the naked eye but sufficiently active to
cause gall-like swellings in the tissues of the root. Because of
the ruptured appearance which the root has when affected by
these tiny organisms, the whole structure, root and slime-mould,
is known as a root-hernia or as club-root.

Most slime-moulds do not, however, live thus as parasites on
other plants, but are found on decaying leaves, rotten twigs,
fallen logs and other debris of the forest-floor in shaded places.
They sometimes grow up from a mucilaginous base, forming
little brown, cylindrical plumes, not more than half an inch in
height and clustered together, a score or more, in a group. The
brown plumes are found upon careful examination to be deli-
cately woven masses of threads, between which is a fine brown

28 Minnesota Plant Life.

dust which can be shaken out upon the hand or upon a piece
of paper. This brown dust, under the microscope, is seen to
consist of innumerable tiny spheres, the spores of the plant. If
the spores be placed in water, after a time their shells break and
out of each comes a little mis-shapen drop of jelly-like substance,
which oozes away with a slow and viscid movement. If several
of these tiny bits of jelly find themselves close together — per-
haps after a rain upon the bark of some rotten log — they crawl
towards each other and fuse into a common patch. The patch
then moves imperceptibly over the wood, increasing in size as it
extracts nourishment from the decayed material. Sometimes
the jelly-masses grow to the size of a man's hand. A common
sort is found in tan yards and often upon railway ties resembling
very much a piece of ordinary thin jelly and generally cov-
ered with a sulphur-colored powder. After the jelly-mass has
increased in size to a certain point it breaks up into little clusters
which afterwards develop fruit-bodies more or less like the
brown plumes spoken of above.

Another kind of slime-mould crawls up the stems of various
plants in meadows and deposits itself upon the leaves in little
foam-patches looking very much like drops of spittle. There
are some insects which make similar spittle-masses on leaves and
an expert investigation is necessary to determine whether such
objects are insect products or the plant bodies of slime-moulds.

Some slime-moulds have the power of incrusting their tiny
fruit-bodies with lime which they extract from their soil or from
rain-water that falls upon them. Such forms are often observed
in Minnesota upon dead wood, or fallen leaves, generally in
moist shady places in the. deep forest. Sometimes the fruit-
bodies are almost round, resembling the familiar pills of the
homeopathist. In other species they are worm-like, coiled like
loose snail-shells, but very much smaller, yet not so small that
they cannot easily be discovered if searched for in the places
that they have chosen. A few slime-moulds will be encountered
among mosses, forming little brown scurfs upon the moss tuft
or displaying themselves as yellowish patches around the bases
of the leaves. None of these plants have any economic import-
ance. The most conspicuous one in Minnesota occurs upon
dead logs as pink, hemispherical bodies, about the size of the

nnesota Plant Life. 29

end of one's finger. Usually these fruit-bodies are seen in clus-
ters of a dozen or more. If one of them is cut into it will be
discovered that the interior consists of a brown moist powder,
which when dry blows away in an impalpable dust. In a single
fruit-body such as one of these, millions of spores originate
which, washed away by the rains or blown about through the
atmosphere, may fall upon suitable decaying substances, open
and liberate each its tiny bit of living jelly that by itself or with
the assistance of others gradually builds up a newr plant-body.

Algae. The plants known as algae secure their best develop-
ment in the sea, where under the name of sea-weeds they are
universally known and many of them admired for their beauty
of color and gracefulness of form. Of the algae there are five
principal groups; i, bacteria; 2, blue-green algae; 3, bright-
green algae; 4, brown algae; 5, red algae. The red algae and
brown algae are chiefly marine, although a few varieties of at
least the red group are found in the fresh wraters of Minnesota.
Most of the algae in fresh waters belong to the blue-green or
bright-green groups, while those lowly and most extraordinary
of plants, the bacteria, are of such various occurrence in soil,
water, air, and the bodies of other organisms that I shall con-
sider them in a special chapter.

Blue-green algae. The plants of this group may generally
be recognized by their bluish-green color, approaching some-
times the hue' of verdigris and never the pure grass-green which
distinguishes the bright-green group. One of the most com-
mon of them is the so-called "water flower" which in summer
develops in such vast quantities in the lakes of Minnesota. The
tiny, bluish, jelly-ball of the water-flower, ordinarily not larger
than a pin-head, if examined closely will be found to have a bub-
ble of gas at the centre, by means of which it floats. If this
bubble is analyzed by chemical methods it will be ascertained to
be more highly oxygenized than the atmosphere. It is pro-
duced by the growth-activities of the plant and incidentally
serves the important purpose of keeping it near the surface of
the water where it may obtain the light. At Lake of the Woods
I have seen these plants in such enormous numbers that the
water looked more like green paint than lake-water and at Lake
Minnetonka the cottagers often complain of the abundance of

30 Minnesota Plant Life.

the water-flower and inquire for methods of exterminating it.
There is, however, no practicable way of destroying it, for if the
water should be poisoned enough to kill the water-flower other
living things, pond-lilies, bulrushes and bass would also disap-
pear.

Structure of the water-flower. A microscopic examination
of the water-flower will show that each tiny jelly-ball consists
of a number of delicate algal threads intertwined and imbedded
in a common mass of jelly which they secrete. When a jelly-
ball becomes sufficiently large it commonly breaks in two and
the pieces continue growing as before. If the jelly be dissolved
hundreds of tiny coiled threads escape from it and multiply,
developing hundreds of new jelly-balls. In the autumn these
little creatures drop to the bottom of the lake, or remain in a
dormant condition frozen in the ice until the warmth of another
season stimulates them into renewed activities.

Larger jelly-balls, in appearance very much like green plums,
but with the characteristic bubble of gas at the centre are often
found floating in ponds. These belong to another species of
blue-green algae but they are closely related to the water-flower
and their structure and life-habits are not essentially different.
Still another variety of blue-green algae is common as little
hemispherical lumps an eighth of an inch in diameter attached
upon the stems of bulrushes, just beneath the surface of the
water. Still other kinds form tufts and stringy masses several
inches in length floating near the surface of stagnant pools. A
curious form which has lost the blue-green color, and may be
classed also as a bacterium, is sometimes found growing in the
outlets of springs, where it resembles a mass of iron rust dis-
solved in water. The red color is not a deception for it is ac-
tually due to iron oxide extracted from the water by the micro-
scopic filaments of the plant.

Rock-forming algae. Some of the blue-green algae have
the power of encrusting themselves with lime, and in watering-
troughs and tanks there sometimes occurs a calcareous forma-
tion reminding one of the deposit in old tea-kettles. Such a
crust is true limestone extracted from the water by the chemical
activities of the algae. Upon a large scale the blue-green algae
play their part in the formation of rock. The best place in

Minnesota Plant Life.

America and, indeed, in the world, to observe their action is at
the Yellowstone National Park, where great masses of traver-

FIG. 8.— Portion of a board which had been standing in the tank shown in fig. 10. It is en-
crusted with lime stone deposited by a colony of blue-green algae. After photograph by
Miss Josephine E. Tilden. From the Botanical Gazette.

tine and sinter are formed, covering acres around the hot springs
in which the blue-green rock-forming algae find a congenial
home. Travertine is a kind of limestone; sinter is a kind of

32 Minnesota Plant Life.

silica or sand rock and it therefore appears that not only can
some blue-green algae extract lime salts from the water, but
other varieties can form quartz as well. No doubt very much
of the limestone and even of the granite that occurs in ledges
over the continent was begun in ancient warm seas by the action
of organisms similar to the blue-green algae, while at the Yel-
lowstone Park, or upon a smaller scale in one's watering trough,
the same rock-forming processes are still going on.

Skin-algae. Still another variety of blue-green alga produces
broadly expanded membranes, or skins, along the bottom of
springs, and on pebbles in streams or lakes. In general the
plants of this group may be recognized by their color and they
are among the lowest of the algae.

Chapter IV.

Bright-green Algae*

By far the greater number of Minnesota algae belong to this
group.

Pond-scums. Probably the most easily recognized is the
familiar pond-scum, which is by many people regarded with
aversion and is supposed to be in some mysterious way con-
nected with the presence of frogs. If the slimy bright-green
scum.be lifted from the pool, taken upon the fingers and closely
examined, it will be seen to consist of long delicate unbranched
hairs., .not much thicker than a spider's web. As it dries in the
hand it curls and sh-rivels, but under the microscope the hairs are
beautiful objects. They are jointed and in each joint lie coiled
one or more green bands, like ribbons in a glass jar. By means
of the green bands the plant can construct starch out of the
carbonic-acid gas in the bubbles of air scattered near it through
the water, using also the water itself in the process. By the
breaking of the threads between their joints the plant abund-
antly propagates itself throughout the summer.

When autumn arrives a very remarkable breeding-habit
comes into play. Two of the pond-scum threads extend them-
selves close together in the patch and from the joints of each,
little protuberances arise which become blended into tunnels,
uniting ordinarily the joints of one filament to the neighboring
joints of an adjacent filament. Through such tunnels the entire
living contents of one joint creep over and combine with the
living contents of a neighboring joint. The fused-body then
contracts like a sponge, expressing much of its sap and secreting
about itself a firm clear membrane. After such a process,
repeated throughout the patch of algae, the walls of the old
joints may slowly break or dissolve, and the hundreds or thou-
sands of oval fused-bodies, inclosed in their special membranes
drop to the bottom of the pool, where they lie dormant until the

34

Minnesota Plant Life.

following spring. Then each membrane dissolves or breaks and
the fused-body extends itself into a new pond-scum thread,
becoming jointed as it grows and elaborating in each of the
joints the green ribbons by means of which it pro-
duces its food from water and carbonic-acid gas just
as did its parents the preceding season. By the
breaking in pieces of this filament in the way that
has been described and by the subsequent growth
of the pieces a large patch of scum, enough to
cover the surface of a small pool, will be produced
before the summer is at an end.

Desmids. Related to the pond-scum are a large
number of tiny crescent-shaped and star-shaped
plants called desmids. These are often particularly
well-developed in the water of peat-bogs, so that if
one goes to the nearest tamarack swamp and
brings away a tumbler full of water which he has
squeezed out from among the peat-mosses, and sets
the tumbler in the window, within a few hours a
green film of desmids will be likely to form upon
the side of the glass turned toward the light. Like
the pond-scums these little plants have their breed-
ing habits and like them they are able to maintain
and distribute themselves throughout the water of
their pool. If in the autumn, the pool becomes
dry, the little eggs of the desmids lying among the
particles of soil may be caught up by the wind
and carried to distant pools where they continue
developing as before.

Rolling algae. Not uncommon in Minnesota
is another bright-green alga which appears in quan-
tity in pools as green globules somewhat smaller
than pinheads. If placed in a saucer of water and
observed closely one of these green globules will
be seen to roll over and over in the water and make
its way from one side of the saucer to the other.
It does this because its surface is covered with tiny contractile
threads, which lash about in the liquid like so many little whip-
cords and roll the whole ball from one point to another as the

FIG. 9. — Portion
of a pond-scum
thread, show-
ing how it is
made up of
transparent-
walled cells
with a coiled
green ribbon
in each, much
magnified.
After Atkin-
son.

Minnesota Plant Life.

35

needs of the plant may determine. Because of its rolling habit
this little plant is called Volvox, or the rolling alga.

Flower-pot algae. Somewhat related to the Volvox, but by
no means so interesting an object, is the bright-green alga which
forms a scurf on flower-pots in green-houses, upon curbstones
near hydrants, upon the foundation stones of houses standing
upon damp places, upon damp soil, and often upon fallen trees
in the deep forest. A microscopic examination of the green

FIG. 10. Patches of pond-scum floating in a tank. A lime-encrusting alga grows on the
boards up to high-water mark. Near Minneapolis. After photograph by Mr. R. W.
Squires.

scurf on a flower-pot would show that it is made up of countless
very tiny green spheres, fifty of which could be laid side by
side across the dot over a lower case "i" on this page. The way
in which these little plants multiply is as follows : While they
are finding food in plenty in the moisture about them, the con-
tents of each of the spheres will be seen to divide into two, four
or eight smaller balls. The membrane of the old sphere then
dissolves and the little balls tumble out and grow to the size of

36 Minnesota Plant Life.

the one which produced them. This process .is rapidly repeated
and in a few days such a geometric progression will bring into
existence an enormous number. A variation of the process
sometimes occurs when there is an unusual abundance of mois-
ture, as after a heavy rain. Each of the little balls formed under
these circumstances is provided with a pair of extremely delicate
lashes by means of which it propels itself through the water
with a curious rotating and wabbling movement, something like
that of a rifle-ball, only, of course, very much slower. It takes
some moments to travel an inch, yet, on account of the very
small size of the plant, its movements viewed under a microscope
seem fairly agile.

Red snow. The famous red-snow plant, which is found upon
mountain heights in the Alps, in Bolivia^ or in the Selkirks, is a
relative of the green-slime so common upon flower-pots in the
Minnesota conservatories. The color of the red-snow plant is
adapted, no doubt, to the cold region which it has chosen for
growth, and, in general, red coloring substances in plants have
been described as warining-up colors — thus the autumn leaves
turn red not because they are dying but for very much the same
reason that men wear overcoats and woolens. Redness may
be regarded as one of the plant's ways of protecting itself against
a low or falling temperature.

Water-nets. Among the bright-green algae a conspicuous
but not extremely common form in Minnesota is the water-net.
This plant grows in quiet pools and resembles very much a piece
of green mosquito-bar rolled up in an irregular cylinder, three
or four inches long, and an inch or more in diameter. Each
side of a mesh in the net is a joint or cell of the plant, and in
each cell the living contents have the power of arranging them-
selves into a tiny net. When the wall of an old cell dissolves
the tiny net begins to grow, enlarging all of its mesh-sides
equally, until it has become as large as its parent. Besides this
propagative process the water-net has the power of breeding
somewhat as does the pond-scum, and produces curious little
microscopic jackstone-shaped fused-bodies which remain dor-
mant at the bottom of pools during the winter months. A
great variety of bright-green algae are found growing upon peb-
bles, upon the stems of submerged vegetation and upon twigs or

Minnesota Plant Life.

37

branches which have fallen into the water. Their characters
are all more or less similar to those which have been already de-
scribed.

Leaf-dwelling algae. One remarkable alga, very rare in Min-
nesota, is found in a peculiar habitat. On the leaves of the
jack-in-the-pulpit there may occasionally be noticed watery blis-
ters, in which, under the epidermis of the leaf, slender green
threads branch and grow, giving a pale green tint to the central
portion of the blister. Here is an example of a parasitic alga,
forms similar to which are more frequent upon leaves in tropical
forests than in temperate regions.

Sphere-algae. Another bright green alga which appears to
be uncommon in Minnesota, but sometimes forms floating tufts
of slender green threads in the waters of overflowed meadows,
is remarkable for its production of true eggs and spermatozoids.
As in the pond-scum, each thread of the body is an unbranched
row of joints or cells all of which are shaped like long glass
cylinders closed at each end. In some of these cells the living
contents break up into a dozen or more spherical green eggs,
which lie close against the wall of the mother-cell and, by fer-
ments which they secrete, make little punctures. Other cells
of the filament convert their contents into thousands of motile
spermatozoids which dart about in the cell-cavity in a compli-
cated dance which finally results in some of them perforating
the wall, and through the apertures all escape into the water.
After swimming about for a time many of them find their way
through the pin-holes which the eggs had made in the walls of
their mother-cells. They enter the egg-mother-cells and one of
them buries itself in the substance of each egg. When the eggs
in a tube have been thus fecundated each encloses itself in a
spiny membrane, assumes an orange color, and after the wall
of the mother cell has broken or dissolved each fused-body
escapes into the water and divides internally into a little group
of spores. The spores in turn escape and develop new filaments
of the alga. This alga is called the sphere-alga on account of
the tubes full of spherical eggs which characterize it.

Green felts. Among the other algae of this group should
be mentioned the green-felts which form plush-like masses in
springs and ditches. They are remarkable for the unjointed

38 Minnesota Plant Life.

character of their filaments and their breeding habits remind
one in some respects of the sphere-alga, for they form true eggs
and spermatozoids.

Bass-weeds. Of all the algae of Minnesota, the largest and
most conspicuous are the bass-weeds. These plants are familiar
to fishermen because tufts of them are commonly entangled by
trolling-hooks which have been dragging along the bottom out-
side the bulrushes. The bass-weeds have stems the thickness
of a knitting needle, with distinct nodes and internodes. Upon
the nodes whorls of branches are produced and upon the
branches subsidiary leaflets. The whole plant, in the more
common form, is encrusted with a limestone deposit, which
gives it a brittle and stony feeling to the touch. Hence these
plants are also called stone-worts. Many of them have the habit
of forming diminutive bulbs which separate and serve to propa-
gate the plant, and they also produce near the bases of their
leaflets very definite oval, brown eggs, not much larger than a
pin-point and inclosed in a little spirally twisted jacket of cells
leaving an opening at the top through which the spermatozoids
can enter. The spermatozoids are derived from curious little
spherical organs of a reddish color, and each spermary, not
larger than a small pin-head, forms as many as 30,000 actively
moving spermatozoids, thousands of which are destined to be
lost in the water, but enough are produced so that the eggs are
reasonably certain of fecundation and may then, after a dormant
period which extends over the winter months, develop into new
bass-weed plants. During the cold weather the eggs and many
of the propagative bulbils lie safely at the bottom of the lake too
deep to be injured by the frosts.

Some varieties of bass-weeds, slenderer than the others, are
not provided with the limestone sheath which characterizes the
more common form, but may be recognized by their general
similarity of structure. When taken out of the water they are
limp, though not slimy like the pond-scums. Bass-weeds form
an extremely abundant vegetation, generally distributing them-
selves in the deeper waters of a lake, outside the zone of pond-
weeds, or of bulrushes. Sometimes they are very common in
shallow waters, and I have seen them in Glenwood lake, and in
some of the northern lakes of Minnesota, growing vigorously
in water only a few inches deep.

Chapter V.
Brown Algae and Red Algae*

Brown algae. Almost all of the true brown algae are marine
and they are remarkable as comprising the longest plants in the
world. It is a popular impression that the big-trees of Cali-
fornia, the Eucalypti of Australia and the Rotang palms of Java
and the Orient are the longest-stemmed plants in existence.
This, however, is a mistake for some of the gigantic seaweeds
of the Antartic ocean extend their stems for over a thousand
feet, making them nearly three times as long as the trunk of the
tallest big-tree in Calaveras county, California. Such huge brown
algae are not unknown along the sea-coast of the United States,
and the giant kelp of Puget sound sometimes reaches a length
of more than three hundred feet. By means of its long cable-
like axis, it attaches itself to the rocks and floats its immense
leaves many fathoms out upon the surface of the sea. Other
brown sea-weeds develop enormous strap-shaped leaves in tufts,
attached by hold-fasts to the rocks. Some of them have their
leaves perforated with numerous holes, an adaptation to prevent
them from being torn by the waves. In the fresh waters of Min-
nesota no such forms as these are to be found and the most
abundant ones are doubtfully to be classed as brown algae at all,
but from their brownish or olive-green color they may here be
considered as if certainly members of the group.

Diatoms. In the early spring, in rivers, one often finds olive-
green membranous masses as large as one's closed fist floating
idly at the water's edge. An examination of them would show
that they consist of great numbers of microscopic boat-shaped
bodies, with clear glassy walls and olive-green or brown con-
tents. Such algae are known as diatoms. They sometimes
occur in great fossil deposits, and in this condition are much
prized for polishing powder. The walls of the diatom cells

4O Minnesota Plant Life.

have the power of depositing in their interstices, silica, and it is
this which gives the polishing quality to the fossil powder.

Some diatoms are provided with slender gelatinous stalks, by
means of which they attach themselves to objects under the sur-
face of the water, but many of them are free-swimming organ-
isms. The exact mechanism by which they swim has long been
a puzzle to students of the group, for they are not, like the switn-
ming cells of the green-slime which grows on flower-pots, pro-
vided with conspicuous lashes by means of which they roll them-
selves through the water. Most of them seem to have, how-
ever, extremely small apertures in their walls through which
the living substance probably protrudes itself and sets up an
agitation in the water, so that the tiny boat moves mysteriously
across the field of view of the microscope like some infinitesimal
electric launch.

Red algae.. This group like the brown algae is essentially
marine and but few forms are found in the fresh waters of Min-
nesota. In rapidly flowing streams or under cataracts certain
kinds display their red bodies, appearing as delicate plumes a
few inches in length or as little pink or purple plates an eighth
of an inch or less in diameter. Their structure is more compli-
cated than that of any of the algae which have been considered.
They are supplied with egg-cells from which long cylindrical
protuberances are developed. The spermatozoids, unlike those
of the sphere algae, have no swimming lashes and are, therefore,
carried to the protuberances of the eggs by currents of water,
or by the ministration of aquatic insects, recalling in this latter
adaptation the extraordinary relation which exists between
insects and flowers. When, however, a little spherical spermato-
zoid comes in contact with the slender cylinder developed on
the egg-cell, it adheres and fuses and, as a result of its stimula-
tion, from the egg are thrust out branches which finally develop
spores, and thus the plant persists from one generation to
another.

Some kinds of red algae are so faintly red that they would be
mistaken for brown algae, if color alone determined the classi-
fication. Such are certain rather stiff, wire-like plants, spar-
ingly branched and preferring for the most part the same rapid
foaming water which the easily recognizable varieties select as

Minnesota Plant Life. ^r

an habitation. Yet on account of their various structural pecu-
liarities botanists assign them to the group of red algae.

General remarks about algae. The account that has been
given is very elementary and the reader must remember that it
covers perhaps as many as a thousand varieties, most of which,
are species of bright-green algae and diatoms. None of the
fresh-water algae has any great economic importance. Some
sea-weeds are employed in the manufacture of iodine, others,
especially the kelps, as fertilizing material for farms near the
sea-shore. The "Irish moss," as it is called, is a red alga and
is used for food ; when cooked it is a kind of blanc-mange. In
China several other kinds of sea-weed are regarded as edible.
The Indian fishermen in Alaska use the stem of the giant kelp
as siphons and for fishing lines. In Minnesota the algae are
sometimes rather noxious than useful. Blue-green algae in
decaying masses are known to give to the water a characteristic
pig-pen odor which is very offensive. It is at times a difficult
problem to prevent them from vitiating aqueducts and reser-
voirs, and cattle are reported to have been poisoned by drinking
water which contained their rotting remains. It is, therefore,
not the water which contains the bright grass-green pond-scums
that is so objectionable, though on account of the slimy charac-
ter of these plants they are more repugnant to most people than
the verdigris-colored water-flower. Cattle should not be allowed
to drink from pools in which the algal vegetation is of a blue-
green shade, but no injury is likely to result if the scums are
bright-green.

In past time it should be remembered that certain lime-
secreting-algae and silica-secreting algae have no doubt done
their part in creating the building-stones of the state. Even the
quartzites and the granites may be the modified sinter deposits
from some hot-water algal vegetation of former ages. In the
sea, to-day, countless millions of algae are busy building coral-
reefs similar to those produced by the coral polyp, while nearer
home, in Lake Michigan, limestone pebbles have been found to
be produced by the concretionary growth of lime-secreting
algae. I have not yet found any of these algal pebbles in the
lakes of Minnesota, but it is probable that they occur. If any
one should chance to find calcareous pebbles the size of an egg,

42 Minnesota Plant Life,

which upon being broken have a moist bluish-green interior or
are hollow, he will doubtless have discovered a growth of rock-
forming algae.

Algae the oldest kinds of plants. The great group of
algae is of peculiar interest to students of nature because it
includes the oldest types of plants living upon the earth. There
is reason to suppose that life originated in the sea, and that all
the terrestrial forms are descendants of those which in distant
epochs learned to leave the ocean and establish themselves upon
the land. One reason for supposing this is that in distant peri-
ods of the earth's history there was very little land in existence,
and almost the whole surface of the globe was covered by the
waters of the ocean. No doubt, at first, before the ocean had
cooled, when the world was still young, warm-water algae,
among which the rock builders are so prominent, came into
being and began their work perhaps among the very first living
creatures of all the hosts that now exist. Some varieties of land-
plants at present, as for example the mosses and liverworts, show
clearly in their structure their relationship to the algae, and
serve as connecting links between the great primal flora of the
ocean and the modern flora of the land. The algae, then, are
the forms from which all other plants are supposed to have orig-
inated. The history of life upon the earth is one of constant
improvement, and as land appeared improved forms of algae
tenanted it, and may have given rise to all the myriad higher
species of forest and prairie as they are now exhibited over the
continents of the world. And finally there are very many excel-
lent reasons for regarding the continents themselves to have
arisen largely through the activities of living organisms — a proc-
ess that may be observed continuing even in these days if one
should visit the coral-islands of the south seas, those enchanted
atolls of the Pacific.

Chapter VI.

The Lower Sorts of Fungi.

Number of fungi in Minnesota. While there are nearly 200,-
ooo known species of flowering plants in existence, there have
been described only about 50,000 species of fungi. Yet in Min-
nesota, while there are but 2,500 or 2,600 flowering-plants grow-
ing without cultivation there are probably not less than 3,000
fungi, so that the state furnishes a field for the development of a
greater comparative proportion of fungi than of flowering
plants. Like the mosses and liverworts, the fungi are believed
to have arisen from primitive algal types and students recognize
two principal series. The lower series known as the algal fungi,
the structure of which is more directly suggestive of algae, is
much poorer in forms than the higher series of true fungi in
which all the peculiar fungal structures and characters have had
an opportunity to be unfolded.

Black moulds. Of the algal fungi a very widely distributed
group is that of the moulds. Among these the black mould is
omnipresent, and easily cultivated. If a slice of bread be dipped
in water, placed in a saucer, a tumbler inverted over it and then
set in a warm place, perhaps behind the kitchen stove, in a few
days the tumbler will be filled with a white cloud of fungus
threads and presently little black, spherical spore-cases will arise
at various points on the fungus network. The white threads
are the vegetative plant-body of the mould; the black knobs
(white when young), smaller than a pin-head, are the fruit-bod-
ies. The black color of each fruit-body is occasioned by the
presence, in a swollen cell, of some hundreds of little black
spores, which have developed by the division of the living con-
tents of their mother-cell or spore-case. When the spore-cases
are broken and the living powder is disseminated, it is caught
in air currents and is held suspended in the atmosphere to such

44 Minnesota Plant Life,

an extent that in the dust of the air in every living' room in Min-
nesota, hundreds of such spores are already floating. It is nec-
essary, therefore, only to dip the slice of bread in water and set
it aside, for the spores which have fallen upon it in the process
to begin their development. It would be a mistake to suppose
that moulds originate spontaneously. A mould plant can no
more come into existence without the cooperation of some
mould-spore than could an oak-tree without the assistance of an
acorn. It is because of the presence almost everywhere of incal-
culable numbers of mould spores floating invisibly in the atmos-
phere that this seeming spontaneity of development impresses
one. There are, however, many places where bread will not
quickly mould if set out in a saucer, for example, if carried to
some high mountain top where the air is pure and free from
spores, or if exposed in a chamber which has been purified and
sterilized by a spray of carbolic acid.

The black moulds have a breeding habit reminding one of the
pond-scums. Two of the white threads close together or touch-
ing each other, may develop little side branches the ends of
which blend and gradually convert themselves into a black
fused-body with very much the character of a fecundated egg
and capable of growing into a new mould thread.

Other kinds of moulds. There are several other varieties of
moulds belonging to this group of algal-fungi, but the well-
known blue-moulds, or green-moulds, with their verdigris col-
ored fruit-bodies are classified in a higher group. Some of the
moulds have curious habits. One, called the pill-throwing
mould, produces a mass of spores upon the end of a filament,
then underneath this mass there develops a swollen cell in which
pressure is exerted, so that after a time the mass of spores is
shot off into the air by the explosive mechanism of the stalk-cell.

Moulds on moulds. Still another mould has the peculiarity
of attaching itself to the vegetative body of .the black mould. It
lives as a kind of mould-louse, extracting its nutriment from the
body of the larger and more vigorous black mould. A plant
which thus fastens itself upon another living creature and
absorbs nutriment from it to the injury of the host is called a
parasite.

Minnesota Plant Life0 45

Fly-cholera fungi. Related to the moulds are the singular
fly-cholera fungi. Many persons will have noticed sticking to
the window-panes in autumn the dead bodies of flies surrounded
for some distance by a faint yellowish film upon the glass. This
film consists of spores of the fly-cholera fungus which have been
shot into the air by a mechanism similar to that described for the
pill-throwing mould. The vegetative body of the fly-fungus
lives within the body of the fly where, growing luxuriantly, it
interferes with the life-processes of the insect, kills it, and con-
verts a large portion of its body into food for its own use. Other
flies approaching the infected individual are peppered with the
tiny spores of the fungus, or they receive the contagion while
walking upon an infected window pane or in a spore-strewn cor-
ner. In this way every autumn unnumbered millions of flies
are killed. A closely related cholera-fungus Attacks the Rocky
mountain locust and is of great economic importance because it
keeps this dangerous insect in check. Still other varieties
attack other insects, but these two will serve as examples.

Cell-parasites. There are a large number of microscopic
algal-fungi of very curious behavior. Some of them find their
way into the skin-cells of flowering plants and there live as para-
sites, while others insinuate themselves into the eggs of algae
and devour them. Some of them are found in the soft sub-
stance of swamp plants ; some may be discovered in pond-scum
filaments where they consume the cell-contents ; some find their
way into desmid cells and destroy them ; some enter the pollen-
grains of flowering-plants, notably of the pines, and feed upon
the living contents. They invade the diatoms and various
algae ; they infect the spongy tissues of the peat-mosses ; they
penetrate the wall of fish-mould eggs and by their omnivorous
habits impress it upon us that no organism is too small or incon-
spicuous to escape its enemies.

Fish-moulds. Related to the fungi which sometimes injure
their eggs are those surprising organisms, the fish-moulds, that
are often found forming gray fur coats on the bodies of dead
minnows or dead frogs. They are especially unwelcome in fish
hatcheries where they attack the eggs of the fish and destroy
them. Some varieties are found upon the dead bodies of aquatic
insects and others grow upon decaying substances when sub-

46 Minnesota Plant Life.

merged in the water, although the majority are parasitic upon
living plants or animals, or make the dead bodies of these their
habitat. The life of a fish-mould differs from that of the black
mould in some important particulars from its being an aquatic
organism. Its spores are not mere passive spheres of micro-
scopic size like those of the black mould, but are provided with
swimming lashes, so that they may propel themselves through
the water in search of other fish or insects upon the bodies of
which they may be fortunate enough to obtain a lodgment. One
fungus related to the fish-moulds, not yet discovered in Minne-
sota, but possibly occurring somewhere within the state, is
noteworthy in botanical annals as being the only fungus known
to produce motile spermatozoids like those of the algae and, as
will be seen later, of the ferns and mosses.

Mildews. Closely related to the fish-moulds are the mildews.
These are fungi which live as parasites upon land plants. A
striking example of the group is the mildew of mustards, which
occasions a rotting of the stems and leaves in the shepherd's-
purse. Another causes a rotting of potato tops and is one of the
most serious diseases of the potato with which cultivators have
to contend. Still another which occurs in Minnesota is the
mildew of the grape-vines, inducing the leaves to wither and
decay. The lives of mildews are in many respects similar to
those of the fish-moulds, but with certain differences owing to
their non-aquatic habits. For example, the mildew of the vine
when it attacks the leaves goes about the task somewhat in this
fashion. From the air, into which from other mildewed leaves
the spores have been projected, certain spores come to fall upon
the surface of a healthy leaf. They lie upon the skin of the leaf
and extend little infecting tubes which crawl around upon the
surface of the leaf until they find one of the air-pores with which
the leaf is provided for respiratory and vapor-excretory pur-
poses of its own. Into such apertures the fungus insinuates
itself, and as its infection-tube crawls beneath the skin of the
leaf among the soft cells filled with leaf-green and starch, it
finds there plenty of food material. Into each cell it drives a
little sucking organ and extracts the nutritive substances and
converts them into its own body. Going thus from cell to cell
it finally saps the life of so many of them that the usefulness of

Minnesota Plant Life. 47

the leaf is destroyed, and thus the vigor of the whole vine is defi-
nitely impaired. When the mildew has accumulated in this
manner sufficient nutriment for its needs it puts forth a branch
which grows out through one of the air-pores of the leaf and
here, in the open air, spore cells are formed. These are sepa-
rated from the branch which produced them and are carried
away by wind-currents to other vine leaves. Moreover the mil-
dew within the tissues of the leaf breeds after its fashion, form-
ing little spherical eggs which after they have been fecundated
divide up internally into a considerable number of tiny motile
bodies, provided with lashes, so that, when the rotting mass of
the leaf has broken down after some rain, these motile cells can
be washed out and swim to fresh parts of the leaf or fall with
the rain drops to other leaves upon the same plant. Such egg-
cells of the mildew serve to bridge over the winter season, and
it is, therefore, important, if potatoes, vines, or lettuce should be
in the habit of mildewing, that all dead leaves in the autumn
should be burned. This diminishes for the following season the
danger from fresh infection.

Chapter VII.

Smuts and Rusts.

Higher fungi. The plants already described may suffice as
examples of the algal fungi. The higher or "true" fungi con-
stitute a very large group of various forms, some of which are
parasitic, attaching themselves to the bodies of plants or of
animals, while others live upon decaying organic matter. No
fungus has leaf-green and consequently no fungus can manu-
facture starch out of carbonic-acid-gas and water, but its nutri-
tion is rather animal-like, in that there must be provided more
-complex food-substances. A fungus cannot live on a diet prin-
cipally of air, salts and water as do the algae, mosses, ferns and
most flowering plants.

Smuts. Among the higher fungi the smuts are a well-known
group. Every one is familiar with the smut of Indian corn
which occasions the appearance of great distorted kernels, many
times as large as the ordinary ones, composed almost entirely
of smut threads and a very copious black mass of smut spores.
Other kinds of smut are found upon oats, upon wheat, upon
millet-grass, upon sedges, and upon sand-burrs. Generally the
smut spore-masses develop themselves in the seed-areas of
plants, and substitute for the seed their own fruit-bodies.
Hence the smut fruit-body in the Indian corn takes the form
of a greatly enlarged corn kernel and the stinking smut of wheat
fills the wheat grain with a mass of spores, allowing the wheat
to produce only the shell of the fruit while the interior is a solid
mass of smut. Sometimes a whole flower-cluster is infected as
in the sand-burr smut. In a few plants the stamens are attacked
by smut fungi and an example is furnished by the corn-cockle,
a weed belonging to the pink family and to be met with in cul-
tivated fields. Here the stamens, when mature, open in the or-
dinary way to cast out their pollen, but if the smut that some-

Minnesota Plant Life, 49

times affects them has gained a foothold, they might as well
save themselves the trouble, for all the pollen grains will have
been destroyed and in their place will be the spores of the smut.

Peat-moss smut. Still another kind of smut develops its
spores in the capsules of the peat-moss, and under such condi-
tions when the capsule opens to eject its spores there are no
moss-spores present, but only the smaller black reproductive cells
of the smut. Until recently this condition of things caused bot-
anists to labor under a misappreherlsion concerning the life-
history of the peat-moss and in most of the books peat-mosses
are described as producing two kinds of spores, some large and
others small. The supposed small spores of the peat-moss are,
however, not peat-moss spores at all, but are developed on a par-
asitic plant which has the interesting habit of forming them in
exactly the same little round capsule which the peat-moss had
been to the pains of developing for its own spores.

The life of a smut. A large number of plants in Minne-
sota are affected by smuts and sometimes two or more va-
rieties will be attacked by the same kind. More often, how-
ever, the smuts which are found on different kinds of higher
plants are themselves specifically distinct. The life of a smut
is interesting because it is typical of the manner in which many
parasitic fungi develop. There may be selected for description
the stinking smut of wheat. Inside the affected kernels clusters
of spores are formed which upon the breaking of the kernels,
during the threshing of the wheat or while it is being shovelled
about in bins or while it is standing in its head, are liberated and
fall upon the ends of other uninfected kernels. There they are
caught in the little hairs which are present at the germinal end,
and when the wheat kernel is sown and germinated the smut
spores germinate also and their delicate threads grow in the tis-
sues of the wheat plant keeping pace with the host as it extends
higher and higher into the air. When the wheat flowers are
formed and the rudiments of the fruits begin to appear some
of the smut filaments grow into the young kernels and, as these
develop, the smut filaments begin dividing themselves into
spore-cells, exerting a disintegrating effect upon the interior of
the kernel, so that finally one thus infected becomes filled with
thousands of spores of the smut. The process may then be re-
5

50 Minnesota Plant Life,

peated and thus smut is perpetuated from year to year. On
account of the habits of the smut it is a disease of grain which
can be eradicated by the intelligent farmer, if he will take the
trouble to kill all the smut-spores which are clinging to the hairy
ends of his seed-wheat kernels. This can be done by "blue-
stoning," or by immersing the seed-wheat for five minutes in wa-
ter of 132 degrees Fahrenheit. By such means the vitality of the
smut spores is destroyed, for they are exposed at the end of the
grain while the wheat plantlet itself inside the kernel is pro-
tected by the firm fruit-wall and is not injured by the poison or
by the heat. By such methods if generally and continuously
employed, it would be possible to terminate the enormous finan-
cial losses which farmers in Minnesota and the Northwest sus-
tain from the various cereal smuts.

Rusts. Related to the smuts are a variety of plants which
may for convenience be grouped under the general name of
rusts. Of these a great many different kinds exist in Minne-
sota. They infest the leaves of numerous species of plants, the
Labrador tea, the pines, spruces, and tamaracks, the golden-
rods, asters, thistles, bellworts and poplars, the flax, willows,
horsemints and sunflowers, the junipers, pears, apples, beans,
violets and a great number of others.

Wheat-rusts. The forms of greatest economic interest are
the three sorts of rusts which attack wheat. There are over
700 different kinds of rusts belonging to the wheat-rust type,
many of which occur on grasses, but the majority on numerous
other varieties of plants. The wheat-rusts are among the most
remarkable of fungi from the singular custom which they have
of changing periodically their habitation from wheat to other
plants. Not only do they change their place of abode, but they
change their form and structure as well, so that it would be im-
possible, unless one knew, to recognize the wheat-rust after it
had migrated to one of the other plants upon which it has ac-
quired the habit of developing. The three sorts of wheat-rust
which occur in Minnesota alternate on different plants, one de-
veloping on barberry leaves and probably also on the leaves of
some other species which has not been identified, another re-
appearing on buckthorn leaves, and a third on borage leaves.
It must be remembered that these are three different varieties

Minnesota Plant Life.

FIG. 11.— Patches of wheat-rust, natural
size and enlarged. The red nist stage.
After Atkinson.

of wheat-rust. They cannot convert themselves into each other
but are independent plants as distinctly as are oats and rye. It is
well-known that there are two stages of wheat-rust, one of which
develops in the early summer and autumn and is known as the
red rust, the other developing in late summer and autumn and
known as the black rust. The char-
acteristic colors of the two stages
are given by masses of spores grow-
ing in layers upon the plant-body of
the rust which in turn consists of a
network of parasitic threads living
in the tissues of the wheat plant, the
skin of which is burst by the fungus.
It is the same plant body which
produces the red spores forming
red streaks on the wheat leaf that
afterwards produces black spores
in equally enormous numbers occasioning the black rust stage.
The red or "summer" spores are ovoid, spiny bodies, properly
described as single cells. Their walls are thinner than those
of the black rust. The black, or "autumn" spores have

smooth walls and are divided into two
cells by a cross partition situated near
the centre of the somewhat elongated
and pointed or rounded body. Red-
rust spores, when separated from their
stalks by the wind, may be carried
throughout the summer to other
wheat plants, and thus the infection
spreads possibly over a whole field.
The black-rust spores remain dor-
mant during the winter upon the stub-
ble and debris of the field. In the
spring each of the two cells of the
black-rust spore develops a tiny jointed body upon which four
very small thin-walled, colorless spore-cells are produced. Now
is the time selected by the wheat-rust for the periodic change of
habitation. It is known that the small spores thus produced
do not so readily germinate if blown upon wheat plants, but

FIG. 12.— Patches of wheat-rust, nat-
ural size and enlarged. The black
rust stage. After Atkinson.

Minnesota Plant Life.

may find their way to the leaves of the barberry. When they fall
upon the epidermis of such leaves they develop infection tubes,
penetrate the skin and form a filamentous plant body within
the soft inner tissues. At their time of fruiting they form two
sorts of fruits, one upon the under side of the barberry leaves,
known as cluster cups, the other, peculiar bottle-shaped fruits,
upon the upper side. In the cup-shaped fruits large numbers
of spherical orange-colored spores are produced which if blown
away to a wheat field will infect the wheat. In the bottle-
shaped fruits smaller elongated spores are formed, but it is not
known how these germinate nor what becomes of them in the
natural order of events. Barberries are by
no means abundant in Minnesota, only a few
of them existing in hedge rows, and while it
is by no means inconceivable or absurd, on
account of the winds which blow over the
wheatfields of the Northwest, to suppose that
barberries in the east might infect the wheat
in Minnesota or the Dakotas, yet it is more
probable, I think, that the wheat-rust passes

its cluster-cup stage
on some common
Minnesota plant
which has not yet
been identified as
maintaining this
particular kind of
rust, or that it omits
altogether its cus-
tomary migrations
to other plants.
It is apparent that such a disease as the rust offers difficulties
to the economic farmer desirous of protecting his crop, far in
excess of those presented by the smut, for while smut spores
caught in the ends of the wheat kernels can be killed there by
hot water, no practicable method exists of policing the atmos-
phere and preventing rust spores from finding their way to the
young wheat. Therefore, the most feasible plan for combatting
wheat rust is by the development of so-called "rust proof" va-

FiG. 13. — Wheat-rust in its barberry -leaf stage; to the left a
barberry leaf with diseased spots; in the middle, a sin-
gle spot with cups; to the right, two of the cups, in top
view slightly magnified. After Atkinson.

Minnesota Plant Life.

53

rieties. While smut is, upon the whole, the easiest of the wheat-
diseases to control, rust is the most difficult.

The remarkable migratory habit of the wheat-rust and its
allies coupled with the extraordinary change in form which the
fungus assumes upon the different habitats gives rise to some
very surprising conditions in rust life-histories. For after the
migratory habit had been formed it would appear that some-
times one or the other of the phases became extinct, so there
are varieties of rusts which exist only in the cluster-cup phase,

FIG. 14.— Magnified section through a cluster-cup of the wheat-rust in its barberry-leaf stage.
Shows chains of spore-cells. The large cells at the sides are those of the barberry leaf
much magnified. After Atkinson.

and others only in the red and black-rust phases. For a long
time students of the fungi thought that the cluster-cups were
entirely different from the rust, and it was only because people
noticed more than a century ago that "barberry bushes," as the
saying was, "blasted the wheat," that a hint was given to mod^
ern research, in consequence of which the astonishing behavior
of the rust fungi is now more thoroughly understood.

Relatives of the wheat-rust. Among the relatives of the
wheat-rust there are some forms in Minnesota characterized by
little peculiarities which enable botanists to classify them in dif-
ferent genera. For example, the black-rust spores formed on

54

Minnesota Plant Life.

some blackberries are three-celled instead of two-celled, and the
cluster-cup masses on some gooseberries are developed upon
protuberant filament-aggregates. Perhaps the three most re-
markable forms are the pine-knot fungi which form knots some-
times as large as bushel baskets upon the branches of pine trees,
the so-called "cedar-apples," which occur as curious bunches,
the size of one's thumb and armed with orange horns, on the
junipers, and the witch's brooms on balsam trees. These latter
are immense, disordered tangles of branchlets forming masses
sometimes several feet in diameter. The disordered branching
is caused by the growth of a rust-fungus of the cluster-cup sort
in the substance of the twigs. When this fungus fruits it pro-
duces its reproductive structures upon the leaves of the balsams,
where they recall strikingly the rust produced on barberry
leaves. The witch's broom is a notable object in the swamps
of Minnesota. When large ones are developed on the balsam
trees they look like great crows' nests up in the branches and
very often birds and animals use the thick tangle of twigs to
conceal their own dwelling places. On the spruce trees there
is a similar tangle of branches produced by the agency of insects,
but there is of course no development of the characteristic clus-
ter-cup fruit-bodies upon the leaves. The related pine-knot
fungus does not commonly fruit every year, but sometimes the
whole surface of the knot will be found covered with the little
orange pustules of the rust.

Chapter VIII.

Trembling Fungi, Club-fungi, Shelf-fungi and Mushrooms,

Trembling fungi. Somewhat related to the rusts, although
one would hardly suppose it from their appearance, are the sin-
gular gelatinous yellow or pink wrinkled masses which are often
found upon decaying logs in shady places. These cannot be
mistaken for the plant-bodies of slime-moulds, because they are
of a firmer cartilaginous texture. They are capable of produc-
ing over their surface a layer of spores which when separated by
the wind or rains may propagate them upon other suitable sub-
strata. From their tremulous character these plants are some-
times called "trembling fungi." Rather more highly organized
but in the same general order of development are the leather-
like gray skins which are often found upon the under sides of
decaying twigs. Related forms are sometimes provided with
little stalks and grow up cornucopia-like from the bark.

Club fungi. Another family of fungi which includes forms
not so very different from these skin-fungi, comprises also those
which stand up on the forest-mould like little yellow Indian-
clubs, an inch or two in height. The upper end of such club-
fungi is swollen, and it is there that the spore-bodies are partic-
ularly developed. Not all of the club-fungi are unbranched;
but some of them are divided like the antlers of a deer, and yet
others in which the branching is more copious grow in pearl-
gray, yellow, white or pinkish tufts, several inches high, and
covering spaces as large as a dinner plate. They may be rec-
ognized by the generally erect habit of all the branches, so that
their forms remind one of the branching of certain night-bloom-
ing cereuses of the New Mexican desert. Commonly the
branches are more or less cylindrical and blunt, but one form,
which is not uncommon in hard-wood forests along river bot-
toms in the southern part of the state, has all its branches

56 Minnesota Plant Life.

shaped somewhat like clam shells, so that the whole plant-body,
often several inches in diameter, seems to be composed of nu-
merous white shells overlapping each other and all attached to
a common base.

Prickle-fungi. The prickle-fungi — at least some of them —
might be mistaken for much branched forms of club-fungi ; but
they can be distinguished by the general downward tendency
of the branches, so that in a well-known species not uncommon
in the valley of the St. Croix where it grows upon decaying tree-
trunks, there is a coral-like aspect to the whole plant-body.
This variety is generally white, or slightly yellowish, or yellow-

HHHHHH||HHHHH||I WHHHHHBnHHHHMHMaHH^

* ,

» .,

FIG. 15.— Growth of club-fungi on decaying wood. After Iyloyd.

ish-brown in color, often as large as a man's head, and made up
of a group of thick, irregular branches upon the under sides of
which great numbers of prickles half on inch or more in length
grow downward. Not all of the prickle fungi have exactly this
kind of a plant-body. Some of them outwardly resemble toad-
stools, and might be mistaken for them if one did not look upon
the under side where he would discover instead of the radiating
gills of the toadstool the whole under surface of the cap cov-
ered with a growth of prickles. Upon the surface of these
prickles the spores of the plant are developed, and by their co-
operation the fungus is able to maintain itself from year to year.

Minnesota Plant Life.

57

In these forms, however, and in many of those to follow, the
conspicuous part of the plant is really nothing more than its
highly developed fruit-body, while the vegetative portion con-
sisting of a spongy or cottony substance lies imbedded in the
decaying timber.

Shelf-fungi. Related to the prickle-fungi are the well-known
pore-fungi, or shelf-fungi, which are such familiar objects in the
woods of Minnesota. Often they seem to be growing upon liv-
ing trees, but it will be found upon examination that they have

FIG. 16.— Shelf-fungus growing on dead stump of oak tree. After photograph by Hibbard.

attacked some wounded or dead portion of the trunk, for these
fungi are none of them truly parasitic. They are more com-
mon, indeed, upon dead timber, either prostrate or standing.
Very pretty examples of shelf-fungi are abundant upon the
birch-trees of Minnesota, and this particular species is known
as the birch-tree pore-fungus. The fruit-bodies hang down
somewhat like bells, are of a white color, not \voody but with
much the consistency of. punk or cork. They grow larger from
year to year, the new growth covering that of former summers,
and every season a new layer of pores is produced upon the

58 Minnesota Plant Life.

under side. In the Minnesota woods there are a great number
of different kinds of pore-fungi which show characteristic dif-
ferences of shape, size, thickness, color, texture, and endurance.
One of them, called the sulphur-colored pore-fungus, which
grows in very large masses is edible when young, but the great
majority of them while not poisonous, are too tough, leathery
and woody to be very appetizing. Some of them, indeed, no-
tably the great shelves a foot or more across which occur upon
oak trees, are almost as solid as the wood of the tree itself.

Upon one occasion I noticed that in the pores of the under
side of one of these fungi, a large number of mosquitoes had
been caught by their legs and had afterwards been covered by
a growth of cottony filaments of the fungus, and I wondered
whether the plant might not derive some benefit from its ap-
parent capture of insects and digestion of their bodies. It is
not at all clear, however, that such a fungus should be included
in the great category of flesh-eating plants, because it is a com-
mon habit of the fruit-body to inclose small objects which
chance to be in its way. Sometimes when these shelf-fungi
grow near the ground they will be found with grass leaves pen-
etrating them and in such cases it is not to be supposed that the
grass leaf has grown through the fungus, but rather that the
fungus has grown around and has enclosed the leaf.

The pores of these interesting fungi are of different sizes and
shapes. In some varieties they are almost invisible, they are
so small. Other sorts have the pores much larger. In some
the pores are circular, in others they are hexagonal or irregular
in shape. In one kind which is common upon willows, form-
ing fruit-bodies not more than two or three inches across, the
pores are labyrinthine in shape, like the passages in the puzzle-
gardens which are sometimes laid out in parks. There is con-
siderable difference too in the upper surface of pore-fungi.
Some of them are white and smooth as in the birch-tree form,
while others are fuzzy. Some are hard and marked by annual
rings showing where the growth of each year has jutted out
beyond the growth of the previous year. Some are sticky, but
rarely slimy in texture ; some are cartilaginous or horny to the
touch, and many are spongy and soft.

Minnesota Plant Life.

59

Different genera of shelf-fungi are established by botanists,
principally upon the character of the pores. A genus which
contains numerous highly poisonous species, is recognized by
the readiness with which the pore-layer can be separated from
the under side of the sterile portion of the fruit-body. One va-
riety of these poisonous fungi is abundant in tamarack swamps
throughout the state. The general shape of the plant is quite
exactly like that of a toad-stool, a short thick stem rises from
the ground, and on top of this a red cap is borne, from two to

Pic,. 17. — Upper and under sides of mushroom-like pore-fungus. After I_loyd.

five or even more inches in diameter. The top is of a dull crim-
son or maroon-red tint, with scale-like markings resembling a
serpent's skin. Upon the under side will be seen a layer of
large yellowish pores, separated from each other by thin parti-
tion walls in which the coloring substance is developed. If
one pulls off the cap of this fungus and breaks it in two he
will find that the whole layer of pores is very easily peeled
away from the rest of the cap. Suppose now that one of
these pores was magnified until it was as large as an ordinary

6o

Minnesota Plant Life.

well. Then if one could
enter it he would see
the whole wall covered
with ovoid spores, now
apparently as large as ap-
ples. Since the pores all
open downwards it is easy
to see that if the spores
fall from their supports
they will gradually if not
immediately tumble out
through the opening and
may then be distributed
by wind or water. It is
altogether best never to
eat any kind of a pore-
fungus in which the pore-
layer is readily separable
from the rest of the fruit-
body, although there are
a few harmless varieties
even in this generally
dangerous group.

Some shelf-fungi are
not truly pore-fungi, but
the under side is perfectly
smooth or marked at best
with 1 o w, longitudinal
wrinkles. These may, per-
haps, be considered as
forms in which the pores
have either not yet come
to develop, or as varieties
in which for some reason
the pores have become
shallower until finally
they have been com-
pletely lost.

FIG. 18. — A pore-fungus lying flat
upon a decaying branch. After
lyloyd.

Minnesota Plant Life.

61

Mushrooms and toadstools. Related to the pore-fungi, and
especially to those in which the pores are elongated or laby-
rinthine, are the well-known mushrooms and toadstools. There
is little systematic difference between mushrooms and toad-
stools. People are in the habit of calling an edible toadstool a
mushroom, and a poisonous mushroom a toadstool. The fact
is that some of the species
of the great mushroom ge-
nus are edible while others
are not, and it is often ex-
tremely difficult even for an
expert to distinguish be-
tween edible and poisonous
varieties. The following are
very good rules to follow if
one feels an uncontrollable
inclination to experiment
with mushrooms as an arti-
cle of diet :

Never eat a mushroom
that is highly colored.

Never eat a mushroom
that has pink gills.

Never eat a mushroom
that seems to grow out of a
little cup at the base.

Never eat a mushroom
that has a milky juice.

Never eat a mushroom
that changes color shortly
after its substance is broken.

Never eat a mushroom
with a pungent odor.

Never eat a mushroom with a sticky or slimy cap.

Never eat an immature mushroom unless absolutely certain
what sort of a form it will be when mature.

None of these rules is absolute. There are exceptions to all
of them, to some more than to others, but, together, they con-
stitute a safe code and one cannot go far wrong in observing it.

FIG. 19.— Deadly variety of mushroom.' After
Atkinson. Bulletin 138, Cornell Ag. Exp.
vStation. This is sometimes known as the
"poison cup."

62 Minnesota Plant Life.

Yet a single rule, which I believe to be the best, is to eat no
mushrooms of any sort unless quite sure that they are edible, for
some of the deadliest poisons known to students of plant chem-
istry are contained in the plants of this genus. One in partic-
ular, which grows from a little cup at the base and spreads out
a rather thin cap is so fatal that a small portion of it is sufficient
to cause death. Still on the other hand, it is true that a great
many edible species are to be obtained in the woods and fields
of Minnesota, and it seems a pity that such excellent food should
go to waste when there are many people who would be glad to
avail themselves of this form of nature's bounty.

FIG. 20. — Under side of two mushroom-fruits. After Atkinson. Bull. 138, Cornell Ag. Exp.

Station.

All true mushrooms are characterized by the presence on the
under side of the cap, of radiating gills or plates, hanging down
like the ornamental tissue-paper decorations which are fancied
by proprietors of butchers' shops. Except for this general char-
acter their forms are various and some of them with long slender
stalks and thin conical or expanded caps present a very different
appearance from those with short, massive stalks and broad
hemispherical caps. A few are devoid of definite stalks and
protrude sideways from dead logs recalling quite exactly the
shelf-fungi in their general habit of growth. The largest mush-
rooms are found in pastures and along roadsides, lifting them-

Minnesota Plant Life. 63

selves sometimes nearly a foot into the air, and provided with
basin-shaped caps, six inches or more in diameter. Another
overgrown form is common on decaying timber and has no
central stalk but stands out somewhat like a bracket-shelf.

Deliquescent mushrooms. Not all of the fungi with radiat-
ing gills on the under side are classed by botanists as true mush-
rooms. One sort, which comes up in the autumn, late in Sep-
tember or in October, oozes into a black and filthy slime as it
matures. When young the fruit-body is elongated, an inch or
so in diameter, sometimes four inches in length, white in color,
with blackish scale markings. In its early stages when properly

FIG. 21.— Common edible mushroom. After Atkinson. Bull. 138, Cornell Ag. Exp. Station.

cooked this is one of the most delicious of edible fungi; but
after it has begun to decay it is neither appetizing nor healthful.
The habit that these mushroom-like fungi have of decaying is
a device for scattering their spores. They are visited by insects
and the spores are picked up in the general slime to which their
presence gives the black color, and are then carried away to be
deposited elsewhere.

Miniature mushrooms. Another relative of the true mush-
room is a very delicate little plant an inch or less in height
growing upon decaying leaves in the forest or in wooded ra-
vines. It has a shiny black cartilaginous stem like that of the
maiden-hair fern and upon the top of this a white cap displays

Minnesota Plant Life.

a small number of loosely arranged gills on the under side. The
diameter of the cap is often no more than one-eighth of an inch.

P c
I .2

Milk mushrooms. Still another close relative of the mush-
room is the milk-mushroom. The various species of this genus
are supplied with a milky juice, white or variously colored,

Minnesota Plant Life. 65

which oozes out if the flesh, is broken. One kind with bluish
gills and juice, gives off, when broken, a distinctive odor some-
thing like that of prussic acid and is very deadly. It is not un-
common under white pine trees in the northern part of the state.

A considerable difference in durability exists among the
mushrooms and their near relatives. Some of them are delicate
and watery in texture, lasting but a few hours after they are
mature. Others are spongy, or of a texture like punk, while
those found for example on railway ties become hard and woody
even before they are altogether mature.

The true mushrooms are classified into five principal groups,
depending upon the color of the spores, i. Forms with black
spores. 2. Forms with dark-brown spores. 3. Forms with
brown spores. 4. Forms with red or reddish-yellow spores.
5. Forms with white spores. Among the dark-brown spored
forms are a number of edible species. Here is included the or-
dinary edible mushroom which is cultivated for the market.

It is an easy matter to determine the exact color of mush-:
room spores by cutting off the cap close to the stem and laying
it down on a piece of paper with the gills towards the paper.
Within a few hours hundreds of thousands of spores will -fall to
the paper, tracing there the gill-arrangement and demonstrating
the precise color of the spores. If with the point of a pen-knife
a few thousands of these spores be lifted and placed under a
microscope, they will be found to be somewhat egg-shaped or
spherical cells usually with smooth walls and provided each with
a bit of living substance in the interior. They are produced in '
clusters of four all over the surface of the gills. The gills them-
selves are made up of interlaced threads, which, when they come
to the surface turn and grow perpendicular to it. Some of the
threads expand their ends, upon which four little ears are pro-
duced. The tip of each of these bulges out into a tiny egg-
shaped spore. A very narrow neck connects each spore with
its stalk and when ripe the spore drops off of itself.

Chapter IX.

Carrion-fungi and Puff-balls*

Carrion-fungi. Another group of fungi not very closely re-
lated to the mushrooms but properly to be considered at this
point includes the stinkhorns or carrion-fungi. These are among
the most remarkable of all plants. During summer and au-
tumn they spring up in door yards from a subterranean vege-
tative body which resembles a tangled mass of white rootlets.
Upon some of these rootlets little knobs the size of a pin head
will be found to arise just as in mushrooms. These grow rap-
idly until they become almost as large as hens' eggs, when sud-
denly the top of an egg is burst by the pressure of the grow-
ing parts within and in a surprisingly short time there is pushed
out a cylindrical stalk — appearing very much as if it had been
cut out of a loaf of bread, for it has the peculiar spongy texture
of the well-raised loaf. This stalk is hollow and upon its top is
borne a wrinkled cap perforated in the middle by an aperture.
The surface of the wrinkled cap is covered with a slimy green-
ish-black mass of spores and mucilage. Once seen this plant
will never be forgotten. It may perhaps be described picto-
rially as a vegetable confidence-game, for if there were any im-
moral plants certainly this would be one. It has almost pre-
cisely the odor of carrion and upon such an imitation of decay-
ing flesh it bases its extraordinary method of distributing its
spores. Attracted and deceived by the stench, various flies and
burying beetles visit it and walk upon it apparently believing it
to be what its odor indicates. They are even said to lay eggs
upon it and to withdraw feeling no doubt that they have made
that due provision for their young which their parental instincts
suggest. During their investigations, however, they have in-
advertently covered themselves with the sticky slime of the cap
in which the spores of the plant are embedded and these they

Minnesota Plant Life. 67

carry away and distribute, thus performing a work for the plant.
But in a few hours the whole fruit-body decays and the eggs,
if any had been entrusted to it under the apparently mistaken
notion that it would be a good place for maggots to develop,
all miserably perish. There seems to be no other way to
describe such behavior except as obtaining service from the in-
sect under false pretences, and if plants were really respon-
sible creatures these carrion-fungi would doubtless find them-
selves in some plant-penitentiary.

Even more remarkable is the behavior of a Brazilian relative
of the stinkhorn, which, in addition to all the devices that are
employed by the Minnesota species, adds a conspicuous white
veil, hanging down from the cap around the stalk. The veil
is reported by travelers to be faintly phosphorescent at night
and, if so, adds to the attractive influence which the plant might
have upon night-flying insects. There are several species of
stinkhorns in the northern United States, but up to the present
time I have seen only three in Minnesota, one of which has a
veil. It is quite certain, however, that others occur. The only
way of eradicating them from a lawn, where they are offensive
objects if produced in large numbers, is to dig up carefully and
remove the underground portion, for if this is not done the
plant will offer its repulsive fruits year after year.

Truffle puff-balls. Some plants, not very distant relatives
of the carrion fungus, produce their fruit-bodies entirely under-
ground. Such forms may be described as subterranean puff-
balls. They are not unlike the well-known truffle of the mar-
kets in outward appearance, but are widely different in struc-
ture. A few of them have been found growing in Minnesota
woods. Dogs or pigs can be trained to dig them, finding them
by their odor, and, indeed, this is the method which is used by
truffle-hunters in the woods of Europe.

Puff-balls. More familiar by far to the ordinary observer
than these underground forms are the puff-balls which are so
common in fields, pastures, woods and meadows throughout
the state. A very considerable number of varieties of puff-
balls may be found by any one who looks for them and is a close
observer. One variety abundant in plowed fields, where it grows
among the stubble after a corn or wheat crop has ripened,

68

Minnesota Plant Life.

is the stalked puff-ball. This plant is distinguished by a gray
stalk a quarter of an inch in diameter and two or three inches
high. At its top is developed a little flattened spherical blad-
der, perforate in the middle, within which are innumerable
brown spores. If the skin is squeezed the spores puff out at
the top like so much brown smoke, hence the common name,
puff-ball, which is applied to this plant and its relatives.

Other puff-balls have not the same slender stalk that has just
been described. Several kinds are more or less pear-shaped,
standing with the small end downward and variously marked
in the different species. One variety is nearly smooth while
another is covered with ._,

tiny warts of different
sizes, sometimes arranged
in patterns over the sur-
face. In others the sur-
face is spiny and some-
times the spines occur in
little clusters, with their
tops drawn together like
the stems of corn when
in the shock. If one of
these puff-balls be cut
lengthwise it will be seen
that the lower part is
spongy in texture and
does not produce spores,
so that this portion may be regarded as a short, thick stem.
The upper portion, however, produces an abundance of spores
which are ejected through an aperture in the ordinary manner.

Still other puff-balls have no stalks, but the whole fruit-body
is a bladder filled with spores and some of the commonest of
all Minnesota puff-balls belong to this division. They are
found abundantly in fields and pastures and, when ripe, are flat-
tened dark purplish or plum-colored bodies from a quarter of an
inch to an inch in diameter. The whole inside of one of these
fruits consists of a fluffy mass of spores and threads — the dried-
up stems upon which the spores develop. In the woods a stem-
less puff-ball is found of a lighter color, growing often as large

FIG. 23. Warty puff-ball. After I^loyd.

Minnesota Plant Life. 69

as a turkey's egg. Both this and its smaller relative of the pas-
tures open somewhat irregularly at the end away from the
ground, or perhaps at the side. Among the short-stemmed
puff-balls two or three large varieties are found ; one, the giant
puff-ball, occurs larger than a man's head and almost spherical
in shape, while another is in outline somewhat like a dinner bell
with the mouth closed and mound-like.

Earth-stars. An interesting variety of puff-ball is the earth-
star. This has an outer skin that splits radially, as one peels
an orange, revealing the inner skin that encloses the spores.
The little mouths of the earth-stars are nicely protected by a
group of bristles which, by their sensitiveness to moisture, as-
sist the distribution of the spores under conditions which are
favorable for their germination.
Apparently the use to the plant of
splitting back the outer skin is the
additional height that it attains
from which its spores can be dis-
tributed. The points of the sec-
tions which have split bend under
and lift the central ball a half inch
or more into the air, and the spores
have an added opportunity of catch-
ing some wind current, which, if
they were closer to the ground, FlG- 24- Tufted Puff-ba11- After

Uoyd.

might not distribute them so far.

Slitted puff-balls. A rather large puff-ball with a short stalk
and a white egg-shaped head is sometimes found in fields and
door yards, the small end of the egg pointing upward and the
large end hanging down over the stalk which seems to grow up
into a depression there. These puff-balls open by slits close
down to the stalk, and the interior is found to be occupied by
irregular, broken, brown plates, radiating vaguely from the
stalk-region somewhat like the gills of the mushroom.

BircTs-nest-fungi. Among all the puff-balls few are more in-
teresting objects than the little bird's-nest-fungi. There are
three sorts of these common in Minnesota. None of them is
very large for they do not exceed a quarter to a half inch in
diameter. They are often seen growing on the planks of old

70 Minnesota Plant Life.

sidewalks, in the cracks, or they may be found attached to twigs
or bits of decaying wood. Each fruit-body is shaped like a vase
or bowl, at the bottom of which half a dozen white or purple
egg-like bodies are lying, so that it has the appearance of some
tiny nest with eggs, hence the popular name which has been
applied. If one attempts to pull out the "eggs" it will be found
that each of them is flattened like two watch crystals placed
together and is attached by a delicate cord growing from the
"nest" and fixing itself upon the middle of one side of the eggs.
It must be understood that the term "egg" as used here, and as
used also for the young stinkhorns, should not suggest that such
bodies have any of the real meaning of an egg, since it is applied
solely on account of their shape. In the bird's-nest-fungus each
"egg" is a miniature puff-ball, with spores enclosed within its
membrane, and the whole bird's-nest-fungus fruit-body might
be described as comparable to a little group of stemless puff-
balls enclosed in a common vase or urn.

Hard-skinned puff-balls. Yet another sort of puff-ball is
readily distinguished by its hard nut-like shell. Such plants are
called hard-skinned puff-balls and some kinds of them grow to
be larger than an ordinary coffee cup. They are white or brown
in color and almost spherical in shape. When they open to eject
their spores the whole top splits by four or five radiating clefts,
and the sections of the shell curve back from the centre some-
what as did the outer skin of the earth-star. As they separate,
the fluffy spores and threads of the interior are exposed as an
umber mass upon which the wind has an opportunity to play,
thus carrying off the spores to other favorable regions for devel-
opment.

Ball-tossing puff-balls. In some respects more remarkable
than any of the others is the ball-tossing puff-ball. This is a
small variety, not larger than an ordinary pill, but a little larger
than the pellets of the homeopathist. It occurs in clusters upon
decaying wood and looks somewhat like slime-mould fruit only
it has a more leathery skin, and would be recognized upon close
observation to be different from the slime-mould fruits in out-
ward appearance as well as in inward structure. The ball-toss-
ing puff-ball has three layers of skin, one outside of the other.
The two outer skins become perforate at the end of the ball,

Minnesota Plant Life. 7 i

exposing the third and innermost skin which remains intact.
The hole enlarges so that there comes a moment when the in-
ner skin lies like a base ball in a tea cup, surrounded by the two
outer skins which have taken a vase-like form. Very suddenly
the middle skin separates from the outer skin everywhere ex-
cept at the edges and inverts itself with explosive force. It is
as if the lining of a porcelain kettle should turn inside out. By
this means the little ball at the centre may be projected several
inches into the air as if shot out of some tiny catapult. In this
way the whole mass of spores enclosed in the inner skin is
thrown to some distance from the point where the parent plant
developed, thus adding to the favorable chances of the species
in distribution.

Chapter X.

Yeasts, Morels, Cup-fungi and Truffles*

All of the higher fungi which have been described, enjoy
one character in common ; their spores are produced upon
stalks. No matter how various the form of the fruit-body may
be, in this one respect all the different varieties agree. The
group of higher fungi now to be considered is marked by the
production of spores in sacs, hence they all pass under the gen-
eral name of sac-fungi.

Yeasts. One of the most simple forms is the yeast plant,
familiar to housewives and brewers the world over. Yeast, as
most people know, is a culture of fungi developed upon malt
and hops and then transferred to various substances for
purposes which differ in the different arts. In bread-making
the value of the yeast lies in its power of liberating carbonic-
acid-gas while it is growing in the dough. When a cupful of
yeast is placed in a baking of bread and the dough is set away
in a warm place beside the stove, the yeast-plants feed upon the
substance in the dough and as they grow and reproduce they
create among other waste products, carbonic-acid-gas and alco-
hol. When the bread is kneaded and allowed to stand again
before placing in the oven, the kneading serves to distribute the
yeast-plants evenly through the loaf and they continue to grow,
forming bubbles of gas and small amounts of alcohol. When
the lightness of the bread is assured the loaves are placed in the
oven and the heat which is applied kills all the yeast plants, but
the bubbles of gas have done their part in leavening the loaf.

In brewing, it is not the gas which is deemed so desirable,
but the alcohol, and the yeasts are permitted to develop until
the proper percentage of alcohol has been introduced. The
hardening of cider, the fermentation of wine, and a variety of
other processes are equally the result of fungus growth. Yeasts

Minnesota Plant Life. .-

are sometimes impure or "bad" as the saying is. This is owing
to the mixture with the genuine yeast of other fungal organ-
isms, which liberate other and often undesirable substances.
For example, certain acids are produced through the activity of
yeast-like plants, and if such acid-forming yeasts are present in
sufficient quantity, the bread or the beer becomes sour. Hence
the cultivation of pure yeast is a prime necessity and when the
housewife or the brewer finds by experience that yeasts in use
are no longer pure, a fresh supply must be obtained from a
neighbor or in the market.

Yeast is a widely distributed plant and will often appear
as if spontaneously, just as black mould does when a substance
suitable for its development is exposed to the atmosphere for a
sufficient length of time. The yeast-plant itself consists of thin-
walled, egg-shaped cells which have the power of budding.
Somewhere the wall bulges and the bulge enlarges until it is the
size of the parent cell. Thus a branching body can be built up,
but the branches and buds readily separate from each other
and in a favorable condition of temperature and food supply
the growth of the plant is extremely rapid. When the yeast-
plant forms spores, which it does not do very abundantly under
ordinary conditions of growth, the contents of one of the egg-
shaped cells will be seen to divide into four portions each of
which becomes spherical in form and secretes about itself a wall
of its own. Then, when the wall of the mother-cell breaks down,
the spores separate from each other and may be distinguished
from the ordinary yeast-cell by their smaller size, spherical
shape and thicker wall. It is on account of their thicker wall,
and probably, too, in consequence of some difference in the
structure of the living substance within that they are able to re-
sist the harmful influence of extreme temperatures much better
than the ordinary yeast-cell. If the conditions favorable to
rapid growth become for any reason unfavorable, the yeast plant
is likely to undertake the formation of spores.

The particular substance that yeast attacks is cane-sugar.
This it splits up, during its life-processes, into carbonic-acid-gas
and alcohol. Such a process is called fermentation, or more pre-
cisely, alcoholic fermentation, because there are various kinds
of fermentation which go on under different circumstances

74

Minnesota Plant Life.

through the activity of different organisms. The peculiarity of
the yeast plant is its capacity for setting up alcoholic fermenta-
tion and no other kind.

Besides the common yeasts a number of others exist. One
kind which grows in cabbage, after it is cooked, produces the
substances which give the flavor of sauerkraut. Another kind
when introduced into milk causes it to ferment, and in the re-
gion of the Caucasus is used by the Tartars to change goat's or
camel's milk into an intoxicating liquor.

Plum-pockets. Very
closely related to the yeasts
is a group of parasitic fungi
capable of attacking a va-
riety of plant-tissues. One
kind, when it infects the
young fruits of the plum or
cherry produces what is
known as plum-pocket.
When such a fungus grows
upon a plum it distorts it
and gives it a singular, ir-
regular baggy appearance
which is easily recognized.
The poplar trees in Minne-
sota are very often attacked
by a pocket-fungus, which
changes their green pods
into yellow sacs distinctly
larger than the ordinary
pod. On cherry trees, a
witch's broom formation in
which the growth of the
twigs is disordered, results from the presence of a fungus of this
group, and upon alders another witch's broom arises under sim-
ilar conditions.

Morels. In the sac-fungi which have been described no
conspicuous special body is developed ; but in the higher forms
large bodies, rivalling the mushrooms in size, and of a great
variety of form and structure may be produced. Of such, one

FIG. 25. Pocket-fungus on sand-cherry. After
Bailey. Bull. 70, Cornell Ag. Kxp. Station.

Minnesota Plant Life.

75

of the best known is the morel. This superficially resembles,
to some degree, the stinkhorn. It grows upon the ground
and the fruit-body consists of a hollow, cylindrical stem, some-
times three or four inches in
height and an inch in diameter.
The texture, however, is much
firmer than that of the stink-
horn stem and the cap upon
the end, though wrinkled like
the stinkhorn cap, is continu-
ous with the stem and not
slimy nor vile-smelling. Mo-
rels are edible and are said to
be especially prized in Bohe-
mia. They are often found
growing in Minnesota woods
and upon Minnesota hillsides,
where their fruit-bodies, unlike
those of the stinkhorn, ripen in
the spring. If one should ex-
amine under a microscope a
thin section cut through the
wrinkled surface of the cap, it
would be perceived that it con-
sists almost entirely of sacs, in
each of which eight oval spores
are produced in a row. Each
sac is cylindrical in form and
not much larger in diameter
than the spores which fill it.
When ripe the ends of the sacs
break or dissolve and the
spores pour out one after an-
other, but they are not, as was
the case in the stinkhorn, uni-
versally carried away by insects, for they depend rather upon the
wind and the rains for their distribution.

A number of plants closely related- to the morel may be dis-
tinguished by the different shapes of their caps. In one the cap

FIG. 26. A morel fruit- body.
After I^loyd.

76 Minnesota Plant Life,

is saddle-shaped ; in another somewhat urn-shaped ; in a third
the whole fruit-body is club-shaped and closely resembles some
forms of the club-fungi which have been described above. In
some the cap is peculiarly coiled and twisted, looking like a
knot of angleworms. The colors of these plants are various —
white, brown, slate-colored, yellowish, pinkish or red. They
occur sometimes upon much decayed logs, but the majority of
them are terrestrial. A few are of an almost gelatinous con-
sistency but a greater number have, to the touch, rather the feel-
ing of cartilage. Several of them besides the morel are edible

FIG. 27. Cup-fungi growing on decaying twig. After I^loyd.

and I do not know of any that are violently poisonous, although
from their texture, a number of them would scarcely be attrac-
tive.

Cup-fungi. Not a distant relative of the morel is the cup-
fungus, which in its numerous varieties is doubtless familiar to
many of the readers of this volume. A dark slate-colored spe-
cies of cup-fungus is abundant in Minnesota woods in early
spring and produces cups an inch or more in diameter. If one
cuts such a cup in two and looks at the cut surface it will be
found that the whole fruit-body has a distinct lining like a por-

Minnesota Plant Life. 77

celain kettle. The lining-layer is made up entirely of sacs and
accessory threads running parallel with them. All of the sacs
are cylindrical, slender and arranged perpendicular to the inner
surface of the cup, while in each sac there are eight spores, ovoid
in shape and developed in a row just as in the morel.

Another kind of cup-fungus is scarlet, almost as large as the
one just described and equally familiar to most persons who go
into the woods with open eyes. Besides such large cup-fungi
there are a great number of smaller kinds, some of them grad-
ing down to the size of a pin-point, while between these and the
large ones are all sorts of intermediate sizes. They differ too
in color and in form and many of them are saucer-shaped, or
merely flat discs, circular in outline. Such small discs of a
bright yellow, or bright red color, are abundantly produced
upon decaying wood and leaves.

In distinguishing the different kinds of cup-fungi the char-
acter of the margin should be observed. This is sometimes
furnished with bristles or scales ; sometimes it is smooth ; some-
times it is rolled back, or it may be rolled in over the centre of
the cup, disc or saucer. It is not possible, however, to recog-
nize exactly all the different cup-fungi without an examination
of their spores, for special sorts develop special kinds of spores
in their sacs. Sometimes the spores are without partitions,
while in other instances they are divided into little chambers.
They may be smooth or provided with knobs, spines or emer-
gences. Growing in the same layer with the sacs are com-
monly to be found much slenderer threads, which help to keep
the sacs moist while they are developing their rows of spores.
When the cup-fungus has matured its spores, the ends of the
sacs — which all lie at the same level in the surface of the cup-
lining — open or dissolve, and the spores are then thrown out.

One kind of cup-fungus which is common on manure-piles
has a special explosive method of ejecting its spores. If such a
cup is taken between the finger and thumb, held to the light and
pressed gently, the sacs all open at once and violently eject their
spores, so that for an instant a little wreath of smoke seems to
fly from the top of the cup. This phenomenon is caused by a
cloud of several thousand spores escaping simultaneously. The
spores in certain species are net individually shot out from the

78 Minnesota Plant Life.

surface of the cup, but rather the sacs themselves with the spores
enclosed.

A particular variety of cup-fungus, very abundant in the
woods of Minnesota, grows upon the ground and produces a
hard, black underground tuber, as large as the end of one's
thumb. This tuber has a firm skin, but when it is cut open the
interior is softer and white. A bud forming under the skin of such
a tuber develops a fruit-body, cup-like in shape, and provided
with a slender stalk. A relative of this fungus produces on the
twigs of tamaracks nut-like swellings from which little cups
arise.

Maple-leaf tar spots. A great variety of cup-fungi and disc-
fungi are parasitic upon the leaves of growing plants. Possibly
the most conspicuous one in Minnesota is the tar-spot fungus
of the maple, often seen developed on the upper surfaces of
maple leaves as one or more black shiny bodies, a quarter of
an inch or so in diameter, and of an irregular roundish shape.
These are the fruit-bodies of the tar-spot fungus, and while the
vegetative portion of the fungus is growing within the tissues
of the leaf, the reproductive portion, consisting of a layer of
sacs with spores enclosed, destroys the epidermis of the leaf and
produces the conspicuous spot.

Truffles. The fruit-bodies of a few sac-fungi are developed
underground and here belong the truffles, which may be de-
scribed in a general way as underground cup-fungi, in which
the cups have closed up into irregular egg-shaped bodies. Upon
the rotting of the truffle the labyrinthine sac-layers are exposed
and the spores escape. Truffles are among the most esteemed
delicacies of the gourmet.

Green and blue moulds. Curiously enough the green and
blue moulds which occur on bread, leather, decaying fruits and
other objects of that sort are rather close relatives of the truffles.
As was observed during the description of the rust-fungi, a
fungus often has the power of producing more than one kind
of fruit-body. The blue mould — if for a sufficient time left to
itself — will form in addition to the ordinary patches of blue
spores arranged in chains on swollen terminal cells of some of
its threads, also certain miniature yellow truffles, not much
larger than a pin-point. These little truffle-like fruits, just as

Minnesota Plant Life,

79

happened in the study of the rust-fungi, were supposed orig-
inally, by botanists, to characterize entirely independent plants,
but it is now known that the blue moulds and their relatives
the green moulds can, under suitable conditions of growth and
nutriment, produce the sac-fruit-bodies. Thus it is apparent
that in the ability to form such tiny orange-colored "truffles"
they are quite unlike the black mould which had no such ca-
pacity. The general plant-bodies of the different sorts of
moulds and their general life-habits are, however, very similar,
so that popularly they are all included under the same name.
Botanically, black moulds and blue moulds are quite distinct.

Chapter XI.

Blights, Black Fungi and Root-fungi*

Blights. There remains to be considered a large group of
sac-fungi, which from the color of their fruit-bodies are classed
together under the name of black fungi. Very good examples
of the black fungi are furnished by the blights which occur on
the leaves of the higher plants. As a type, may be selected the
lilac-blight, which in autumn forms a white scurf on lilac leaves.
This scurf is the vegetative body of the blight and consists of
a cobwebby mass of delicate, white, branching filaments, some
of which penetrate the tissues of the leaf, while others spread
themselves over its surface. If one, in the autumn, looks closely
at a blighted lilac leaf it will be discovered that there are pres-
ent on its surface a great number of tiny black specks which by
the naked eye can be seen to have a spherical shape. These are
the fruit-bodies of the blight. Within the black skin of each,
sacs are formed, much as in the truffle, and in the sacs spores
are produced. The fruits of the blights are many of them re-
markable for their development of peculiar anchor-like append-
ages which grow out from the surface. In the lilac-blight
these appendages are branched in a regular fashion forming at
the ends a series of curved prongs. The willow-blight, on wil-
low leaves, has the ends of its fruit-appendages hooked and such
blights are called hooked blights. The blights common on
grass leaves in autumn and causing portions of the turf to look
as if a little whitewash had been spilled upon it are supplied
with fruit-appendages which are not hooked or branched at the
end. In another sort of blight the appendages are sharply
pointed like thorns.

Toadstool-blight. A few of the so-called black fungi belie
their name, for instead of black, their color is rather yellowish

Minnesota Plant Life. 81

%

or red. Here may be included a curious fungus which is par-
asitic on toadstools. When a toadstool is affected by this par-
asite the gills are all destroyed and the area they occupied pre-
sents a pimply red surface. The pimples are small, about the
size of a pin-head, and in each of them is developed a mass of
spore-sacs. Such a plant illustrates the tendency of what were
independent fruit-bodies in the truffles, the blights and the blue
moulds, to aggregate themselves into layers. Such layers are
in higher forms of black fungi variously disposed over branch-
ing or swollen bases, so that a large compound fruit-body is
developed.

Ergots. A good example of an interesting black fungus
with a compound fruit-body is the well-known ergot of rye.
Ergots occur, however, upon other plants than the rye, and,
for instance, a very interesting kind is found in the fruiting
panicles of the wild rice. The life-history of an ergot is about
as follows : The plant-body develops within the tissues of the
grass and when the grass is ready to set its fruits, the ergot
plant, somewhat after the manner of smuts, produces in some
of the .kernels, a dense network of filaments, occupying the
place of the grain. The ergot does not here, however, form its
spores as the smuts do, but gives rise rather to a tuberous
propagative body, consisting of a softer white interior, with a
black shell and exactly comparable to the underground tubers
formed, as mentioned above, by one kind of cup-fungus. Such
ergot tubers take about the same shape as the rye kernel, finally
falling out from between the chaffy scales of the rye and lying
dormant over winter. In the spring, buds arise under the skin
of the tuber and grow out into little slender threads and at the
end of each a more or less spherical swelling appears. The sur-
face of the swelling is occupied by a layer of ergot fruit-bodies,
in each of which a group of slender sacs, with long jointed
spores, is developed. It should be added that other sorts of
spores, ovoid in form, are produced upon wrinkles at the surface
of the propagative tuber, so that as in so many other fungi,
there are here two kinds of spore-cells. Either variety of spore
falling upon the proper host plant will infect it and initiate the
development of a new ergot plant-body.

7

82

Minnesota Plant Life.

Ergot is of considerable commercial importance on account
of its tubers, which form certain alkaloids used in medicine.
Of fungus alkaloids there is a considerable group, of which
those in poisonous mushrooms, poisonous pore-fungi and er-
got-tubers are examples. Ergot in rye sometimes occurs in
sufficient quantities to poison persons or animals that eat the
grain and where rye-bread is a staple article of diet it is neces-
sary to remove the ergot-tubers before the rye is ground into
flour.

Caterpillar fungi.
Very closely related
to the ergot is a small
group of fungi which
live parasitically in
caterpillars and other
insect larvae. Some-
times on mossy banks
one will notice a little
reddish-yellow, pimply,
club-shaped body ris-
ing up among the
mosses and an inch or
more in height. If
this is carefully pulled
out from between the
moss-plants it will be
found to spring from
the body of some dead
caterpillar or other in-
sect. The plant-body
of the caterpillar-fun-
gus grows within the

tissues of the insect and forms there a tuber-body similar to
that of the ergot. From this a bud develops into the club-
shaped stem over the end of which, and covering the sides,
a layer of somewhat bottle-shaped fruit-bodies is produced.
One kind of caterpillar-fungus has its compound fruit-body
branched, so that the unfortunate caterpillar seems to be carry-

FlG.

I,eaf-spot disease caused by fungus.
After Halsted.

Minnesota Plant Life. 83

ing upon its head an elkhorn-like protuberance three or four
inches long. A remarkable variety of caterpillar-fungus has a
slender tongue of sterile tissue projected beyond the end of the
fruit-body area.

Leaf-spot-fungi. Among the black fungi a considerable
number form what are known as leaf-spots. Very often on
leaves little pale areas develop, not infrequently surrounded by
a reddish circle. This red circle is caused by a secretion of red
coloring matter by the leaf, owing to the irritation occasioned

FIG. 29. I^eaf-spot fungus growing on pear leaves. After Duggar. Bull. 145, Cornell Ag.

Kxpt. Station.

by the spot fungus. The pale centre of the red circle is the in-
jured portion of the leaf, where the fungus has destroyed the
cells and devoured the particles of leaf-green. If in autumn one
looks very closely at a leaf-spot he will generally be able to see
the tiny black fruit-bodies of the fungus. Usually they are
separate from each other as in the blight, but a considerable
proportion of them are blended together in layers, as was de-
scribed for the much larger fungus, parasitic on the toadstool.

84 Minnesota Plant Life.

There must be at least a thousand different kinds of leaf-spot
fungi growing in Minnesota. Not all leaf-spot fungi are cer-
tainly black fungi; but the great majority of them belong to
that group. Neither do all leaf-spot fungi develop fruit-bodies,
for some of them are able to form only a simpler sort of spore-
cluster. Yet in most instances it is believed that this is because
the fungus has abandoned for some reason the formation of
true fruit-bodies. As already observed in the account of the
wheat rust — a most instructive object of study — a fungus may
acquire the habit of developing one kind of fruit-body upon
one leaf and another kind upon another. It is very probable,

FIG. 30. Fungus spot-disease of strawberry leaf. After Bailey. Bull. 79, Cornell Univ. Ag.

Expt. Station.

v/here leaf-spot fungi fail to develop their ordinary fruit-bod-
ies and provide themselves with spore clusters, that they
may on other plants develop the true fruit-bodies, or that
they have, as is often probable, ceased altogether to produce
them.

Not only do these spot-fungi find pasture upon the tissues
of living leaves but closely related forms browse upon old pieces
of paper, upon straw, leather, decaying cloth, the shells of nuts
and seeds, and even upon such curious fields as the inner sur-
face of roasted chestnuts, the feathers of fowls, the hair and
hoofs of cattle, and, in short, wherever they can find food-ma-
terials suitable for their growth.

Minnesota Plant Life.

Twig-fungi. A large group of black fungi grow upon twigs
and these may be known generally as twig-fungi. One of the
most prominent forms is the black knot of plum and cherry
twigs, a plant which is very common upon various species of
wild plums in Minnesota, and upon the wild choke-cherry.
It forms black swollen bodies, half an inch or so in height!
and two or three inches or more
in length, distorting the twig
where it grows, and bursting the
bark to display its layers of black
fruit-bodies. A close examina-
tion of a black knot mass will
show that its surface is covered
with little round emergences or
pustules, and each emergence
marks the point where a bottle-
shaped fruit-body is imbedded in
the general layer. As before no-
ticed, each fruit-body contains its
lining of sacs in which the black
knot spores are found — for the
elaboration of which the plant-
body derives sufficient s u s t e-
nance from the cells of the twig
which it robs of its sap. The
black knot is but a single exam-
ple of a large group of black
twig-fungi. Some of them like
the black coin-fungus form coin-
shaped discs. Others develop a
few little gourd-shaped fruit-
bodies in a group. One curious kind of which there are in
different parts of the world about 400 species known, forms on
twigs little black patches in which three or four fruit-bodies are
imbedded, one of the group being entirely different from the
rest. The central one, in its bottle-shaped cavity, produces
spores displayed on stalks, while the others produce spores de-
veloped in sacs. The spores produced on stalks are much

FIG. 31. Fungus spot-disease on leaf of
false Solomon's seal. After Hal-
sted.

86

Minnesota Plant Life.

smaller than the others. An explanation of this peculiarity may
be obtained from the behavior of the blue mould. It will be
remembered that in the latter kind of mould, spores were ordi-
narily formed on branches loosely distributed over the plant,
while at other times tiny orange truffle-like fruit-bodies arose
after the method of sac-fungi. Now if it can be imagined that
the loosely formed spores of the blue mould are aggregated to-
gether in a bottle-shaped structure, they lining the interior of
the bottle, there would arise a fruit-body like the peculiar cen-
tral one of the
plant in question.
The name of a
plant, which
forms these two
kinds of fruit-
bodies is Falsa.
Plants somewhat
related to the Val-
sas are found on
butternut twigs
where they form
little low black
mounds.

Staghorn-fungi.
The last black
fungus that needs
consideration in
this general
survey of the im-
portant types is
sometimes called

the staghorn-fungus. It grows upon stumps, decaying timbers,
sometimes on rafters in cellars, or in damp places about barns
or granaries, and is a very curious looking object indeed. It
is often three or four inches in height and shaped much like one
of the antlers of a moose. Its whole surface is warty and black,
each pustule marking the position of a fruit-body The interior
of the plant is white and consists of a very densely tangled skein
of threads. A smaller species is unbranched but stands up like

FIG. 32. Fungus spot-disease on pear. After Duggar. Bull.
145, Cornell Ag. E)xpt. Station.

Minnesota Plant

a little black Indian club an inch or more in height and a quar-
ter to half an inch thick through the thickest part.

The life of a fungus. There have now been passed in re-
view a sufficient number of fungi to give a fair idea of the group
as a whole. But the great variety of different species, and the
almost innumerable peculiarities of structure, form and function
which are possible, can scarcely be comprehended by any but a
careful student of the group.
Some general observations
concerning their lives de-
serve to be made.

Regarding their nutrition
this may be said — that they
are animal-like. Not one of
them has the power of mak-
ing starch out of gas and
water, as green plants have,
and all of them must obtain
organic substances from
which to construct their
bodies. In a great majority
the vegetative area is incon-
spicuous because it is con-
cealed in the sub-stratum
upon which the fungus lives.
The sub-stratum may be the
soil, a rotting log, a living
twig or leaf, a piece of pa-
per, the hair or feathers of
an animal or bird, a bit of
dung, or, for aquatic fungi,
various similar objects submerged in lakes, streams, pools or
springs. Concerning the reproduction of the fungi, it may be
noted that the higher forms commonly develop at least two
kinds of spores, one being entirely disconnected with the breed-
ing-habits of the plant, the other dependent upon the breeding
act — a process which often takes place upon areas concealed in
the sub-stratum. The rudiments of all true fruit-bodies, such
as those of the cup-fungus, the morel, the ergot, the cater-

FlG.

Fungus spot-disease of bean pods.
After Halsted.

88

Minnesota Plant Life.

pillar fungus, the black knot and all the other sac-fungi, arise
as a necessary consequence of some fusion of cells, equivalent
to that which took place in the black moulds. In the stalk-
fungi, to which group the mushrooms, puff-balls, club-fungi and
all their relatives belong, it is not so certain that a breeding-act
is always the necessary precursor of the fruit-body, but there is
much good evidence in
favor of such a supposi-
tion.

All of the fungi which
have been considered up
to this point may be re-
garded as derived from
certain of the lower algse,
while the bacteria — yet
to be discussed — are very
closely related to the
blue-green algae. The al-
gal fungi seem, for the
most part, to be connect-
ed with the pond-scums,
leading over to such
forms as the black mould,
or with the green felts,
leading over to mildews
and fish-moulds. It is
reasonable to suppose
that all of the higher
fungi which have thus far
been passed in review are
derived, by a continuous
series of improvements,
from the algal fungi.

Root-fungi. There are a few rather remarkable types of
fungi which should be treated separately. One of these is not
commonly known to make fruits of any sort, and, since botan-
ists depend upon fruit-bodies as the basis of their classification,
it is difficult to say where these fungi about to be considered
should be placed in the general system. They will be found

FIG. 34. Twig-fungus on currant canes. After
Durand. Bull. 125, Cornell Expt. Station.

Minnesota Plant Life.

89

encircling the roots of many kinds of trees or herbs, and some-
times developing within the outer tissues of roots or under-
ground stems belonging to plants growing in very rich soil.
An example of the first kind is to be met with on rootlets of the
tamarack. Another is found upon the rootlets of the oak, and,
often, too, upon the young roots of birches. Such fungi form
rather thin, felted masses inclosing the roots as in sheaths. The
sheaths become of a dark brown color as they grow older, but
at first they are almost white. So constant is the association
of the fungi with the roots or subterranean stems of some plants
that they may be regarded as necessary concomitants of these
higher plants. It is probable that they play a very important
part in the nourishment of roots which they inclose or infest.
It would seem that they have something to do with the conver-
sion of the food materials in the soil into a condition in which
they are the more easily absorbed and assimilated by the roots
themselves. If this suggestion, which is generally accepted
among botanists, is the correct one, there is presented the inter-
esting fact that all the tamarack trees in a swamp and all the oak
trees by the road-side are largely dependent for their life and
prosperity upon the little sheaths of fungi which feed their roots.
In a considerable number of plants the fungal threads do not
form a sheath around the outside of the root but grow in mi-
croscopic tangled masses resembling skeins of yarn, one mass
in each of certain outside cells of the root. The orchids of Min-
nesota are provided with such structures in their roots and the
Dutchman's pipe, the Pyrolas, and a number of other plants
which live in humus soil, resemble the orchids in this respect.
Sometimes underground stems among the orchids are, through
the irritation of the fungus in their outside cells, peculiarly knot-
ted and distorted into structures quite different from the ordi-
nary forms of growth. A very good example of this is the
coral-root orchid. Really this variety of orchid has no roots at
all and the underground portion is a curiously modified branch-
ing root-stock, which from its resemblance to coral, gives occa-
sion for the common name of the plant. There is good reason to
suppose that some of such underground fungus-masses which
enclose the roots of trees, or develop themselves in the roots of
humus plants, were originally the vegetative bodies of truffle-

90 Minnesota Plant Life.

like plants, and that on account of long association with the
roots they have abandoned their fruiting habits. Seemingly
they are able to maintain themselves without going to the
trouble of fruiting, and in a sense they may be regarded as form-
ing a partnership with the higher plants to which they have at-
tached themselves. They can scarcely be called parasites be-
cause their presence is not harmful to the higher plant, but,
rather, as has been explained, beneficial, because they enable it
to use substances in its nutrition which would otherwise be be-
yond its power to absorb from the soil. Among the bacteria
there are similar partnerships with higher plants, and they will
be considered in their place.

Ear-fungi. There are some other obscure forms of fungi,
such as the curious little necklace-like bodies, which sometimes
live in the ears and throats of birds and animals. They may
be considered as truly parasitic, but it is not easy to say exactly
where they belong in an orderly classification. Sometimes they
attack men and women and the bad habit of dropping sweet-oil
in the ear as a remedy for ear-ache may stimulate their growth.

Chapter XII.
Lichens and Beetle-fungi.

The life of a lichen. The group of plants known as lichens
is familiar to all observers. Some varieties are called gray or
hanging moss by persons who do not discriminate accurately
between these plants and the very different forms which are
rightly known as mosses. A still greater error is made in com-
mon speech, when the little hanging, gray, flowering plant, so
abundant in the south upon tree-branches, is given the name of
''Spanish moss." Lichens are found in a great variety of posi-
tions. They are exceedingly prevalent all over the world on
rocks, making characteristic patches on weathered cliffs, walls,
boulders, and pebbles, provided there be not some constant agi-
tation upon the surface of the rock, as by drifting sand or surf,
which might prevent their growth. They are seen very com-
monly upon the trunks of trees, usually preferring the side
toward the north. One characteristic lichen hangs from the
branches of tamaracks everywhere in Minnesota, and is some-
times called "old man's beard" from its gray color and thread-
like texture. Other varieties produce little patches on tree
trunks and they may be distinguished by their generally circular
form, by their flat habit of growth, and by their greenish, red,
yellow or gray color, which is very rarely a pure leaf green, but
varies more or less toward the other shades.

Stone-corroding lichens. Lichens upon stones are very
often so firmly attached that they cannot be removed, having
eaten their way into the stone by means of acids which they
secrete for that purpose. Curiously enough, a lichen which can
live upon limestone is not always able to live upon sandstone,
because it takes a different kind of acid to corrode limestone
from that which eats away the quartz of a granitic rock. A
great many of the lichens upon stones are not, however, firmly

92

Minnesota Plant Life.

FIG. 35.— Rock-lichens growing profusely in a glacial pot-hole. Near Taylor's Falls. After
photograph by Mr. E). C. Mills

Minnesota Plant Life.

93

attached, and such kinds may often, too, be found upon tree-
trunks, fence-rails, twigs or the roofs of houses. A true rock-
lichen does not commonly occur upon wood, so that different
series of forms will be found if one examines the different hab-
itats where these plants are wont to display themselves.

Structure of lichens. Lichens are very extraordinary plants,
or rather pairs of plants, for a
lichen is essentially a partner-
ship between a fungus and an
alga. Several different groups
of algae are employed in the
building up of lichen bodies,
especially the blue-green algae
—such as the water-flower—
and the bright-green algae. I
do not know of any lichens
which employ red or brown al-
gae in their partnership. Sev-
eral varieties of blue-green and
bright-green algae are con-
cerned, but a particular species
of lichen rarely exhibits more
than one kind of alga and one
kind of fungus in its partner-
ship-structure. As will be ex-
plained, such partnerships are
self-perpetuating, and the part-
nership comes to have the ap-
pearance and very much the
character of a plant-unit, so
much so, indeed, that for con-
venience lichens are generally
viewed as independent unit-
plants rather than as the
double organisms which in reality they are.

If one makes a very thin slice through the plant-body of a
lichen it will be found to consist of certain algal cells or fila-
ments quite able to propagate after their kind, and these en-
closed in a tangle of fungus filaments which are equally capable,

FIG. 36.— "Old man's teard." A lichen
growing attached to the twigs of tam-
arack. I<ake Superior, north shore.
Natural size, six inches in length. After
photograph by Professor Bruce Fink.

94 Minnesota Plant Life.

for the most part, of developing their special types of fruit-
bodies. In addition to the algal propagation which goes on
among the algae of the lichen-body, and the fungal spore-forma-
tion which characterizes the fungal member of the firm, there
is commonly a production, superficially, of little granules, con-
sisting of two or three algal cells with a web of fungal threads
around them. Such minute granules, which may, form a green-
ish dust over the surface of the lichen, are separated from the
region where they arise and serve as special partnership propa-
gative bodies.

By means of the algal growth which goes on in the lichen
body, the algal partner increases in size while it is protected by
its fungus neighbor. The fungus, too, grows, keeping pace
with the alga, and in this way the double organism increases in
size. When the fungus bears fruits — a process which in some
lichen plant-bodies occurs very seldom, and in a few forms ap-
parently never — the spores that are produced are in many in-
stances thought to be incapable of germination, and it would
appear that then the fungal partner has entirely lost the power
of existing independently of its alga. If the algae are removed
by careful methods from the plant-body they are usually able
to develop independently and could not under such circum-
stances be distinguished from the same kinds of algae living
their ordinary life in pools or moist places. There are, how-
ever, exceptions to this rule, and some algae when removed
from their long accustomed partnership do not find it easy to
continue an independent existence, though in no case are they
so helpless as may be the fungi. It must doubtless be as-
sumed that lichens began to exist by the attachment of certain
fungi to algae, and that such a relation proved mutually bene-
ficial. Under it the algae were protected from desiccation by the
presence of the moist fungus threads and the fungi were able to
absorb nourishment from the algae, which they in turn, by
means of their leaf-green, were able to manufacture from gas
and water. As time went on these partnership structures began
to improve along paths favorable to the more perfect work of
the partnership as a whole, and hence in lichens there have
arisen leaf-like bodies, and even little tree-like stems with leafy
expansions upon them — not at all an unreasonable course of

Minnesota Plant Life.

95

development, for clearly the problem of obtaining illumination
is much the same for a lichen-partnership that it is for an inde-
pendent moss or fern.

Lichen-fungi. The kinds of fungi which have formed a habit
of entering such lichen-partnerships are as various as the species
of algae. There are among them a few stalk-fungi, related
somewhat to the mushroom group, and when these fungi bear

FIG. 37. — A lichen growing upon a rock, and covered with the characteristic saucer-shaped
fruits of its fungus component. After Atkinson.

fruit, in the lichen-partnership, they produce their spores on
stalks in groups of four just as the mushroom does. Most of
the lichen-fungi are, however, sac-fungi, a few of which could
be classified among black fungi, but by far the greater number
in the group of the cup-fungi and the disc-fungi.

Kinds of lichens in Minnesota. There are probably some
500 species of lichens in Minnesota, and the total will rather
exceed this estimate than fall below it when the work of dis-
covery is completed. Among the simpler forms are a number

0,6 Minnesota Plant Life.

of little circular discolored patches found on bowlders and cliffs.
In the centre of such a discolored patch are scattered the irreg-
ular-shaped fungus fruit-bodies, in which are produced numer-
ous spores incapable of germination. In rock-lichens of this
sort the fruit-bodies are not exactly circular, as in the majority
of the group. The algae which are present are of rather higher
types than in some of the more complicated lichens. They be-
long to the class of bright-green algae, and sometimes branched,
filamentous algae are found in the partnership, while at other
times isolated green-slime cells are the rule.

Rock-lichens. The majority of rock-lichens in Minnesota in-
clude bright-green algae rather than blue-green, and the fungus,
when it fruits, produces a circular disc, reminding one exactly
of many of the cup-fungi. The centre of the disc is often va-
riously colored, red, black, yellow, blue, purple, pink or dull
green. The texture, too, of the lichen-body differs in different
kinds, for in some it is papery and thin, while in others it
may be brittle and encrusted. Again it may be leaf-like, or
gelatinous. In addition to the closely attached forms growing
upon rocks are certain loosely attached varieties — one very con-
spicuous species being held by a delicate stalk at the centre, and
then spreading out into a round flat structure the size of a pond-
lily leaf and much resembling a piece of leather. Related to
this form on rocks is a kind which is common among mosses,
producing a broad green, leaf-like expansion, but it may easily
be recognized as a lichen if it is turned over to reveal the white
fungus-like appearance of its under side.

Reindeer-mosses. Most remarkable of the lichens is the
reindeer moss which is so predominant a form of vegetation in
polar regions. There are a large number of different species
and for the most part they grow upon the ground. Reindeer
moss in Northern Minnesota often forms patches of hemispher-
ical shape and "as large as a bushel basket. Plants of this size
must be very old, possibly over a hundred years, for they grow
slowly and are of perennial habits. I have seen them most
beautifully developed on an island in Lake Saganaga, where
they covered the soil among the pine trees and I could not help
remarking that they seemed to be as old as the pine trees above
them, indicating what is rare in Minnesota, that the island had

Minnesota Plant Life.

97

never been touched by fire. Beside these large reindeer mosses,
which are the particular kind that bear that name, there are a
number of small relatives common along roadsides, on clay
banks and among mosses in the woods. One sort is called the
cigar-moss by children because of the flaming red ends of its
branches, while another might be mistaken for a cup fungus on
account of its vase-like form, but would be easily distinguished
by its grayish-green tint.

FIG. 38.— A tuft of "reindeer moss." Natural size, 2% feet in diameter. Age, probably over
one hundred years. North shore of I<ake Superior. After photograph by Professor
Bruce Fink.

A curious thing about the much-branched body of the rein-
deer moss is this, that it all belongs to the fruit-body area of the
fungus. The real vegetative body is a flat, rather insignificant
tract below, and instead of developing simple discs or cups upon
the surface of this body, it is the habit of the reindeer moss to
form much-branched cups which, unless one observes carefully
their elaboration, would scarcely be recognized for their true
significance.

Lichens are of much economic importance in the polar re-
gions where they are for animals and even for man, a staple arti-

gS Minnesota Plant Life.

cle of diet. Reindeer moss if cooked is edible, calling to mind
the blanc-mange made from the red seaweed, known by the
name of Irish moss or carragene, and previously alluded to.
Some also of the gelatinous lichens are edible, but none of them
is of any particular importance as an article of diet in Minnesota.

Black-fungi-lichens. A very few lichens, in which the fungus
partner is a black fungus, are known to exist, in Minnesota.
They could not be recognized by their outward appearance from
certain forms of the disc-lichens, but their fruit-bodies are little
black bottle-shaped objects in which the spore-sacs are pro-
duced, and are quite different from the open plates and saucers
of the more common varieties.

Lichen parasites. The study of lichens has been confused
by the presence upon their bodies of numerous kinds of parasitic
black fungi which really have no connection with the lichen
whatever, but merely come to attack it just as their relatives at-
tack the leaves and twigs of the forest. Yet when one remem-
bers that a portion of the lichen itself may be a black fungus, it
will be seen how puzzling might be the presence of a closely
related black fungus parasite, and it is not remarkable that some
of these parasites have been described as true fruit-bodies of the
lichen.

Lichen partnerships. Although there are a great many part-
nerships in the plant kingdom there is no group of organisms
where the principle of partnership has been carried so far as in
the lichens, for the combination-structures have taken forms
under the stress of their struggle for existence that neither of
the two component elements would have been at all likely to
assume if living independently. The reindeer moss, for exam-
ple, has become a little shrub, while the "old man's beard"
dangles its cylindrical stems and branches from tamarack bark
much as if it were a plant of higher degree, and the flat leaf-like
lichens which live among mosses spread themselves out to the
sun quite like some of the flat liverworts. Indeed there arises in
lichens a physiological division of labor in view of which areas
similar to those in higher plants must appear. The outer layer
of the plant-body is made up of fungus elements and serves as
an epidermis, resisting the evaporation of moisture. The next
layers underneath are crowded with algal cells and do the work

Minnesota Plant Life. gg

of starch-making for the partnership. The central layers in
cylindrical lichen-bodies are of a fungus character and perform
the office of conducting moisture. The whole double organ-
ism, then, is built upon the same physiological plan as are the
higher plants and has work to do which neither an alga nor
a fungus living by itself could well do on land. It is true some
algae, like the gulf-weed, develop leaves and branching stems,
recalling in their appearance the higher plants, but on land it
would scarcely be possible for an alga to adopt such a form,
while it would be unnecessary for a fungus, having no leaf-green
to illuminate, to assume structures essential to the requirements
of leaf-green at work. But when the two organisms have been
brought together into a partnership it becomes possible for this
partnership to assume forms and structures favorable for the
illumination of leaf-green, for the proper protection of it while
at work, and for the maintenance of a sufficient supply of water.
Beetle-fungi. The group of plants to which I have given
here the common name of beetle-fungi is so remarkable as to
deserve separate treatment. In structure the plants are extra-
ordinarily unlike any other fungi. They are certainly not un-
common in Minnesota, although from the peculiar places in
which they live they have never been brought in by collectors,
and, indeed, I have seen but a single specimen collected within
the borders of the state. It is their habit to attach themselves
by a tiny disc to the bodies of water-beetles and other insects
living in damp places. Some varieties of them are occasionally
to be found attached to the wing-cases of the little scurrying
beetles that get together and whirl about upon the surface of
quiet water. The plants resemble tiny brushes of camel's hair,
a sixteenth of an inch in length or less, and when examined
closely they have been found to be, in their structure, very much
like the red algae. Indeed, they might almost be taken for
red algae, which at some remote time had contracted the habit
of obtaining food without the aid of leaf-green. Yet, in the
details of their structure, in some respects they widely differ
from the red algae. The character in which they most resemble
the red algae is their method of breeding. Just as in the algae
the egg-cells are here provided with slender cylindrical projec-
tions upon which the sperm-cells fix themselves, thus fecundat-

ioo Minnesota Plant Life.

ing the egg and making the development of spores possible.
But when spores are formed they are not, as in red algae, pro-
duced on stalks, but in sacs, and in this peculiarity the beetle-
fungi resemble the sac-fungi. Taking all their qualities into
account it may safely be said that they are but distantly related
to the rest of the fungi and are entitled to stand in a group by
themselves. More than a hundred and fifty of, these curious
beetle-fungi are known, most of them from America, and it will
reward observers in Minnesota to search for them on the bodies
of aquatic insects and of insects living in damp places.

Chapter XIII.

Various Kinds of Bacteria*

The story of the bacteria is one of the most astonishing that
modern science has had to tell, and although they are the small-
est and simplest of all plants, I have thought it best to devote an
entire chapter to their discussion; — so many are the ways in
which they touch human life. In these days almost everything
is attributed in some form or other to a microbe, and when the
extraordinary character of these remarkable plants is appre-
ciated one is not surprised to read that some savant has dis-
covered the microbe of crime, the microbe of drunkenness or
the microbe of insanity, all of which have at various times been
heralded by the newspapers. While crime, drunkenness and in-
sanity are not the result of microbe activity, yet microbes actu-
ally serve in a number of capacities which at first sight seem
quite as impossible, and one can scarcely blame the public for
believing, as it does, almost anything that it is told about mi-
crobes, or for going to the other extreme and believing nothing
whatever.

What a microbe is. The term microbe, meaning "little liv-
ing thing," has been applied to some organisms which are not
bacteria, as, for example, the slime-mould-like creature which is
the cause of malaria, or the yeasts which have already been de-
scribed in the chapter upon the fungi. By far the greater num-
ber of microbes are bacteria, and bacteria themselves are very
lowly plants related to the blue-green algae, and to be consid-
ered, perhaps, as forms of this algal series which very long ago
abandoned their leaf-green and began, like the fungi, to make
their living in other ways.

Classification of bacteria. In size bacteria are the smallest
of living things, the least of them being less in diameter than
one thousandth of a millimeter, so that three hundred of them
could stand side by side across the dot over the letter "i." Oth-

IO2 Minnesota Plant Life.

ers of the group are comparatively much larger, the largest be-
ing barely fifteen-thousandths of a millimeter in diameter.
Sometimes they cling together in chains or threads thus becom-
ing filaments of considerable length. In form, bacteria are
either spherical, ovoid, cylindrical, twisted like corkscrews, or
irregularly shaped. They never possess leaf-green, though some
of them are capable of producing coloring substances of other
kinds. It is now impracticable to group the bacteria as was
done years ago into different species based upon form. The
older students called a spherical bacterium a coccus, an ovoid
bacterium kept its name, while a cylindrical-elongated form was
called a bacillus ; but it has been shown that one and the same
organism may successively assume the coccus, the bacterium
and the bacillus shape. To-day it is more common to classify
them physiologically, and there are recognized the following
principal groups, not including, perhaps, all of the forms, but
excluding only the unimportant ones. The groups are as fol-
lows:

A. Disease-producing bacteria: Of these there are two
classes; those producing diseases in animals and those produc-
ing diseases in plants.

B. Ferment-producing bacteria: Of these there are four
principal classes; those producing butyric acid, in which class
are included most of the bacteria of putrifaction ; those pro-
ducing lactic acid, including the forms which make milk sour, of
which there is a great variety; those producing alcoholic fer-
mentation, like the yeasts; and those producing vinegar fer-
mentation.

C. Heat-producing bacteria : Sometimes the cause of spon-
taneous combustion of cotton waste and the heating of ensilage
and hay.

D. Light-producing bacteria: To which is attributed in
part the phosphorescence of the ocean.

E. Color-producing bacteria : Including a variety of forms
which produce different sorts of coloring substances.

F. Nitrifying bacteria: Which fix atmospheric nitrogen.

G. De-nitrifying bacteria : Which decompose urea.

H. Sulphur bacteria: Which produce granules of sulphur
in mineral springs.

I. Iron bacteria : Which secrete iron rust or iron ores.

Minnesota Plant Life. 103

Substances formed by bacteria. Before presenting in de-
tail an account of some of the principal forms under each of
these groups, a few words may be said upon the general physi-
ology of the bacteria, which, if thoroughly comprehended, will
make clear how there may be a fundamental similarity in all the
apparently dissimilar processes dependent upon bacterial action.
Bacteria are living plant cells. As such they need food, and
absorb it, using it in their own way and excreting their waste
products which may be as various as the food substances, and
the methods of digestion. The waste products given off may
be solid, liquid or gaseous ; and among the substances excreted
are a great variety of organic compounds. From an economic
point of view the most important waste materials of bacterial
nutrition may be classified in three groups: i. Organic poi-
sons; 2. ferments; 3. nitrates or nitrites. For the moment,
consideration of the iron, sulphur and de-nitrifying germs is
omitted. If a bacterium secretes some poisonous substance in
the body of an animal or of man, the higher organism will be
poisoned just as if bitten by a snake. Disease-producing bac-
teria are principally those forms which, entering the animal
body, grow there, nourish upon its tissues and produce poisons
that are carried into the blood and, when in sufficient quantity,
produce death. Plants are subject to such bacterial poisoning
quite as much as animals. Pear-blight and potato-scab ; carna-
tion disease and cucumber-rot are well-known examples of
bacterial plant diseases.

Ferments. Ferments are peculiar organic compounds which
are remarkable for their property of initiating changes in other
compounds. A very little, for example, of the ferment which
is capable of converting starch into sugar, if put into a starchy
substance will transform thousands of times its own weight of
starch into the form of sugar. Nor will it be destroyed in the
process, for it seems to take into itself the starch on the one side
splitting off sugar on the other, but always remaining the same
although it produces very great changes in the substances upon
which it operates.

Nitrogen salts. Nitrates and nitrites are salts of nitrogen
which are demanded by most higher plants as indispensable ar-
ticles of food. Such organisms use scarcely any of the free nitro-

IO4 Minnesota Plant Life.

gen of the atmosphere. Further, they are able to assimilate am-
monia but sparingly, and such a nitrogenous compound as urea
is almost worthless as a food. Therefore, in three great fields
of interest to the human race, bacteria are active ; first, as causes
of disease through the poisons they secrete; second, as the
sources of ferments which are used in the various arts of brew-
ing, wine-making and the dairy, not to mention tanning, cigar-
manufacture, and a variety of technical processes which are de-
pendent upon the proper control of ferment-bacteria; third,
as fertilizers of the soil, where they live in countless billions and
under a variety of conditions play their part in fixing the nitro-
gen of the atmosphere in the form of salts to serve as food for
the plants of forest, field and plain.

Energy produced by bacteria. It should be remembered
that among the activities of living things not only are there
processes which result in the production of particular substances,
but sometimes, also, in the development of particular forms of
energy. Heat, for example, is a form of energy which arises
in the human body, as a result of its vital activity, and light
arises in the body of the glow-worm, in many fungi, and in a
large variety of marine animals. It is not, therefore, astonish-
ing that heat and light should be among the results of bacterial
activity, and it may, therefore, be comprehended how two such
apparently unrelated phenomena as an epidemic of smallpox and
the phosphorescence of the ocean should each of them be but
the results of bacterial growth and nutrition. In the one in-
stance, the waste products formed are substances belonging
to the group of organic poisons. Secreted in the body they
injure its tone and may even shatter its mechanism, causing
death. In the other, light is one of the results of bacterial ac-
tivity, just as in the physiology of the fire-fly, and when innumer-
able germs are floating at the surface of the ocean they may give
to it that faint, uniform illumination which is recognized as bac-
terial phosphorescence — a phenomenon which has been exactly
reproduced in the aquaria of laboratories by artificial cultures
of light-producing bacteria.

Substances and forces harmful to bacteria. Bacteria differ
among themselves in the kinds of food which they demand, in
the nature of the waste products which they produce, and in the

Minnesota Plant Life.

varieties of substances by which they are themselves poisoned.
Almost all of them are incapable of existing in direct sunlight.
Hence there is much sound scientific basis for the belief that
sunshine is healthful. Bacteria are destroyed when subjected
to the action of certain chemicals — of which corrosive sublimate
is the strongest germicide. Next to this, in general use, is
carbolic acid, an excellent compound to employ for disinfection,
like the one first named ; while a great number of other sub-
stances may be used in the destruction of bacteria. One of the
first methods resorted to in the history of the world was the
utilization of sulphur fumes by the ancient Romans to prevent
their grape-juices from fermenting. Singularly enough men
learned how to keep bacteria out of their wine long before they
practiced intelligently the important hygienic rules for keeping
bacteria out of themselves. Formaldehyde gas is a strong dis-
infectant and is much used. lodoform sometimes advertised as
a useful germicide, is of doubtful utility.

Not only is it possible to destroy bacteria by sunlight, and by
numerous substances such as corrosive sublimate and carbolic
acid, but in various other ways, principally employed in labora-
tories. The application of heat is a most important mode of
preventing the growth and development of bacteria, and is es-
sential to many processes by which it is desired to destroy or
prevent the appearance of bacterial life. Electric currents may
also be employed and are said to be in use in some distilleries
abroad, where wine is permitted to flow for a time in an electric
field, thus preventing the development in it of certain germs
which might be harmful to its flavor.

If, then, it be kept clearly in mind that bacteria have their
definite food requirements, their characteristic excreta, solid,
liquid, and gaseous, their enemies and their poisons, one is pre-
pared to comprehend a great variety of technical, hygienic, surg-
ical, medical, agricultural and other natural facts, which, until
the behavior of bacteria was known, could scarcely be explained.

Disease-producing bacteria. There may now be examined
the habits of some forms of bacteria in each of the groups named
above. In Minnesota there must be two or three hundred dif-
ferent kinds of bacteria. New varieties are being discovered,
one might say, every day, and no doubt a great number still

IO6 Minnesota Plant Life.

await investigation. But of the disease-producing group there
are some with which men are unfortunately only too familiar. I
may name three of especial interest, and valuable in the illus-
tration of different points. The diseases known as consump-
tion or tuberculosis, typhoid fever and smallpox are certainly
produced in the human body by three distinct species of bac-
teria, known respectively as consumption-bacteria, typhus-
bacteria and smallpox-bacteria. The contraction of any of
these diseases does not necessarily follow the entrance into the
body of the bacteria, for, in the first place the bacteria may
enter in a weak, non-virulent condition; in the second place,
they may be destroyed in the body in a great variety of ways
before they can develop and multiply sufficiently to do any
harm ; in the third place, they may find the body in a state which
would prevent their nourishment so that they would die of
their own accord. It is probably true that men frequently take
into their bodies harmful germs, which, under the beautiful
police-system of the blood, are snapped up by the white blood-
corpuscles and destroyed before they can accomplish any mis-
chief by their poison-secreting habits. That condition of the
body, in whatever way it should be explained, under which bac-
teria of a certain disease cannot grow, is called immunity, and
immunity may be apparently either inherited or acquired. Im-
munity to yellow fever seems to be inherited by certain classes
of people living in the tropics, but it may be acquired by persons
born outside the tropics after they have passed through the ex-
perience of acclimatization.

Contagious, infectious and invasive diseases. If, however,
one is not immune to consumption, typhus or smallpox, and the
germs of one of these diseases enter his system, and multiply too
rapidly for the white blood-corpuscles to destroy them, then
very soon what are termed the symptoms of. the disease begin
to appear and the patient has the disease, or rather, the disease
has him, for he is now the prey of an invading force of tiny fun-
gus parasites. Here a distinction must be made between three
types of bacterial disease which affect animals, and are known
as contagious, infectious and invasive diseases. A contagious
disease is caused by a germ which can ordinarily live only in the
body of the diseased animal or in that of some closely related

Minnesota Plant Life. IO7

form. An infectious disease is caused by a germ which may feed
and develop in the body of the animal, but habitually feeds and
develops in not-living substances, such as sewage, river-water
or the soil. Both varieties of germ are alike in one respect, that
they poison the body, for they secrete into it certain substances
known under the general name of ptomaines, comparable as has
been before said, to snake, alkaloid or albuminoid poisons. An
invasive disease is produced by the development, in the body, of
a germ which though not violently poisonous yet causes disease
through the multiplication of the bacterium itself. Smallpox is
an example of a contagious, typhoid fever of an infectious, and
lumpy-jaw in cattle of an invasive disease, though the germ
which causes the latter is scarcely a true bacterium. The cow
writh lumpy-jaw has the tongue and jaw leavened by the germ
much as though they were loaves of bread, but the animal is not
seriously poisoned and does not generally perish as quickly as
does an animal when attacked by some fatal infectious or con-
tagious disease like Texas fever, anthrax or hog-cholera.

Quarantine and sanitation. It is apparent that between con-
tagious and infectious diseases — the one produced by what is
called an obligatory parasite and the other by what is termed a
facultative parasite — demand widely different hygienic methods
of prevention. Against contagious diseases quarantine is the
great preventive, for if the person who is diseased can be kept
by himself others will not be affected. Against infectious dis-
ease hygiene is the great preventive, including here especially
what is known as sanitation. When one knows that dangerous
germs such as those of typhoid fever may develop and multiply
in garbage heaps, in sewage, in unfiltered river water, in neg-
lected reservoirs, in badly prepared foods and stale fruits, he
understands the importance of removing his garbage, attending
to his sewage, boiling his water and taking heed to his kitchen,
his ice-box arid his diet. All the methods of modern quaran-
tine and sanitation are intelligently prosecuted in the light of
an increasing knowledge of bacterial lives and habits.

Inoculation and vaccination. Passing from simple preven-
tive measures to somewhat more complicated procedure it be-
comes necessary to consider the processes known as inoculation
and vaccination. Inoculation is a name given to the intentional
and actual transference of the germs of a disease to the body,

io8 Minnesota Plant Lift.

and this under such conditions of general health that it is hoped
the patient may contract the disease, become acclimated to it,
so to speak, and thus avoid it at a time when his physical state
might not be so favorable to withstand it. In the old days this
means was adopted to diminish the mortality from smallpox and
is still practiced in China. Vaccination is a jiame given to the
injection, into the body, of a mild form of disease-bacteria;
because when the body thus becomes acclimated it is more re-
sistent to the virulent form. The remarkable discovery of Jen-
ner that cow-pox was a mild form of smallpox, and that after
vaccination had "taken," as the saying is, one would not then
easily contract the malignant disease, was the precursor of other
types of vaccination, such as those of Pasteur, who vaccinated
successfully with mild anthrax and mild hydrophobia, thus ren-
dering the vaccinated individual immune to the more virulent
types of these maladies.

Koch's lymph. Quite a different attempt to control such a
disease as consumption was that of Koch, whose famous lymph,
a few years ago, was much exploited in newspapers and peri-
odicals. It had been known for some time that the bacteria of
consumption could be cultivated outside the human body upon
a variety of substances such, for example, as beef-broth jelly.
Cultures of the consumption germ were made in this way by
Koch, and by means of glycerine an extract of their poison was
prepared. The extract of poison was then injected into the
body — a very different process from vaccination, because in that
case the germs themselves are placed in the body of the patient.
It had been observed that the consumption bacteria, like other
sorts, produced around the patches where they grew, excreta to
such an extent that they poisoned the tissues of the body and
limited the growth of their own colonies, which were unable to
absorb food from the poisoned tissue. Thus is explained the
habit of the consumption-germ of making tubercles in the lungs.
It was Koch's idea that he could, by means of his lymph, poison
the lung-tissues artificially, not enough to kill the patient, but
enough to prevent the bacteria from developing. In this effort
he was not entirely successful.

Serum therapy. Another and more hopeful method of com-
batting infectious and contagious diseases after they have begun
to develop in the patient, is supplied by the process known as

Minnesota Plant Life.

scrum therapy. In order to understand this it must be noticed
that the relation between bacteria and an animal which they are
infesting is reciprocal. Just as they poison the organism so do
certain compounds in the blood-serum poison them. The sub-
stances generated in the blood and poisonous to bacteria are
known technically as anti-toxins. Now acclimatization to
germ diseases seems to be in part, at least, due to a develop-
ment of anti-toxins in the blood-serum — that is, in the watery
part of the blood in which the corpuscles are suspended. So if
a horse or other animal be acclimated to a disease — diphtheria,
for example, — and then the serum from such an animal be in-
jected into the veins of a patient suffering from the disease in
question, a supply of anti-toxins is put in a position where it can
poison the disease germs. This treatment, indeed, has been re-
ported as successful for diphtheria — so much so, that if proper
serum is quickly obtainable, even a malignant case, taken in its
early stages, can be combatted. A time may be expected when
anti-toxins will have been discovered for all of the dangerous
germ diseases which kill annually so many hundreds of thou-
sands of the human race. Serum-therapy may be described as
a sudden acclimatization of the blood through the injection of
acclimated serum from another animal, and it is exactly com-
parable to the use of antidotes for ordinary cases of poisoning.
The antidote, however, is taken directly into the blood and not
into the stomach.

Diseases of animals and plants. Not only are men subject
to a large number of bacterial diseases, but also domestic ani-
mals, birds, fish, tiny water insects and crustaceans, or even
plants — and among the latter should not be omitted the bacteria
themselves, for it is well-known that some varieties are so in-
imical to others that they may produce a growth which will de-
stroy the original colony. Plant bacterial diseases, such as pear-
blight, potato-scab, cucumber-rot and carnation-blight are not
uncommon in Minnesota and considerable damage results from
their activity. No highly effective methods of combatting them
have as yet been devised. Plant-quarantine against infected
plants, plant-hygiene and sanitation and the selection of resist-
ant varieties represent about the extent of modern treatment.

Bacteria of putrifaction. Among the ferment-producing bac-
teria, those which convert organic substances into compounds

iio Minnesota Plant Life.

of which butyric acid is an important member, are concerned in
the processes known under the general name of putrifaction.
Sometimes it is advantageous to distinguish between putrifac-
tion and decay, both of which may be bacterial in their origin.
When an organic mass putrifies it gives off offensive odors, but
it may decay without such odors becoming noticeable. The
offensive stench of putrifaction indicates that butyric fermenta-
tion is taking place and this is produced by bacteria which work
in the absence of the free oxygen of the air. But the modifica-
tion of organic bodies, known as decay, proceeds when there is
an abundant supply of free oxygen for the bacteria. It should
be noted, however, that some forms of bacteria are unable to
live in the presence of free oxygen, while others are as depend-
ent upon its presence. The odor of putrifaction towards which
all have a feeling of repulsion, just as towards a snake lying
coiled in the grass, is caused by volatile ethers or ill-smelling
gases emanating from the putrifying mass. Such characteristic
odors are instinctively recognized by the human race as indica-
tive of danger— in this case due to the presence of bacteria. In
themselves, it is difficult to understand how one odor should be
preferred to another, but experience has taught to some extent
what odors may be presages of danger and what may not, hence
that natural repulsion when one is brought into contact with
those useful and necessary changes by which dead bodies are
converted into materials which can be used again in the round
of life.

Canning of fruits and other technical processes. Various
technical processes involve a control of the germs of putrifac-
tion. Among many examples is the canning of fruits, meats
and vegetables, where heat is applied to destroy the bacteria and
the substances are then sealed up in such a manner that bac-
teria cannot gain ingress. Milk, too, is sterilized or Pasteur-
ized, and preserved in bottles, a process in which heat may be
used, or chemicals, notably boracic acid. Other processes de-
pendent upon the exclusion of putrifying bacteria, are the salt-
ing of meat and fish, as when corned beef is prepared in vats
of brine, the smoking of fish practiced by the Indians in Min-
nesota, as well as by the whites, the smoking and drying of
meats, and all those in which cold is used as a preservative.

Minnesota Plant Life. 1 1 1

The refrigerator cars and cold-storage warehouses which are
such important features of modern civilization, making it pos-
sible for Minnesota dressed beef and dairy products to be
shipped even across the waters of the Atlantic, are purely de-
vices for limiting the growth of putrifactive bacteria by keep-
ing the temperature below a point where they can develop.

Bacteria in tobacco-curing. In the general group of putri-
factive fermentive processes should be mentioned one or two
which are not precisely like the others. For example, the "fla-
vor" of tobacco and cigars is largely due to certain waste prod-
ucts of bacteria grown <upon the tobacco while it is being cured.
The difference between a "good" cigar and a "bad" cigar lies
principally in the curing of the tobacco from which it is manu-
factured, and that is an operation in which bacteria take part.
A technical method has even been devised by which the Havana
bacteria have been cultivated, and it has already been applied
upon a small scale to tobacco-curing in Germany. As a result
of this process German tobacco, not at all the best, was con-
verted into qualities which could not be detected by experienced
smokers from the genuine Havana.

Tanning and retting bacteria. The tanning of hides is an-
other industry which is dependent upon the action of bacteria,
and likewise the separation of hemp and flax fibres in the vats
where they are macerated.

Bacteria in the dairy. None of these processes is so im-
portant to Minnesotans as those of yet another line of industry
in which bacteria play a necessary and extraordinary part. I
mean the dairy industries, for the successful production of the
best butter and cheese is as essentially dependent as is brewing
upon the proper control of bacteria. Even the "June flavor"
of butter has been artificially produced by careful control of its
bacterial content, while in one word, the difference between the
various brands of cheese, with few exceptions, lies in their bac-
terial flora. Edam, Neufchatel, Gorgonzola, Camembert and
Roquefort cheeses — distinct from each other in consistency,
flavor, and odor — largely depend for these qualities upon sep-
arate kinds of bacteria, which easily appear in the "natural
home" of each kind of cheese, because under such conditions of
climate and soil they may be produced in cheese without artifi-

1 1 2 Minnesota Plant Life.

cial inoculation. But a cheese made in Minnesota may be in-
oculated with Edam germs or Brie germs, and if the control of
its manufacture were as perfect as that which has been attained
through the researches of Pasteur in the brewing industry,
there would be little difficulty in sending out such choice prod-
ucts from any dairy in the world. Indeed, in Denmark, where
dairy industries have reached such high perfection, pure cul-
tures of Edam bacteria can be everywhere obtained and Edam
cheeses can be manufactured at will. The flavor of the cheese
and its odor come largely from ethers which are the result of
bacterial activity. Since certain bacteria produce certain ethers,
it is evidently necessary to keep careful control over the growth
in the cheese and through failure to do this, highly offensive
odors are exhaled by the cheeses of careless dairymen. This re-
sults from putrifactive germs gaining ingress to the mass and
such cheeses, without straining the language, may be called dis-
eased. A peculiar form of diseased cheese is the blown cheese
in which gas-forming bacteria produce bubbles large enough to
destroy the proper texture of the mass. Cheese may also be
soured by the presence of lactic-fermenting bacteria, as well as
by offensively-scented and undesirable butyric forms.

Ripening of cheese. One is now in a position to under-
stand the various processes described as the ripening of cheese.
After the cheese has been set away to ripen, and during this
process, there is opportunity for the growth of desirable bacteria
and moulds — for some kinds of cheese such as Stilton, are de-
pendent for their flavors largely upon mould. When a dairy is
manufacturing bad cheese it is evident that the "sanitation" has
been poor, or that quarantine methods should have been adopted
against offensive germs. Hence it is easy to understand how
necessary is cleanliness in the dairy, for the practice of cleanli-
ness includes both quarantine and sanitation.

Diseases of butter. All that has been said about cheese ap-
plies equally to butter, for the flavor of this product, including
both its taste and odor, is dependent upon bacterial activity.
Diseases of butter exist — of which rancid butter may serve as an
illustration.

Diseases of eggs, bread, milk and cigars. Many other arti-
cles of food or stimulants may be diseased in the sense in which

Minnesota Plant Life. i { 3

this term has been applied to cheese and butter. Eggs, for
example, while still in the body of the fowl, may become infected
with bacteria, and unless used within a short time after they are
laid they become stale or bad. The extremely bad smell of an
egg which has ptttrified is of bacterial origin and it is the same
little plants which are the sources of the gas that causes the bad
egg to explode when cracked. Bread, too, is sometimes af-
fected with diseases through which it becomes sticky or ropy,
and milk has a peculiar tendency to bacterial contamination.
Milk that gradually turns blue upon standing, or that gradually
turns red, or becomes filled with mucus, or that sours, or that
curdles, or that gives off offensive odors, is generally affected
by some disease. The so-called "turnip odor" of milk, popu-
larly attributed to the cow having eaten turnips, is more often
of bacterial origin than connected in any way with turnip roots.
Tobacco is generally diseased and the singularly bad cigars
which are everywhere encountered should be regarded as the
proper prey of germs and be made objects of quarantine.

Diseases of meat, cheese, vegetables and ice-cream. Dis-
eased canned meats, cheese, vegetables and ice-cream, not in-
frequently cause death to persons eating them, because such ma-
terials sometimes furnish a medium for the growth of bacteria
that secrete dangerous poisons.

Milk-souring bacteria. The ferment-producing bacteria
which have been hitherto noticed may be classed under the gen-
eral head of butyric-acid ferment-producing germs. Another
group of ferment-producing germs are those which occasion the
composition of lactic acid. This was- probably one of the first
acids known to the human race, for the shepherds of pre-historic
days, wrhen their milk turned sour, were observing the result of
lactic acid fermentation initiated by specific germs. To-day the
souring of cream and milk may be brought about artificially in
the dairy. Most butter-eaters prefer sour-cream butters, that
is, butter made from cream a little soured. Just as it is now
possible immediately to separate the cream from the milk by
centrifugal machines, without waiting for it to rise, so is it pos-
sible to sour it by inoculation with lactic acid germs without
waiting for spontaneous infection from the atmosphere. Milks

and creams soured artificially are used in a number of dairies.
9

U4 Minnesota Plant Life.

Fermented milk. Together with yeasts, there are lactic-acid
fermenting bacteria employed in the manufacture of the fer-
mented liquor made in the region of the Caucasus from goat's
milk and known as kephir. In Minnesota, while the souring
of milk is a natural phenomenon which has been observed by all,
I am not aware that fermented milks are commonly produced.

Milk-curdling bacteria. Different from the souring of milk
is its curdling, which takes place when rennet is placed in it.
Rennet types of fermentation may be initiated by bacteria, al-
though a more common source of rennet is the calf's stomach.

Souring of wine, beer, bread and ensilage. Lactic types of
bacteria are not only common in milk but in wines and beers,
so that in the brewing industry some sorts of souring which beer
undergoes arise from lactic-acid germs, while others are due to
vinegar-fermentation. The souring of bread by lactic fermen-
tation is not unknown and in the souring of ensilage and fodder
the activity of these bacteria is ordinary.

Vinegar-bacteria. Still another type of fermentation is the
vinegar-fermentation by which sugars, such as those of sweet
cider, are converted into acetic acid, commonly known as vine-
gar. In the manufacture of vinegar the activity of these bac-
teria is utilized and upon their growth depends every art in
which vinegar is employed. Acetic acid ferments may originate
also in beers and wines, in breads, and sometimes in fruit-jellies.
The bacteria which produce the ferments are not all of the same
sort but are of several different kinds.

Antiseptic surgery. One very important special technical
process is largely dependent upon the control of various fermen-
tive bacteria, namely, antiseptic surgery. The precautions which
the surgeons take in entering upon an important operation, are
intended to prevent the ingress of putrifactive or other fermen-
tive bacteria into the wound through the operation. Hence the
carbolic-acid-spray, the heating of the knives, lint, bandages and
sponges, the dress devised to catch as little dust as possible, the
cleanliness of all utensils, and the frequent illumination of the
operating room in good hospitals by sunlight. With the suc-
cess of antiseptic methods it has been discovered that pus or
"matter," as it is popularly termed, is not an unavoidable con-
comitant of wound-healing. Wounds not of surgical origin,

Minnesota Plant Life. i i 5

such as bullet-wounds, commonly undergo bacterial infection
after which pus forms and, in serious cases, blood poisoning may
follow. With the increase of humanitarian methods in warfare
the time may come when sterilization of bayonets and swords
will be insisted upon under the laws of nations, thus diminishing
the mortality from wounds in battle. To-day, unless it were for
the modern knowledge of bacteria and their habits, surgery
would be as rough and ready and generally fatal as it was a hun-
dred years ago.

Light-producing bacteria. Regarding light-producing and
heat-producing bacteria there is little necessity to add anything
to a mere mention of their occurrence in the state. It is true
no ocean bounds the Minnesota of to-day and glows during the
activities of light-producing bacteria, but sometimes upon rotten
logs or upon damp places in the forest a faint phosphorescence
is visible which may be attributed to the presence of light-pro-
ducing germs. This power of illumination, however, exists in
some higher fungi, so one cannot be sure that the dim radiance
of decayed logs in the forest is due to bacteria unless a careful
examination be made.

Heat-producing bacteria. The heat-producing bacteria,
while they are, like all the rest, invisible, are known by their
works, and their peculiar habits are tacitly recognized by the
insurance companies which send inspectors to see that cotton
wastes and refuse are not allowed to accumulate where they
might be ignited by "spontaneous combustion." The impres-
sion should not be received that all forms of spontaneous com-
bustion are of bacterial origin. Some are, however, and the
power which bacteria of this kind have of raising the tempera-
ture in a mass where they are growing has been clearly demon-
strated.

Color-producing bacteria. Turning now to the examination
of color-producing bacteria much might be said, for this is a
group of considerable interest and importance. In the middle
ages and in regions where science has not yet dispelled the
clouds of ignorance and superstition, many men have lost their
lives on account of the appearance of red bacteria that excited
the fears of those who saw them. The phenomenon of ''blood-
spots" on linen which has been lying in damp places, or upon

ii6 Minnesota Plant Life.

bread or food-materials, is often due to the growth of bacteria
with the power of secreting a red dye. When such spots ap-
peared, very naturally, upon sacramental bread in the churches
and monasteries of the Middle Ages, it was regarded as an ex-
tremely bad omen, and this same phenomenon in earlier times
and in older civilizations was no less terrifying. Many an un-
fortunate man or woman has been seized and put to the torture
on account of these red bacteria, and even yet their presence is
regarded with superstitious horror in most parts of the world.
Besides the red forms there are those capable of producing
blue, pink and yellow dyes which are alike conspicuous. Such
growths will appear "spontaneously," developing from atmos-
pheric germs, upon the surface of steamed potatoes kept in moist
places where they occur as more or less flattened hemispherical
drops of colored slime. If a bit of slime is placed under a power-
ful lens it will be discovered to consist of unnumbered millions
of tiny bacterial cells, imbedded in a common jelly of their own
secretion. The shapes which such little masses of bacteria take
when growing upon a steamed potato, or a piece of bread, may
be compared with the tubercles formed in the lungs in cases of
consumption. The mass of bacteria becomes inclosed, as it were,
within a shell of its own excrement and may be thus prevented
from extending uniformly and continuously over the surface of
the potato.

Purple bacteria. One very remarkable kind of color-bacte-
ria deserves especial notice since it is an exception under the
general definition of fungi given above. Such bacteria are
known as purple bacteria and they have the ability to develop
in a thin layer just inside their cell-walls, a remarkable organic
substance known as bacterial purple. It has been found that
germs provided with bacterial purple in their cells are able to
assimilate carbonic-acid-gas in the dark as well as in the light.
The number of such germs is small, but they are of extraordi-
nary interest because their behavior is similar to that of green
plants which decompose carbonic-acid-gas in sunlight or under
the electric arc, using the products in starch-manufacture. Bac-
teria with bacterial purple are, therefore, independently nour-
ished plants in very much the same sense that green plants are,
and they can use in their nutrition much the same simple food

Minnesota Plant Life. ! \ j

substances which will suffice for plants with leaf-green. It is
not clear why bacterial-purple is limited to so small a number
of tiny and fowly organisms, while leaf-green, which does much
the same kind of work, is present in almost all of the types of
higher vegetable life.

Nitrogen bacteria. Among the bacteria described as nitri-
fying, there are t\vo principal classes, those which live in the
soil or water, and those which associate themselves with higher
plants, forming a chemical partnership that suggests, a little,
the arrangement between the lichen fungus and its algal mate.
Nitrifying germs which live independently in the soil or water
have apparently the power of producing chemical changes, as
a result of which the nitrogen of the air, or of ammonial com-
pounds, is combined with minerals in such a way as to pro-
duce the nitrogen salts called nitrates or nitrites. Bacteria
of this character are found in guano beds, and the ripening of
guano into the high grade of fertilizing material, which it is
known to be, must be attributed to the presence of nitrifying
and de-nitrifying bacteria. Germs of this general group are
found in Minnesota in old manure piles, and in other masses of
decaying animal substances as well as in ordinary loam.

Bacteria on clover roots. Still more interesting are the ni-
trifying bacteria which join forces with higher plants and de-
velop a nitrogen-fixing mechanism. If one pulls up by the
roots the first patch of clover which he sees, and then carefully
washes out the soil and examines the rootlets, he will discover
upon many of them little irregular nodules the size of a pin-
head. Upon cutting open one of these nodules and applying a
suitable magnification it would be seen that the swelling on the
root was caused by the growth in its tissues at that point of a
colony of nitrifying bacteria. Apparently the presence of these
bacteria is recognized by the plant as desirable, for an apparatus
known as infection-threads is produced in the root-substance of
the clover and prolonged into some of the root-hairs. Root-
hairs, with infection-threads, pick up from the soil the nitrifying
germs and these are then led back along the threads to the inner
tissues where they develop and multiply in the nodules. A plant
like clover, possessing such nodules, grows very much more vig-
orously than one without them and certain interesting agricul-

n8 Minnesota Plant Life.

tural experiments have illustrated this fact. In Alabama, for
example, clover grown under conditions where the nodules
could not form, produced only about one-sixth as much fodder
to the acre as did the same kind of clover when grown in such
a way that the nodules could develop. All kinds of peas, beans,
alfalfas, clovers, vetches and other pod-producing plants, are
capable of producing bacterial nodules. They will not form
them if planted in a soil where no bacteria of the proper kind
exist and this is a reason why clover crops fail to do well in cer-
tain regions where the conditions seem outwardly favorable.
In Germany some laboratories have produced cultures -of nod-
ule-forming bacteria, which they supply to farmers under the
trade name of mtragin. If, now, a soil in which nodules would
ordinarily develop poorly, is inoculated with nitragin, the clover,
pea or bean crop will grow with double, triple or quadruple
vigor. Agriculturists may reasonably look forward to a period
when the soil will be regularly inoculated for a variety of crops
just as cheeses are inoculated for a variety of flavors. For
these remarkable facts the explanation is not far to seek. Dur-
ing their life-processes the bacteria are able to fix the nitrogen
of the atmosphere and develop nitrogen salts. But these ni-
trates and nitrites are precisely what the higher plant demands in
its nutrition and it seizes and assimilates them. What is for the
bacterium a waste-product is for the clover a food-product. In
return for a supply of nitrogen salts developed and delivered in
its root area, the clover affords protection to the bacteria against
desiccation and supplies them with certain of its waste products
for use in the bacterial economy. It is a striking fact that
after a crop of clover with nodules has been harvested there are
more nitrates and nitrites left in the soil than there were when
the crop began to grow, and this, too, notwithstanding that clo-
vers use themselves a considerable quantity of these salts.

Bacteria and crop-rotation. From the facts above presented
it is possible to understand how the technical process familiar to
farmers and known as "crop rotation" is at bottom bacterial.
After nitrates or nitrites have been exhausted by the growth of
cereal crops, or root-crops, such as turnips or sugar beets, the
soil may be replenished and invigorated by the growth of some
pulse crop, such as beans, peas or clover. It would be a great

Minnesota Plant Life. iIO/

triumph of agricultural science if enough could be learned about
the nodule-bacteria and their habits to train them to grow upon
wheat, oats, barley or rye. The problem of the world's food sup-
ply would then be solved, for every cereal crop under such cir-
cumstances would "do its own rotating" and instead of impover-
ishing the soil the crop taken from it would leave it in a better
condition than before. It is true, plants demand a variety of
other substances in their nutrition than salts of nitrogen, but
these are the only substances which are not present everywhere
in almost unlimited quantities. Silicon, sulphur, phosphorus,
calcium, potassium, iron, oxygen, hydrogen and carbon and the
other elements appropriated by plants in their food-economy
can usually be delivered in adequate quantities and in assimilable
form. The peculiar inability of green plants to make any use
of atmospheric nitrogen would in a few generations put an end
to all plant and animal life on the globe were it not for the ac-
tivity of nitrifying germs in the soil and water. Through the
agency of these the store of nitrogen salts, from which plants
can absorb the nitrogen they need, is constantly replenished and
the successive generations of life are permitted to continue on
the earth.

Other root-tubercle bacteria. Plants of the pea family are
not the only ones that develop root nodules containing nitrify-
ing bacteria, for such nodules are also produced upon alders and
upon a plant related to the buffalo-berries of the western Minne-
sota prairie. Since these plants are not cultivated in fields their
root-nodules are of less economic importance to the agricultur-
ist.

Bacteria of urine. Of quite a different class from those just
treated are the de-nitrifying bacteria which play an important
part in the economy of nature by their ability to decompose
urea. It is generally known that urea is the ordinary form of
nitrogenous waste material excreted from the animal body, but
this substance while a compound of nitrogen is not available for
the nourishment of green plants until it is decomposed and re-
combined into nitrogen salts. The decomposition of urea,
wherever it occurs, is ordinarily accomplished by the activity
of de-nitrifying germs. As a result of their action, ammonia
appears and this, again further reduced in complexity, may lib-

I2O Minnesota Plant Life.

erate free nitrogen to the atmosphere of the soil — and it is to
be understood that ordinary soil contains a considerable amount
of such gaseous material together with oxygen and carbonic-
acid.

Sulphur bacteria. The sulphur and iron bacteria are of some
economic importance from their growth in mineral springs.
Sulphur bacteria, when present, occasion an odor of decaying
eggs, revealing the presence of a gas known as sulphuretted
hydrogen. During their nutrition granules of sulphur are de-
posited in their cells and they form a stage in that round of life
in which sulphur waste products are given off by animals, then
are broken up with the production of sulphur granules in the
bacteria, which upon the death of the germ may be re-combined
into sulphur salts and in this condition may again be used by
green plants for food. Animals, then, directly as do the herb-
devouring species and indirectly as do the flesh-devouring
forms, make use of the substances produced by green plants and
the waste is again begun and the process repeated.

Iron bacteria and iron-ores. Iron bacteria form iron pre-
cipitates where they grow and assist in the rusting of iron in
some parts of the world. They frequently extract iron-rust
from the waters of springs and form flocculent red masses of the
oxide. There is reason to suppose that the masses of iron-ore
in Northern Minnesota upon the Mesaba range were deposited
there by the activity of iron-bacteria, living in the warm waters
of an ancient ocean. We may imagine such a primeval sea, hot
like the geysers of the Yellowstone, its waters impregnated with
iron and furnishing a splendid field for the peculiar activities of
the iron-bacteria. Living in such an ocean for thousands of
years, as they may have done, there is nothing unreasonable in
attributing to them the deposits of iron ore which during these
latter days are being mined for commercial purposes.

Manifold relations of bacteria to man. Enough has now
been said, about the bacteria of Minnesota to justify their appel-
lation of most extraordinary plants. It seems inconceivable at
first thought, that iron-mining, cheese-making, phosphorescence
in the forest, the tanning of leather, the rotation of crops, the
ripening of guano, the blight of pear-trees, epidemics of typhoid-
fever, the souring of milk and the sacrifice of innocent people

Minnesota Plant Life. 121

when blood-spots have appeared upon the shew-bread, should
all be various results of bacterial growth. Such, however, is the
fact, and the whole may be comprehended upon returning to
the statement made in the opening of the chapter, that bacteria
are plants needing various foods and forming a variety of waste
products. The poisonous ptomaine produced by bacteria in ice-
cream may cause the death of an entire picnic-party ; the waste
products of a bacterial population of some ancient ocean, ag-
gregated in enormous quantities, may furnish work for thou-
sands of miners and lie at the foundation of great modern in-
dustries.

In this brief account by no means all of the possibilities of
bacterial habits and characters have been exhausted, but enough
has been said to open up this most fascinating field of investiga-
tion and to show in what a multitude of ways bacteria touch
human life.

Chapter XIV.

Mosses and Liverworts as Links Between the Algae and the

Higher Plants*

The plants known as liverworts and mosses constitute a
group intermediate between the algae and the ferns. They
may be regarded as the descendants of algae which at some re-
mote time in the past climbed slowly out of the water and es-
tablished themselves upon the land. They still retain a number
of algal characteristics, although they have naturally, on account
of their terrestrial habitat, varied from the structural types which
were characteristic of the algae themselves. As is generally the
rule, it is. during their early stages that they most resemble
algae. All mosses and liverworts when first developed from
their spores, in a great many ways recall the algae. This is
especially true of the lower group of liverworts.

The mosses and liverworts, embracing some five or six hun-
dred Minnesota species, are found for the most part in groups
of large numbers of individuals, for they are essentially social.
A moss-tuft at the base of some tree or in some crevice of the
rocks consists of hundreds of moss plants growing very close to-
gether and possibly all derived from the propagation of a single
original individual which had become established at that point.
Many of them prefer moist places and some are entirely aquatic,
floating freely in the water, or attached to pebbles at the bottom
of the lake or stream. Under such conditions they might pos-
sibly be mistaken for algae. It is not, however, probable that
these aquatic mosses or liverworts are the ones most closely
related to the algae, although such a supposition would seem
reasonable. On the contrary, they may rather be regarded as
land forms which have returned to the water as a secondary
adaptation ; for in a careful study of the plant world it becomes
evident that plants in the history of their development have
changed their habitations more than once.

Minnesota Plant Life. I2*

Mosses are abundant, too, in very dry localities and are found
in little blackened tufts upon the bare surfaces of bowlders and
cliffs. Many of them cling to the bark of trees occupying posi-
tions like those frequented by lichens. Some are found regu-
larly at the bases of trees, the trunks of which serve as concen-
trators of moisture; for when the rains fall upon the twigs of
trees many of the drops are conducted along the branches to the
trunk ^of the tree and in this way the region around the base of
the trunk becomes more moist than the soil at a little distance.
Having taken advantage of this natural irrigation-system a va-
riety of mosses frequent the bases of tree-trunks. The kinds
which grow in such positions are in general different from those
growing on moist cliffs or on dry bowlders, or in swamps, or
mixed with grass along the road-side edge or in fields, or on
hillsides.

Mosses and liverworts are distinguished from each other in
a variety of ways. They unite in having a young stage which
resembles the plant-body of the algae. Upon this buds are
formed that develop into the mature moss or liverwort plant.
Liverworts constitute a group of organisms more variable than
the mosses. They show more types of structure and have been
described as Nature's experiment-ground from which the higher
plants have originated. Two groups of higher plants are con-
ceived to be improvements of the liverwort stock. These are
the mosses (a terminal group) and the club-mosses or Christmas-
green plants which gave rise to the ferns and pines. Though
they are of somewhat different degree, as well as of different
kind of structure, the liverworts and mosses may well be con-
sidered together. Their habits and habitats are much the same.
In most instances their general appearance is similar, though
there are some liverworts which have the flat, prostrate, leaf-
like appearance of certain lichens, quite different from the leafy-
stemmed habit of the mosses.

Breeding habits and life-histories. All of these plants pro-
duce true eggs and spermatozoids. After fecundation, the egg
develops into what is called a liverwort-fruit or moss-fruit. But
such fruits are really independent organisms, and here one
meets with that remarkable fact in the life of plants technically
known as alternation of generations, — a phrase which means that

124 Minnesota Plant Life.

each alternate generation in the life-history is made up of sim-
ilar organisms, while the generations between, although similar
to each other, are, in structure, entirely dissimilar to the alter-
nating generations.

The life-history of a liverwort or moss is briefly as follows:
Inside the capsules — those little urns which rise on their slender
stalks above a moss-tuft — large numbers of spore-cells are
produced, in little spherical sacs, four spores in each sac. The
sacs lie loosely in the interior of the developing urn. When the
urn is ripe the sacs will have all dissolved, the spores will have
separated from each other and in the form of a fine powder lie
loose and dry within the urn. In mosses, the urn in most in-
stances has a lid which is thrown off and then the spores are free
to sift out over the neck and are carried away to places favor-
able for their germination. The variety of ways in which mosses
and liverworts arrange to scatter their spores at the most ap-
propriate times for their well-being need not here be discussed,
but later will be given some attention.

When one of the spores has found a place where the moisture
is sufficient for its growth its wall breaks and almost always a
green cell is protruded. In a few liverworts the spores divide
internally into a little group of cells before their walls break, but
in most species this is not common. The green cell grows and
divides, building either a little flat plate of cells, reminding one
of the flat, fresh-water-algae, or a branching thread, reminding
one of some of the thread-algae. In any case not all of the
plant-body of this young moss or liverwort is green. Some
colorless threads are produced which serve as root-hairs for ab-
sorption and attachment. Such an immature moss or liverwort
plant is called the first-stage of the moss. The first-stage may
continue for some time and in a few little mosses it forms a
green mass of creeping threads which covers on clay banks a
considerable area. Usually, however, the first stage in both
mosses and liverworts is comparatively small and transitory. In
peat mosses it makes a difference in the structure of the first-
stage whether the spores germinate in water or on land. When
they germinate in water the first-stage has been known to take
the form of a branching thread, but when they germinate 011
land, the first stage becomes a flattened plant-body half an inch
or more in length, and one layer of cells in thickness.

Minnesota Plant Life.

If mosses proceeded no farther in their development than
the first-stage, they would be regarded as algae; but there is
the capacity in all of them to develop branches upon the first-
stage, arising from little buds of cells. The branch which thus
arises quickly takes the form of the mature moss or liverwort
and is known as the second-stage, or mature stage of the sexual
plant. Sometimes this mature stage is
itself a flattened body as in those broad,
forked, green plates which are found so
commonly on the damp sides of ravines.
More often the second-stage takes the
form of a stem upon which are borne
leaves. In liverworts
this stem is almost in-
variably quite pros-
trate, bearing two rows
of leaves, right and left,
and a third row of
scales on the under
side. Liverworts of
this sort are therefore
called, in common par-
lance, scale-mosses.

In the moss division
of the general group
there are no forms in
which the second-stage
is a flat forking plate of
tissue, but without ex-
ception the plant-body FIG. 39. A male moss FIG. 40. A female moss plant.

consists of a leafy stem, plant The, spTn' The ***-*J&™ are inclosfd

* anes are produced in in the tuft of leaves at the

Sometimes Unbraiiched, clusters at the end of tip of the stem. After At-

« ., . the stem. After At- kinson.

while in other varieties kinson.

it may be branched in

a definite manner, often with some of the branches subordinated

to others, building up a fern-like or tree-like branch-system.

Very often this leaf-bearing branch-system in mosses stands

more or less erect and then the leaves are generally arranged

around the stems in spirals quite as in higher plants. In one

126

Minnesota Plant Life.

variety of moss in Minnesota the stem is erect and there are but
two rows of leaves, each with a peculiar crest on its mid-rib.
When, on the other hand, moss stems are prostrate in habit
there is commonly something in their leaf-arrangement or in
their structure which indicates that they were not always pros-
trate but have adopted this position for some peculiar reason.
But among the "scale-mosses" — those liverworts which bear
leaves in two rows — there is nothing in the structure to suggest
that they ever maintained an erect position. Therefore, it is
possible to make this general distinction between mosses and
liverworts; that liverworts are essentially
prostrate plants and that mosses are essen-
tially erect plants in some of which the
prostrate habit of growth has been second-
arily resumed.

Of whatever sort the plant-body may be
in the second-stage, it is always character-
ized by a variety of functions, of which the
breeding-function may be regarded as the
most important and secondary to that the
nutritive. When mosses are about to breed
they produce, in some species upon the
same plant, in others upon neighboring
plants — organs of two sorts. The male
structures are commonly ovoid-cylindrical
in shape, situated sometimes in little clus- FIG. 4i. The c
ters at the ends of stems and surrounded
by leaves of slightly different color, more
purplish, yellowish, or reddish than the
ordinary leaf. Along with these bodies,

standing on their short stalks, there are ordinarily developed
glandular hairs which serve to keep them moist by retaining a
little water in their vicinity. Each ovoid organ consists of a
layer of cells surrounding a central mass of small cells, several
thousand in number. Each one of the small cells is capable of
producing from the living substance of its interior, a single sper-
matozoid. When the whole organ is ripe, the end opposite the
stalk opens, separates or dissolves and the cells of the interior
are squeezed out. Their walls liquify and a horde of sperm-

spermary of a moss,
much magnified, and
two spermatozoids, very
highly magnified. After
Atkinson.

Minnesota Plant Life.

127

cells are liberated in the water which may have accumulated as
dew or rain, or is, perhaps, the natural habitat of the plant.
Each spermatozoid is provided with a pair of swimming threads
by means of which it propels itself with great agility. Mean-
while upon the same plant, or upon neighboring plants of the
same species, there have been developed egg-producing organs.
These arise, mingled with glandular hairs upon the ends or
surfaces of branches and consist at first of solid masses of cells,
consisting of two
well-marked areas, a
spherical base and a
slender neck pro-
t r u d e d outwardly.
When the egg-pro-
ducing organ is ripe,
the cells at the end
of the neck separate
from each other and
a central row of cells
in the neck turns
into mucilage and
oozes out, leaving at
the bottom a large
egg-shaped cell now
inclosed in an organ
shaped like a bottle
with a long, slender,
hollow neck. The
opening from the

exterior down to the egg is produced by the transformation into
mucilage of a row of cells as has been described.

Reproduction of mosses and liverworts. All mosses and
liverworts produce sperms and eggs. Attracted in some man-
ner by chemical substances dissolved in the water near the eggs,
the spermatozoids find their way to the mouth of the egg-pro-
ducing organ. They crowd into its neck, swimming down the
canal which has been opened for them until they reach the egg
lying at the bottom of the flask. One sperm more active than
the others, or first upon the ground, buries itself in the sub-

FIG. 42. Tip of a leafy moss plant, sectioned lengthwise and
magnified. The flask-shaped egg-organs, one with an egg
in place, are shown. These bodies are barely visible to
the naked eve. After Atkinson.

128 Minnesota Plant Life.

stance of the egg, and immediately the egg forms around itself
a membrane by which the ingress of other sperms is prevented.
Such an egg is said to be fecundated and in a short time it di-
vides by a cross-partition — in a direction perpendicular to the
long axis of the bottle in all mosses and liverworts with the
exception of the horned liverworts, in which the first partition
is parallel with this axis. The egg now consists of two cells
and this two-celled body is reasonably to be considered as the
first-stage of the embryo-plant of the next generation. Such
an embryo normally develops into a spore-producing capsule,
provided in some species with a long and slender stalk, but in
other varieties having only a short nub of sterile cells at the
base. In the lowest family of the liverworts there is no stalk
of any kind, but the entire matured product of the embryo be-
comes a little spherical capsule imbedded in the tissue of the
sexual plant. Whatever may be its structure the capsule finally
produces spores. The function of a moss or liverwort capsule
may be described in brief as the production of as many and as
certainly germinable spores as possible. In high types of moss-
fruits the number of spores rises into the thousands, while in the
lowest forms of liverwort-fruits, the number of spores runs from
sixteen to sixty four.

What is meant by "alternating generations." It is evident
that there exist, in the moss life-history, two plants alternating
with each other. One, the sexual plant, has two phases, the im-
mature or first-stage and the mature or second-stage. The first-
stage does not, except in one kind of moss, produce the organs
of sex, and in this peculiar moss it is not the egg-organs but
the spermaries that are formed upon it. Therefore, one may
describe the second-stage of the moss sexual plant as a repro-
ductive branch of the first-stage. The other, the capsular plant of
the life-history, is entirely devoid of sex, but is a spore-produc-
ing organism. This serves to illustrate one of the very remark-
able differences between higher plants and higher animals. In
higher animals a fecundated egg develops into an organism like
one of those that cooperated in the production of the fecundated
egg, thus the egg of a fowl develops into a fowl, and the egg
of a fish into a fish ; but the egg of the moss does not develop
into an organism like the ones that cooperated in its produc-

Minnesota Plant Life. j

tion. On the contrary, it develops into an entirely different
creature, in the body of which there may be produced some
thousands of spore-cells and each one of these if planted under
favorable conditions, may originate a new first-stage moss or
liverwort plant. Upon one of the first-stages a great number
of buds might then arise initiating the second-stage of the sex-
ual form. Thus it is seen that while animals can generally
derive but a single individual from a fecundated egg, mosses

and liverworts — and higher plants still more strikingly are

able to bring into existence thousands of organisms from one
egg. The only thing analogous to this in animals is the phe-
nomenon of true or identical twinning. When twins are of
precisely the same appearance and sex it is believed that they
have developed by the two halves of the embryo in its youngest
stage separating from each other. Each half, relieved from the
pressure of the other, develops now respectively not into the
right or left half of the body, as it normally would, but into a
separate individual. If one can imagine, not twins nor quad-
ruplets, but great numbers, even thousands of individuals to
arise from a single animal's egg, he would have something com-
parable with the condition in plants which is known as alterna-
tion of generations.

The origin of the higher plants. In the light of what has
been said it is apparent that the two alternating generations in
the life-history of a moss or liverwort are not equivalent to each
other, and one of them, the spore-producing generation, has
no analogue in the life-history of those animals with which peo-
ple are familiar. When, in the algae, an egg after fecundation,
instead of developing at once into a new organism as an animal
egg does, cuts itself in two into a pair of spores, it has accom-
plished normally what happens accidentally in the case of true
twins. It seems that what is an accident among animals be-
came the rule in the plant world ; so in other algae the number
of spores thus developed from a fecundated egg was increased
to four or even to eight in the sphere-alga. Then in a little alga,
the disc-alga, which has been regarded as standing closest to
liverworts, the number of spores \vas increased to sixteen ; and
for one fecundated egg, by this division into sixteen spores, the
plant was able, perhaps, to secure sixteen new individuals, pro-

10

130 Minnesota Plant Life.

vided that all the spores found the opportunity of germination.
Such little clumps of spores, originating by the partition of a
fecundated egg, then underwent a division of labor, so that the
superficial spore-mother-cells acquired the character of capsule-
wall-cells and did not ordinarily retain the power of spore-
production. This was in order to protect the cells of the in-
terior, which remained as true spore-forming cells, and there is,
in such an instance, a fundamental peripheral sterilization of the
spore-mass, so that it comes to consist centrally of functional
spore-mother-cells while sterilised spore-mother-cells take the
character of wall tissue. Really, by this time, a new kind of
organism has come into existence, something entirely unlike
anything in ordinary animal life-histories.

The new organism, beginning thus simply as a mass of
spores, then in higher types assuming the form of a mass of
spores enclosed in a wall, underwent further improvement in
other families of liverworts and mosses until finally it became
a large capsule with long slender stalk, several layers of wall
cells and a supporting column of sterile cells running up the
middle. By means of such improvements the possible number
of spores was increased and they were better managed by the
plant ; for when the spores of a moss are distributed from a cap-
sule on a tall slender stalk they will fall farther on every side,
thus obtaining more favorable chances of persistence than if
scattered from a short-stalked capsule.

To the philosophical botanist this profound need of coun-
terbalancing the unfavorable conditions of the environment
suggests itself as the occasion of erect habit in herbs, shrubs
and trees. By maintaining the erect position plants can also
enjoy better illumination ; but it may be safely assumed, for the
reasons that have been given, that the erect position and the
slender habit of growth of the moss-fruit, based as it is upon
an instinctive effort to enlarge the opportunities of spores, is the
precursor of all erect habits in the terrestrial spore-producing
areas of plants, — and essentially all plant shoots are spore-pro-
ducing areas. Pine trees, for example, develop pollen, a form
of spores, in their little cones. Roots never develop spores, and
may be regarded as derivatives of that original end of the cap-

Minnesota Plant Life. 131

sular plant which was nearest the sexual plant and was not
thrust up for the purpose of scattering the spores.

This further fact next presents itself for consideration : that
among the higher plants, all prostrate forms of stems arc secon-
dary; for stems must originally have been erect, like the moss
fruit-body. Thus it is not surprising to learn that the oldest
forms of terrestrial plants were of the forest rather than of the
prairie type. This, at least, is the conclusion that is reached
upon a study of the most ancient plant-fossils preserved in the
rocks.

Chapter XV.

Liverworts of Minnesota*

Mud-flat liverworts. The lowest family of liverworts is char-
acterized by a flat and prostrate leafless plant-body, such as may
be seen in the little circular forms growing upon mud-flats.
These may be recognized as different from lichens of similar
habit by their bright green color unmodified by any tint of gray
or blue. They occur as discs an inch or so in diameter and are
made up of forking flat stems seeming to radiate from a com-
mon centre. The upper side has
a spongy look which is caused
by the existence of air-cham-
bers in the plant-body. At
the edge of the disc are the
ends of the forking branches
and each of these is notched,
while at the bottom of such
notches lie the growing-points
of the branches. The tip cells
of a branch do not divide so

fast aS the Older Cells and thus FlG- 43- Mud-flat liverwort, showing method

of growth and branching. After Atkin.

the older parts protrude be- so,i.
yond the true tip. This ex-
plains why the tips of all the branches in this family of liver-
worts are notched.

Floating liverworts. A close relative of the mud-flat liver-
wort, of which there are several different species in Minnesota,
is the floating liverwort. The plant-bodies of this variety are
found in ditches and small pools of water. Sometimes in lakes
they are found entangled among the cat-tails and bulrushes
along the water's edge. The plant consists of delicate forking
branches of a bright green color, sometimes gathered together

Minnesota Plant Life. 133

by the waves into masses as large as one's fist. The branches
are ribbon-like and generally not more than a sixteenth of an
inch wide, but they may be an inch or more in length. It is
impossible to mistake this plant for an alga or for any form
of duck-weed if one observes the notch at the tips of all the
branches. The three-pronged duck-weed, which is often found
with it, is a flowering plant and may be recognized by the con-
vex ends of its little flat branches and the greater breadth of the
stem in comparison with its extension.

Swimming liverworts. Another form of lower liverworts is
the swimming liverwort, which might be mistaken for a duck-
weed since it much resembles it in habit. It is its custom to
float in large patches upon the surface of quiet pools. Each
plant dangles from its underside a tuft of root hairs into the
water thus obtaining special absorptive areas and counterpoises
against being turned upside down by the wind. The swim-
ming liverworts differ, however, from duck-weeds in being
somewhat heart-shaped, on account of their terminal notch,
while duck-weeds are rather oval discs or shaped something like
little trefoils as they lie upon or in the water.

Cone-headed liverworts. The next higher family of liver-
worts has the same general character in the sexual generation
which has been described for the mud-liverworts and their allies,
but the plant-bodies are in many instances larger and more
perfected. The cone-headed liverwort is an example of this
group. It spreads out its broad forking branches of a dark
green color upon logs, cliffs and bowlders in wet places. Its
surface is marked by diamond-shaped areas in the centre of
each of which is seen a whitish dome-like eminence not much
larger than a pin-point. The width of a single branch is from
a quarter to three-quarters of an inch while it may be several
inches in length. On the under side are produced numerous
root-hairs and tiny purple scales along the conspicuous mid-rib.
When the cone-headed liverwort is fruiting, there will be ob-
served during summer and autumn certain green cone-shaped
branches close to the surface of the flat stem. In this condition
they remain throughout the winter, but in early spring the stem
of the cone-headed branch elongates into a pale stalk a couple
of inches in height and about a sixteenth of an inch in diameter.

134 Minnesota Plant Life.

In two grooves along the stalk root-hairs are produced. The
fruit-branch now resembles in outward appearance a small
green-headed toadstool attached to the broad flat branch below.
In the cone-headed liverwort there are, apparently, two kinds
of branches, the ordinary vegetative and the special repro-
ductive branches which bear the capsules. If one of the cone-
heads be separated from the main stem in autumn or in early
spring, it will be found that imbedded in the under side of the
cone and surrounding the cavity about the stalk lies a ring
of black capsules inclosed apparently in the tissue of the cone.
The number of these capsules varies from three to eight, not
usually exceeding the latter number. With the point of a pin
they may be dissected out, if the little cones are handled with
sufficient care and tact. Each capsule removed from the tis-
sues which were surrounding it will be found to show over most
of its surface a dull black color. But at the end, where the
pear-shaped body was imbedded most deeply, for a little dis-
tance the color is green. With very great care, by the use of
a sharp pin-point it is possible to remove an exterior membrane
from the body which was dissected out of the cone-head and
when this close outer membrane is separated a little object of a
shiny black color, except at the pointed end where the color is
bright green, will be obtained. If it has not been broken in
the process of extraction it may now be split in the palm of the
hand and a brown or blackish mass of spores and accessory cells
may be removed from the interior. The shiny black capsule
is the fruit-body developed from the liverwort egg and consists
of a small, short green stalk or foot and a larger capsular por-
tion, the whole constituting a slender pear-shaped object about
a sixteenth of an inch in length.

In the cone-headed liverwort and in all its allies, mingled with
the spores in each capsule, are certain very curious cells with
microscopic spiral bands or hoops developed on the inner sur-
faces of their walls. These cells are of an elongated spindle-
shape and their spiral bands are very sensitive to moisture.
When placed under a powerful lens and moistened by the breath
these cells writhe and struggle in a remarkable fashion, owing
to the alternate shortening and lengthening of their spiral bands.
The movement is not a vital one, but purely physical, like the

Minnesota Plant Life.

135

warping of a plank, yet it serves a purpose in assisting the spores
to escape from the capsule. By means of the writhing motion
of these curious cells the spores are separated from each other
and are not permitted, in the economy of the plant, to fall in
an inert mass at one place.

In its stalked capsule and in the development of these elaters,
as the writhing cells are called, the cone-headed liverwort marks
an advance in its spore-producing generation over the mud-flat
liverwort ; for in that plant and its immediate allies the capsule
had no stalk nor were there any elaters mingled with the spores.
In the sexual generation of the cone-headed liverworts there
exist a variety of other improvements in structure over the
mud-flat species. The plant-body is much larger and more
robust, the air-chambers are more regularly disposed, giving,
as they shine through the skin of the plant, the diamond-shaped
marking to the surface. Each air chamber has a central dome
of colorless cells and in the middle of each dome there is an
opening or air-pore which serves as an aperture through which
an interchange of gases may take place between the starch-
making cells that line the chamber — where they are best dis-
played on its floor — and the outer air.

Another improvement is observed in the production of spe-
cial branches with cone-shaped heads for the development of the
egg-producing organs. In the mud-flat liverwort neither these
nor the spermaries were formed on branches differing in any
important respect from the ordinary branches. Therefore, in
the mud-flat liverwort when the egg had developed into an
embryo the spore-producing capsule found itself imbedded in
the general tissues of the sexual plant, and was not able to dis-
tribute its spores until the stem had decayed. But in the cone-
headed liverwort with its special branches, the egg-producing
organs, when their eggs had been matured, fecundated and de-
veloped into embryos, were all lifted up into the air a couple of
inches or so by the elongation of the slender special stem. By
this means the ring of capsules on the under side of the cone-
head gain an opportunity to scatter their spores over a much
wider circle, thus adding to their chances of germination and
growth. In order to eject the spores the tiny green stalk of
the capsular plant elongates a little just before the capsule opens,

136 Minnesota Plant Life.

thrusting the end of the capsule out beyond the rim of the cone.
In this way each capsule scatters its spores under much more
advantageous conditions than were possible for the mud-rlat
liverwort.

The spermaries in the cone-headed liverwort are produced
upon short blunt branches arising at the tips of ordinary

FIG. 44. The umbrella-liverwort; showing the prostrate vegetative body, and the upright
branches on which the egg-organs are borne, and where later the capsular plants will
be found perching. After Atkinson.

branches, but seeming to grow upon their surface because they
are somewhat displaced in the after-growth of the whole sexual
plant-body. A cut made vertically through one of these sper-
mary branches would show a large number of ovoid sperm-
producing organs apparently imbedded in the general surface
of their special branch.

Minnesota Plant Life. 137

Umbrella-liverworts. Related to the cone-headed liverwort
is the umbrella-liverwort, growing in localities similar to those
favored by the plant just described. The flat stem is a little
smaller, usually not of so dark a green, with somewhat crumpled
margins and less conspicuous diamond-shaped areas on the sur-
face. In this species the special branch which bears the ring of
capsular plants has a head shaped somewhat like an umbrella
with thick ribs but without a covering. The branch bearing
the spermaries is larger with broader top than in the cone-
headed liverwort, and after the spermaries have opened to re-
lease their sperm cells the general spermary-bearing branch
elongates.

Purple-edged liverworts. In still another liverwort related
to the two described, the plant-body is still smaller, averaging
about a quarter of an inch in width and an inch or two in length,
but distinguished by the same flat prostrate habit of growth, the
same notched branch tips and the same little diamond-shaped
areas upon the upper surface. This, from the color of the mar-
gins of its flat branches, may be called the purple-margined
liverwort. Its special erect stems are shorter and more delicate
than in the varieties before mentioned. The head which bears
the capsular plants is rather flat, of somewhat square outline,
and usually supports but four of the spore-producing capsular
plants of the life-history.

Besides these, which are among the commonest forms in the
state, there are a few others related to them but less likely to be
encountered.

Cuplets and gemmae of the umbrella-liverwort. The um-
brella-liverwort just mentioned is remarkable among species
native to Minnesota for its production of curious tiny propaga-
tive branches clustered together, a score or more in a group,
at the bottoms of little cups from a sixteenth to an eighth of an
inch in diameter and borne upon the upper surface of the sex-
ual plant-body. These little cups have a bottom composed of
a layer of cells some of which bulge out from the general surface
and divide into a stalk- and a head-cell. The head-cell then
produces a small convex organ shaped somewhat like a pair of
watch crystals placed with their concave surfaces together and
notched at the sides. Such bodies are called gemmae. They

138

Minnesota Plant Life.

may be regarded as little two-forked branches modified by
the pressure of their mates in the cup, into the bi-convex form
which they have assumed. Growing among such gemmae at
the bottom of the cup are a number of mucilage-hairs which
produce a slime capable of swelling. By this, as soon as they
mature, the gemmae are lifted from their stalks and hoisted over
the edge of the cup. They are then carried away by rain-water,
or by currents if the plant is living in a ditch, to other places
suitable for the growth of umbrella-liverworts. It makes no
difference which
side of a gemma
falls toward the
ground. The un-
der side, after the
gemma has fallen
into position, pro-
duces root - hairs
which attach it to
the soil and the
upper side begins w
the development
of air - chambers
while the whole
branch increases
in size. In this
manner the plant
is abundantly

propagated without the intervention of eggs, sperms or spores.
Another way in which liverworts propagate is much more anti-
quated than the gemma-method and probably suggests the origin
of gemma-propagation. As the general plant-body grows and
forks, the branches may become separated from each other by
the dying away of parts behind the forks. Thus ordinary branches
are isolated and if carried to a distance they may behave very
much as gemmae do. Ordinarily, however, they remain attached
to the soil and serve to propagate the plant only to adjacent por-
tions of the sub-stratum. The gemmae may be regarded as
tiny portable propagative branches and the apparatus for sepa-

FIG. 45. Stem of the umbrella-liverwort, showing the little cups
with bodies inside, which are employed by the plant for pur-
poses of propagation. After Atkinson.

Minnesota Plant Life. I^Q

rating them from the floor of the cup in which they are pro-
duced may be regarded as a special improvement of the dying-
away processes which served to separate the unmodified larger
branches. The wall of the cup may be considered to be a pro-
tective layer of cells originating in earlier forms as a mere collar
or ring and perfected in the umbrella-liverwort into the little cup
or vase. Such small cups with their inclosed propagative bod-
ies are the result of considerable improvement over earlier and
cruder devices. In a liverwort known as the crescent-cup liver-
wort, the cup in which the gemmae occur is not circular in out-
line but is shaped like a crescent moon. Most liverworts do
not produce such cups with gemmae growing from their bot-
toms, but are dependent rather upon their reproductive pro-
cesses or upon the crude type of propagation in which ordinary
branches separate from each other.

The livenvorts which have been mentioned are related more
or less closely to each other. They fall naturally into two
series, a lower, in which the capsule has no stalk and a higher,
in which very short stalks are developed that do not, however,
elongate to any considerable degree in any of the species.

Horned liverworts. Quite a different kind is the horned
liverwort, plants of which without doubt occur in all sections
of Minnesota, but have been collected in but one or two local-
ities. The sexual plant is a flat, somewhat irregular-shaped,
green, prostrate stem devoid of leaves. It lies upon decaying
timber or mud and forms circles which have not the bright,
fresh green color of the mud-liverwort but are of a duller and
darker hue. From the upper side of the plant-body spring
slender horn-like projections which may become an inch or
more in height. These horns are the capsular fruit-bodies of
the plant and are developed from eggs produced in egg-organs
imbedded in the upper surface of the flat green stem. It is a
peculiarity of the capsular plant in this kind of liverwort that
it never fully matures. It consists of a somewhat bulbous foot
which is inclosed in the green prostrate stem and above the
region of the foot are layers of cells which continue to divide,
constantly forming new capsular tissue, so that the capsule may
be said to grow from the base. The capsule consists of a wall,

140 Minnesota Plant Life.

more than one layer of cells in thickness, and a central column
of cells giving strength and support to the whole structure.
Between the central column and the wall is the area where the
spherical spore-mother-cells develop. Each of these is capable
of forming its group of four spores. Mixed with the spore-
mother-cells are some rather crude elaters which play their part
in the distribution of the spores somewhat as did the more
mechanically perfect elater-cells in the cone-headed liverwort
and its allies. When the capsule of the horned liverwort is
ripe, it splits longitudinally through its whole length and the
two dry halves twist about each other and about the little col-
umn of the centre now exposed as a thread. By the twisting-
movement of the two halves of the capsule the distribution of
the spores is facilitated.

This kind of liverwort is extraordinarily interesting to bot-
anists because it seems to be a connecting link between the
liverworts and the club-mosses. The horned liverwort differs
considerably from the cone-headed liverworts, the mud-liver-
worts and their allies, in the character of its capsular plant. As
will be seen from the description this is of higher structural
rank. A greater proportion of its substance is sterilized, that
is, not dedicated to the production of spores, while in the um-
brella-liverwort the only sterile portion of the plant was the
wall and the short stalk or foot. In the horned liverwort there
exists in addition, a central column of cells making possible, by
the support which it gives, the development of a much larger
capsule containing many more spores. Furthermore, with its
indeterminate growth the capsule continues and is not com-
pleted, as were simpler forms of capsular plants, after a certain
definite number of cell divisions. In this capsular plant one ob-
serves the first tendency of such an organism to become peren-
nial. In all other liverwort capsular plants there is aimed at,
in the development, a definite and finished structure, and when
the capsule has been once matured there is no further growth.
Under such conditions it is not possible for a capsular plant to
arise capable of maintaining itself from year to year. The
horned liverworts do not really produce perennial capsular
plants, but they indicate how in the asexual generation perennial

Minnesota Plant Life,

141

plants might easily have originated ; and it is believed that club-
mosses are actually to be compared with such perennial cap-
sules. While it is one of the rarer Minnesota liverworts, the
horned variety is of peculiar interest and should be sought by
amateurs in all parts of the state. It is very easily recognized
by its peculiar habit. The only plants likely to be mistaken for
it are certain kinds of reindeer moss in which similar slender
horns are developed from a flat prostrate body. But these,
like all lichens, can be easily distinguished by the gray or blue
tint which is given to the plant by the fungus element. Be-
sides, the erect horn-like bodies of the reindeer mosses do not
split and are of course not capsules at all but erect portions of
a fruit-body bearing little propagative granules over their sur-
face or giving rise to superficial discs made up of sacs and sterile
threads.

Leafy liverworts and their allies. The higher division of liver-
worts is represented in Minnesota by a considerable number of
species. Some of them are very much like the lower forms in the
habit of the vegetative body, while others are more moss-like,
consisting of branched, prostrate leafy stems. These higher liver-
worts are divided into two series, those in which the plant-body
is flat and leafless constituting one division and those in which
a leafy stem is maintained constituting the other. All agree,
however, in the general character of the capsular plant, and this,
when it matures, stands erect upon the surface or at the tip of
some branch of the vegetative plant. It is provided with a
slender stalk which is usually of a translucent green tint, dif-
ferent in appearance from the brown or red stalks of most moss
capsular plants. At the end of the pale green stalk is produced
a black spherical capsule which, when ripe, generally splits from
the tip, making four flaps that turn back to permit the escape
of the spores and elater-cells. Plants classified as higher liver-
worts are often found upon the bark of trees or upon moist soil.
\Yhen growing upon the smooth bark of the birch they make
delicate green traceries, in their general appearance reminding
one slightly of the sea-weeds. They do not form little tufts as
mosses would in such positions but remain so tightly pressed
to the surface upon which they grow7 that it is difficult to re-

142 Minnesota Plant Life,

move them without breaking their stems in pieces. In such
liverworts it is not the stem of an egg-organ-bearing branch
that elongates to assist the spores in their dissemination but the
true stalk of the capsule, showing that the plant has developed
in the spore-producing generation itself the structures requisite
for assistance in spore-distribution. Unlike the horned liver-
worts, the capsules in this group, which are commonly spherical
in form and considerably smaller, do not need and accordingly
do not develop a central column of supporting tissue, but the
entire cavity of the capsule is occupied by the spores and elaters.

A peculiar thing about the vegetative plant in many of the
higher liverworts is the production of two lobes in the leaf, one
of which is turned under the other. The one turned under and
facing the lower side of the prostrate stem is sometimes modi-
fied into a little pitcher and is then called a water-pocket because
it serves to retain moisture that in drouths the plant might find
serviceable. In such little water-pockets on the under sides of
certain liverwort leaves tiny worms often make their homes.
It is difficult to see how they can be of any great advantage to
the liverwort, but they are so invariably present in some species
that there must be a partnership arrangement between the plant
and the worms which dwell upon it. In the water-pockets, too,
there are often found colonies of simple algae which avail them-
selves of the small drop of water to grow and develop. In
certain exotic species the water-pocket becomes a trap which
catches small insects, as bladderworts do.

A very great variety of leaf-forms characterizes the leafy
liverworts. Sometimes the leaves are flat and scale-like, hence
the name of scale-mosses which is commonly applied to plants
of this group. Again the leaves are slender or dissected into
fine teeth, and they may even become modified into little
branching green bristles, which look quite unlike an ordinary
leaf. In the tropics such leafy liverworts dispose themselves
upon the leaves of larger flowering plants and often make char-
acteristic patches of vegetation where there is an abundance of
moisture. The greater number of kinds in Minnesota display
themselves upon the bark or upon damp soil along with mosses
from which they are not at first very easy to distinguish. They

Minnesota Plant Life.

143

may be regarded as a special development of the liverwort type
and among them are found the greatest variety of plant-bodies
anywhere in the liverwort group, as well as the large majority
of liverwort species.

None of the liverworts is of any particular economic impor-
tance, but they are all of great scientific interest on account of
their intermediate position in form, structure and development
between more primitive oceanic types of vegetation and later
terrestrial types.

Chapter XVI.

Mosses of Minnesota*

The mosses may, like the ferns, be conceived to be the de-
scendants of ancestral forms somewhat similar to the horned
liverworts, although none of them are to-day very close in their
structure and life-histories to that group of plants. All mosses
are distinguished by the following peculiarities, in which they
differ from liverworts. The second-stage of the vegetative sex-
ual plant is in every instance a branched or unbranched, leaf-
bearing stem. While it is sometimes prostrate in habit this
position is an adaptive one and not original, as among the liver-
worts. Finally and most important, the young capsular plant
before maturity always bursts the wall of the egg-organ in which
it began to develop and never, like most liverwort capsular
plants, matures while still within that membrane. A moss
capsular plant is decidedly a creature of more complicated struc-
ture than a liverwort capsular plant and it consists, even in the
simple forms, of a generally greater number of cells. There
are, however, one or two mosses in which the capsular plants
are greatly reduced in size, and these would scarcely come with-
in the general rule.

Mosses have acquired the ability to live in much drier places
than liverworts are accustomed to frequent, indicating their
stronger adaptation to terrestrial life. While the rock-dwelling
liverworts are found usually on moist cliffs or banks, it is not
uncommon to find some mosses growing upon the driest bowl-
ders, where a little crevice or hollow in the stone gives them a
soil upon which their rootlets may work. Such mosses are gen-
erally of a blackish green color and look very crisp, crumbling
easily if rubbed with the fingers. Yet in this condition they are
not dead; for if moistened, they rapidly revivify and proceed
with their functions of growth. Other mosses choose very wet

Minnesota Plant Life.

145

localities. One variety, the river-moss, is a common aquatic
plant in Minnesota, forming slender tufts of delicate leafy stems,
attached to pebbles and rocks, on river-bottoms, in rapids or in
pools. Besides this particular species of aquatic moss, there
are a number of others which have the same habitat.

Peat-mosses. The peat-mosses belong to the lowest family
and are in some instances aquatic. They are familiar objects
in the tamarack swamps of Minnesota, where, if undisturbed,
they may produce hemispherical patches usually of a gray

FIG. 46. Road across a peat-bog; tamaracks and birches in background. Near Grand Rapids.
After photograph by Mr. Warren Pendergast.

color but often shaded with a purple, yellow or red, and rarely
of a bright grass-green. They are peculiar for their power
of absorbing water, and this they do by means of special
water-reservoir cells which are mingled with the green cells of
the leaves. Indeed the water-reservoir cells form the principal
bulk of a peat-moss leaf, while the starch-making cells are dis-
posed over them or between them in a delicate green network.
The stems and branches, too, are covered with layers of such
reservoir-cells so that if a tuft of peat-moss is wrung in the hands
water can almost always be squeezed out as from a sponge,
ii

146 Minnesota Plant Life.

The peat-moss vegetative plant consists of a central axis
upon which are produced lateral leaf-bearing branches of two
kinds. Some of them protrude at an angle from the axis and
upon these the leaves contain leaf-green and are the starch-
making areas of the plant. Others with pale leaves hang limply
down along the axis, covering it and acting as conservators of
moisture. The leaf-bearing branches commonly stand very
close together forming a terminal tuft, and towards the end the
axis itself is sometimes branched repeatedly. At the very tips
of the branches, especially when they are young, a red or purple
dye often stains the leaves and the surface-layers of the stem.
This is a warming-up color and is useful as a device for raising
the temperature around the delicate cells of the growing buds.

Formation of peat-bogs and coal. Peat-mosses are inher-
ently social plants as are the rest of their group, and they often
occupy large areas to the almost total exclusion of other kinds
of plants, except certain cranberries and heaths, pitcher-plants,
cotton-grasses and orchids which are to be sought in peat-bogs.
Every year the axes of the plants increase in length and the
older stems of former years sink lower into the bog. In this way
the centre of bogs, especially those fed by springs, becomes often
much higher than the circumference. Such raised peat-bogs
have been studied in New Brunswick and occur also in St. Louis
county, Minnesota. In such formations while one must ascend
to pass from the edge to the centre, yet the texture of the bog
becomes looser as the margin is left behind. When peat-moss
has been growing thus for many centuries, filling what was once
perhaps a lake, the remains of the old stems become matted
together by the pressure of the heavy water-logged fresh areas
above and after a time such a mass becomes compacted into
what is known as peat — probably one of the stages in the pro-
duction of coal. It is by no means certain that coal was devel-
oped from mosses like the living peat-mosses, but it is alto-
gether certain that it originated in ancient swamps by the same
general process which is to-day building the peat-bogs. So, some-
what as iron-bacteria deposited beds of iron ore in ancient warm
oceans, mosses and other plants in the illimitable swamps of the
coal age contributed their part to modern human industry.

Minnesota Plant Life.

147

Fruiting habits of peat-mosses. Peat-mosses are in such a
favorable position for simple propagation by the development
of branches which become separated from each other upon the
death of the older portion of the stem, that they rarely fruit at
all. Sometimes, however, whole bogs
will be found in fruit at one time.
The fruit-body is a little egg-shaped
black capsule with bulbous base, the
whole shaped somewhat like a dumb-bell
with one end larger than the other and
a short neck between. The smaller end
of the dumb-bell is imbedded in the
enlarged cushion-like tip of a slender,
erect leafless branch of the vegetative
plant. Around the bottom of the cap-
sule may be found a thin broken mem-
brane which is a relic of the wall of the
egg-organ in which the capsule began its
existence. Peat-moss capsules open by
little circular lids which, when the cap-
sule is ripe, separate from the bowl-part,
allowing the spores to escape. It will
be observed that for the elevation of the
spores the same general contrivance is
adopted by peat-mosses that appeared
earlier in the umbrella-liverworts and
their allies. The slender stem which lifts
the capsule into the air is not a portion
of the capsular plant as in the "scale-
moss" liverworts and the other mosses;
but, as in the umbrella-liverwort, it is a
portion of the vegetative plant special-
ized for the purpose of elevating the cap-
sule. When peat-moss spores germinate

they develop under ordinary conditions a flat plate-like first-
stage, but rarely this first-stage arises as a branching filament.
The first-stage usually persists for weeks or even months, sel-
dom, however, becoming very large and in no case exceeding
an eighth of an inch or so in length. Upon the first-stage, buds
form which mature into the ordinary peat-moss plants upon

ded at the tips of short ieaf-

less erect branches. After

Atkinson.

148 Minnesota Plant Life.

which the microscopic organs of sex arise. The sperm-pro-
ducing organs are spherical with long slender stalks and arise
in the axils of the leaves. The egg-producing organs are
formed upon the tips of certain branches and in each, as is the
rule, a single egg is produced, and this when fecundated may
segment into an embryo which in time matures into the cap-
sular plant of its species.

Granite-mosses. Another group somewhat related to the
last are the granite-mosses — representatives of which may pos-
sibly grow upon granitic rocks near Carlton peak and along the
north shore of Lake Superior. They are small black tufted
plants distinguished from all other mosses by the longitudinal
splitting of the capsular plant by four lateral slits which do not
meet either at the top or bottom of the capsule. When dry the
capsule seems to shorten and the slits are thus opened so that
spores may sift out at the sides. The valves of such capsules
are somewhat sensitive to moisture and when conditions are
unfavorable for the distribution of spores the slits are likely to
remain closed.

In both of the families of mosses which have been described
there is a central column of sterile cells giving strength to the
capsule, and the spore-mother-cells are developed in the region
between the column and the wall. In neither of the families does
the column run clear through the capsule, but the spore-mother-
cell area extends over its top like a cup set over a mould. Quite
the same general structure of capsule was observed in the horned
liverworts except that in those plants the growth of the capsule
was not definitely terminated but continued from the base. In
peat- and in granite-mosses the growth of the capsule is termi-
nated after a time and it then contains no more vegetative cells
capable of further division. Therefore, the capsule of peat- and
of granite-mosses may be regarded as built on the general plan of
a horned liverwort capsule, except that the power of continuous
development is lost. It might be mentioned here for the sake of
clearness that the club-moss spore-bearing plant is also supposed
to be an improvement over the horned liverwort type. But in
club-mosses and ferns a power of continuous growth is retained.

Higher mosses. A peculiar little group of mosses, very
tiny and insignificant in appearance, form reduced capsules in

Minnesota Plant Life. 149

which no central column exists. Mosses of this family have
not yet been found in Minnesota, although they possibly ex-
ist. The rest of the mosses belong to a division sometimes
called the true mosses, to distinguish them from the peat-
and from the granite-mosses. There is no particular occa-
sion for the use of the term "true" since all alike belong to
the general moss division of the plant kingdom. There are
more than 30 families of "true" mosses — not all of them rep-
resented in the state — and of "true" moss species there are prob-
ably from four to five hundred in Minnesota. The simplest
true mosses are very small and the first-stage of the sexual plant
is more conspicuous than the second, for the latter nearly always
occurs as almost microscopic buds, each consisting of a short
stem, three or four tiny leaves and a little group of spermaries
or egg-organs at the tip. In these mosses the capsule has no
lid and opens irregularly. Only a very few varieties with such
capsules are known to exist in Minnesota and the great majority
of mosses have capsules which open by lids and may be known
as lid-mosses. It is impossible here to mention, even briefly,
examples of all the different families of lid-mosses to be found
within the limits of the state. In some kinds the plant-body is
erect and the egg-organs are produced terminally upon the
axis. In others the plant-body is not so commonly erect and
the egg-organs are produced near the tips of the branches.
In general the lid-mosses are divided into two principal se-
ries; those which bear their capsular plants at the tips of the
stems, and those which carry them on the sides. Sometimes
it requires a close examination of the moss to determine to
which of the two series it belongs. A view of the whole tuft
might lead one to suppose that the capsular-plants were ter-
minal on the branches, but if a single plant were isolated from its
neighbors and closely examined it might be discovered, per-
haps, that the capsular plant was developed laterally.

White mosses, bark-mosses and dung-mosses. Among the
many mosses which develop their capsular plants at the ends
of the axes may be mentioned the white mosses — grayish green
varieties that produce in the northern forest regions tufts the
size of one's head. In these plants the leaves have very much
the same structure as peat-moss leaves, hence the grayish green
color of the tufts. Related to such varieties are many of the

Minnesota Plant Life.

bark-mosses which attach themselves to the bark of trees, es-
pecially near the base of the trunk. In this series, too, occurs
a kind of moss remarkable for stationing itself upon the excre-
ment of animals and deriving part of its nourishment from or-
ganic substances. There are no mosses which are parasites
upon other plants, or which absorb their food-materials ready-
made, as do the fungi; but the dung-moss seems to be develop-
ing in that direction and its descendants within the next few
hundred years may find themselves within the category of de-
pendent plants.

Turf-mosses, rose-mosses and cup-mosses. Another group
of mosses which belongs to the first series may be termed the
turf-mosses from their prevalence in damp lawns, especially near
the foundation of houses and around verandas. They evidently
select regions a little more moist than the lawn-grass prefers.
When they fruit they form somewhat pear-shaped capsules with
large central columns of sterile tissue. Here, too, are the rose-
mosses which produce what are called, for lack of a better term,
"moss-flowers." Mosses of this sort growing in clusters in
some shaded ravine or upon moist logs in the forest resemble
clusters of little green roses a quarter of an inch or so in diam-
eter. At the end of each short erect stem a rose-like cluster of
leaves is produced and at the centre of each cluster the egg-
organs or spermaries are developed in little clumps. Related
to them are the small stolon-bearing mosses \vhich under some
conditions are erect-bodied plants, but when about to propagate
have the power of pushing out prostrate, runner-like, leafy stems.
These become rooted at the tips and thus enable the plant to
widen its circle of growth.

Among the mosses of this general series there are some forms
which produce gemmae a very little after the fashion of the
umbrella-liverwort. In one variety, which may be called the
gemma-cup-moss, cup-shaped groups of leaves at the end of a
stem inclose a growth of tiny stalked gemmae. When the
gemmae fall off they send forth alga-like threads of the first-
stage and upon these threads buds may develop carrying the
plant over into its second-stage. In other kinds the gemmae are
produced upon the leaves, forming little clusters generally to-
ward the tip of the leaf that bears them. In mosses, the gem-

Minnesota Plant Life.

151

niae cannot be viewed as they were in the gemma-liverwort, as
little modified, specialized branches of the general plant-body,
but they must rather be considered to belong to the first-stage.
When they are produced upon a leaf or at the end of a stem,
the best explanation seems to be this: The first-stage of the
moss-plant is the most fundamental and is the original state of
the plant. The second-stage — what is called the "moss-plant"
—is a more or less highly organized reproductive branch. Then
any cell of the second-stage about to develop as a propagative
body would naturally grow out into the filaments of the first-
stage ; and this actually takes place when moss leaves or bits of
stem are separated from the rest of their body. But when
gemmae are produced it would seem that these filaments, grow-
ing out from the ordinary cells of the plant-body, have gained
the power of forming small, massive, bulging tubers in which
more nutriment can be stored than in the ordinary slender fila-
ments. So then the gemmae, although apparently borne upon
the body of the second-stage, should be considered as really be-
longing to the first-stage of the moss sexual plant.

Hairy-capped mosses. A number of other forms must be
passed with brief mention. Among these are the hairy-capped
mosses, remarkable for the peculiar structure of their leaves,
for the formation of capsular plants during the summer and au-
tumn of one year and their maturation during the spring of the
next, and for the curious Robinson-Crusoe-like hoods that are
carried on the tops of the capsular plants. They are many of
them adapted to very dry localities and are common in pine
barrens.

The second series of lid-mosses includes those forms in which
the egg-organs are developed near the axils of leaves rather than
terminally upon the stems.

River-mosses. Here are the river-mosses, characterized by
their three-ranked arrangement of leaves without midribs and
the short stems of the capsular plants. Since the capsules are
formed below the surface of the water there is no necessity of
their being borne on long slender stems. The object of the
slender stem is to aid in wind-dissemination of spores and ob-
viously, then, short stems might be expected to support the
submerged capsules.

152 Minnesota Plant Life.

Arbor-vitae mosses. The arbor-vitae moss, developing pros-
trate branches of a peculiar fern-leaf aspect and growing in
moist woods, furnishes another example in which the egg-organs
are not terminal on the stem. The branch systems of this moss
are exceedingly beautiful objects. They consist of central
stems with lateral rows of shorter branches diminishing towards
the apex of the main axis, so that the whole branch-system looks
like a small green fern-leaf or feather. Sometimes three or four
of such feather-like branches are produced in a series, one at-
tached to another. Such a structure illustrates the develop-
ment of branches of different orders in the same plant-body.
The axial branches may themselves bear other axial branches
and these latter may bear the subordinated short branches.

Tree-like mosses. In the tree-like moss which is found
growing near decaying logs in the forest or on dark wooded
banks, the axial branch stands erect like a little tree-trunk on
different sides of which are arranged the subordinated branches
so that the whole aspect of the plant is very much like that of
a miniature palm-tree two or three inches high. These tree-
like mosses have also another sort of stem which runs along the
ground — a kind of rootstock from which the erect stems spring.
The leaves upon the trunk of the tree-like moss are brown scales
without leaf-green and it is only upon the secondary branches
—the short branches — that leaves with leaf-green are abun-
dantly formed. In high-types of moss plant-bodies a consid-
erable differentiation may exist between the kinds of stems.
There may be prostrate creeping stems, erect axial stems, di-
vergent secondary foliage stems, prolonged stolons extended
for propagative purposes, and special stems upon which the
egg-organs and spermaries are particularly aggregated.

Carpet-mosses and pool-mosses. Among the mosses of this
highest division, the carpet-mosses which cover the surfaces of
fallen logs, peeling off regularly in carpet-like masses, furnish a
type in which a considerable variety of branching exists. Some
plants of the carpet-moss varieties are quite aquatic in their
habits, and are to be sought not so much in the running wa-
ter which the river-mosses frequent as in quiet pools among
algae, in overflowed meadows and in lakes.

Minnesota Plant Life.

153

Spore-distribution by mosses. Before closing the account
of the mosses it will be profitable to examine somewhat more
fully the methods of spore-dissemination which are employed

by the high-
ly developed
forms, and
' the carpet-
mosses may

be chosen as examples. Here the plant-
body is variously branched, the branches
being interlaced and the whole spread
out in a soft green turf. On some of the
lateral branches rising vertically into the
air are borne the capsular plants. Their
slender stalks are of a reddish-brown col-
or and if closely scrutinized will be found
to be twisted or fluted. They are an inch
or more in length and at the end, nodding
strongly to one side, is the slender urn-
shaped capsule with a distinct lid. The

cells of the
wall where
the lid joins
the urn are
peculia rly

flat and low, so that when the proper con-
ditions of moisture are at hand the urn
easily cuts off its lid and on account of
the inclined position of the capsule opens
its mouth towards the side. The greater
portion of the mouth of the urn is closed
by a plug consisting of the end of the
central strengthening column, and only
a narrow circular slit between this plug
and the wall is left through which the
spores may be sifted out. After the lid

has fallen two rows of curious, slender teeth are seen to pro-
ject outside the circular slit arching over it toward the cen-
tre. These teeth are very sensitive to moisture and when

FIG. 48. A moss leafy-plant,
with prostrate propagative
branch and erect female
reproductive branch. On
the latter two egg-organs
have developed their eggs
into capsular plants, one
of which is ejecting spores.
The two round bodies are
spores much magnified.
After Atkinson.

154 Minnesota Plant Life.

the conditions are favorable for spore-dissemination they separate
from each other a little and allow the spores to scatter out be-
tween them. But when the conditions are unfavorable they close
over the slit and the spores are not permitted to escape. The
ring of teeth is one portion of the automatic spore-distribut-
ing machinery of the capsular plant and the twist in the stalk
is another device which plays its part in the perfected mechan-
ism. Under varying states of moisture the stalk slowly twists
and untwists so that the mouth of the nodding urn is carried
through a circle dispersing its spores as it turns from side to side.
Such an apparatus insures the dissemination of spores toward
all points of the compass and the teeth at the edge of the urn
may be depended upon to retain the spores if the conditions
are not suitable for their ejection.

Such artifices as these, together with the large size of some
moss-capsules and the considerable number of spores which they
contain, mark an advance over liverwort mechanisms and the
moss capsular fruit, exceedingly nice in its adaptations, is the
most perfect and logical result of those lines of development
which were begun in the peat-moss capsule. The failure of the
moss capsular plant to achieve the highest rank is because of its
having lost the valuable power of indeterminate development
which was possessed by its horned liverwort prototype.

Superiority of the moss-capsule over the liverwort-capsule.
Another point of difference between the moss capsular-plant
and that of the liverwort, and indicating the higher rank of the
former, lies in the greater development of starch-producing
areas in the moss. This is why the capsules of liverworts are
generally black while the capsules of mosses are generally green.
The liverwort capsule is merely a thin shell surrounding the
spores and the black color of the whole body is given equally
by the spores and their wall, but the wall of the moss-capsule
is like a leaf in its physiology. It consists of several layers of
cells, the outer portion of which functions as skin, while under-
neath there are areas in which leaf-green is formed. Thus the
moss capsular plant is not merely an elaboration of a fecundated
egg into a group of spores enclosed in a protective membrane,
but it is in a marked degree an independent organism. It is
quite independent so far as its assimilative power goes, and if,

Minnesota Plant Life, 155

instead of remaining perched upon the sexual plant at the point
where its parental egg-organ was developed, it had the knack
of stepping off and driving its own root-system into the soil it
would be entirely independent. This, however, is exactly what
the ancestral fern capsular plants are supposed to have done, so
that the fern plant as it grows in the woods may be compared
properly, not to the leafy moss-plant but to a very highly im-
proved moss capsular plant with leaves and roots of its own.

A primitive attempt to develop a special leaf-area is seen in
the capsules of the dung-mosses. In these the region between
the capsule proper and the stalk is flared out into a green collar
and this is essentially a starch-making expansion of the general
plant surface. But that is precisely what a leaf is structurally,
for it also may be described as normally a starch-making expan-
sion. It is true a great many leaves come in higher forms to as-
sume entirely different functions, but the appearance of the leaf
must be regarded as connected with starch-making, for orig-
inally this was probably the function of all leaves, however far
some modern forms may have abandoned it.

Had the moss capsular plants not originally given up, in the
peat-moss types, the power of growing continuously, or if they
had independently attained this power, there is no reason why
they should not have given rise to many interesting and complex
higher forms. But no matter how perfect a moss capsular
plant may become, no matter how skillfully it may distribute its
spores, or provide for the manufacture of starch by its own leaf-
green independent of the parent sexual plant, it always comes
to a point when it is completely mature, can develop no farther,
must eject its spores and perish. For this reason mosses con-
stitute what is called a terminal type and there are no higher
forms of plants regarded as derived from them.

Chapter XVII.

Christmas-green Plants or Club-mosses*

The plants known as club-mosses are the ones so abun-
dantly used in the manufacture of Christmas-green decorations,
wreaths and festoons. Their spores are collected and sold
at the drug-stores under the name of lycopo-
dium powder, since the small, smooth, oily
spheres are very difficult to moisten and are
useful to prevent chafing. There are about
twelve species in Minnesota, of which some,
known as the smaller club-mosses or rock-
club-mosses, are distinguished by the posses-
sion of two sizes of spores, the significance of
which will be considered later. All Minne-
sota species of club-mosses are terrestrial,
growing particularly in the pine woods, and
they are known also as ground-pines. In the
tropics, however, and in the southern hemi-
sphere there are varieties of club-mosses which
perch upon the branches of trees and hang in
festoons along the trunks.

Life-history of a club-moss. The life-his-
tory of the common Christmas-green club-
moss is somewhat as follows : The spores,
produced in large quantities, germinate near
the surface of the ground and there form di-
minutive sexual plants about the size of pin-
heads. Upon these tiny creatures the sperma-
ries and egg-organs are produced. The sperms
have two swimming-hairs like those of mosses. The gen-
eral structure of the spermary and egg-organ is quite like that
in the horned liverwort, and the sexual plant of the club-moss
may be compared to a horned liverwort prostrate stem very

FIG. 49. Branch of a
club-moss plant,
bearing two cones;
with a single leaf of
the cone, showing
the spore case and
one of the spores,
the latter much mag-
nified. After Atkin-
son.

Minnesota Plant Life.

157

much reduced in size. When an egg lying at the bottom of the
organ which produced it has been fecundated, it segments by
partition-walls. One of the first two cells develops into the
embryo. Some of the cells later produced form the first leaf
of the embryo plant. Another group forms the apex of the
stem, and still another matures into a bulbous body which nurses
upon the tissues of the sexual plant ; while, much later, from the
interior of a root-like elongation a group of cells pushes its way
out as the first true root.

In all the higher plants roots seem to have originated from
inner portions of the plant-body and may be regarded as being
everywhere protrusions of the sap-conducting areas, so that the
root is essentially an absorbent tract, while its functions of sup-
port are secondary.

The embryo plant thus started on its career continues to
grow, thickening its stem, forming new leaves and branches and
multiplying its roots. Unlike the moss capsular plant, but like
the capsular plant of the horned liverwort, it never of its own
accord stops growing, but only when the growth is terminated
by outward unfavorable conditions. As it grows and branches
year by year, it soon becomes strong enough to form spore-
producing areas of its own.

In club-mosses the spores are in little pouches, one on the
upper side of each leaf on the cone-shaped tip of some branch.
The end of the branch which produces spores becomes cov-
ered with leaves, sometimes of a different color, drier and paler
than the ordinary foliage leaves. Such cones are equivalent
to the cones of pine-trees which are supposed, indeed, to have
arisen from similar simple types. Each cone consists of an
axis clothed with spore-bearing leaves. Since the latter in most
club-mosses are specialized to some extent for their reproduc-
tive functions, they progressively abandon the starch-making
function ; hence, not needing illumination, they stand closer to-
gether, overlapping each other as they would not do if depend-
ent upon the sunlight for leaf-green energy. Having taken
such positions they become bleached and while the general
plant-body of a club-moss is provided with green, unbranched,
rather needle-shaped leaves, the cones by their yellow color and
flatter and more closely crowded leaves, become distinct areas
of the plant. Yet in types of club-mosses lower than the ordi-

158

Minnesota Plant Life.

nary Christmas-green variety, the same leaf which produces a
spore-case upon its upper surface is also depended upon by the
plant for leaf-green work, and the division of labor marks only
the higher types.

The lowest in structure of all club-mosses is a New Zealand
form not more than an inch and a half or two inches in height
and typically unbranched. A single slender erect axis is pro-
duced, bearing foliage leaves near the base in a little rosette, while
above, the end of the stem develops as a cone with small spore-
forming leaves. Such a plant may be regarded as equivalent
to the cylindrical capsule of a
horned liverwort in which longi-
tudinal and transverse bands of
sterile cells have been developed
— something which was foreshad-
owed in certain horned liver-
worts— separating into chambers
the general layer of spore-moth-
er-cells surrounding the central
column. It is conjectured that
the sterile tissue in the ancestral
plants underneath each chamber
bulged out into a leaf-like expan-
sion and these leaves separated
from each other longitudinally.

Therefore the axis Or Stem Of a FIG- 50. Flat-branched club-moss. After

Britton and Brown.

club-moss is conceived to com-
pare best with the central cylinder of supporting tissue in a
horned liverwort capsule and not with the stalk of a moss cap-
sule. The leaves of the cone are conceived to compare with
sections of the capsular wall, each section bearing on its inner
surface its own portion of the spore-mother-cell tract. The root
is conceived to be a new structure, and outgrowth of the central
cylinder. The tip of the horned liverwort capsule is regarded as
equivalent to the tip of the cone in a club-moss. All these points
may be best understood by comparison with the simple New
Zealand club-moss in which abundant branching of the spore-
producing plant does not take place.

As the spore-producing plant of the club-moss has acquired
new powers and new perfections of structure along vegetative

Minnesota Plant Life.

159

as well as along spore-producing lines, so the sexual plant — the
one developed from the spore — has become reduced and is sim-
pler, smaller and less important than the sexual plants of liver-
worts or mosses.

Different kinds of club-mosses in Minnesota. The different
kinds of club-mosses in Minnesota are distinguished by differ-
ent habits of branching, different shapes of leaves and the vary-
ing distinctness with which the cone-area is blocked out in the
general plant-body. Some, as the tree-like club-moss or ground-
pine, have erect stems with subsidiary branches like those of a

pine. Another kind has the leaves
flattened in a peculiar way like the
leaves of the white cedar. In still
another species the plant-body
branches loosely and trails over the
ground, while in yet another the
stem forks, and tufts
of branches are pro-
duced, reminding one
a little of the true-

FIG. 51. Smaller club-moss. To the left a plant with three JVIQCCPC
cones, next a single cone dissected to show the spore

cases, next a single large-spore-case with four spores The fOCk-Cltlb-

revealed, and on the right a small-spore-case with the ^^ . .

small spores sifting out. After Atkinson. mOSSCS. 1 he Smaller

club-mosses or rock-
club-mosses are pretty abundant throughout the state wher-
ever dry rocks or rocky hills occur. The leaves in the com-
mon species are pressed close together along the stem and
each has at the end a white bristling hair, giving a hoary ap-
pearance to the whole plant. The cone-areas are not so dis-
tinctly different in appearance from the rest of the plant-body
as in the larger club-mosses. The great peculiarity of these
plants is their production of two kinds of spores. In some of
their spore-cases two hundred or more small spores will be
produced, each somewhat pyramid-shaped, while in other spore-
cases — perhaps in the very same cone — there will be produced
four much larger spores with variously marked walls and of a
generally spherical shape. When a smaller spore germinates,
it produces a little male plant so insignificant that it never comes
outside its spore-wall, but forms and matures altogether within.
This little male creature produces a few sperm cells. When

160 Minnesota Plant Life.

the spore-wall breaks, as it does eventually, the sperm-cells are
liberated and swim away in the water after some rain or heavy
dew. When the large-spores germinate each produces a fe-
male plant which, like the male, remains within the spore and
does not push out as did the sexual plants of liverworts, mosses
and the larger club-mosses. The female is very much larger
than the male, and each plant fills the spore from which it de-
veloped. When the female is mature, one, or sometimes more,
egg-producing organs are formed at the surface of the cell-mass
inclosed in the large-spore. After the egg-organ with its in-
closed egg has matured, the wall of the large-spore breaks just
over the imbedded neck of the egg-organ. This permits sper-
matozoids to enter and by means of one of them the egg is
fecundated and begins segmenting into an embryo in which
stem-areas, root-areas, leaf-areas and nursing-foot-areas are pro-
duced. In the smaller club-moss a great reduction of the sex-
ual generation is apparent. The sexual plants do not even
come outside of their spore-walls. They do no independent
vegetative work but the species depends for its subsistence upon
the starch-making power of the spore-producing plant.

Origin of the seed of higher plants. The smaller club-
mosses while of slight economic importance are of extraordinary
scientific interest because they illustrate how in the history of
the vegetable kingdom that important structure, the seed of
higher plants, probably originated. The habit of the female of
remaining within the spore must have antedated the origin of
the seed. In seeds not only does the female remain within the
spore but the spore remains within its case and the female ob-
tains fecundation of her egg by the cooperation of a pollen-tube,
while the spore-case need not open. When the embryo has
begun to form from the egg the whole spore-case, with some
adjacent layers of cells, ripens and a seed is the result. The
smaller club-mosses foreshadow this still more strongly in some
species where the large-spores begin to germinate internally be-
fore they fall from their spore-cases. Yet no smaller club-moss-
plant ever really produces a seed, for in all of them sooner or
later the spore is ejected from its case and thus there is pre-
vented from arising the exact combination of conditions upon
which seed formation depends.

Chapter XVIII.

Ferns and Water-ferns.
If

Related to club-mosses in about the same manner that true
mosses are related to horned liverworts are the ferns, a very
ancient and singular group of plants. In Minnesota about fifty
species occur, found for the most part in woodland. One va-
riety, the brake, is an exceedingly common plant in all burned
districts of the forest region.

Adder's-tongues and moonworts. There are two principal
groups of ferns recognized by botanists. Of the lower group,
the so-called grape-ferns or moonworts and the adder's-tongue
ferns are specimens. In these each leaf consists of two lobes,
one — the so called sterile lobe — being devoted entirely to
starch-making, the other — the so called fertile lobe — having for
its exclusive function the production of spore-cases. The fer-
tile lobe grows from the inner face of the sterile lobe, occupy-
ing relatively to the sterile lobe the same position maintained by
the spore-case of a club-moss with reference to the leaf upon
which it was situated. It is believed that the fertile lobe of an
adder's-tongue fern-leaf is equivalent to a large, chambered and
overgrown spore-case as displayed in the club-mosses, and it is
believed that the sterile segment of the leaf is equivalent to the
blade of the spore-case-bearing leaf in the club-mosses.

The adder's-tongue ferns with their slender fertile lobes bear-
ing two rows of spore-cases and their undivided sterile seg-
ments, are simpler than the grape-ferns with their palmately
branched leaf-segments. In these plants the spores upon germ-
ination give rise to little tuberous sexual plants which lie almost
imbedded in the soil and are devoid of leaf-green, being humus
plants. Upon such little tubers the egg-organs and spermaries
develop and after fecundation the egg forms an embryo which
nurses for a time upon the sexual plant, then thrusts its own

12

162

Minnesota Plant Life.

FlG. 52. Adder's-tongue fern. After E. N. Williams in Mediates Monthly.

Minnesota Plant Life.

163

roots into the soil and begins an independent life. The spore-
producing plants like those of club-mosses are perennial, but
the egg- and sperm-producing plants die within a few weeks or
months after they are formed.

Quillworts. A very curious group of plants known as quill-
worts, found growing on lake bottoms in northern Minnesota,
are considered to be distant relatives of the adder's-tongue ferns.
They produce two sizes of spores, large and small, and quite as
in the life-history of the smaller club-mosses the large-spores
give rise to internally developed females, while the small-spores
produce diminutive males
not protruded beyond the
spore walls. K ni b r y o
quillwort plants originate
from the fecundated eggs
and when they have be-
come old enough renew
the production of spores.
These are formed in cu-
riously partitioned cham-
bers at the base of, and on
the inner face of the long
quill-shaped leaves. The
spore-producing area of
the leaf occupies the same
relative position with ref-
erence to the starch-mak-
ing area that was seen in
club-mosses and adder's-
tongue ferns. The upper portions of the leaves contain air-
chambers by means of which the leaves stand erect at the bot-
tom of the lake. Some varieties of quillworts, also represented
in Minnesota, grow in swamps and marshes and cannot be dis-
tinguished except by the closest observation from tufts of sedge
or grass.

Ordinary ferns. Quite different in a number of structural
details are the "true" ferns, the group to which almost nine-
tenths of the Minnesota species belong. These are plants with
habits of growth which are, in a general way, pretty well known

FIG. 53. Virginia grape-fern. After Brittoti and
Brown.

1 64

Minnesota Plant Life.

by all who frequent the woods. Of true ferns there are nine
families, only four of which are represented in Minnesota.
The filmy ferns, the tree-ferns, the forking ferns, the twining
ferns and the Borneo ferns are not represented by plants in-
digenous to the state. The families present are the bracken-
ferns and their various allies, the flowering ferns, the floating-
ferns and the four-leaved water-
ferns. Of these the lowest in type
are the flowering ferns, three spe-
cies of which occur in Minnesota.
One of them, known as the inter-
rupted fern, is a common plant,
presenting a peculiar appearance as
if somewhere near the middle of the
large leaf two or three leaflets had
shriveled. These leaflets, unlike

Fie*. 54. A quillwort plant. After At-
kinson.

FIG. 55. Clayton's or interrupted fern. After
Hritton and Brown.

the rest, have a brown and withered look. If examined closely
it will be discovered that this is due to their being covered with
spore-cases of a brown color, while the rest of the leaflets pro-
duce no spore-cases whatever. Another fern of this family is
the cinnamon fern which forms leaves of two sorts, some

Minnesota Plant Life.

'65

much larger and green, adapted solely to starch-making, others
smaller, of a cinnamon color and devoted particularly to spore-
making. A third species is sometimes known as the royal fern.
The leaves are compoundly branched and leaflets towards the
tip produce spore-cases, while lower branches of the leaf make
leaf-green and form no spores.

Of the common ferns belonging to the family of bracken-
ferns, there are the polypody, abundant upon rocks in all

FIG. 56. Bed of ferns. Sensitive fern in middle of foreground. After photograph by

Williams.

parts of the state; the maiden-hair, with its slender, wire-like
leaf-stems and graceful leaflets, common in woodlands; the
bracken-fern with its loosely branched leaves; the cliff-brakes
growing in crevices on cliffs and high banks; the spleen-
worts and lady-ferns with their delicate leaves; the walking
ferns found upon rocks and so named from their habit of
stretching out their long leaves and driving the tips into the
ground forming there buds from which new plants develop;

1 66

Minnesota Plant Life.

the beech-ferns; the shield-ferns, and the bulblet-ferns recog-
nized by the formation on their leaves of bulbils which drop
off and propagate the plant. Besides these there are the little
brown Woodsias found upon rocks and distinguished by the
dry aspect of their leaves, and, in rich woods, the sensitive
ferns and ostrich-ferns peculiar among bracken-ferns for the
development of two kinds of leaves much as in the flower-
ing ferns. The ostrich-fern especially is a regal plant. Grow-
ing in damp glades of
the forest it spreads its
tall graceful fronds, out-
lining a green Corinthian
capital. In the centre
there spring up four or
five smaller feather-
shaped brown leaves
which have abandoned
starch-making and devote
themselves entirely to the
production of spores.

The four-leaved water-
fern. Most remarkable
in some respects of all
ferns is the four-leaved
water-fern. It does not
always grow in water but
is found in dry creek-
beds at the extreme western edge of Minnesota. The plant-
body consists of a thread-like, creeping, branched stem from
which small leaves, resembling four-leaved clovers, arise. These
are the vegetative leaves of the plant, but the spore-producing
leaves are modified into capsules about the shape of an ordinary
bean but considerably smaller. If one of these beans is chipped
on the side and placed in a dish of water it will open like a clam-
shell and in about twenty minutes a centipede-like object, three
or four inches long and as thick as a crochet needle will uncoil
itself. It seems absolutely impossible that so large an object
could have been packed away inside the bean-like leaf. The

FIG. 57. Cliff-brake. After Britton and Brown.

Minnesota Plant Life.

backbone of the centipede-shaped affair has, however, the ap-
pearance of clear jelly and is enormously swollen by the ab-
sorption of water. The "legs" of the centipede, twelve to
eighteen in number on each side, are yellowish and upon close
examination appear to be elongated transparent sacs in each
of which a number of pearly yellow bodies of generally oval

!•'!<;. 58. The interrupted fern (in background) and shield-ferns (in foreground). After
photograph by Williams.

shape are situated. These bodies are spore-cases, some of
them containing sixty four small-spores and others containing
one large-spore, each. As* in quillworts and smaller club-
mosses, the small-spores produce little reduced males while the
large -spores develop females. The egg of the female, never
more than one to the plant, segments, after fecundation, into

1 68

Minnesota Plant Life,

Four-leaved water-fern.
Brown.

After Britton and

an embryo which sucks
up all the surplus food-
materials that were de-
posited in the large-
spore, produces a root of
its own, thrusts it into the
soil or water and begins
an independent existence.
The Minnesota variety is
a land-dwelling species of
a group which is more
generally aquatic, hence
the name of water-fern.

The fusion of the egg
and the sperm in ferns can
take place only after heavy
rains, or when the melt-
ing snows of early springs FlG-
have flooded the station
of the plant. All ferns, and indeed, most plants, up to and includ-
ing the cycad-palms and ginkgo trees, are essentially aquatic in

their breeding hab-
its. Most of them
have motile sperms
provided with swim-
ming hairs, and un-
less there is a me-
dium in which the
sperm can swim it
will never reach the

egg-

Floating ferns.

The family of the
floating ferns is rep-
resented in Minne-
sota by a little plant
called A zolla, not un-

FIG. 60. A sexual fern-plant somewhat magnified. Its nat- COmmon m greeil-

ural size is about a quarter of an inch across. The round h O U S C S where it

bodies are spermaries, the chimney-shaped ones are egg- ,,

organs, seen from below. After Atkinson. floats UpOll the SU1~-

Minnesota Plant Life.

169

face of the water in tanks. It has a much branched stem and
tiny, rather ovate leaves. The whole body resembles that of a
scale-moss. As they grow the leaves form peculiar cavities,
opening by a narrow aperture through which a little alga in-
serts itself and is a constant companion of the Azolla plant, for
in all Azolla leaves are found growths of this little blue-green
alga. Like the leaves of the scale-mosses, those of Azolla have
two lobes, one, the floating lobe, lying upon the surface of the
water and the other, the submerged lobe, lying below. The
spore-cases are borne in groups upon the submerged lobe.

FIG. 61. A fern-plant embryo imbedded in the enlarged egg-organ, where it arose by seg-
mentation of an egg. S, tip of rudimentary stem; I,, tip of first leaf; R, tip of primitive
rootlet; F, nursing foot. Much magnified. After Atkinson.

There are twro kinds of spores, large and small, and several of
the spore-cases which produce small-spores are developed in
clusters and inclosed by a general protective wall. The spore-
cases which develop the large-spores occur singly within such
a wall and each large-spore-case produces a single large-spore.
When the small-spore-cases open, simultaneously several small-
spores escape imbedded in a lump of frothy mucilage upon
which curious little anchor-shaped barbed hairs are disposed.
The large-spore, when its case opens, is found to have one end of
its wall provided with low flat-topped excrescences from each

Minnesota Plant Life.

of which a tuft of delicate threads protrudes. As the frothy
masses in which the small-spores are imbedded drift near one
of the large-spores,
their anchors be-
come entangled i n
the hairs of the large-
spore, and thus one
or more of the mass-
es is secured in such
a position that when
the small-spores
germinate, protrud-
ing from each a

little tubular Olailt- ^IG- 62. Portion of maiden-hair fern-leaf, showing marginal

pockets, which serve to protect the clusters of spore -cases
bOCly, the SpermS, under each flap. After Atkinson.

formed by the male,

will not have far to swim to reach the egg.

Explanation of what fern
leaves really are. In all the
ferns belonging to the series
known as the true ferns, the
spore-cases are little stalked pods
containing from one to about
sixty four spores, never much ex-
ceeding that number. These
spore-cases may be seen in the
polypody, forming on the under
side of the leaves small brown
circular patches. In the maiden-
hair and bracken-ferns they oc-
cur under pocket-shaped flaps of
the leaf-margin. In the shield-
ferns each group of spore-cases
on the under side of the leaf is
protected, at least while young,
by a shield-shaped or umbrella-
shaped membrane growing over
the group. It is the rule among

the true ferns that the leaf which bears the spore-cases also

serves as the starch-making organ of the plant, but in the OS-

FIG. 63. A patch of spore-cases on the back
of a common polypody-fern-leaf. Mag-
nified. After Atkinson.

Minnesota Plant Life.

171

trich-ferns, the sensitive fern, one of the flowering ferns, the
four-leaved water-fern and some other forms which have not
been mentioned, there is a division of labor and the leaf which
makes starch is not also designed to produce spores.

In comparing the true ferns with the adder's-tongue ferns,
it would appear that the condition of things is somewhat pe-
culiar. Since it bears the spore-cases it would seem that the

cr^

^

~- rs^^j&^U Xs.

p:a" " JT^X^ •% ^

o^o^^T^^^SS ^>S
s^s^WAte^1: / -'- ~^ -N^ °*>

-•*• - .- *-N\ \ N i, \^

!•'!<'•. »>4. Spore-cases of the common fern, much magnified, showing how the spring back
reverts and then snaps shut again, throwing the spores as from a sling. After Atkin-
son.

ordinary fern-leaf compares only with the fertile lobe of the
adder's-tongue fern-leaf. This fertile lobe has greatly enlarged
and assumed the function of starch-making. At the same time
the spore-cases have come to be developed from special cells at
its surface, not from mounds of cells as in the lower form.
\Yhat, now, has become of the sterile segment of the adder's-
tongue fern-leaf? The most reasonable reply to this question
that can be offered is that it has undergone steady reduction and

172

Minnesota Plant Life.

FIG. 65. A walking-fern climbing down a hillside. Buds form at the very tips of the slender
leaves and grow into new plants. After Atkinson.

Minnesota Plant Life.

173

has finally disappeared. In a family of tropical ferns not rep-
resented in Minnesota are found traces of this sterile segment
as stipular plates at the bases of the leaves. Therefore, we arrive
at the interesting and remarkable hypothesis that the entire
fern-leaf compares with a much elaborated and improved club-
moss spore-case. It will be remembered that the fertile seg-
ment of the adder's-tongue leaf was believed to be an over-
grown chambered spore-case arising from some club-moss-like

FIG. 6(3. Maiden-hair ferns and lady ferns. After photograph by Williams.

ancestral condition. Therefore, among true ferns the common
type of leaf in which both starch-making and spore-production
are combined, is the primitive one. By a division of labor,
some leaves quite abandoned the habit of producing spore-cases
and others in the same plant intermitted the production of leaf-
green. Thus are explained the two sorts of leaf in the ostrich-
fern and the same explanation serves for the cinnamon fern and
its allies and for the four-leaved water fern.

174 Minnesota Plant Life.

In a word, the most distinctive feature of the ferns is this:
They loosened that cone-arrangement of leaves which had arisen
in the club-mosses and greatly developed the spore-case-area
of each leaf until such an area became itself a leaf-like structure,
while the original blade of the leaf deteriorated and disappeared.
The pine trees, also related to the club-mosses, pursued a very
different course of development and retained the cone as a struc-
tural unit. From bodies somewhat similar to pine-cones it
is probable that the flowers of all higher plants arose. The
club-mosses then have originated two great lines of improve-
ment, one in which the cone was abandoned as a structural fea-
ture, giving rise to the ferns, the other, in which the cone was
retained as a structural feature, leading to the flozvering plants.

Chapter XIX.

Scouring-rushes and Horse-tails.

The peculiar family of plants known as scouring-rushes or
horse-tails was very much better developed during the age when
coal was being deposited than it is to-day. Most of its species
are extinct, but there remain, widely distributed over the world,
some forty different varieties, of which ten occur in Minnesota.
They are not very closely related either to the ferns or to the
club-mosses, although they clearly belong in their general vicin-
ity. The unbranched forms are known as scouring-rushes on
account of the usual deposit of silica in their outer layers.
This mineral is useful for scouring tinware, and rushes are
actually thus employed by some housewives in the country.
The branched forms are known as horse-tails from their peculiar
aspect as they stand in fields, in the woods or along the road-
side or railway tracks.

Each variety of scouring-rush or horse-tail is distinguished
by an underground rootstock which shows much the same struc-
ture as the above-ground portions. Sometimes on the root-
stocks tuber-like propagative swellings are formed. Both the
erect and subterranean branches are divided into very distinct
joints which may be separated from each other like sections of
stove-pipe, hence the plants are also called joint-rushes. In
some species the plant produces only one kind of erect stem
and at the tip of this, or more rarely at the tips of lateral
branches, firm and solid cones are borne, each made up of little
shield-shaped leaves with central stalks. The leaves are ar-
ranged in circles about the axis, not in spirals as in the cones
of club-mosses. On the under side of each of the shield-shaped
leaves a ring of spore-cases is developed, commonly about eight
in a group. The cones bear the leaves so close together that
from their mutual pressure they assume a more or less hexagonal
outline.

176 Minnesota Plant Life.

Scouring-rushes with two sorts of erect stems. In a few
of the species there are formed two kinds of erect stems. One
is pale or reddish in color, softer to the touch, provided with
longer leaves below the cone, devoid of leaf-green and de-
voted to the work of spore-production. The other is repeat-
edly branched, the branches arising in circles at the top of
each joint of the stem. Upon such erect stems no cones
are ordinarily displayed, but the whole plant-body is
green and starch-producing. Both kinds of erect
branches are, however, very similar in internal struc-
ture. They are hollow and their wood-threads are ar-
ranged in a circle, usually with air-canals between them
and within them. At the top of each joint a group of
leaves arises in a ring. These are not used for starch-
making but are reduced and scale-like and commonly
blended together by their edges into a collar closely
enveloping the lower part of the joint immediately
above. On the special spore-producing branches the
leaves are often larger and less completely fused to-
gether. Sometimes the leaves are black in color with
gray tips, as in a well-known joint rush of Minne-
sota. In all the varieties the starch-making is done
not by the leaves but by the branch-system, so that in
this respect the plants resemble the well-known aspar-
agus, to which they bear, however, no close botanical
relation.

When the spore-cases on the shield-shaped leaves
open to eject their spores, the spores may be shaken out
into the hand as a green dust. If one watches this dust
as it lies upon the hand immediately after

JIG. 67. A fruiting stem

of the horse-taii. having been shaken from the cone, it will be
s™ere-£aertagtTeds seen that within a couple of seconds after its
are aggregated in a deposit it fluffs and becomes of 3. lighter

cone. After Atkin- . .

son. color. By warming it gently with the breath

it regains its darker hue and more solid ap-
pearance, but in a couple of seconds it fluffs again as it did
before. This remarkable behavior is explained if the spores be
examined under a good microscope. It will then be observed
that apparently attached to each of them are four delicate spoon-

Minnesota Plant Life. 177

shaped appendages which are very sensitive to moisture. These,
when dampened, contract around the green spherical spores,
hugging them tightly, but as they dry they straighten, loosen-
ing the spore-mass in the process. This is why the moistened
dust seems more solid than the same dust when dry. The
spoon-shaped appendages originate by the splitting of the
outer wall of the spore into two ribbons, as if a couple of peel-
ings had been removed. An idea of the arrangement can be
obtained by imagining the cover of a base-ball unsewed and laid
back. The two pieces of cover would then occupy much the
same position with reference to the ball as do the four longer
and slenderer spoon-shaped appendages with reference to the
spore.

Germination of spores. Although all the spores are of the
same size and appearance, yet it is the nature of some of them
upon germina-
tion to develop
little green,
prostrate
male s, some-

tlllllP' like Small FIG. 68. Scouring-rush spores; to the left a spore with appendages
i 1 i • curled up, in moist air; to the right a spore with appendages ex-

n O r 11 6 Q liver- tended, in dry air. After Atkinson.

wort plants,

while others develop females, slightly larger than the males but
in general closely resembling them. Both the male and the fe-
male scouring-rush plants are provided with leaf-green, emerge
from the spores, strike their root-hairs into the soil and lead
an independent existence. The males produce microscopic
spherical spermaries in which arise spermatozoids with large
numbers of swimming threads. The females produce a few
egg-organs of the characteristic bottle-shape, at the bottom of
each of which a single egg is formed. After the fecundation of
the egg during rains, or when in some other way plenty of
water is available as a medium for the locomotion of the sperms,
the embryo of the scouring-rush begins to grow very much
as did that of the fern. An erect stem is first produced, then
from its base a rootstock. If at the end of the year the erect
stem dies, buds on the rootstock remain to form the stems of
the succeeding year. By means of its underground stem the
13

178 Minnesota Plant Life.

spore-producing generation of the plant is perennial, but the
sexual plants die after they have performed their functions.

Male and female plants. It is now possible to understand
the meaning of the curious sensitive appendages of the spores.
The spores when ejected are separated from each other into little
groups by the writhing of their appendages. The individual
spores are not, however, entirely isolated, and that degree of
moisture which is favorable for germination impels the append-
ages to pull the neighboring spores close together, so that when
they germinate, male and female plants shall not be too far apart
for the convenience of the swimming sperm. This is a very good
example of the extraordinary adaptive relations which come to
exist between sexual and spore-producing plants of the same
species. The appendages of the spores have seemingly no mean-
ing in the life-history of the spore-producing plant itself, but they
function in such a way that the task of the sperm-producing plant
is made easier and thus the development of fecundated eggs is
insured, for the perpetuation of successive generations. Upon
clay banks, where there are shade and moisture, one will often
find among the young scouring-rushes or horse-tails some of
the tiny sexual plants looking very much like diminutive liver-
worts as they lie more or less prostrate upon the soil.

Different sorts of horse-tails and scouring-rushes. The dif-
ferent kinds of horse-tails and scouring-rushes in Minnesota are
distinguished by slight structural peculiarities that need not be
discussed in detail. The rigid, jointed, unbranched forms, three
or four feet in height, which grow along shaded banks are per-
haps, in their tissues, the richest in silica or sand, and are the
ones which have particularly merited the name of scouring-
rushes. The very much branched variety which is such an abun-
dant weed in neglected fields, along roadsides, and in the edges
of woods, is a different species. A third species, in which the lat-
eral branches curve downward in a characteristic way, is abun-
dant in northern woods and is named the forest horse-tail. Still
another kind is often found growing at the edges of ponds and
streams, now and then forming great patches in bays and occu-
pying the same general position that is ordinarily selected by
bulrushes. This, which may be termed the water horse-tail, is
commonly not very much branched although under certain

Minnesota Plant Life.

179

growth-conditions it is capable of branching almost as abun-
dantly as the field horse-tail. A curious dwarf variety two or
three inches high is sometimes found growing in tufts in deep
woods. It is reported from the St. Croix river valley, but I
have not seen authentic specimens of it from Minnesota.

Underbrush habits of horse-tails. When the branched va-
rieties of horse-tails grow in the edges of woods they often be-
come very much taller than in fields. This they accomplish by
thrusting out their rigid side-branches in every direction and
permitting them to rest upon the twigs of surrounding shrubs
or herbs. Thus they can distribute their weight in such a way
that the main stem is relieved and the axis may extend itself
vertically farther than otherwise. Plants which lean in such
fashion upon surrounding plants are known as braced-plants.
They are not exactly dependent for their well-being upon the
presence of other plants as are the climbers and twiners, but
they do derive some advantage from their habit of letting a
portion of their weight rest upon plants near them.

It is really, if one stops to think of it, quite as much of an
engineering problem to erect a slender stem as to build an Eifel
tower, and it is no less impossible to extend a leaf into the air
without due regard to the strength of materials than it would
be to build a cantilever bridge from wet paper. Plants mani-
fest architectural design and the problems of structural engi-
neering are not at all unlike those requiring solution by the
human architect or bridge-builder when he enters upon the
plans of a new .structure. So it is obvious that the bracing of the
side branches of horse-tails, thus diminishing the strain upon
the main axis, might enable it under the same general type of
structure, to reach a greater elevation into the air. In South
America, by bracing devices scouring-rushes grow to a height
of twenty or thirty feet, though they are not thicker than an
ordinary walking-stick. Where the forest is dense and dark
such a plan is seen to be highly advantageous and perhaps even
necessary, but in the lighter, thinner forests of Minnesota there
is no need of such extreme length.

Chapter XX.

What Seeds are and how they are Produced.

About 150,000 different kinds of plants produce seeds. A
seed may be defined as a young plant and its reserve-food-
material enclosed within a normally protective layer. Some-
times the food-material is deposited beside or around the
plantlet, as in the seeds of Indian corn and wheat. Again the
food-material may be collected in the plantlet itself, giving to
it a white, meaty appearance, and pumpkin and bean seeds are
of this structure. It is a mistake to say that plants grow from
the seed, or rather it is a half-truth, for the question is whence
did the plantlet come that is already present in the seed and
needs only to renew its development when the seed germinates?
This can be answered in a word. Leaving out of considera-
tion some abnormal or peculiar conditions of development, it
may be said that all plantlets in seeds arise from eggs. The
next question is whence comes the egg from which the plantlet
in a seed develops? The reply is, that the egg, as in all other in-
stances, is produced in the body of a female plant. Still an-
other question — where is one to look for the female plant of a
rose or willow, or any other seed-producing species? To this
inquiry the answer is, the female, like all other females in the
great series of terrestrial plants, develops from a spore. Again,
one inquires, where is the spore to be sought? To this is the
response that it is formed in the young ovule or rudimentary
seed, occurring as a more or less oval, cylindrical or elongated
cell in the centre of the seed-rudiment.

What then is the seed-rudiment? It is a spore-case which
produces at its centre the single, large, thin-walled spore. In
seed-plants such a spore is called an embryo-sac and it may
easily be found by opening young pine-seeds in cones not more
than twelve months old. Unlike the large-spores of the smaller

Minnesota Plant Life.

181

club-moss, these seed-plant spores are not ejected from their
spore-cases, while, just as in the smaller club-moss, they de-
velop females which are retained within the spore-wall and upon
the bodies of these females egg-cells are formed. How is it
possible for such an egg, developed and retained within the
tissues of a spore-case, to ob-
tain fecundation? Here comes
into play an adaptation on the
part of the male-plants of the
seed - producing varieties.
Where is one to look for the
male cottonwood tree? Like
other male plants it originates
from a spore, not, however,
the large-spore, enclosed in the
rudimentary seed, but the
small-spore known as the pol-
len-grain, developed in large
numbers upon special leaves
known as stamens. What sort
of a plant arises when a pollen
spore germinates? Before re-
plying to this question another
must be asked. Where does a
pollen-spore germinate? Not

Upon the Soil, Or in the Water, FlG- «• Diagram of an ovary, with one seed-
rudiment, in a higher seed-plant, s. The

as did the small-spores of ferns

stigma, where two pollen-spores have germi-
nated; o, wall of ovary; f, stalk of ovule;
ai and ii, rudimentary seed-coats; n, spore-
case, with single large spore, which has
germinated to produce the reduced female
plant; k, the egg; e, the body which forms
the albumen; b, other cells of the female.
The male plant is shown as a tubular
thread growing towards the egg. After
Atkinson.

and smaller club-mosses, but
upon a certain portion of the
body of a spore-producing
plant of its own species, a part
usually in close proximity to
the rudimentary seeds. This
area upon which a spore of the smaller kind is able to germinate
is known as the stigma in higher flowering plants, but in the
lower families the pollen-spores fall immediately upon the im-
mature seeds.

Breeding habits of seed-plants. Returning now to the ques-
tion, what sort of a plant arises when a pollen-spore germinates,

1 82 Minnesota Plant Life.

the reply is, a delicate thread, like a cobweb, comes into exist-
ence and grows much as a parasitic fungus filament would
grow through the tissues of the immature fruit down to the
surface of the large-spore, imbedded in the rudimentary seed.
By this time the female has developed within the large-spore and
has produced her egg. The end of the pollen-tube, as the male is
termed, penetrates the wall of the large-spore and transfers a
male nucleus, or sperm, which fuses with the egg and thus
fecundation is accomplished. Then the egg becomes an embryo
which grows and produces a short stem, one or more seed-
leaves (in most plants) and a root. While the embryo is devel-
oping, the tissues of the spore-case and the membranes sur-
rounding it become modified into the outer layers or seed-coats.
When the embryo pauses in its growth and passes into a tem-
porary dormant condition the seed is said to be ripe. It may
not, however, be able at once to germinate.

If the reader has closely followed this explanation he will
be aware that is is improper to call a pollen-producing plant
a male and he will understand that there is no comparison at
all between the sowing of pollen-spores on a stigma where
they are to germinate and a breeding habit, although the older
botanists supposed that such analogy existed. It is found that
seed-producing plants, like the smaller club-mosses, have two
sorts of spores, small-spores producing males, and large-spores,
females. As in the lower type, so also in the seed-plant, there is
a retention of the female within the wall of the spore from which
she originated. Unlike the smaller club-mosses, the male plant
is not retained within the wall of the small-spore, but pro-
trudes in the form of a thread of miscroscopic minuteness. The
retention of the large-spore within its spore-case, together with
the adaptation of the male plant so that fecundation may take
place without the opening of either the large-spore or its case,
lays the foundation for that compound and complex body, the
seed.

By these devices the embryo is kept in close proximity to
the vegetative areas of its species and in a pine seed there are
represented three successive generations. The coats of the seed
and sometimes a portion of the food-supply, as in water-lilies,
belong to the older spore-producing generation, for they are

Minnesota Plant Life. 183

parts of the same plant that produced the large-spore. The
meat of the seed, or albumen, belongs to the female, for it is
produced within the large-spore as it germinates. The embryo
plantlet of the seed belongs to the new spore-producing genera-
tion and arises by the segmentation of an egg. After it has
renewed its development — when the seed has germinated and
the plantlet has become old enough — it will be able in its turn
to produce spores. Therefore, the life-history of a cottonwood,
for illustration, is twice as complex as that of a man. While
there are only two kinds of individuals in the human species,
there are four in the cottonwood: first, the pollen-producing
tree or staminate cottonwood; second, the seed-rudiment-pro-
ducing tree or pistillate cottonwood; third, the male cotton-
wood or pollen-tube arising from the pollen-spore and growing
as a parasite upon the tissues of the young cottonwood fruit;
fourth, the female cottonwood, a microscopic plant inclosed in
her spore deep within the rudimentary seed. Indeed there may
even be five kinds of cottonwoods, for in higher seed-producing
plants there is strong reason to suppose that the albumen of the
seed is in reality a degenerate plantlet — a twin brother of the
embryo — produced from an egg, rather than, as in the pines, a
portion of the female plant-body.

From this discussion it will be seen how inaccurate is the
common statement that higher plants grow from seeds while
lower plants are produced by spores and it is understood how
erroneous is the phrase, so general, especially in popular works,
that the spores are the seeds of the fungi or ferns. The higher
plants produce spores just as truly as do the lower plants,
but in the former a peculiar relation of dependence has come
to exist, precisely the reverse of that which was observed in the
liverworts. In the latter the capsular plants, that is, the spore-
producing plants, were dependent upon the sexual plants for
their food-supply and remained perched upon their bodies all
through life. In the club-moss group these little perched plants
learned how to maintain an entirely independent existence and
put forth leaves and roots of their own. In the seed-plants they
have become so important and powerful that they do all the
vegetative work of their species while the once stronger and
larger sexual plants are reduced to microscopic structures of

184 Minnesota Plant Life.

an altogether dependent life-habit. A few definitions may not
here be out of place and will be given in as tmtechnical language
as possible.

Definitions of certain words. Pollen is a dust consisting of
small spores, capable, upon germination, of producing male
plants. The embryo-sac is a large-spore developed in the rudi-
mentary seed and capable of producing a female. The pollen-
spores are produced in special spore-cases situated on leaf-like
organs called stamens. The embryo-sacs are commonly pro-
duced singly in bodies called ovules borne upon leaves known
as carpels. An axis upon which stamens or carpels or both are
generated is called a flower. An ovule which has matured,
normally as the result of a breeding act, is called a seed. The
carpel, or carpels of a flower with the enclosed seeds, is called
a fruit.

Two series of seed-producing plants. There are two series
of seed-producing plants, the lower, in which the pollen-spores
fall directly upon the immature seeds and germinate, and the
higher, in which the carpels close around the immature seeds
and the pollen-spores fall and germinate upon a special portion
of the carpel or carpels known as the stigma.

Chapter XXI.

Ground-hemlocks and various Pines,
if

Of lower seed-plants there are five living and at least two
extinct families. In Minnesota but two of the five living fam-
ilies are represented. These are the yews and the pines.

Ground-hemlocks. The yews are represented by a single
species, the ground-hemlock, a well-known plant of wooded
banks and forests throughout most of the state. In England
a species of yew exists which becomes a large tree, but of the
four species in America none reaches any very great size, and
the ground-hemlock is the smallest of the group. It is an ever-
green shrub with leaves much like those of the balsam, and rec-
ognized by its crimson berries the size of small gooseberries.
The berry of the yew, however, is not a fruit but a seed, sur-
rounded by a red pulp-cup which may be regarded as a basal
outgrowth. Of all seed-producing plants in the state the yew
gives its seeds the least protection. In pines the seeds are en-
closed by the scales of the cone, and in all higher seed-plants the
seeds are developed within fruits and are never, from the first,
exposed, as in the ground-hemlock. The red pulp which en-
circles the yew seed makes it attractive to birds and it is dis-
seminated by their agency. Besides the seed-rudiments on
the branches, the yew produces little round cones consisting of
axes upon which are borne a few shield-shaped leaves. Each
of these resembles the spore-producing leaves of the scouring-
rush and on the under side of each a circle of pollen-spore-cases
are developed. The yew plants, of all Minnesota seed-bearing
forms, produce the largest number of pollen-spore-cases on a
single stamen. Usually the number is four, often but two, while
in the yew the number may be six or even more. The micro-
scopic male and female yew plants are short-lived, but the spore-
producing plant, beginning as an embryo in the seed, then after

1 86 Minnesota Plant Life.

the germination of the seed achieving independence, is a long-
lived shrub of somewhat prostrate habit, and with dark-green
leaves and tough-fibred wood in which resin does not occur,
while it does in plants of the related pine family.

Pines of different sorts. The pine family includes 13 or 14
Minnesota species out of a total of about 300 distributed over
all parts of the world. In these the rudimentary seeds are pro-
duced upon the inner sides of scales or carpels which, like the
stamens, are aggregated into cones. The pines and their allies
may therefore be said to produce two kinds of flowers, stami-
nate and pistillate.

Among the members of the pine family in Minnesota may
be mentioned the tamarack, a deciduous tree of social habit;
the pines of which three varieties, the white, the jack and the
red or Norway, grow within the borders of the state and are
dominant species of the northern forest; the spruces, of which
there are three varieties, the black, the white and the muskeg;
the balsam or fir, common in swamps; the white cedar or
arbor-vitae, a tree that flourishes best in the northern part of
the state; the hemlock, very rare in Minnesota, but occurring
in two isolated patches in St. Louis county and Carlton county ;
and the junipers, of which there are four species, one tree-like
in habit and known as the red cedar, the others low shrubs and
called savins or junipers.

The white pine. Among all these plants the white pine, the
most important timber tree of -the state, is of especial interest.
Its wood is light, resinous and easily worked. It is used in the
manufacture of lumber, laths, shingles, matches, sashes, doors,
blinds, woodenware, telegraph poles and the masts of ships.
Many millions of dollars are invested in mills for its manu-
facture into lumber, and in railways for the transportation of
the logs. This tree often grows over a hundred feet in height
with a trunk sometimes more than three feet in diameter. Its
bark is rough and deeply divided by clefts. When growing in
the open, as sometimes upon hills, for example, near lake shores
in Cass county, the lower branches are much prolonged and
the whole tree has a broadly conical form. But when a native
of the forest the lower branches become shaded out of existence
and the tree has the well-known compressed slender appear-

Minnesota Plant Life.

ance. The topmost branches usually dispose themselves in a
flamboyant manner, which makes it possible to recognize this
variety of pine as tar as it can be seen. The leaves are slender
prismatic needles, borne in groups of five, on special short
branches. They are of a somewhat bluish-green color, and dur-
ing their first winter are inclosed in small bright green buds.
The staminate cones are light-brown, egg-shaped, about a third
of an inch long and mature in a single season. The pistillate
cones are somewhat smaller at first, of a purplish color and
borne on the topmost branches of the tree, while the staminate
cones are usually developed on the lower branches. Originally
the pistillate
cones are erect,
but during the
first year of
their lives they
become heavier
and take a hori-
zontal position.
At this time
they are nearly
an inch in
length. The
next year they
grow rapidly,
become pendu-
lous, and reach their full size in mid-summer. They are now six
inches in length and seven-eighths 0f an inch or thereabout in
diameter. During the autumn of the second year, they open and
scatter their brown seeds, each of which is furnished with a del-
icate wing by means of which it is disseminated by the wind.
Within the seed will be found an edible albumen, with, however,
a strongly resinous odor, and in the centre of this stands the
straight young pine with from eight to ten seed-leaves growing
in a crown about the short apex of its stem. The root, before
it issues from the seed, is already provided with a root-cap and
the stem-area below the seed-leaves is short. The white pine
contains more resin than any other variety, yet it is not ordi-
narily used in the manufacture of turpentine as is the pitch pine
of the south.

FIG. 70. White pines on the rocks at Taylor's Falls,
graph by Williams.

After photo-

1 88

Minnesota Plant Life.

Pine trees do not spring up again after fires with nearly the
vigor possessed by a number of hardwood trees. In Minne-
sota hundreds of thousands of young trees are annually de-
stroyed by fire and their place is occupied by plants which are
comparatively worthless in the commerce of the state.

The Norway or red pine. The other commercial pine of
Minnesota is a somewhat smaller tree, averaging fifty to eighty
feet in height. This is commonly called the Norway pine by log-
gers, though a more correct name would be red pine. The bark
is of a reddish tint and much smoother than that of the white
pine. When standing in groves the tops of the red pines are

round, not irregular and crested
as are the tops of the white pine.
The leaves are produced in pairs
on short special branches. They
are dark-green, five or six inches
in length and shaped somewhat
like half-cylinders. The stami-
nate cones are longer and slen-
derer than those of the white
pine, grow in more elongated
clusters and are of a purplish
color. The pistillate cones are
at first almost spherical, red in
color and a quarter of an inch or
more in length. Like cones of
the white pine these pistillate
flowers take two years to mature and finally drop from between
their scales the smaller, darker seeds with wings shaped differ-
ently from those of the white pine seeds. The seedling plant
has fewer seed-leaves and is limited to eight, while five, six
or seven are more common numbers. The \vood is not so
easily worked as that of the white pine, nor do the logs float
so well in drives. The timber is, however, abundantly em-
ployed in the manufacture of buildings, trestles and sometimes
in railway construction.

The jack pine. The third species of pine in Minnesota, the
jack pine, is very prevalent in sandy soil throughout the north-
ern part of the state. It is a smaller tree than either of the

FIG. 71.

Jack pine. After Britton and
Brown.

Minnesota Plant Life. 189

others, but may in groves reach the height of seventy or eighty
feet. The top is more pointed or spire-like than that of the red
pine and the bark is rather thin and irregularly divided, a little
like elm bark. The leaves arise in pairs and are much shorter
than those of the red pine, varying from three-quarters of an
inch to one and a quarter inches in length. The staminate
cones are produced in clusters much like those of the red pine,
but smaller. The pistillate cones are nearly spherical in shape,

FIG. 72. Rock-vegetation near Duluth. White pines, white cedars and junipers. After pho-
tograph by Williams.

purple in color and appear on the topmost branches of the tree.
When the pistillate cones mature during the second season of
their lives they are generally curved to one side, by which char-
acter they may be recognized and distinguished from the short
cones of the red pine. The seeds are small, winged, and black-
ish in color and the embryo plantlet has only four or five seed-
leaves. There is no difficulty in discriminating even between
the seedlings of the three species. The wood of the jack pine

190 Minnesota Plant Life.

is not strong and is little used as lumber, though it is cut for
firewood in some parts of the state and occasionally employed
in the manufacture of posts or ties. This pine is particularly
abundant in the region around Brainerd, where it covers hun-
dreds of square miles in an almost unbroken forest.

The white cedar. The white cedar or arbor-vitse is a tree
fifty or sixty feet high with a short, thick trunk. It is especially
abundant in the far northern region of the state, not coming
south so readily as the pines. It is prominent along lake shores
on the international boundary and its branches jutting out over
the water make picturesque scenery on the shores of most lakes
east of Rainy lake. The leaves are large and remote on older
shoots, but on the younger, which are arranged in flat, fern-
like groups, they are short and tightly lapped over each other
like shingles. The flowers, opening in the spring, are purple
in color and the fruits ripen in a single year. The seeds are
winged along both margins, thus differing from the pines in
which the wings are principally terminal, and are only an eighth
of an inch long. Seedling plants of the white cedar have but
two seed-leaves, in this respect resembling most higher seed-
plants. The wood is very light and peculiarly durable, sweet-
scented and brown in color. It is highly prized for railway ties,
shingles and fencing lumber and is used by the Indians in the
manufacture of paddles and as ribs for their canoes. They em-
ploy also the inner bark in the manufacture of mats, cutting it
up into strips which they dye and plait elaborately in quaint
and traditional patterns. Young arbor-vitae plants are used in
Minnesota for hedges.

The hemlock. The hemlock is a tree sometimes no feet in
height with a trunk four feet in diameter, but in Minnesota, in
the two small patches where it is known, it does not reach this
size. The lower branches are generally drooping and the leaves
are short and flat, dark-green above and lighter below. The
cones are slightly longer than the leaves. The wood is soft
and light, brown or white in color and the general appearance
of the twigs with their foliage is quite similar to that of the
ground-hemlock — hence the common name of the latter. The
two plants, however, are really members of different families.
Hemlocks are of much economic importance from their bark,

Minnesota Plant Life.

191

to the exclusion of other varieties, being employed in tanning.
The substance known as tannin is abundant in hemlock bark
and by its action upon hides they are cured and converted into
leather.

The tamarack. The tamarack differs from the other Min-
nesota pines in its habit of shedding its leaves in autumn. The
leaves are never of the dark rich green of the spruces, firs or
pines, but are of a paler color. In autumn they turn golden yel-
low before they fall and after the severe frosts of November

FIG. 73. Tamarack swamp with sedge border. After photograph by Williams.

they separate from the twigs by means of cork layers and the
tree passes the winter in a leafless condition. Tamaracks oc-
cupy wet ground, forming by their growth the well-known
feature of the landscape known as the tamarack swamp. The
cones of the tamaracks are small. The wood is hard, resinous
and durable, weighing twice as much as that of white cedar, and
is used in the manufacture of railway ties, as fence poles and
for fire-wood. Occasionally, too, it is manufactured into tele-
graph poles.

192 Minnesota Plant Life.

The spruces. The spruces are known for their spire-like
habit of growth and serve as the Christmas trees of the children.
They do not grow to any great size in Minnesota although the
white spruce under suitable conditions may reach a height of
150 feet. In Minnesota the black spruce seems to be rather
more frequent and together with tamaracks, or to their exclu-
sion, forms characteristic swamp growths, the trees standing
very close together. A slightly different variety, the muskeg
spruce, with peculiar drooping branches is particularly abundant
in such localities. Spruce leaves are short and four-sided,
spreading in all directions from the twig. The cones are small
and plump, with shell-shaped scales closely lapping over each
other. In the white spruce the cones are oblong and some-
what cylindrical in form, while in the black spruce and muskeg
spruce they are egg-shaped in general outline. When the
leaves of the black spruce die they fall, leaving little hummocks
on the twigs. None of these plants except the true pines has
special leaf-bearing branches which separate as a whole when
the leaves have finished their work.

The balsam. The balsam or fir is a slender tree growing in
somewhat drier soil than that preferred by the tamaracks and
black spruces. In Minnesota it rarely exceeds a height of 40
feet. The leaves are flat and sessile, arranged apparently in
rows right and left on the twig, but really in spirals. The twigs
have a much flatter look than the twigs of spruces. Only one
species occurs in Minnesota and this has a smooth bark in which
resinous blisters are formed. The whole plant is sweet-scented
and the wood is .soft and light. From the resin blisters is de-
rived the product known as Canada balsam. The balsam tree
may be known from the spruces by its erect cones as well as
by the flat branch systems, for in spruces the cones are pendu-
lous.

The junipers and red cedar. There remain to be men-
tioned the junipers, a group of evergreens remarkable for trans-
forming their pistillate cones into little round blue berries. The
scales of the cone become fleshy, inclosing the seeds. They are
fragrant and an extract of juniper is used in the flavoring of gin.
Birds pick the berries, thus providing for the distribution of the
seeds. Therefore, as one would expect, the seeds are not winged

Minnesota Plant Life.

193

as in most of the other pines. One of the junipers, the red
cedar, grows in Minnesota as a tall tree. It is not very com-
mon in the state, but is found at Redwood Falls and on lake
shores and bluffs at a few isolated localities in the southern
part. The leaves are short and broad with sharp points and
are developed in four rows. The red cedar is the most widely
distributed plant of its family in North America. The wood is
light, perfumed, of a reddish color, except in the outer layers,
where it is white. It is largely used in cabinet making, in the

FIG. 74. Red cedars on the banks of a Minnesota lake. After photograph by Williams.

manufacture of lead pencils, and is believed to be so particularly
distasteful to moths that closets in which woolen clothing and
furs are to be hung during the summer months are sometimes
lined with it.

The other junipers of the state are low shrubs. One is char-
acterized by spreading awl-shaped leaves arranged in whorls of
three, and this form sometimes growls into a low tree. The
others are prostrate shrubs creeping over the rocks or sand, and
are abundant in the northern part of the state where they form
a distinctive vegetation on some of the islands in Lake of the

14

194 Minnesota Plant Life.

Woods and Rainy lake. Their leaves, like those of the red
cedar, lap over each other, are short and slightly pointed. They
stand in four rows, giving the branch upon which they are borne
a square appearance.

Characters of lower seed plants. There are a number of
features in which the yews and pines agree. The seeds of each
are produced in such a way that when young the pollen spores
may fall close to their ends, so that the only tissues through
which the pollen-tube must grow to reach the female plant are
the cells of the spore-case that surrounds the large-spore in
which the female plant is situated. For this reason the lower
seed-plants are sometimes called the naked-seeded plants. While
the seeds are maturing they are enclosed, except in the ground
hemlock, quite as truly as are those of higher forms. In the
juniper-berry, for illustration, when it is full grown, the scales
which constitute the little fleshy cone are blended at their edges
in such a manner that the seeds are entirely enclosed and can-
not at all be termed naked. In the pines proper, too, the young
cones appress their scales so tightly that the seeds are quite
as effectually protected as they would be in the closed fruits of
higher types. At first, however, even in the junipers, the scales
of the immature cone are open and it is possible for pollen-
spores to fall between them, thus reaching the ends of the young
seeds growing upon their inner surfaces.

A character in which the lower seed-plants all agree is the
production of albumen in the seed before the egg of the female
is fecundated by the sperm-nucleus of the pollen-tube. In the
higher seed-plants the albumen of the seed, when present; does
not form until the egg which is to produce the embryo has re-
ceived its fecundation. The albumen of the seed may be re-
garded as the body of the female plant and the young embryo
nurses upon it during its life within the seed just as the young
spore-producing plants of a liverwort or moss nurse upon the
vegetative body of the sexual plants of their species.

In still another respect the lower seed-plants agree and differ
from all the higher seed-plants. In them, on the body of the
female plant produced within the large-spore, true egg-organs
are formed, each enclosing an egg and provided with a short
neck the end of which is near the inner surface of the spore-

Minnesota Plant Life.

'95

wall. In higher seed-plants there is no definite egg-organ, but
the egg lies loosely among the other cells of the extremely re-
duced and degenerate female.

Relation between lower seed-plants and primitive seedless
plants. A very remarkable character, which shows clearly the
connection between smaller club-mosses and lower seed-plants,
is not known to be presented by either of the Minnesota fam-
ilies of the latter group, though it is now described for two that
are exotic. It is, however, a fact of such extreme interest that
it should be mentioned at this point.

FIG. 75. Rock on the St. Croix river, near Taylor's Falls. vShows zonal distribution of trees.
White pines stand on top of the rock, and birches and poplars on the sides. After photo-
graph by Mr. H. C. Cutler.

In the sago-palms and ginkgo trees the pollen-spores fall as
in other naked-seeded plants, upon the ends of the immature
seeds, then germinate and produce their pollen-tubes. In the
end of each pollen-tube in these plants there develop a pair of
motile spermatozoids provided with swimming lashes. In the
cycad family to which the sago-palm belongs, are a few Amer-
ican species finding their home in Florida. In these when
the pollen-tube comes close to the egg a motile spermatozoid
swims into it, peeling off its swimming-lashes in a spiral coil

196 Minnesota Plant Life.

and leaving them at the edge of the egg just inside its wall.
The remainder of the sperm-nucleus finds its way to the centre
of the female cell. In higher forms of naked-seeded plants, of
which the yews and pines are examples, the swimming-lashes
of the spermatozoids seem to have been quite abandoned. They
are indeed no longer necessary, for the old algal type of aquatic
reproduction has been finally outgrown. It is a most remark-
able and impressive fact that in all the terrestrial forms, from
the liverworts up to the cycads, including all the ferns, club-
mosses and their allies, the primitive aquatic nature of the plant
reasserts itself during the reproductive phase and one finds such
plants as the granite-mosses, accustomed to life upon bare, dry
rocks, quite unable to bring their sperms and eggs together
except immediately after heavy rains, when the surface of the
rock is flooded with water, thus enabling the aquatic sperms to
use their swimming threads. This long persistence, ages after
the aquatic habitat had been abandoned by the ancestral algae
from which the higher plants are supposed to have arisen, is a
striking example of the really profound inertia of living struc-
tures.

Chapter XXII.

From Cat-tails to Eel-grasses.
if

Higher seed-plants. The characters of this group are as
follows : the rudiments of the seeds are protected by the fusing
together of the specialized leaves upon which they are borne
into a fruit-rudiment known as the ovary. The leaves which
thus fuse are called carpels. In some types the ovary consists
of a single carpel, in others, of several carpels blended into a
single fruit-rudiment, while the number of carpels in a flower
varies in the different families. The female plant, produced in
the large-spore of the seed-rudiment, consists of a few cells,
commonly eight in number, near the time that the egg is fecun-
dated. The albumen of the seed is not of the nature of a
female plant, but is rather to be considered as the twin of the
embryo, and does not form until after the sperm and egg have
fused. In the latter characters it will be seen that the higher
seed-plant differs from the lower.

The lower class of higher seed-plants. There are two prin-
cipal classes of higher seed-plants. The lower class is distin-
guished by the production of embryos with but a single seed-
leaf. In such plants the stem develops fibrous or woody threads
which become entirely mature and do not blend into a cylinder
from which to form a layer of growing tissue between the wood
and the bark. Hence the stems of perennial plants of this class
do not show "annual rings" of growth like those of the other
and higher class. For the most part the leaves have parallel
veins although some, such as those of the jack-in-the-pulpit, the
smilax and the skunk-cabbage have netted veins. The flowers
are ordinarily made up of five whorls of leaves, the two lower
and outer whorls constituting the perianth, then two whorls of
stamens and, in the centre, one whorl of carpels. The number
of leaves in a whorl is generally three, but in certain types *the
number varies, especially in the three inner whorls, so that
water-plantains, for example, produce a large number of sep-

198

Minnesota Plant Life,

arate carpels at the middle of a flower while grasses produce
but one. A variety of plants belonging to this division of the
vegetable kingdom exist in Minnesota. The class is divided
into orders of which eleven are recognized, and the orders are
divided into families.

Cat-tails. The cat-tails belong to a small order, including
also the bur-reeds and the screw-pines, the latter of which are
not represented in the state. Cat-tails, however, are common
enough at the edges of marshes, swamps and lakes, and a single
species, the broad-leaved cat-tail, is familiar in such localities.

It is provided with a
creeping rootstock which
lies imbedded in the mud.
The leaves are slender
and flat, sheathing the
upright branches of the
rootstock by their bases.
The flowers are of two
sorts, some containing
only carpels and others
only stamens. The two
kinds are produced in the
same spike-like cluster,
the staminate aggregated
above and the pistillate
below. The brown cyl-
inder or "cat-tail" is the
compact mass of pistillate
flowers. The little fruits are provided with cottony hairs and
burst when they have been lying in water for a short time.
Each seed consists of a hard shell within which is considerable
albumen surrounding a single embryo plantlet.

Bur-reeds. There are at least six sorts of bur-reeds in Min-
nesota. They occupy similar habitats to those preferred by
the cat-tails. Their prostrate creeping rootstocks are rooted in
the mud and from them erect branches arise. On these are
developed grass-like leaves. The flowers are of two sorts as
in the cat-tails, and are gathered in globular heads, varying in
size from a pill to a large marble. The staminate heads are

FIG. 76. Bur-reed. After Britton and Brown.

Minnesota Plant Life.

199

smaller and higher on the stem than the pistillate. The fruit
has but a single cavity. The seeds are furnished with con-
siderable albumen and within this the embryo stands nearly
straight. These plants are sometimes mistaken for sedges, but
are easily recognized by their globular flower-heads of two sorts
on the same general branch. Sometimes the heads are pro-
vided with stalks ; in other varieties they are sessile.

The second order in the ascending series includes seven fam-
ilies, of which five are represented in the Minnesota flora.

FIG. 77. lyakeside vegetation. Just off shore is a growth of the floating pondweed, then of
arrowheads, while further out are reeds and rushes. After photograph by Williams.

Pondweeds. These are for the most part submerged plants
growing in ponds, lakes and slow streams throughout the state.
About twenty Minnesota species are known to exist in such
localities. They all root at the bottom of the water. Their
stems are slender, often branching, and when taken out of the
water are limp, owing to their poor development of woody tis-
sue. The flowers are commonly collected in spikes which in
spring are barely thrust above the water in order that the wind
may carry the pollen from the stamens to the stigmas. These
spikes are the little objects upon which lake-flies like to perch

2OO

Minnesota Plant Life.

— as must often have been observed by every one who has fished
in Minnesota lakes.

The different species of pondweeds may be distinguished
by their leaves. In one common variety leaves of a somewhat
oval shape float upon the surface of the water, but besides these
there are present upon the submerged portions of the plant
short, reduced, grass-like leaves. In another with leaves some-
what similar, but crowded together and altogether submerged,
there wrill not be found the special grass-like leaves. Still an-
other has clearly two very different sorts of leaves, some finely
dissected and others elliptical in outline. In yet another the

leaves are all delicate and thread-
like. A great variety in the
shape and size of pondweed
leaves may be observed upon
looking down through the clear
water upon s u b me r g e cl bars
where they grow so luxuriantly.

In all these plants the seeds
are curved or straight and the
embryo has no encasement of al-
bumen. The fruit, in which are
the seeds, consists of four little
bodies much like diminutive
peaches. Very closely related to

FIG. 78. Clasping-leaved pondweed. After the pondweeds are the naiads
Britton and Brown. «•••". i- -111

which may be distinguished by

the solitary pistil which forms the fruit. They grow in exactly
similar localities and one species is common in Minnesota.

Arrow-grasses. A third family is known as the arrow-grasses.
Four species are described from Minnesota localities and are
to be found in some abundance in tamarack swamps, especially
in the northern part of the state. The leaves are rush-like and
the flowers, arranged in terminal, loose spikes, produce stamens
and pistils upon the same axis, while from three to six carpels
fuse together to make the fruit. One variety of arrow-grass is
discriminated by the small number of flowers in the spike. All
of these plants are perennial and some of them are to be pretty
generally met with in all portions of the state, while others are

Minnesota Plant Life.

201

rare. They should be sought in rather moist peat-bogs or in
marshes at the edges of lakes.

Water-plantains and arrowheads. A fourth family includes
the water-plantains, the arrowheads and a few related plants
in which the flowers are similar though the leaves are of differ-
ent appearance. The common water-plantain is known by its
large oval leaves, two or three inches in length and with several
strong longitudinal ribs. The flowering stem is much branched,
bearing a number of pretty flowers each with three round white
petals, from six to nine stamens and usually several separate

FIG. 79. Evening scene in Minnesota. Arrowheads, bulrushes and willows in foreground.
After photograph by Williams.

carpels which form, as the structure matures, a little fruit-
cluster. The embryo in the seed is curved like a horse-shoe
and there is no albumen. These plants produce large masses
or colonies in favorable localities. They are abundant in ditches
and pools and along railway tracks, as well as in pond margins
and in marshes, but they do not commonly occur in peat-bogs
or tamarack swamps, except at the edges.

Related to the water-plantains are the arrowheads, plants of
similar habitats and generally to be distinguished by their broad
leaves, shaped like spear-heads. The arrowheads, like the
pondw7eeds, frequently put forth two kinds of leaves, and if a

2O2

Minnesota Plant Life,

FIG

Arrowhead. After Britton
and Brown.

plant is pulled up by the roots it will be discovered very possibly

that there are broad or slender grass-like leaves submerged in

the water. In one Minnesota va-
riety the arrow-headed leaves float

upon the surface of the water like

those of the pond-lilies, but more

commonly they are not natant. In

some species all of the leaves are

grass-like or slender, while the

plants must be recognized rather by

their characteristic flowers. A large

number of separate carpels are pro-
duced in each flower and when it

ripens the group of carpels become

a more or less spherical head. In

each of the closed carpels or ovaries

is a single erect seed slightly curved.

In Minnesota there are at least six species of arrowheads.

Eel-grasses. A fifth fam-
ily in this second order in-
cludes the well-known eel-
grass, the plant which gives
so delicate a flavor to the
flesh of the canvas-back
duck, which is very fond of
pulling it and eating the
soft parts of the leaves and
stems. There is something
very remarkable about the
way in which this plant pro-
duces its flowers. The gen-
eral plant-body consists of a
(short stem rooted in the
mud on the bottoms of lakes
near their edges. The leaves

FIG. 81. Eel-grass. After Britton and Brown. are long, graSS-Hke and of a

diaphanous translucent green, rarely floating at the surface,
more generally submerged and ascending. The pistillate flow-
ers are produced at the end of a very long, slender spiral stem

Minnesota Plant Life, 203

which rises in sinuous coils through the water, bringing the
flower just to the surface. The staminate flowers are in clus-
ters on a short stem deep down in the water. When they are
nearly ripe they separate from the stem and rise to the surface,
where they open, revert their perianth leaves and are free to be
blown about on the quiet surface of the pool like so many min-
iature boats. Some of them thus approach the pistillate flowers
and the pollen-spores can fall upon the stigmas where they ger-
minate. After pollination the long, coiled stem contracts and
pulls the pistillate flower down into the depths where it may
ripen its fruit in safety. The fruit itself is a cylindrical capsule
with numerous seeds.

In near affinity to the eel-grass is a little plant which is some-
times called ditch moss or water weed and is known by its short
leaves of a crisp texture when taken from the water. The leaves
are opposite, rather close together and commonly not more than
half to three-quarters of an inch in length. Their points are
often turned back so that a characteristic appearance is given
to a branch.

Chapter XXIII.

Grasses and Sedges*

The third order is not represented in Minnesota, but the
fourth order, which includes the grasses and sedges, is abun-
dantly represented by a large variety of forms. There are in
the state about 160 different species of grass and about the same
number of sedges.

Grasses. Grasses are characterized by their habit of forming

the sort of fruit which is
termed a grain. They are, in
Minnesota, all of them annual
or perennial herbs, but in In-
dia and the Orient some va-
rieties become large trees, in
which condition they are
termed bamboos. The stems
are for the most part hollow,
the leaves slender and sheath-
ing, though some panic grass-

FIG. 82. Wild rice and pond lilies. After

photograph by Williams. CS have broad leaves Ol" CVCU

ovate leaves in certain foreign

species. The flower clusters are generally spikes composed of
little spikes known as spikclets. In the flower clusters and
flowers, the leaves are developed as chaffy scales and the flowers
themselves lack any colored perianth. There are usually three
stamens and the ovary has but one cavity producing but a single
seed. The ovary is conceived to consist of one carpel, the other
two having disappeared. The branched stigma on top of the
rudimentary fruit is feather-like, and for its pollination the chief
agent is the wind. The ripened fruit inclosed in its chaffy
scales is called a grain. The seed inside the grain is not sep-
arate but fills up the fruit-cavity so that the whole is one solid

Minnesota Plant Life.

205

FIG. 83. Beard-grass. After Britton and
Brown.

body. There is always albumen in the seed and the embryo

lies toward one side, nursing on the albumen by its peculiar

sucker-shaped seed-leaf. This

may be seen when one carefully

removes the embryo or germ

from a corn fruit or from a

wheat kernel. It will then be

noticed that the embryo has on

one side a flattened disc which

presses itself against the albu-
men, and by it the plantlet nurses

as the seed begins to germinate.
There are several tribes of

grasses recognized : the maizes,

to which Indian corn belongs;

the bluejoints, including also the

sugar-cane ; the panic-grasses,

with which the barnyard grass,

the sand-burrs and their allies are

grouped ; the rices, of which the Minnesota representative is the

well-known wild rice or Indian rice; the canary-seed grasses;

the timothies and millets, in-
cluding also some sand-bind-
ing grasses and tumbling-
grasses; the oats, comprising
the well-known wild oats and
a number of kindred genera;
the fescue grasses, with blue-
grass and reed-grass as types;
the buffalo-grasses, and the
barleys with which tribe are
also grouped both wheat and
rye. Only two of the large
tribes of grasses are unrepre-
sented in Minnesota by native
varieties. These are the maizes
and the bamboos; but Indian
corn, one of the maizes, is so

abundantly cultivated that it may rightfully be regarded as a
Minnesota plant.

FIG. 84. Barnyard grass. After Britton and
Brown.

206

Minnesota Plant Life,

FIG. 85. Minnesota Muhlenberg grass.
After Britton and Brown.

Varieties of grasses. It is not possible in the space at com-
mand to give any adequate idea of
the various species of grasses which
grow within the borders of the
state. The majority of them are
turf-forming plants and are marked
by strong underground rootstocks
which branch and creep beneath the
surface of the soil, sending lateral
offshoots into the light. A great
many different types of flower clus-
ters are to be met with, varying
from the solid spikes of the timothy
or millet to the very loose and
straggling clusters of the tumble-
grasses and blue-grasses. A few
grasses are aquatic, permitting their

leaves to float on the surface of the water. These may be
recognized, when in flower or in fruit, by the characteristic

grass-like aggregates which they
produce. Some are semi-aquatic,
finding their homes on the edges
of lakes or swamps, as, for ex-
ample, the reed-grasses and the
wild rice. A number of varieties
are found only in tamarack
swamps and marshes or where
there is an abundance of shade.
A few, with sparsely clustered
flowers and rather broad, thin
leaves, frequent the depths of the
forest, but the great majority are
to be looked for in meadows and
on the prairie. Some of them, like
the buffalo grass, with their shriv-
eled aspect and vigorous root-
system, indicate a strong adap-
tation to dry regions or deserts.

Indian corn. Sometimes in the grasses the flowers are sep-
arated so that the staminate flowers occur in different clusters

FIG. 86. Beckman grass. After Britto
and Brown.

Minnesota Plant Life.

207

from the pistillate, just as in the cat-tails. It is so with the
Indian corn, where all the staminate flowers normally develop
in the area known as the tassel, where all the pistillate flowers are
gathered together on a thick stem and form the ear. In the
Indian corn the process which connects the stigma with the
ovary is long and slender and is known as the silk. Surround-
ing the cluster of pistillate flowers on their thick stem or cob
is a group of somewhat modified protective leaves known as the
husks of the corn. Since the plant depends upon the wind
for carrying the pollen-spores to the stigma, the silk threads
protrude in a
little tuft at the
end of the ear.
By selectin g
ears which have
not yet opened
to expose their
silk and inclos-
ing them in a
gutta-p e r c h a
bag it would be
possible to pre-
vent the devel-
opment of the
kernels.

A number of
cultivated vari-
eties of Indian corn are recognized, differing in minor peculiar-
ities. Hybrids between different varieties are interesting and
sometimes red and white corn are crossed ; in that instance tinted
kernels may develop upon the cob. Or if red, white and black
varieties are grown together in the same field some kernels may
be fecundated by male plants arising from one kind of pollen
while others depend upon males developed from other pollen,
so that the ears contain kernels of each color.

Wild rice. Another grass which is of interest from its im-
portance as an economic plant among the aborigines of the
state, is the wild rice or Indian rice. The Chippewas call this
plant manotnin and gather it in the autumn of the year for food.

FIG. 87. Indian corn in the shock. After photograph by Williams.

208

Minnesota Plant Life.

It occurs in large quantities, especially in narrows between lakes,
in outlets or inlets, but not so commonly in bays or stagnant
water. It is not so frequent in lakes without an outlet. The

FIG. 88. Wild rice in a Minnesota lake. After photograph by Williams.

grain is longer and thinner than the rice of the orient, but when
boiled is quite as agreeable to the taste as the cultivated form.
The Indians collect it in September, beating it into their canoes,

Minnesota Plant Life.

209

FIG

Wild rice. After Britton and
Brown.

and after harvesting it is winnowed by hand. Under the crude
manipulation of the Indian much chaff is usually left with
the grain, so that the wild rice
cake or porridge which the In-
dian makes is not always so ap-
petizing as one might desire.
The wild rice, when it flowers,
behaves somewhat like Indian
corn, but both varieties of flower-
clusters are rather broad panicles.
The spikelets contain one flower
each and the pistillate spikes are
borne higher on the stem than
the staminate, thus reversing the
relative position in the Indian
corn. Each staminate flower con-
tains six stamens. The pistillate
flower consists of a single ovary
with two divergent feathery stig-
mas.

Wheat. More important to man than any other grasses in Min-
nesota are the wheats, which form the principal agricultural prod-
uct of the state. In the wheat the
flowers are perfect, not separated
as in the corn or wild rice. Sur-
rounded by its own cluster of
stamens each pistil is normally
sure of pollination. When the
fruit develops it forms an ovoid
grain with the embryo basally
and laterally disposed. A large
number of varieties of cultivated
wheat are known, the hybridiza-
tion and selection of which are of
the utmost importance to the
agriculture of the future, since by
such intelligent methods will it
eventually be possible to produce

varieties which are rust-proof and far richer in flour-making sub-
stances than are the wheats of to-day.
15

FIG. 90. Kalm's brome-grass. After
Britton and Brown.

210

Minnesota Plant Life.

Distribution of grass grains. A few grasses in the state
have interesting special methods of distributing their fruits.
The sand-bur, for example, encloses its fruits in bur-like scales.
If carefully examined, the points on the burs will be found to
have barbs directed backwards along their sides, so that a bur
sticks very closely to the fur of an animal or to clothing and

thus brings about the dissemina-
tion of the fruits within. An-
other grass known as spear-grass,
or to children as "fairy's spears,"
is remarkable for the "self-
planting attachment" of the
grain. In this variety the grain
is enclosed in a chaffy scale, the
end of which is prolonged into a
slender awn, while the base is
sharply pointed, hard, and pos-
sessed of hairs pointing back-
wards. When such grains fall
upon the soil the tips penetrate
a little, owing to the heaviness
iof the seed. The
slender bristle
then begins to
coil and uncoil
under the stim-
ulus given to it
by changes in
the moisture of
the air. Since
the grain holds
all the ground
that it gains on

FIG. 91. A cluster of sedge-flowers (Carex-type), a single
pistillate flower with one fruit rudiment, and a stami-
nate flower with three stamens. After Atkinson.

account of its backward-pointing hairs it is slowly driven into
the soil and thus enjovs a certain advantage over varieties
which have not such self-planting mechanism. Grasses are not
alone in apparatus of this sort, for the fruits of the clematis and
of some geraniums are similar to a degree. Other species of
grass are provided, upon their fruits, with expansions or tufts
of cottony hairs, by which the wind assists them in their dis-

Minnesota Plant Life.

21 I

tribtition, while tumbling grasses — after they have ripened their
seeds — separate their flower-clusters, bring them together into
balls and permit the wind to roll them over the plains or
meadows.

Mat-grasses and dune-grasses. A few grasses take the form
of what are known as mat-plants or carpet-plants. These are
found in waste fields and the plant-body has a marked prostrate
appearance, lying flat upon the ground and producing, if unin-
terfered with, a circular disc a foot or more in diameter. Such
vegetation-forms could not very well arise in the forests or in
marshes, but are charac-
teristic of open, sandy
fields. Peculiar varieties
of grasses are usually
found on sand-d u n e s .
These, of which the wild
rye is a conspicuous ex-
ample, have a luxuriant
subterranean body made
up of rootstocks and
roots by which they bind
the sand together — hence
they are known as sand-
binding grasses. The
planting of grasses of this
sort where sand-dunes
show a tendency to en-
croach inland, is Often FIG. 92. Cyperus-sedge. After Britton and Brown.

sufficient to stay the ad-
vance of the dune. In France such grass-planting is employed
by the inhabitants along the coasts of Brittany to prevent the
beach sand from being blown continuously in shore. In north-
ern Indiana, between Chicago and Elkhart, there is an area
where the sand of Lake Michigan has been blown inland for
many miles, covering the soil and by its thick drifts making val-
uable farms worthless. In such positions considerable growths
of wild rye would serve to bind the sand and raise a barrier to
its farther encroachment.

212

Minnesota Plant Life.

Sedges. The sedges are a family of plants closely akin to
the grasses and with them constituting the fourth order. They
are mostly grass-like in appearance, though some, like the bul-
rushes, are singular in aspect owing to their special habitats.
As compared with the grasses they present some differences
which may be kept in mind and should enable one to distin-
guish the two families at a glance. The stems are slender, gen-
erally solid, instead of hollow as in almost all the grasses. Very
often the sedge stem is triangular or quadrangular, a character

FIG. 93. Cotton-grasses growing in a bed of peat-moss. Near Grand Rapids. After photo-
graph by Mr. Warren Pendergast.

not at all common among grasses. Some sedges, however, like
grasses, have cylindrical stems. The leaves are, when present,
altogether grass-like. The flowers resemble those of grasses,
except that the number of stamens is rarely more than three.
The ovary is one-chambered, develops a single seed and in gen-
eral resembles the ovary of the grass. The stigma is often
three-cleft but sometimes simple or two-cleft. The fruit is
ordinarily a three-cornered nutlet with mealy albumen and minute
embryo.

Minnesota Plant Life.

213

Cyperus-sedges. Here are included the Cyperus plants. To
this genus the familiar umbrella-plants of window gardeners
belong and here, too, is to be placed the papyrus of Egypt,
famous in ancient days as a substitute for paper. The papyrus
stems were pounded out into flat plates which, matted together,
furnished the papyrus rolls upon which so many ancient manu-
scripts are written. In Minnesota the Cyperus sedges are found
principally along the muddy borders of ponds and streams, in
marshes, ditches and wet places. In many of them the stem is
triangular with most of the leaves clustered at the base. The
spikes are often borne in the kind of cluster known as an umbel,

FIG. 94. L,ake border vegetation. Bulrushes and reed-grasses. After photograph by

Williams.

of which the parsley family furnishes such good examples.
Sometimes these umbels are loose and compound, in other spe-
cies they are compacted into almost globose heads, while in still
others they are lax and simple.

Cotton-grasses. In this family are the cotton-grasses, such
characteristic plants of the tamarack swamps and peat-bogs of
the state. The fruits of the cotton-grasses are clothed with
white bristles growing up from under their bases so that the
head of a cotton-grass looks much like a tuft of cotton at the
end of a slender stem. There are several varieties in Minne-
sota.

214

Minnesota Plant Life.

Bulrushes. Here are also the bulrushes and their allies, a
number of which are natives of the state. The most common
bulrush is the one that forms beds at the margins of many
Minnesota ponds and lakes, This plant has stout creeping
rootstocks which branch underneath the soil of the bottom.
Lateral branches of the main stem arise into the air, growing
sometimes from seven to nine feet tall, with a few sheathing
leaves at the base and a leaf or two at the point where the flower-
cluster branches originate. The erect stem as a whole is a
slender green cylinder, whip-shaped and beautifully constructed
to withstand the wind and surf of its habitat. The bulrush is
an example of a small adapta-
tional group known as surf-
plants. The leafless character
of the stem may be regarded
as the result of experience in
surfy water, for in such a posi-
tion the leaves, if they had
existed, would probably have
been torn away and the plant
has therefore learned how to
exist without any leaves over
the principal portion of its sur-
face.

There are a variety of rea-
sons why different p 1 a n t s
abandon their leaves. Some-
times the leafless habit is an adaptation to very dry atmospheres ;
therefore a number of desert plants are leafless, because if they
had leaves they would tend to transpire moisture more rapidly
than they could absorb it. Again, the absence of leaves may
be an adaptation to strong winds ; thus the switch-plants on the
islands of the Adriatic may be regarded as varieties which have
abandoned their leaves because of the frequency of violent blasts
that would be likely to tear or destroy them. In the bulrush,
however, the leafless habit is partly a response to the prevalence
of surf in places where the plant is accustomed to make its
home.

FIG. 95. Bulrush-sedge. After Brittou and
Brown.

Minnesota Plant Life.

2 I

Many bulrushes have three-cornered stems and grow in
marshes or even upon prairies, but these are to be connected
with the ordinary cylindrical bulrush of lakeshores because
of the exact similarity of their flowers and fruits. Indeed, the
three-cornered stem was probably primitive and the cylindrical,
adaptational.

Carex-sedges. The largest genus of plants in Minnesota
— after the rusts — belongs to the sedge family, and there are
about no species of Car ex in the state. The Carices are grass-
like sedges, for the most part small and slender plants and per-
ennial by underground rootstocks. Each pistillate flower de-
velops a sac-shaped leaf which
incloses the rudimentary fruit,
so that when ripe it stands in
a little bladder, reminding one
somewhat of the ground-
cherry, only very much smaller.
These sacs may be either pa-
pery or hard and they may be
either smooth, furrowed or
winged. Usually the stigmas
are protruded far beyond the
top of the sac which itself takes
the form of a bottle, and
through the neck of this the
stigmas are thrust. Some-
times the stigma is two-lobed,
while in other species the number of the lobes is three. A con-
siderable variety exists in the shape of the sac in which the fruit
is formed. Sometimes it is slender, while again it is swollen
or even globose. In many sedges the pistillate flowers — their
fruit-rudiments inclosed in the sacs — are displayed in special
spikes or heads, while the staminate flowers stand in other spikes
above or below the pistillate — if the two occur on the same
general axis — or entirely separate from them. Among the
Carices the flower clusters, in their general shape and in their
position on the plant-body, show great variety. Sometimes
they are cylindrical and pendulous, again cylindrical and erect
or ascending, again globose or loosely aggregated. In still

FIG.

Carex-sedge. After Britton and
Brown.

216 Minnesota Plant Life.

other instances they form long clustered groups made up of
numerous spikes of flowers. One of these little sedges is an
extremely common flower of early spring, dotting the prairies
with its little yellow spikes of staminate flowers below which
whitish spikes of pistillate flowers are formed. The yellow color
is given by the stamens themselves.

Some of the sedges are robust, strong plants, almost like bul-
rushes in their general aspect, while others are very delicate,
low-tufted plants, bringing to mind the smaller sorts of grasses.
In the classification of this large genus of plants a variety of
characters are taken into consideration — the number and posi-
tion of the flowers, the character of the sac which incloses the
fruit, the distribution, shape and color of the scales, the width,
length and texture of the leaves, the number of branches of the
stigma and the general distribution of the flowering tracts upon
the axis where they develop. Economically, sedges are by no
means as important as grasses; neither are their stems so val-
uable as fodder, nor do their fruits serve to feed mankind as do
those of the rice, wheat, rye and maize, all of which belong to
the other family of the order. Yet a considerable industry is
being developed in the manufacture of matting from one com-
mon Minnesota variety and the plants are not without their
uses.

Chapter XXIV.

From Callas to Water Star-grasses.
if

The fifth and sixth orders — the palms and cyclanthuses —
are not represented in Minnesota, but the two families of the
seventh order are, by a few well-marked species. Here come the
plants of the arum family, comprising in Minnesota the jacks-in-
the-pulpit, the calla, the skunk-cabbage and the sweet-flag.
These are of somewhat different habits and structure, but they
agree in producing their flowers upon fleshy spikes subtended
or surrounded by peculiar leaves known as spathes. The com-
mon jack-in-the-pulpit, for instance, develops such a fleshy
spike of flowers and the spathe encircles the cluster as a cu-
rious hood. The spathe in the calla lily of greenhouses
forms a white, vase-like chalice beneath the fleshy spike, while
in the skunk-cabbage it becomes a livid purple cowl open at
one side. In the sweet-flag the spathe is prolonged straight
above the apparently lateral fleshy spike and seems like a con-
tinuation of the flattened stem. In most of these plants the
rootstocks are commonly short and solid and contain a very
acrid sap. The unpleasant taste of the Indian turnip is given
in part by crystals of lime oxalate enclosed in certain cells of
the bulb.

The fruit of the arums is a berry. In the jack-in-the-pulpit
the berries are scarlet and mature in the autumn. In the
sweet-flag they are crowded together and gelatinous — often
failing to mature. All of these plants have special peculiarities
of growth that would be interesting to follow in detail and a
few points are particularly worthy of attention. If in the curi-
ous flower clusters of the skunk-cabbage a thermometer be in-
serted, and after fifteen or twenty minutes it be removed and
read, it will be found that the temperature may be from five to
fifteen degrees higher than that of the surrounding air, showing

2l8

Minnesota Plant Life.

the power of the purple substances in the spathe, together with
the respiratory activity of the fleshy spike, to increase the tem-
perature. In the jack-in-
the-pulpit flower the pecu-
liar little club-shaped sterile
end of the spike is probably
a respiratory organ and to-
gether with the special col-
oring substances does its
part in raising the tempera-
ture. Small insects learn
that these flower clusters
offer them comfortable
shelter and seek them, and
as a result pollination is se-
cured. The flowers of most
of the arums depend upon
this ability to furnish heat
rather than upon perfumes,
gaudy colors or the secre-
tion of nectar to attract
their insect visitors.

Burrowing bulbs. An-
other curious feature in the
lives of many arums is the
burrowing habit of the
young bulbs. If a flower
pot about six inches tall is
filled with rich loam and
some seeds of the skunk-
cabbage or jack-in-the-pul-
pit are planted about half
an inch below the surface
and permitted to germinate,
the plantlets when they
burst forth will at once be-
gin the formation of bulbs
by expanding the lower
portions of their stems into

FIG. 97. A skunk-cabbage in early spring, be-
fore the leaves have unfolded. The purple
hood covering the flower cluster is shown on
one side. After Atkinson.

Minnesota Plant Life. 219

round and solid bodies. In a week or so after such a bulb has
been formed, if sought where it first appeared, it cannot be
found, for by this time it will have burrowed to the bottom of
the pot. In this manner the erect rootstocks of skunk-cab-
bages sink a foot or two into the soil — as any one who attempts
to dig up a perfect plant will soon discover. The way that this
is accomplished is by the development of contractile roots on
the young nodes. Four or five of these roots are sent obliquely
down into the soil on different sides of the stem. When they
are long enough they produce some short lateral branches near
their tips, thus anchoring themselves. They then contract and
the bulb or stem — the base of which may be sharply pointed —
is pulled down into the earth. By this means the plant estab-
lishes its stems sometimes twenty inches below the point where
they began to form. The contractile roots, differing consid-
erably from the ordinary absorptive roots, may be recognized
by their large size and by the wrinkles on their surface.

Although the berries of most of the arums are exceedingly
unpleasant to the taste, some birds seem to fancy them and their
bright red color in the jack-in-the-pulpit, calla and skunk-cab-
bage is no doubt in the nature of an advertisement to attract
the attention of such as will eat them.

All of these plants except the sweet-flag grow in rich soil, in
deep woods, ravines or swamp borders. Like most shade-
loving plants, they have large leaves of thin texture. The jack-
in-the-pulpit is a typical shade plant in structure. Unlike most
of its class, its leaves are netted veined and the broad, thin blades
are fitted to catch as much sunlight as possible. The flowers
in this plant are commonly of two kinds. The staminate may
occur either upon the same fleshy axis with the pistillate, and
just above them, or upon a separate axis. The peculiar club-
shaped elongation of the flowering axis in the jack-in-the-pulpit
is not characteristic of the calla, the skunk cabbage or the sweet
flag, for in the latter plants the flowers cover the axes to their
tips. The sweet-flag occupies a different habitat from the oth-
ers preferring the edges of streams and swamps. Its rootstocks
are used in pharmacy and are often collected and chewed by
children, for they have not the acrid taste and are harmless.
The leaves of the sweet-flag are similar to those of the blue flag

22O Minnesota Plant Life.

or iris and quite different from the great oval leaves of the
skunk-cabbage, the small heart-shaped leaves of the calla, or
the three-parted leaves of the jack-in-the-pulpit.

Duckweeds. The duckweeds are small natant or submerged
plants which form green scums on pools and puddles. They
have no foliage-leaves but develop little flat, oval or triangu-
lar stems which float upon the surface of the water. Some
of them have roots which hang down as counterpoises, but
others are without roots and appear suspended in the water as
tiny green ovoid balls not as large as a pin-head. The latter
are the smallest of all flowering plants and are marvels of reduc-
tion. When the duckweeds flower, which they very seldom
do, the stamen and pistil stand together in a little depression
on the surface. For the most part these plants depend upon
propagation for their persistence and do not reproduce by seeds.
In Minnesota there are five or six species. The two kinds of
duckweed which are most abundant are the ivy-leaved or three-
cornered duckweed and the smaller duckweed. In the latter
the floating discs are about an eighth of an inch in diameter
and of nearly circular shape. In the former the plant-body is
branched more abundantly and builds up a group of three-cor-
nered or arrowhead-shaped branches. In each of these plants
a single root hangs down from the middle of the plant-body.

Another somewhat larger duckweed, with discs a quarter of
an inch or so in diameter is easily distinguished by the forma-
tion of tufts of roots on the under side. In these plants there
are traces of an original terrestrial existence, although they
have become so much modified by their aquatic life that they
now resemble some forms of algae. Nevertheless the roots in
all the species which produce these organs are supplied with
root-caps, structures of value to all terrestrial plants, because
they protect the young roots as they penetrate the soil. They
are, however, of no value to aquatic plants and some aquatic
plants shed their root-caps. The little floating fern of Minne-
sota is interesting from its general habit of dispensing with the
root-caps shortly after the roots have begun to extend into the
water. But when plants like the floating fern or the duck-
weed develop roots with caps and afterwards drop these caps,
now become useless, into the water, it may be assumed that they

Minnesota Plant Life. 221

are, by this action, indicating their original terrestrial habits
and proclaiming as distinctly as possible that they were not al-
ways floating plants. Of the duckweeds the one most per-
fectly adapted to the aquatic habitat is at the same time the most
simple of all flowering plants. One must carefully distinguish
between that simplicity of structure which is rudimentary and
the similar simplicity which comes from reduction. Low types
of plants like some of the algae are simple in form, like the
smallest duckweed, but their simplicity need have no com-
plexity behind it. Sometimes these tiniest of duckweeds, mere
little green specks in the water, lie at the surface and produce
each on its upper side a neat little stamen and pistil quite in the
style of their earlier terrestrial days.

The eighth order includes eleven families, of which but four
are represented in Minnesota, the yellow-eyed grasses, the pipe-
worts, the spiderworts and the pickerel-weeds.

Yellow-eyed grasses. There is one species of this family in
Minnesota. It is not very common but occurs in the vicinity
of the Twin Cities. The general appearance of the plant is
grass-like and a few little yellow flowers, each with three dis-
tinct petals, are formed in the axils of a group of scales which
stand in a more or less ovoid head at the tip of a slender erect
stem. The most favorable place to seek these plants is near the
edges of a tamarack swamp where the country is somewhat
open, or on banks near the shores of lakes. The size of the
plant and its general appearance reminds one a little of the
blue-eyed grass, a common plant of the iris family, but the color
of the flowers at once serves to distinguish it.

Pipeworts. Related to the plants last described are the curi-
ous little forms known as pipeworts, of which a single species
has been found on the muddy shores of some Minnesota lakes
near St. Paul, in Chisago county, in Douglas county and in Cass
county — stations indicating a wide distribution over the state.
The pipeworts have very short stems on which little tufts of
grass-like leaves are borne. From the centre of the tuft rises
a slender stem one to six inches in height. At the end of this
is formed a spherical head of minute flowers. If the plant grows
beneath the surface of the water, as it often does, the erect stem

222 Minnesota Plant Life.

may be several feet in length, coming up like a wire from the
bottom of the pool and bearing the little head at the surface of
the water. The name pipewort is given on account of the hol-
low stem which bears the flowering head.

Blue-eyed-Marys. The spiderwort family includes two Min-
nesota species, the common spiderworts or blue-eyed-Marys
frequent on banks, along roadsides and railway tracks and at
the edges of meadows. The plants are mucilaginous and when
broken excrete a viscid slime. The leaves are rather thick,
grass-like in form, and arise from a simple or branched stem.
The flowers are produced in generally terminal umbels and are
of a bluish-purple color an inch or so in diameter. There are
three purple petals and three green calyx leaves below. There
are three carpels fused together to form the fruit rudiment, sur-
rounded by six stamens. When the ovoid fruit is mature it
splits by three longitudinal lines equi-distant from each other,
as does also the iris fruit. The stamens in these plants possess
tufts of interesting purple hairs which are very beautiful objects
for microscopic study.

Pickerel-weeds. A somewhat common green-house member
of the pickerel-weed family is known as the water-hyacinth and
is similar in its flowering clusters to the rather rare native pick-
erel-weed of Minnesota. Any one who has seen the flowers of
the water-hyacinth will recognize the pickerel-weed if he
chances upon it at the edges of a marsh or in tamarack swamp.
The leaves are thick, shaped somewhat like those of the arrow-
head, and arise from a prostrate rootstock. The flowering stem
stands erect, bearing one large heart-shaped leaf, with some
sheathing bracts at the base. The whole flowering stem varies
from one to four feet in height, while the large leaf may be
ordinarily as much as six inches long. The flowers are pale
blue and delicate in texture like the flowers of the water-hya-
cinth. They occur in clusters on a somewhat fleshy spike at
the base of which is a small thin spathe.

Water star-grasses. Related to the pickerel-weed and a
member of its family is a little mud-flat plant known as the
water star-grass. When growing in water the stem of this
plant is two or three feet in length, no thicker than a knitting-

Minnesota Plant Life. 223

needle, branching frequently and possessing short, very slender
leaves with rather sharp points. The flowers are of a lemon-
yellow color and one or two are produced at a time. This form
is, however, rare in Minnesota and usually the water star-grass
appears on mud-flats as a plant two or three inches long with
characteristic lemon-yellow flowers, each with six equally col-
ored portions.

To this order belong also the pineapples and Spanish mosses
of the south and several tropical families not represented in the
United States.

Chapter XXV.

Rushes, Lilies, Blue Flags and Orchids,

The ninth order includes the rushes, the lilies, and their allies,
the bloodworts, the amaryllises, the yams, and the blue flags
or irises. These all unite in the general character of the flower
which is made up of the six portions belonging to the perianth,
three or six stamens and three fused carpels. The flower of the
familiar Easter lily is, in its structure, typical of the whole order.
Rushes. About twenty species of rushes occur in Minne-
sota. They are for the
most part perennial
grass-like herbs, com-
mon upon sand beach-
es, in prairie sloughs
and back a little way
from the borders of
marshes or 'swamps.
The flowers are ordi-
narily clustered and
are characterized by
the inconspicuous
chaffy appearance of
the six perianth leaves.
They are not, however,
subtended by scales

and arranged in spikelets as are the grass and sedge flowers;
and rushes need not be mistaken for any of the lower families
if their flowering tracts are carefully observed. The fruit in
rushes is a small capsule which splits at the sides like the much
larger fruit of the iris. The seeds vary in number from three
to several. There are usually three or six stamens in each
flower.

FIG. 98. Sedges and rushes. After photograph by
Williams.

Minnesota Plant Life.

225

Two genera of rushes,
the wood rushes and the
bog rushes are found in
Minnesota. The wood
rushes are recognized by
their habitat and by the
position of the bractlets
beside the flowers. The
bog rushes, while of the
same general appearance,
commonly produce more
seeds in each capsule than
do the wood rushes. No
little variety exists among
the rushes in the shape of
their flower-c lusters.
Generally they are rather
flat-topped, but some spe-
cies exhibit the flowers in

globular heads and Otll- FIG. 99. Dog's-tooth violet in flower. After Atkinson.

ers in loose panicles.

Lilies and their allies. About forty species of plants be-
longing to the lily family are known to occur in Minnesota.

Among them may be men-
tioned the trilliums, or wake-
robins, the hellebores, the
asphodels, the bellworts, the
clintonias, the false and true
Solomon's seals, the asparagus,
the tiger-lilies, the dog's-tooth
violets and the wild onions.
These plants occupy a variety
of habitats. Some, like the
asphodels, are to be sought in
tamarack swamps; others, like
the bellworts and Solomon's
seals, in the edges of the
woods; others, like the clin-

1'ic.. UK). Clintonia. After Britton and Brown. tOniaS and trilHlimS, ill the
16

226

Minnesota Plant Life.

depths of the forest. One interesting form, known as alkali-
grass, grows on the high prairies in the western part of the state.
The onions are found in six different varieties and are best de-
veloped in the prairie region of Minnesota, but they occur also
in the forests.

The hellebore is notable as the source of the alkaloid ver ci-
trine, a valuable medicinal compound. The bellworts, of which
there are three varieties, are common and attractive flowers
of the middle spring. The onions, with their characteristic
bulbs, smooth in some species, in others fibrous or reticulated;
the tiger lilies of three sorts with their showy flowers, the dog's-
tooth violets of three varieties with
their peculiarly spotted leaves and
white or yellow flowers are all familiar
and common forms. The peculiar
habit of the Solomon's seals which
separate the erect stems of the year
from the strong perennial subterra-
nean rootstocks in such manner as to
give rise to circular scars, has occa-
sioned the common name. Asparagus
which grows wild in Minnesota differs
from the rest of the family in being
largely devoid of leaves, the fine green
foliage consisting of small starch-mak-
ing branches rather than true leaves.
Smilax. Among the lilies may be
included also the green briars or
smilaxes, noticeable for their netted

leaves and, in most varieties, tendril-bearing stems. Five spe-
cies of smilax are known to occur in Minnesota. The flowers
in these plants stand in umbels and the fruits mature as berries
of a red or blue color, shading towards purple or black. The
stems, which twine or climb upon the vegetation near them,,
arise from large swollen underground rootstocks. One variety
of smilax common in Minnesota is quite destitute of tendrils
and exists as an erect herb a foot or so in height. Some of the
smilaxes are very bristly with prickles upon the stems or edges
of the leaves, whik others are smooth.

FIG. 101. Blue flags. After pho-
tograph by Williams.

Minnesota Plant Life.

227

Yams. A single species of yam is common in woods through-
out the southern part of Minnesota. The body of the plant is
herbaceous or slightly woody. Underground rootstocks are
produced from which slender twining vine-like stems arise,
bearing heart-shaped broad leaves with elongated pointed tips.
The flowers are small and borne in elongated clusters. When
the plant fruits, deeply three-furrowed papery capsules are
formed in each of which from three to six very flat thin seeds
are enclosed. The rootstock is fleshy and some of the tropical
varieties are of commercial value as articles of food. The sweet
potato, sometimes confused with the yam, is an entirely differ-
ent plant.

Blue flags.
In Minnesota
the iris family
includes three
species. O n e,
the blue flag or
iris or fleur-de-
lis, is a familiar
object in swales
and mar s h e s
and is common
throughout the
state. The

large blue flowers are borne on erect steins with leaves similar
in appearance to those of the cat-tail. The stems arise from
woody tuberous rootstocks. The three-celled ovary matures
into a capsular fruit in which the seeds are very much flattened
by mutual pressure.

Blue-eyed grasses. The other plants of the iris family are
known as blue-eyed grasses. Of these, two species, by some
botanists combined into one, occur in Minnesota. They are
but diminutive blue flags, being tufted grass-like plants with
small blue flowers about a quarter of an inch in diameter. They
are to be found in meadows and upon wooded slopes.

Star-grasses. One species of star-grass is fairly common in
the southern part of Minnesota. In general appearance it is
grass-like with a swollen solid bulb of rather oblong shape

FIG. 102. Stream-side vegetation. Blue flags in foreground.
After photograph by Williams.

228 Minnesota Plant Life.

and usually about half an inch in diameter. Upon a somewhat
short erect stem, generally surpassed in length by the leaves,
are borne three or four yellowish flowers, of small size, in a flat
topped cluster. This plant cannot be mistaken for the yellow-
eyed grass because it has not the spherical scaly head from which
originate the flowers in the latter variety.

Besides the families of the ninth order which have been men-
tioned there are four others not represented in the state. Nor
are the plants of the tenth order found so far beyond the tropics.
It is to this order that the bananas and the zingibers, the cannas
and the arrow-roots belong. Cannas, however, with their un-
symmetrical red flowers and large leaves are planted for orna-
ment in many Minnesota lawns and parks.

Orchids. The eleventh order includes but two families, one
of which is not found in Minnesota, while the other, the orchid
family, presents a number of interesting varieties. Of orchids
there are about 45 species in the state, including the rein orchids
in a number of forms, the tress orchids, the Arcthusas, the
Pogonias, the Calypsos, the coral-roots, the putty-roots, and the
lady's slippers or moccasin flowers, together with some others.
Orchids differ from the rest of their class, so far as Minnesota
is concerned, by developing flowers with bilateral symmetry,
while the flowers of lilies, irises, yams and the rest are radially
symmetrical like a star-fish. Orchid flowers have a distinct
upper and under side like snap-dragon or pea flowers. This is
probably because for ages they have stood laterally on their
stems and long ago in response to this habit came to show a dif-
ference between the side toward the ground and the side toward
the skies. Many orchid flowers display a long spur, as do the
larkspurs. Others produce boat-shaped or slipper-shaped bags
as does the moccasin flower. In none of them has the flower
the even, radial symmetry possessed, for example, by the tulip
or the tiger lily. Not only for the presence of flowers of this
type, a character which they share with the cannas and bananas,
are the orchids noted, but also for the immense number of very
small seeds which they produce.

In numerous orchid flowers a peculiar reduction of some of
the stamens takes place, so that in many of them there remains

Minnesota Plant Life.

229

but a single functional stamen out of the group, the others be-
ing reduced to mere vestiges. In the lady's slipper, however,
two stamens of the group remain functional. The curious
shapes of orchid flowers are connected with insect pollination
and the orchid flower may be regarded as a machine, or tread-
mill, in which some definite species of insect, different for the
different species of orchids, is temporarily captured and forced
to work for the
purposes of the
flower.

In the com-
mon r o u n d -
leaved orchid
of Minnesota,
which has but a
single stamen,
if a pin be in-
serted into the
spur of the
flower, passing
along a groove
between the
two pollen-
pouches of the
stamen, a
couple of cir-
cular adhesive
discs spring out

and attach themselves to each side of the pin. On each of
these discs is a stalk at the end of which a mass of pollen-
spores is collected. The two little masses stand up like dimin-
utive Indian clubs for an instant and then droop forward.
Here one sees the mechanism designed for the moth that
pollinates the flower. When the insect comes to the plant it
finds attractive perhaps only one flower of the two or three
which are finally produced. It stands in a definite posi-
tion, generally upon the portion of the flower turned toward
the ground, and introduces its bill into the spur where a little

FIG. 103. Yellow lady-slipper. After photograph by Mr. R. S.
Macintosh.

230

Minnesota Plant Life.

honey is secreted. In order to obtain the honey it must thrust
its bill along the groove where the two adhesive discs are sit-
uated. When the insect has sipped the drop of honey which
it seeks, having been drawn to it by the perfume and color of
the flower, it flies away, carrying with it the two pollen-
masses, one on each side of its bill. Immediately after the
insect leaves the flower the two pollen-masses bend forward
and the next flower visited receives these pollen-masses fairly
on the sticky end of the stigma, where the pollen-spores ger-
minate and give rise to the male orchid plants. From this sec-
ond flower the moth carries
away a fresh pair of pollen-
masses.

Such very wonderful and
perfect devices secure what is
termed cross-pollination. The
pollen is taken from one flower
and carried to the stigma of
another upon another plant,
thus apparently insuring a
greater vitality and breadth of
experience in the embryo
plantlets which are to be de-
veloped in the seeds. A va-
riety of such mechanical de-
vices are employed by plants.
Those of the orchids with their

automatic adhesive discs and curving-stalked pollen-masses be-
ing among the most marvelous in their perfection. Yet it may
be said that the orchids are over-refined and almost too per-
fect. The exactness of the machine is indeed so great that the
chances against its working are apparently infinitesimal. The
seeds, however, are so small and the embryo plantlets are pro-
vided with so little nutriment with which to enter upon their
independent life that the great majority of them must certainly
perish. The orchids, in their development, have given their at-
tention, so to speak, to the elaboration of highly complicated
methods of cross-pollination, but have at the same time neg-

FIG. 104. Wild orchis. After Britton and
Brown.

Minnesota Plant Life. 231

lected the proper nutrition of the plantlet in the seed. For this
reason orchids are everywhere rare plants. One scarcely ever
finds them in great beds such as those in which many other sorts
of plants habitually occur, and possibly their infrequency may
be attributed to the failure on their part to produce sufficiently
virile seeds.

The habitat of Minnesota orchids is somewhat various. The
moccasin flowers which, especially in their fruiting season, are
poisonous to the touch like poison ivy, are to be met with
in tamarack swamps or drier localities throughout the state.
There are six varieties in Minnesota, differing in the size, shape
and color of the flowers. One of them, the yellow moccasin,
is the legal "state flower." About a dozen varieties of rein-
orchids may be found, and in these several flowers are produced
in a spicate cluster. The flowers in some of the rein-orchids
are fringed like those of the fringed gentians, and one, with
rather large purple flowers, is not uncommon in damp places
both north and south. Another variety with fringed petals is
found in tamarack swamps. In this the flowers are greenish
or almost white. Still another type of orchid, not very com-
mon anywhere except in the woods north of Lake Superior, is
the rattlesnake plantain. In this the leaves are shaped much
like those of the common plantain and are curiously mottled
with different shades of green. The tress-orchids are delicate,
slender plants, six inches or so in height, not uncommon in pine
woods near the bases of old stumps. They may be distin-
guished from the other orchids by their somewhat spirally
twisted spikes of flowers.

Perhaps the most ornamental native orchid, when seen un-
der favorable conditions, is the Calopogon or grass-pink. This
is most prettily conspicuous in northern peat-bogs, where it
grows among the cranberries and kalmias, often forming
patches of considerable size. The flowers are of a beautiful
shade of purplish pink and are visible for some distance on
account of their brilliant color.

The coral-roots have very small and poorly developed leaves.
They are humus plants, deriving their nutriment to a large
extent through the cooperation of fungus filaments in the super-
ficial layers of their rootstocks, and the singular coral-like ap-

232 Minnesota Plant Life.

pearance of the infected rootstocks has occasioned the popu-
lar name of the plant. There are three varieties, rather more
common in northern woods than in the southern part of the
state.

In several of the orchids bulbs are produced, and in the little
putty-root, not very rare in hard-wood timber where the
ground is covered with decaying vegetable mould, the bulb is
well-formed and about the size of one's thumb.

The only Minnesota orchids known to be poisonous to the
touch are the lady's slippers, and, especially in the autumn, it
is advisable to avoid handling these plants. The leaves and
stems are furnished with two kinds of hairs, some pointed and
apparently harmless, others with globular tips which secrete
small quantities of oil. Either the oil itself or substances in
solution may irritate the skin, and careless handling of a plant
is frequently the beginning of much discomfort. In the early
spring, when they have first come above the ground, their se-
cretions do not seem to be so virulent. The seeds of the
lady's slipper are very light and after the pods containing them
have opened they depend upon the wind for distribution. That
the plant should be more poisonous while the seeds are matur-
ing is possibly a device to discourage grazing animals from
attacking it at this time.

Chapter XXVI.

Poplars and Willows.

There have now been passed in review the principal Minne-
sota types of higher seed-plants in which a single embryonal
leaf is produced. In all such forms the first leaf springs from
the tip of the nascent plant in the seed, and the rudiment of the
stem arises as a lateral protuberance of the young embryo.

Plants with two-leaved seedlings. The plants included in
the lower class are not so numerous as the species which be-
long to the other and highest group of the vegetable kingdom.
The latter produce a pair of seed-leaves by bulgings at the end
of the young spherical embryo shortly after it has begun to
form from the fecundated egg. The two seed-leaves are devel-
oped opposite to each other and between them is situated the
growing point of the stem, so that when seedlings of plants of
this group come above ground they may generally be recog-
nized by the pair of seed-leaves between which the little bud
of the stem gradually unfolds itself. There are, however, some
exceptional cases which need attention before passing on. In
a few forms the growth of one of the seed-leaves is at a very
early stage arrested, so that when in a ripe seed the plantlet is
observed it may seem to have but a single seed-leaf. This is
true of some bladderworts. Another irregularity is to be no-
ticed in the embryos of certain parasitic plants like the mistletoe
or dodder. In these the seed matures without the develop-
ment of any seed-leaves whatever, and the embryo, upon dis-
section of the seed, will be found to exist as a tiny, more or
less spherical body near one end. Here, too, it may be recalled
that some members of the pine family produce a pair of seed-
leaves, yet they would not on that account alone be included
in the class now under consideration. In all instances of irreg-
ularity it is conceived that special influences must have been

234 Minnesota Plant Life.

brought to bear upon the embryo plantlet to modify it from the
ordinary type; but when the other structures of the plant are
taken into account there is usually no difficulty in assigning it
to its proper class.

Stem structure. A very constant character of plants of the
highest class is the presence in the stem of fibres in which a
longitudinal layer of cells remains without finally maturing. In
trees, the seedlings will be found to have at first a little circle
of such fibres, which by mutual pressure upon each other be-
come blended together around the central pith. The layer of
cells known as the cambium in each of the fibres thus joins with
the layer of a fibre next to it and a cylinder of cambium origi-
nates, inclosing the young wood and inclosed by the young
bark. This layer of cells ordinarily gives rise, during every year,
to new wood tissue and new bark tissue. The oldest parts, there-
fore, of a tree-trunk, are the outside where one can lay one's
hand, and the heart-wood. The bark is younger as one cuts
from the outside toward the wood, but the wood is younger
as one cuts from the centre toward the bark. In a tree there
are just as many bark rings as there are wood rings, but the
outer bark is constantly sloughing off, being cracked by the ex-
pansion of the wood within and by exposure to the disintegrat-
ing effects of the weather. Besides this, the ring of bark that is
formed by the cambium during a year is commonly not so thick
as the ring of wood. For these reasons bark may be only an
inch or more thick, while the wood from circumference to cen-
tre may measure even several feet.

Herbs and trees. To non-botanical observers it is sometimes
difficult to explain that there is no very essential difference in
structure between an herb and a tree, providing they both belong
to the same general family of plants. The elm is so very much
larger than the nettles which grow in its shade that upon
any one who considers the two together it naturally makes a
very different impression. Yet, nevertheless, the general plan
of structure in the two is very similar. In the nettle there is a
disposition of woody tissue inside, with bark tissue outside, just
as in the elm, but the tree persists possibly for hundreds of years,
thickening its trunk with every season, while the stem of the
nettle dies at the end of the first season of growth. The proper

Minnesota Plant Life.

235

way to compare trees and herbs in order to understand their sim-
ilarity is this: Let an herb be pulled up by the roots and laid
down before one. Then let a fresh leaf-bearing twig of a tree,
such as a willow or poplar, be selected and removed from the last
year's branch upon which it is standing. Let one of the young
roots of the tree, if it is found, be attached to the end of the twig
that was broken from its support. Let the two specimens be
placed side by side and their fundamental resemblance will be-
come apparent. The same fact will be understood if one com-

FIG. 105. Cottonwoods on the Minnesota. After photograph by Williams.

In

pares the seedlings of trees with the seedlings of herbs,
essential respects they will appear altogether similar.

Other characters of plants with two-leafed seedlings. The
plants included in the highest class ordinarily produce leaves
with netted veins and the flowers are built generally upon the
plan of four or five rather than upon the plan of three. That
is to say, while one finds three sepals, three petals, six stamens,
and three carpels forming the fruit-rudiment in many flowers
of lower-class plants, one would more probably find four or
five sepals, four or five petals, four, eight or some other number

236 Minnesota Plant Life.

of stamens, and five carpels, or more, fused together to make
the fruit-rudiment in the flower of a plant belonging to the
higher class. In both classes of higher seed-plants there are
many variations from the rule and in some plants of the highest
class, flowers very similar in general plan to those of the lily
might be observed. Yet the differences which have been
pointed out are fairly general and in most instances serve to
distinguish the proper class of a plant in question.

The highest class, comprising over 120,000 species, is by far
the richest in forms of any in the vegetable kingdom. Two
sub-classes are recognized, in each of which are grouped a
number of orders. The higher sub-class comprises all those
forms in which the petals are normally fused together by their
sides to make a corolla-tube — a structure of which the honey-
suckle, or the morning-glory affords typical examples. When,
however, the petals are distinct from each other or are quite
reduced and insignificant, the flower is regarded as typical of
the lower sub-class.

Casuarina trees. The first and lo\vest order of the highest
class includes a curious family of trees, the casuarinas, not rep-
resented in North America. In appearance their branches
would remind one of those of the horse-tail. They are abun-
dant in northern Australia and the Malay archipelago, and differ
from most other seed-producing plants in forming more than
one large-spore in the ovule, so that in a single seed more than
one female plant may arise. Another odd habit of the casu-
arinas— which appears, however, in some of the other families
of the class — is the penetration of the seed-rudiment by the
pollen-tube, not through a canal at its tip, as is the rule, but
through a cleft in the base. Therefore the seed-rudiment, which,
it must be remembered, is equivalent to a spore-case in the
ferns, may be regarded, in these plants, as splitting open and
partially exposing the spores inside — a behavior recalling very
strikingly the ordinary opening of spore-cases in lower forms.

Lizard's-tails and peppers. The second order includes four
families of which the pepper family is the most important.
Here belong the peppers and cubebs from which spices are
obtained. They are nearly all tropical and none of them occur
in Minnesota.

Minnesota Plant Life.

237

A single curious little plant, the lizard's-tail, belonging to a
related family, is found in far northern Minnesota. The lizard's-
tail is an herb with heart-shaped leaves and flowers arranged
in little spikes like those of the dooryard plantain. There are
no petals or sepals and the stamens grow from the base of the
ovary, which consists of three or four carpels, sometimes fused
and sometimes almost separate. From four to eight seeds are
formed in the fruit and in each seed there is an abundant albu-
men. The embryo is small and located near the end of the

FIG. 106. Poplar vegetation of burnt district. Near Rat Portage, Ontario. After photograph

by the author.

seed, imbedded in the albumen. These plants are to be sought
in swamps or near the edges of small woodland lakes.

Willows and poplars. The third order includes but a single
family — the willow family — to which the willows and poplars
belong. About eighteen species of willow and seven species
of poplar grow without cultivation in Minnesota. The willows
are wind-pollinated plants with rather slender leaves. The
poplars are insect-pollinated and have generally broad, trian-
gular or heart-shaped leaves. This family of plants is charac-
terized by separate flowers, the staminate and pistillate occur-

Minnesota Plant Life.

ring in different clusters, and both kinds are arranged in erect
spikes or drooping catkins. The fruit is an oblong or rounded
capsule containing small seeds with numerous white silky hairs
instrumental in distribution of the plantlets in currents of air.
There is no albumen in the seeds.

Poplars. The poplars in Minnesota are represented by the
very common white poplar, the large-toothed poplar, the cot-
tonwood, the balsam-poplar, the balm of Gilead, the silver-
leafed poplar — sometimes called silver-leafed maple — and the
Lombardy poplar. The last two are not native plants, but
occur spontaneously, having escaped from cultivation in some

parts of the state. Of them
all, the white poplar is the
most abundant tree through-
out the northern part of the
state, and is not uncommon
in the southern counties.
This, indeed, is the most widely
distributed tree in North
America. It often reaches
a height of seventy-five or
one hundred feet, but in the
region of the Great Lakes does
not apparently grow so large.
The wood is soft and is of
great importance, together
FIG. 107. cottonwood. After Britton and with spruce, as the variety em-

ployed in making wood-pulp,

from which paper is manufactured. It is used also for fire-
wood, and is a most prominent plant in burned districts, readily
reaching them by its buoyant air-distributed seeds. The leaves
are hung upon stems of peculiar shape and tremble in the slight-
est breeze.

The large-toothed poplar has much ampler leaves with broad
teeth upon their margins. By these characters it may be dis-
tinguished from the white poplar. It prefers soil damper than
does its relative and is generally found upon the more sheltered
banks of lakes. Its wood is also of value in the manufacture
of paper.

Minnesota Plant Life.

239

The balsam-poplar has longer, sticky leaves and the balm
of Gilead — a variety with more spreading branches — is culti-
vated as a shade tree in some parts of the state. The leaves
are dark green on one side and dirty brown or white on the
other, and are considerably longer than those of any other Min-
nesota species.

The cotton wood, which may be distinguished from the white
poplar by the glistening paler green of its leaves, is an abund-
ant tree throughout the state, and is found along streams
where it often forms considerable forests. Under favorable

FIG. 108. Peach-leafed willows on shore of stream. After photograph by Williams.

conditions it may grow to the height of a hundred feet with a
trunk seven or eight feet in diameter, but I have seen none in
Minnesota to exceed five feet in thickness. The wood is of
little value save for pulp and fuel. In the older towns and vil-
lages of Minnesota the cottonwood has been freely planted;
but it is not regarded as the most desirable of shade trees, for
it is always dropping something from its boughs — either stam-
inate flower-clusters, cotton, scales or leaves — and it litters a
lawn or street throughout the spring and summer. The stam-
inate flowers of the cottonwood are crimson in color, borne in

240 Minnesota Plant Life.

rather dense drooping catkins. The pistillate flowers, produced
on other trees, are green in color, and likewise gathered in
pendent clusters. The capsule opens by three clefts and is
regarded as composed of three carpels. A considerable num-
ber of silky-tufted seeds are produced in each capsule.

The other poplars need no special mention since they are
not indigenous to the state. One of them, the Lombardy pop-
lar, with its spire-like habit of growth, is an attractive and val-
uable ornamental tree. It is propagated by cuttings and seems
to have lost the power of fruiting. No doubt almost all the

I:

FIG. 109. Clusters of willow flowers; on the left the pistillate flowers and on the right the
staminate. Each pistillate flower consists principally of a single fruit-rudiment, and each
stamiiiate flower of two, or sometimes a larger number of stamens. After Atkinson.

Lombardy poplar trees in America might be traced back to a
single poplar egg. The tree which developed from the em-
bryo plantlet was originally propagated by cutting the twigs
and planting them in the soil. The process was repeated and
in this way a vast number of Lombardy poplars have come to
•exist — a very odd thing, indeed, when one thinks of it and com-
pares it with the behavior of animal eggs.

Willows. The willows of Minnesota are not all trees like the
poplars. The majority are shrubs — some of them low bushes
like the myrtle-leafed willows in peat-bogs and tamarack

Minnesota Plant Life.

241

swamps. A few, however, are trees and of goodly size. The
distinctive habitat of willows is along the banks of streams and
around the shores of lakes or marshes. Their twigs are used
in the manufacture of wickerware ; and bushed-willows or pol-
larded willows, are favorite plants for hedge-rows in the east
and in England, but are not so frequent in Minnesota. The
two most conspicuous willow trees of the state are the black
willows with their slender leaves bearing conspicuous stipules
at the base, abundant in the north, and the peach-leafed wil-

r

FIG. 110. Beach vegetation, Garden Island, lyake of the Woods. The long-leafed willow
forms the outer zone, and the black willow the inner. After photograph by the author.

lows, with much broader leaves and devoid of stipules on ma-
ture twigs, more common in the south.

The hoary willow, the gray willow, the pussy-willow, the
heart-leafed willow, the myrtle-leafed willow and the long-
leafed or sand-bar willow are encountered ordinarily as low
shrubs up to ten or twelve feet in height. The familiar "pussies"
of early spring are the spicate flower-clusters of some willow
from which the bud-scales have opened or fallen, revealing the
branch covered with bractlets in the axils of which the flowers
will open. The edges of the bractlets have silky hairs which

'7

242 Minnesota Plant Life.

serve to protect the flower-buds during the cold nights or oc-
casional freezing weather of early spring.

As beach plants, the long-leafed willow, the hoary willow,
the heart-leafed willow, the shining-leafed willow and a few
others are common, especially along sand-bars, where there is
considerable spray from the surf. At Lake of the Woods some
very interesting willow-clothed beaches have been observed.
Different species of willows on such beaches often arrange them-
selves in zones, one variety nearer the water, and another far-
ther back. Some of the willows, notably the hoary willow and
the heart-leafed willow, along the shores of northern lakes,
grow7 in a very regular more or less hemispherical fashion, re-
sembling the trimmed shrubs of some city park.

The bark of the willow is bitter and is sometimes used as a
febrifuge in place of quinine, but it is not particularly efficacious.

Chapter XXVII.

From Bayberries to Oaks, Elms and Nettles.

if

Bayberries. The fourth order includes but a single family,
of which two species grow in Minnesota — the bayberry, found
on lake shores along the international boundary, and the sweet-
fern, rather abundant in the northern part of the state and ex-
tending south to the vicinity of Minneapolis. These plants
are shrubs, their leaves dotted with resin glands, and the name
"sweet-fern" is given on account of the scent which arises from
the glands. The two sorts of flowers are separate and in cat-
kins somewhat like those of the willows but shorter and plumper
in appearance. The fruit is a nut or stone fruit, differing in
this respect from the willow fruits, which are capsules. The
leaf of the sweet-fern is especially characteristic, resembling in
shape a willow leaf with deep narrow incisions along the margin.

The fifth and sixth orders are not represented in Minnesota.
One of them contains a few species of New Caledonian plants,
the other, one species found in the southern United States.

Walnuts and hickories. The seventh order comprises but a
single family, in which are classified the walnuts and hickories,
both represented in Minnesota. There are present two species
of walnuts — the black walnut and the butternut — and three
species of hickories — the white hickory or shell-bark, the pig-
nut hickory, and the swamp hickory. The walnut family is a
group of trees with compound leaves and separated flowers.
The staminate flowers stand in catkins and are furnished with
a perianth. The pistillate flowers are solitary or in small
groups. The ovary is one-chambered and contains a single
seed-rudiment. The fruit is similar to that of a peach in which
the fleshy part should split and separate as three or more husks.
The seed is large, inclosed in the stony inner layers of the fruit,
the whole constituting the well-known walnut, hickory-nut or

244

Minnesota Plant Life.

pecan. There is no albumen in the seed and the two seed-
leaves are large, wrinkled and oily, forming the "meat" of the
nut. The black walnut occurs in the southern part of Minne-
sota, where it is found in low glades along streams. Almost
all the large trees have been cut for their very valuable wood,
useful in cabinet making. This is of a rich, dark brown color
and takes a high polish. The butternut is more abundant and
is a frequent inhabitant of groves in the river valleys, especially

through the southern part of
the state. It is not commonly
more than forty or fifty feet
high in Minnesota, though it
is known to grow twice as tall.
The wood is of a light brown
color, easily polished and of
much value in the manufacture
of furniture and cabinet work,
though by no means the equal
of the black walnut.

Hickories. The three kinds
of hickories in the state may
be recognized by their leaflets,
nuts and buds. In the shell-
bark hickory the leaflets are
from five to seven in number,
with hairy margins. The nut
is four-angled, pale or whitish
in color. In the pig-nut hick-
ory, with the same number of

leaflets, these are USUally
, , . , -

smooth or slightly furry, but
not hairy at the margin. The nut is oblong, with a slightly
bitter kernel. In the swamp hickory the leaflets are from five
to nine in number, the nut thin-shelled and short. The buds
in winter are yellow. The wood in all these plants is very
heavy, strong and tough, and is used in the manufacture of
wagon-tongues and plow-handles, while the young saplings of
the swamp hickory are split and bent into barrel-hoops. The
nuts are common in markets, but are not so agreeable to the

FIG. 111. Hickory trees. l,ake Minnetonka.
After photograph by Williams.

Minnesota Plant Life.

245

taste as the pecan nuts, which are derived from a species of
hickory that does not grow in Minnesota. Hickories are often
a hundred feet in height, with tall trunks two feet in diameter

FIG. 112. Ironwoo

d oaks. The smaller trees are ironwoods and hop-hornbeams. l,ake
Calhoun. After photograph by Hihhard.

at the base. They are among the most valuable of the hard-
wood timber trees of the state.

The eighth order comprises two families, one including the
hazels, ironwoods, hop-hornbeams, birches and alders; the other

246 Minnesota Plant Life.

the beeches and chestnuts, not represented in Minnesota, and
the oaks which form a large and characteristic portion of the
hardwood forest of the state.

Ironwoods. Of ironwoods there is a single species in Min-
nesota, known also as the water-beech or hornbeam. This
plant is a small tree with very strong, tough wood. It is
found principally along streams. It has the leaves of a birch,
but when in fruit displays each of its little nuts at the base of
a large three-lobed bract shaped somewhat like a spear-head.
By means of these bracts and also by the rough bark, quite
unlike birch-bark, the ironwoods may be distinguished. Re-
lated to them are the hop-hornbeams, the fruit clusters of which
look very much like hops, while the general appearance of the
tree is similar to that of the ironwood. An examination of
such an hop-like fruit cluster will show that it is an axis upon
which little nuts are formed, each one inclosed in a membranous
sac structurally equivalent to the spear-shaped bract of the iron-
wood.

The hazels. The hazels, of which there are two varieties in
the state, are shrubs with broad notched leaves. They pro-
duce their staminate flowers in catkins and the pistillate flowers
in very inconspicuous little buds from which the stigmas of the
pistils protrude as red threads. In the common hazelnut, which
is so abundant as underbrush in the woods, the nuts, when
mature, are inclosed in ragged scales not prolonged very much
beyond the ends of the nuts. In the beaked hazelnut, a some-
what larger bush, ten or fifteen feet in height, the nuts are in-
closed in scales which grow out into a long tubular beak, a
structure by which this plant is easily distinguished from the
more common variety. The nuts of the hazels are much larger
than those of the ironwoods and hornbeams, are edible and are
gathered in quantities in the autumn.

Birches. Of birches there are six species in Minnesota, the
black birch, the canoe or paper birch, the river or red birch,
the yellow or gray birch, the low birch or tag-alder, and the
scrub or glandular birch. These plants range in size, in the
different species, from large trees to low bushes, but may be
recognized in most instances by their bark, which peels off in
thin layers, most easily in the canoe birch, but with very little

Minnesota Plant Life.

247

difficulty in the others. Of the trees, the canoe birch will be
known by its white bark, the river birch by the stems of the
fruiting catkins and the brown or greenish-brown bark, the
black birch by the sessile fruiting catkins and the leaves of shin-
ing green, the yellow birch by the dull green color of the leaf,
otherwise like the black birch. All of these just mentioned are
trees, while the rest are shrubs. In the low birch the twigs
are not covered with glandular pimples, but such are present
on the twigs of the glandular birch. Of all the birches the

FIG. 113. The paper or canoe birch. After photograph by Williams.

canoe birch is the most interesting, on account of the peculiar
bark that plays so important a part in the domestic arts of the
Indians who employ it in the manufacture of a great variety
of useful objects. Their canoes and the houses, dishes, bas-
kets, drinking-cups and scrolls for writing are produced from
birch-bark; while from the wood they manufacture a variety
of tools, snow-shoe frames, sledge-runners and tepee-poles. By
the whites, birch wood is employed in cabinet making, for
spools, for shoe-pegs and for lasts. The wood of the red birch
or river birch is of particular value in the manufacture «>f fur-

248

Minnesota Plant Life.

Minnesota Plant Life.

Minnesota Plant Life.

249

niture, being utilized as an imitation of mahogany. For this
purpose, too, the wood of the black birch is even more excel-
lent. This species, however, occurs but sparingly in Minne-
sota and is found only in the extreme northern part of the state.
It is from this species that birch-oil and the extract used in
flavoring birch beer are manufactured. Of the shrubby birches
the most abundant is the low birch which is found in peat-bogs
pretty commonly through-
out the state.

Alders. Related to the
birches are the alders, of
which two varieties occur in
Minnesota, the green alder
and the black alder. These
may be distinguished from
the low birch, which they
resemble, by their more en-
tire leaves and short, com-
pact, cone-like clusters of
nutlets. The low birch has
rather more elongated
spikes of pistillate flowers,
two and a half times as long
as they are thick, while the
alder spikes are about half -
as long again as thick. The
alders are to be looked for

in tamarack SWampS Or in FIG. 115. An oak twig with leaves and both sort-*

j i of flowers. The one with three prongs is the

Open WOOdS, Where, eSpe- pistillate flower; the other, with five stamens,

daily in damp places, they is the rtaminate. The *aminate flowers grow

3 in drooping clusters. After Atkinson.

may form an underbrush.

Oaks. There are in Minnesota sev^n species of oaks, the
red, the scarlet, the black, the white, the bur, the chestnut and
the scrub chestnut-oak. Oaks form a large genus of plants,
comprising some three hundred species and well distributed
throughout the temperate regions of the northern hemisphere
and at high altitudes in the tropics. There are some
species in North America. They are distinguished by the fru:
known as the acorn, consisting of a nut or one-seeded fruit.

25°

Minnesota Plant Life.

inclosed within, or standing in a cup composed of numerous
bractlets ordinarily grown together and woody. In some oaks
the fruit matures within a year, but in other varieties a longer
time is required. Oaks are employed for a variety of purposes
— as firewood, in the manufacture of timbers in which great
durability is demanded, and as plants from which tan-bark may
be procured. The acorns are eaten by domestic animals, and
the various species are prized as shade-trees.

FIG. 116. Oaks and blue flags. A marshy place in the oak-woods. After photograph by

Williams.

The different varieties in Minnesota may be thus distin-
guished : Of those forms in which it takes the acorn two years
to mature, the red oak has leaves green on both sides and the
acorn cup much broader than high, while in the scarlet oak the
cup of the acorn is about as high as broad, the leaves are smooth
on each side, and the inner bark gray. In the black oak, which
is much like the scarlet oak in appearance, the leaves on the
under side develop a few hairs where the veins branch, and the
inner bark is orange in color. In all three species which have
been mentioned the acorns do not mature until the autumn of

Minnesota Plant Life.

251

the second season. In the scarlet oak the foliage turns scarlet
red in autumn, while in the black oak the leaves turn brown.
In this way the three related species may be distinguished. In
some instances, it should be mentioned, the inner bark of the
scarlet oak is red rather than gray. The other Minnesota oaks
mature their acorns in the autumn of the first year. Of these
the white oak is distinguished by its deeply lobed leaves and
shallow cups, while the bur-oak has the cup deep and com-
posed of scales which form a bur-like growth different from the
smooth hard cup of the white oak. In the remaining native
oaks the leaves are notched
but are not lobed in the char-
acteristic oak fashion, and in
both of them the acorns are
sessile on the branches. The
chestnut-oak is a tall tree with
grey bark and has a chestnut-
like aspect. The scrub chest-
nut-oak is a shrub with the
leaves considerably broader
than in the chestnut-oak
proper.

Some of the oaks, notably
the black oak, cling to their
leaves for a long time after the
frosts have killed them, some-
times even throughout the
winter. This habit is possibly

the indication of an original southern range for the black oak
and a late extension of its range to the north, so that it has not
fully learned how to cut its leaves from the twigs as the other
more northern varieties are able to do. The bur-oaks in Min-
nesota, together with the black oaks, form oak-barrens. These
wastes, covered with grotesquely branching trunks, form pic-
turesque forests in the central part of the state.

The ninth order includes three families, the elms with the
hackberries, mulberries and Osage oranges; the India-rubber
trees, figs, hemps and hops, and the various kinds of nettles.

FIG. 117. American elm. After Britton and
Brown.

252

Minnesota Plant Life.

Elms. Of the elms there are represented in Minnesota three
varieties, and one species of hackberry. The elms which are
present in the state are the white or American elm, the slippery
or red elm, and the rock- or cork-elm. Their flowers are small,
clustered or solitary, quite devoid of petals. The ovary is one
or two-celled, with a solitary seed. The fruit of the elm is
winged. In the hackberry it is a berry-like nut. The seeds
have little albumen. The three varieties of elm which occur
in Minnesota may be distinguished by the following characters :
When the young fruit is very hairy and the branches are without

FIG. 118. American elm. L,ake Miunetonka. After photograph by Williams.

corky wings, the tree is the white elm. When the fruit has no
hairs, is larger and the twigs are not supplied with corky wings
the tree is the slippery or red elm. When the fruit is hairy
and the branches are provided with curious flat cork wings,
especially prominent on the young twig, the tree is the rock-
or cork-elm. All of these occur in similar regions and, together
with the basswoods, maples and oaks, form the most abundant
growths in the hardwood forests of the central part of the state.
Elms are generally to be recognized by the uneven bases of
their leaves, by the strong development of the terminal buds

Minnesota Plant Life. 253

of their branches, and by the little, oval, flattened fruits with
wings on each side or extending entirely around the middle.
The wood of the elm is tough and is employed for ox-yokes,
the handles of tools and portions of farm machinery. The inner
bark of the slippery elm is mucilaginous and is thought to have
some medicinal virtue. It is frequently gathered by children.

Hackberries. The hackberry, which in its flowers and foli-
age much resembles the elms, is distinguished by the produc-
tion of a berry-like nut. It is abundant throughout the south-
ern part of the state and occurs in a few localities far to the
north ; as for example, on Sable island, Lake of the Woods.
The trees are valuable shade trees and are common along the
streets of towns and villages.

Mulberries and hops. The mulberries are represented in
Minnesota by the red mulberry — a species reported from the
southern part of the state. It is a tree with fruits superficially
resembling those of the red raspberry. These are not, however,
like those of the raspberry, produced from a single flower, but
are rather aggregates of fruits like the spikes of the birch, or
the catkins of the poplar. The foliage of a mulberry is not
unlike that of the elm. The fruit-clusters are edible and the
tree is both ornamental and valuable in cultivation. The com-
mon hop, related to the mulberries, is a twining vine with rough
stem and foliage, and found in thickets and woodsides through-
out the state. It is more abundant in the central and northern
portions of the state than southward. The general appearance
of the fruiting area is like that of the hop-hornbeam, but the
floral structure is in most of the essential details like that of the
mulberries. Hops are of value in the manufacture of yeasts and
have besides a distinct medicinal value. They are gathered as
herbs in Minnesota but not, so far as has been learned, on a
commercial scale.

Hemp. The hemp, introduced from Asia, is a very abund-
ant roadside weed and a denizen of waste fields throughout the
state. It is a robust annual herb, growing to a height of more
than ten feet, forming thickets, and really becoming a sort of
herbaceous tree. The inner fibrous bark is exceedingly tough
and is pounded out of the stem by special machinery and con-
verted into rope and mattings. It is not generally employed

254 Minnesota Plant Life.

in Minnesota for these purposes, though it is evidently capable
of producing as strong a fibre here as elsewhere. The hemp
leaves are divided into from four to eight or nine slender lobes
arranged in palmate fashion. The staminate flowers are ar-
ranged in panicles, while the pistillate stand in short leafy spikes.
Nettles. The nettles are represented in Minnesota by the
stinging and the slender nettles, the wood-nettles, the clear-
weeds, the false nettles and the pellitories. The first two va-
rieties of nettles, one of which is introduced, are distinguished
by the different shape of their leaves. In the stinging nettle

FIG. 119. Roadside vegetation of nettles and vines. Winter aspect. After photograph by

Williams.

the leaves are ovate in outline, while in the slender nettle they
are lance-shaped and slender pointed. Both of these plants are
provided with peculiar stinging hairs, consisting of cells with
very sharp points and swollen bases around which a group of
cells comes up like a cup. Hairs of this sort are found on both
the leaves and stem. Upon being brushed against, the ends
of these hairs break, forming a chisel-like point which penetrates
the flesh and the cup of cells around the base of the hair con-
tracts and injects irritating poison, very much as if from a syr-
inge. The peculiar stinging sensation which arises when one
touches a nettle is a result of this injection of acid into the flesh.

Minnesota Plant Life.

255

The wood-nettles, from their name to be looked for in the
forest, have tall stems as much as four feet in height, stinging
hairs like the ordinary nettles, and flowers disposed in axillary
compound clusters. The leaves are thin, shaped much like
those of the stinging nettle, and provided with a solitary stip-
ule which often falls off. The clearweecls have no stings. The
leaves are opposite and the stems are translucent and succulent,
resembling the stems of the touch-me-not. The leaves are del-
icate and thin. The flower clusters are borne on short stems
in the axils of the leaves. The clearweed is a shade-plant,
preferring deep woods where there is an abundance of moisture.
The false nettles resemble the true nettles in outward appear-
ance and are found in similar localities. They have, however,
no stinging hairs. The pellitories have willow-shaped leaves,
are devoid of stipules and develop the flowers in little clusters
at the bases of alternate leaves. The flower clusters are of the
general nettle type.

The tenth order is best developed in Australia and South
Africa and has no native forms in Minnesota.

Chapter XXVIII.

From Sandalwoods to Buttercups*

Toad-flaxes. The eleventh order includes six families, one
of which, the sandalwood family, is represented in Minnesota
by three species of toad-flax. In this same order are included
the mistletoes and other curious parasitic forms of vegetation.
The toad-flaxes belong to a group known as root parasites.
They seem to be independent plants, but if their roots are care-
fully dug up it will be found that they have attached themselves
to the roots of other plants growing near them, and that from
these other plants they are sucking their food. They are, in
Minnesota forms, slender herbs with leaves shaped like those of
a willow and with flowers in corymb clusters, or cymes. The
fruits are drupes or nuts. There is abundant albumen in the
seed, but the embryo is small and imbedded near one end. The
berries of one of the toad-flaxes are of red color and are edible.
These plants occur in dry or moist soil, and one variety is very
common throughout the state. They ordinarily have a rather
peculiar brownish-green foliage — except the pale toad-flax, of
which the leaves are lighter green. Some exotic sandalwoods
occur as trees, and from them the highly scented sandalwood
of jewel-boxes is obtained.

Wild gingers. The twelfth order comprises three families,
two of which are remarkable aggregations of alien parasitic forms,
while the other includes the wild ginger and pipe-vine or Dutch-
man's-pipe of Minnesota. The parasitic Rafflesias, which be-
long to this order, are among the most extraordinary of plants.
One, which is found in the island of Sumatra, is famous for
having the largest flower in the world, over a yard in diameter,
of the color of livid flesh, and of a very penetrating, unpleasant
odor. These flowers originate as buds, resembling cabbage
heads, upon the exposed roots of certain Sumatran trees or
vines. The vine or root has, however, no structural connec-
tion with the cabbage-head bud. This is developed upon a
curious parasitic plant-body that lives within the tissues of the

Minnesota Plant Life. 257

vine, bursting its way out when about to flower. The flower
is much more conspicuous than the rest of the Rafflesia plant-
body. Some small relatives of the Rafflcsias are found on certain
pod-bearing trees in the southern states. Their little flowers
burst through the bark of the twig in which the plant-bodies
are growing, thus apparently producing the remarkable phe-
nomenon of twigs with flowers growing in the crevices of the
bark. Here, however, as in the Sumatran variety, the twig is
only the host-plant and the flower is a portion of the internal
parasite.

The two Minnesota members of the order are not parasites,
but are independent green plants. The wild ginger, of which
several species are known to exist in the United States, is met
with in Minnesota on shaded banks of ravines where the root-
stocks of the plant, branching and scented, send up short erect
stems usually with a pair of large kidney-shaped leaves and pro-
ducing single, purplish-brown flowers very close to the ground.
The calyx of the flower has three leaves with slender pointed
tips. These are recurved in the Minnesota variety. The calyx
is fused with the surface of the six-chambered fruit-rudiment
which develops numerous seeds in two rows in each chamber.
When ripe, the fruit is a capsule inclosed in the calyx, and it
bursts irregularly.

Pipe-vines. The pipe-vines are twining vines with alternate
leaves — in the Minnesota species heart-shaped. Curious irreg-
ular tubular flowers are formed, destitute of petals and with the
calyx adhering to the base of the ovary. The edge of the tubu-
lar calyx is divided into three lobes and the flower is curved
into a horse-shoe shape. These remarkably shaped flowers are
insect-traps. Insects are induced to enter them and are forcibly
detained as prisoners until they can be covered with pollen.
They are then released to visit some other plant. The pipe-vine
is found only in the southeastern counties of Minnesota, -while
the wild ginger is abundant throughout the state.

The thirteenth order includes a single family in which are
gathered the true sorrels and docks, the rhubarbs, the buck-
wheats and the smartweeds.

Docks and smartweeds. In Minnesota there are ten vari-
eties of docks and about twenty five of knotweeds or smart-

18

258 Minnesota Plant Life.

weeds. The smallest of the docks has spear-head shaped leaves
and is known as sorrel. The other docks are some of them
large-leaved plants most luxuriant in marshes or swamps.
Among them are the water-, the swamp-, the yellow, the golden,
the red-veined, the pale, and the curly-leaved docks, differing
principally in leaf characters. The only one in Minnesota with
sour leaves is the sorrel, and on account of this pleasant acid
taste the leaves are often picked and eaten. These sorrels are
not to be confused with the sheep-sorrel, in wrhich the leaves are
shaped like clover leaves, — an entirely different kind of plant.
The different species of dock, besides by their leaf characters,
are to be distinguished by the wings on the fruits.

The smartweeds, knotweeds, or bindweeds fall into three
groups of species; some, in which the leaves are shaped like
those of the willow, others, in which the leaves are small and
slender, and still others with heart-shaped or arrow-shaped
leaves and twining or climbing stems. The forms with willow-
shaped leaves are known under the general name of smartweeds ;
those with the small leaves are called knotweeds, jointweeds,
knot-grass or doorweeds, while those with arrow-shaped or
heart-shaped leaves are termed bindweeds, false buckwheat or
tear-thumbs. They are all similar in the structure of their flow-
ers and fruits. One variety, the water-smartweed, produces its
stem under the water and sends its leaves to the surface, where
they float like the leaves of the pond-lily. The flowers are
clustered in bright pink spikes thrust above the surface of the
water. Another kind with similar habit is found as a surf-plant
in northern lakes. The ordinary smartweeds grow in moist
soil and ditches, where their bright pink or red spikes of flowers
are conspicuous objects. The knotweeds are common mat-
plants of dooryards. In most of the varieties stipules at the
bases of the leaves coalesce and form tubular sheaths around
the stem. The bindweeds or false buckwheats occur either as
twining vines with heart-shaped leaves and flowers like those
of the buckwheat, or they grow with slender erect stems reclin-
ing against the vegetation near them and supporting them-
selves by sharp recurved prickles. These. are known as tear-
thumbs, and belong to a small adaptational group of hook-
climbing plants.

Minnesota Plant Life.

259

The fourteenth order includes the goosefoots or pigweeds,
and the amaranths, known also as pigweeds, redroots or tumble-
weeds, including the coxcombs and one variety of water hemp.
Here also are the fotir-o'clocks, pokeweeds, ice-plants, carpet-
weeds, purslanes and portulacas, pinks, cockles and catchflies,
besides some other families not represented in Minnesota.

Pigweeds. The goosefoots are represented in Minnesota by
about fifteen species, many of which are introduced. Here are
the common, scurfy-leaved, pale pigweeds of farm-yards and
roadsides. Several sorts of these pigweeds occur in the state.
Here are also to be placed the
winged pigweeds, plants
found on lake shores, espe-
cially upon sandy beaches in
the central part of the state,
and the bugseeds, abundant
on the beaches of Mille Lac
and near Duluth — also the
blites on the shore of Lake
Superior, and two salt-marsh
plants very rare in Minnesota,
but reported from salt marshes
in the Red river valley.

Glassworts. One of these
salt-marsh plants, the glass-
wort, is a curious, leafless, suc-
culent organism, resembling
some slender cactus-forms. In color it is green during the
summer, but turns red in autumn. The stem is from six inches
to two feet tall, repeatedly branched and provided with tiny
scales at the nodes of the fleshy branches. These scales are all
that remains of the leaf-system. Glassworts are abundant in
salt marshes along the Atlantic ocean and occur at various
points inland. Such leafless, succulent plants seem to have a
peculiar reason for reducing their evaporative surface. It is
not on account of the scarcity of moisture, as in the instance
of the cacti, nor of surf, to which bulrushes are adapted, nor
of high winds, in response to which the switch-plants have taken

FIG. 120. Glasswort. After Britton and Brown.

260 Minnesota Plant Life.

their peculiar forms; but rather on account of the presence in
the soil of salt in such quantities that, if the plant had a large
evaporative surface, it would absorb so much salt-water from
the soil to meet the evaporation that its tissues would become
surfeited with saline deposits.

The other saline plant, known as the western blite, occurs
in the Red river valley, in the region of Pembina and St. Vin-
cent. It is a fleshy herb, with thick or cylindrical leaves quite
sessile upon the twigs. It maintains the same generally suc-
culent character that characterizes the glasswort, but has not
undergone so great a reduction of its leaf-tract.

FIG. 121. Poke-weed. After Chesnut. F. B. 86, U. S. Dept. Ag.

Russian thistle. Another variety of pigweed, not native to
the state, but introduced in large numbers, has excited a great
deal of attention on account of its rapid development in the
wheat fields of the Red river valley. This is the Russian thistle,
a tumbling weed, succulent when young, but turning hard, dry
and thorny when older. A variety of plant very similar to the
Russian thistle is found along the Atlantic seacoast. It has
not, however, the bushy branches of the thistle.

Coxcombs. The amaranths or coxcombs also include a very
common tumbleweed which grows in globular form, two or

Minnesota Plant Life.

261

three feet across. The common coxcombs of the country
flower-garden are relatives of this, and the redroot pigweed,
a familiar barn-yard plant, is another closely related form. Still
another amaranth grows flat upon the ground in dooryards and.
along the roadside, in its appearance somewhat resembling purs-
lane.

Water-hemp. The water-hemp which grows in swamps has
flower clusters reminding one of the common amaranth of the
dooryard. The leaves are slender and willow-shaped, while
the habitats selected by the plant are preferably the gravelly
shores of lakes or rivers in the southern part of the state.

Pokeweeds. The poke-
weed family is represented
in Minnesota by a single
species that occurs in the
southern part of the state
rather rarely. In this plant
the fruit is a black berry
with from five to fifteen
chambers, one seed in each
chamber. The root is poi-
sonous, and the whole plant
has a strong, unpleasant
odor. It may always be
recognized by the division
of its stem-pith into disks
separated from each other
by cavities.

Four-o'clocks. The four-o'clocks are represented by three
species known as umbrella-worts, and remarkable for the in-
volucre which stands below the pink or reddish flowers. Three
to five flowers occur in a single circular involucre which, when
the fruits develop, becomes enlarged and papery. The flower-
ing area in this order is more ornamental than that of former
families ; yet there are no petals, the colored portion being of
the nature of calyx.

Carpetweeds. The carpetweed family is represented in Min-
nesota by the common carpetweed, a mat-plant forming pros-
trate disks of vegetation, made up of the much branching, flat,

FIG. 122. Carpetweed After Britton and Brown.

262

Minnesota Plant Life.

plant-body. The leaves are in whorls, a character by which
this plant can be distinguished from other mat-plants of waste
fields. The flowers are small, borne in the axils of the leaves,
.and without petals. The carpetweed grows in the same re-
gions that many mat-
grasses, mat-knotweeds,
purslanes and mat-spur-
ges select.

Purslanes and spring-
beauties. Of the purs-
lanes three genera are na-
tive to the state : the com-
mon purslane or "pus-
ley," a prevalent weed in \
dooryards and gardens,
the rock purslane, ap-
pearing upon ledges of
granitic rock in the Min-
nesota valley, at Taylor's
Falls and at Duluth, and
the spring-beauties or Claytonias, of
which there are three varieties. In
the state there are two species of
purslane : the common garden form
with leaves round at the end, and
the notched purslane with leaves
notched at the end. The latter
plant is doubtless a native of Min-
nesota, while the former is a recent
immigrant. Purslane is one of the
most common of the mat-plants and
is remarkable for the numerous
flowers which it produces in a sea-
son and for the little pods which
open by a lid, revealing a large
number of small seeds within. The rock purslane is a dimin-
utive herb found growing in the crevices of granitic or eruptive
rocks, especially in the Minnesota valley between New Ulm and
Big Stone lake. The stem bears at the base a few alternate,

FIG. 123. Spring-beauty in flower.
After Atkinson.

Minnesota Plant Life. 263

almost cylindrical leaves, from among which rises a slender
peduncle, four to twelve inches high, upon which the small
portulaca-like flowers are arranged in flat-topped clusters or
cymes.

The spring-beauties are succulent herbs with delicate flowers
of a pinkish color, developed in terminal cymes on short slender
stems. In two of the species the roots are tuberous, while in
the third they are fibrous. In each flower are two sepals, five
petals and five stamens. The fruit is a three- to six-seeded cap-
sule opening by three clefts. The two varieties with tuberous
roots may be distinguished by the leaves on the stem. In the
ordinary form the leaves are narrow and linear, while in the
rarer variety they are lance-shaped. They are not uncommon
plants in the southeastern part of the state, flowering in spring.

Corn-cockles, chickweeds and carnations. The pink family
contains about twenty five Minnesota species. Herein are the
corn-cockles, the campions or catchflies, the pinks, the soap-
worts, the chickweeds, the stitchworts, the pearlworts and the
sandworts in their different varieties. The plants of this family
are all small herbs with opposite entire leaves, both sepals and
petals present and a single ovary ripening into a capsule or
unopened nut. The corn-cockles are not native to the state,
but have been introduced into the wheat fields of the Red river
valley. They have red flowers which are very ornamental.
The catchflies are so named from the very sticky calyx of the
flowers. The chickweeds, sandworts and stitchworts are dimin-
utive, generally white-flowered herbs of no particular impor-
tance, but rather abundant in woods, along the beaches of lakes
and in low places on the prairies. The cultivated pink or car-
nation belongs to this family, and while its flowers are doubled
and distorted by the selection which has been given to them
by horticulturists, yet they preserve the general type of their
family, and may serve as comparative plants when some of the
wild forms are under investigation.

All the families of the fourteenth order unite in one pecu-
liarity, that of having the embryo in the seed coiled around the
albumen. In some seeds the embryo is curved almost like a
snail-shell, while in others it is not bent more than a horseshoe.
The albumen lies inside the coils of the embryo, which are

264

Minnesota Plant Life.

appressed to the seed-coat layers. The lower families of the
order are devoid of perianth, while in the higher families, such
as the pinks, both calyx and corolla are well developed.

Almost all the families hitherto mentioned — with the ex-
ception of the pinks and portulacas — are characterized by the
quite general failure of the flowers to develop two kinds of
perianth leaves. When only one layer or whorl of perianth
leaves is present in the flower, this group of parts is regarded
as the calyx, hence the great majority of plants in the families
that have been under examination are considered to be devoid
of petals. In the remaining families both calyx and corolla are

for the most part present, al-
though there are numerous
exceptions, especially in the
lower families of the series.
The fifteenth order in-
cludes the water-lily family
and a curious little related
plant known as the horn-
wort, also of aquatic habit.
Here, too, is placed the \vell-
known crowfoot family, to
which the anemones, lark-
spurs, peonies, buttercups,
aconites, columbines, marsh-
marigolds or crocuses, gold-

Fm.124. Water-shield. After Britton and Brown, threads, mCadoW-FllCS and

clematis belong. In this

order, also, are included the barberries and their allies, the moon-
seeds, the magnolias, the pawpaws, the laurels and a few small
exotic families not represented in the United States.

Water-shields. The water-lilies in their various forms are
familiar inhabitants of the lakes and ponds for which Minne-
sota is so justly famous. There are a number of varieties,
some more common than others. One of the most inter-
esting is the water-shield, which alone has perfectly shield-
shaped leaves that always float upon the surface of the water.
The leaves of the Indian lotus are also truly shield-shaped;
however, many of them do not float upon the top of the water,

Minnesota Plant Life.

265

but rise above it. Besides, the leaves of the water-shield are
oval and not more than four inches in length, while those of
the lotus are circular and much larger. Water-shield flowers
are purple, less than an inch in diameter, and the whole plant
is easily distinguished from any other kind of water vegetation
that might be mistaken for it by a very abundant deposit of
transparent jelly over the stems, buds, flower pedicels and the
under sides of the leaves. The leaves are commonly purple

FIG. 125. Water-lilies. After photograph by Williams.

below and dark green, shaded with purple above. The pres-
ence of the purple dye on the under sides of floating leaves
is not uncommon. It will be found to some extent in water-
lily and pond-lily leaves and in the leaves of the floating pond-
weed. The purple substance is a heat-producing color, and
apparently such sunlight as the plant does not utilize in starch-
making may be converted into heat by the lower layers of the
leaf and employed as a source of energy in various growth-
processes of the plant. The stem of the water-shield is some-

266 Minnesota Plant Life.

times several feet in length, and it creeps at the bottom of the
pond as a slender rootstock. In the flower there are from
twelve to twenty stamens and from four to eighteen carpels,
separate from each other, forming in the fruit a cluster of one
or two-seeded nuts.

Pond-lilies. The pond-lilies may be known by their broadly
arrow-shaped leaves with rounded bases, their yellow flowers,
and their fruits, consisting of a number of carpels united to-
gether in a compound body. There are two varieties in Min-
nesota : the common yellow pond-lily, abundant throughout the
state, and the small yellow pond-lily, of which the flowers are
less than an inch in diameter when open. The latter species
is limited to the northern district between Duluth and Lake of
the Woods. The pond-lilies have thick cylindrical rootstocks,
which show conspicuous scars where the leaves break off. In
the large pond-lily there are sometimes submerged leaves which
are thin and almost circular in shape. These submerged leaves
are always present in the smaller pond-lily.

Water-lilies. The water-lilies, of which three species occur
in the state, may be recognized by their white flowers, rounder
leaves and almost globular fruit. The form known as the tuber-
bearing lily is probably more common than the sweet-scented
lily, though both are found growing side by side in the same
ponds. In the tuber-bearing lily the rootstock is thick, with an
abundant production of short lateral branches that readily sep-
arate and serve to propagate the plant. In the sweet-scented
lily the rootstock is thick and but sparingly branched. Fur-
thermore, the flowers of the sweet-scented lily are very fragrant,
while those of the tuber-bearing lily are either scentless or but
slightly fragrant. These two varieties are the abundant ones.
In a few lakes along the international boundary may be found
the small white water-lily, with its flowers scentless and scarcely
two inches wide. In this variety the petals are generally in
but two rows instead of being disposed in numerous whorls as
in the common forms. The leaves are considerably smaller
but of the same general shape.

The great pale rootstocks of the water-lilies and pond-lilies
are often torn up by the ice and cast ashore in early spring.

Minnesota Phnt Life. 267

They are spongy, and when released from the bottom of the
lake float to the surface.

Indian lotus. The largest flowered and most interesting of
the native water-lilies is the Indian lotus — not very frequent in
Minnesota, and confined to a few localities. It occurs in the
Mississippi river at Red Wing, Mendota and La Crosse; also
in Lake Pepin and at the extreme north end of Halstead's bay,
Lake Minnetonka. The leaves are shield-shaped with central
stem, and from one to two feet broad. Some of them are raised
above the water and become slightly vase-shaped, while others
float upon the surface. The flowers, which may be ten inches
in diameter, though not commonly reaching this size, are of a
pale cream-color, and differ from those of the other water lilies.
The fruiting area is quite remarkable. The top of the flower
stem is flattened out into a biscuit-shaped body in which the
little nuts, the size of an acorn, are imbedded. They loosen
as the fruit matures and rattle about so that the lotus in some
districts goes by the name of "rattlebox." This plant belongs
to the same genus in which the famous lotus of the Nile and
the Orient is classified. The true oriental lotus is also known
in the east as Indian lotus because it grows in India. Such a
fact is illustrative of the confusion that sometimes arises when
only popular names are employed in the designation of plants.

The water-lilies, like very many aquatic flowering plants, dis-
play their flowers at the surface of the water, and, after pollina-
tion has been effected, close the flower into a bud again and
retract it beneath the surface, ripening the seeds beyond the
reach of aerial dangers. The lotus, however, ripens its fruits
in the air.

Hornworts. The hornworts are apparently very rare plants
in Minnesota, but are known to grow in the vicinity of St. Paul
and Minneapolis — in White Bear lake and Lake Calhoun ; and in
the western part of the state — in Lakes Osakis and Alexandria.
They are submerged plants with slender stems, and the leaves
are arranged in whorls and are finely dissected into thread-like
filaments. The flowers are produced singly in the axils of the
leaves and are less than half an inch in length. There are
numerous stamens in each staminate flower, while the pistillate
flower develops a single one-chambered ovary, containing a

268

Minnesota Plant Life.

solitary seed rudiment. The fruit is like a miniature lotus nut.
There is no albumen, and the embryo is remarkable for having
four seed leaves instead of two. This, however, may be re-
garded as due to a forking of the seed leaves as they develop.

Magnolias. Magnolias do not occur in Minnesota. Their
flowers are very much like those of the water-lilies, and they
may be regarded as terrestrial, tree-like water-lilies, or con-
versely, water-lilies might be considered as magnolia-like plants
which at an early time went into the water and adapted them-
selves to the aquatic life. Re-
lated to the magnolias are the
tulip-trees or whitewoods which
are such noble forms in the for-
ests of Indiana and Ohio.

The pawpaws, abundant south-
ward, constitute a family of the
fifteenth order, but are not known
to occur so far north as Minne-
sota.

Crowfoots. The crowfoot
family is abundantly represented
in Minnesota where there are to
be found one species of golden
root, two of marsh-marigolds,
one of goldthread, one of false
rue-anemone, two baneberries,
the red and the white, one colum-
bine, three larkspurs, seven or
eight anemones, two hepaticas,

one rue-anemone, one pasque flower or gosling, two clematises,
one mousetail, twenty buttercups and their allies, and three
meadow-rues. Many of these are common flowers of the spring
and summer. The marsh-marigolds, termed also crocuses, are
abundant throughout the state, their yellow flowers blooming
in early spring. A peculiar form, known as the floating
marsh-marigold, occurs among the northern lakes. It is much
like the ordinary variety except that its leaves float upon the
surface of the water and the plant is generally small. The
goldthreads are little three-leaved plants with white, buttercup

FIG. 126. Marsh-marigold or cowslip.
After Britton and Brown.

Minnesota Plant Life. 269

flowers and slender, bright yellow rootstocks, by which they
may be recognized. They are abundant in tamarack swamps.
The baneberries are erect herbs with large compound leaves.
The flowers are small, white and arranged in terminal racemes.
One variety produces red berries and the other white. The
columbines are particularly abundant upon rocky hillsides, on
cliffs and along river gorges. The flowers are recognized at
once by the spurs on the petals, and stand with their mouths
directed downward. The spurs are supplied with honey glands
at the tip, and the whole contrivance is a machine for obtaining
cross-pollination through the agency of insects.

Larkspurs. The larkspurs are the first type of two-sided
flowers that have been encountered in the discussion of plants
with pairs of seed-leaves. Their flowers stand in terminal clus-
ters, are loosely arranged and shaped so that there is no diffi-
culty, even when they are separated, in determining how they
stood upon the stem. One of the petals is provided with a spur
as in the columbines. This again is an apparatus to utilize some
insect for the advantage of the plant.

Anemones and Hepaticas. Anemones are herbs with rather
characteristic flowers and fruit-bodies. In one type the nutlets
of the fruit are massed in cylindrical clusters, clothed with
woolly hairs. In others the clusters of 'nutlets are more nearly
spherical. Closely related to the anemones are the Hepaticas,
known by their three-lobed, shining leaves and their purplish
flowers put forth in early spring. One kind of Hepatica has its
leaves rather round-pointed while the other shows much sharper
lobes. Akin to the Hepaticas is the rue-anemone, which devel-
ops three-parted leaves, each lobe of which is again divided into
three. The stem, four to seven inches in height, arises from a
little cluster of small tuberous roots shaped like diminutive beets.
This plant may be distinguished from the false rue-anemone,
which resembles it superficially to a marked degree, by the
character of the tuberous roots. In the false rue-anemones the
tubers do not form a little cluster near the base of the stem, but
develop, in many instances, two or three of them on the same
root and often some distance from the base of the stem. Be-
sides, the fruits of the true rue-anemone are aggregated as
nutlets at the tip of the fruiting stem, while in the false the

270

Minnesota Plant Life.

fruits are not strictly nuts but capsules, opening along one
side to release the seeds. There are several seeds in each cap-

£.5
Si

sule of the false rue-anemone, but only one seed in each nutlet
of the true. Both plants are abundant in the woods through-
out the state.

Minnesota Plant Life.

Pasque flowers and clematis. The pasque flower or gosling
is known to the children of Minnesota as the first flower to
bloom in early spring. There are several kinds of flowers which
really open before the pasque-flower, but they are either rare
or inconspicuous, so that the pasque flower may be popularly
regarded as the earliest flower of the year. The sepals are of
a pretty light purple color, and the whole flower is an inch or
more across. Around its base is a group of hairy involucral
leaves. At the center is a circle of separate carpels which ma-
ture into a head of nutlets, each
of which has a long plume-like
appendage, recalling the similar
structures in the fruiting heads
of clematis. In this latter plant,
which in Minnesota occurs as a
climbing vine, the same general
appearance of the fruiting heads
is to be observed, and conse-
quently the pasque flower is also
termed the ground-clematis. The
true clematises are not always
climbing vines throughout the
United States, but the Minnesota
varieties both belong to the vine
division of the genus. They have
an odd way of climbing, for, not
being provided with true ten-
drils, they twine their leaves
around such supports as come in

their way, thus using the stems of the leaves just as a squash
vine uses its tendrils. This habit of the clematis gives an idea
of how, in some instances, tendrils may have originated. After
the leaves of a plant acquired the habit of turning themselves
about twigs or other supports that came in their way, there
arose a division of labor, in consequence of which some leaves
devoted themselves to their new function and gradually aban-
doned their starch-making, thus becoming converted into true
tendrils, while others assumed no tendril functions, but contin-
ued as the starch-makers of the plant.

FIG. 128. White water-buttercup.
Britton and Brown.

After

272

Minnesota Plant Life.

Mousetails. The mousetail is a little herb three or four
inches in height, known to occur in the extreme southwestern
part of the state. The center of the flower is prolonged into
a spike-like axis upon which the nutlets are arranged in spirals.
From the resemblance of this axis or receptacle of the flower,
to the tail of a mouse has arisen, the common name.

Buttercups. Buttercups are well-known plants, usually with
yellow flowers by which they may be distinguished from anem-
ones, the flowers of which are pale. There are a number of
sorts characterized by the different forms of the leaves, the sizes

of the flowers and the shapes
of the nutlets or groups of
nutlets in the fruiting state.
Three buttercups in the
United States are aquatic,
and two of these occur
abundantly in Minnesota.
Owing to their aquatic habit
the water-buttercups have
finely dissected leaves con-
sisting of thread-like fila-
ments, and their flowers are
white. The two varieties
may be distinguished from
each other by the rigidity
of their stems when with-

FIG. 129. Early meadow-rue. After Britton and c[rawn from the water. The
Brown.

white water-buttercup col-
lapses into a flabby bundle when lifted from the water, while
the stiff water-buttercup does not, but maintains the ends of its
stems in a rigid position. The water-buttercups are interesting
plants to observe on account of the automatic curvatures of the
flowering pedicels. The flowers are exposed above the sur-
face of the water and after pollination the stems bend over, as
if aware of what was needed, and thrust the flowers into the
water, so that the fruits are matured below the surface. Such
beneficial habits are ordinary among water plants, which are
generally compelled to expose their flowers for wind or for in-
sect pollination, but afterwards derive advantage from ripening

Minnesota Plant Life. 273

their fruits under less dangerous conditions. Thus the flowers
of the water-lilies, of the pondweeds, or of the eel-grass are in
a variety of ways retracted. What the eel-grass secured by a
spiral contraction of the flowering stem is accomplished by the
water-buttercup through an automatic curvature. Such curv-
atures are sometimes employed by terrestrial varieties for the
insertion of their fruits into the soil. Thus the peanut plant
flowers above the ground and then thrusts its young pods into
the soil, where they mature underground.

Meadow-rues. The meadow-rues are robust perennial herbs
with leaves compounded repeatedly on the plan of three. The
flowers are small, whitish-green and aggregated in large pan-
icles or racemes. In one variety, the most common in Minne-
sota, there are two sorts of flowers, staminate and pistillate,
borne on different plants, so that all the flowers on a plant will
be of one kind or the other. The other two species have each
on the same plant three kinds of flowers, some producing only
stamens, others producing only pistils, and others in which
both stamens and pistils occur. One variety is often glandular
or waxy in the texture of its leaves, while the other is smooth or
slightly hairy, but not glandular or waxy. The former blooms
earlier than the latter and is usually shorter, reaching in favor-
able positions three to seven feet in height, while the latter
attains a height of from ten to eleven feet. Although the
species in which the flowers are always separated, and a single
plant produces only one kind, is easily identified, the other two
are hard to distinguish.

Most of the plants in the crowfoot family have pungent
juices, and from some of them highly poisonous substances, such
as aconite, are obtained.
19

Chapter XXIX.

From Barberries to Witch-hazels.

Barberries. The three plants of the barberry family which
occur in Minnesota are of quite different appearance. One, the
common barberry, introduced from Europe, grows as a wild
plant in the southern part of the state, but is by no means
abundant. It is a smooth shrub with ovate saw-tooth-mar-
gined leaves and flowers produced on drooping racemes in the
axils of some the leaves. The flowers are yellow and unpleas-
antly scented. The fruit clusters are racemes of scarlet sour
berries, somewhat oblong in shape and about half an inch in
length. Many of the leaves are reduced to three-pronged thorns.
This is the plant which is famous as the host of the cluster-cup
stage of the wheat rust, and for this reason it is a dangerous
shrub to cultivate. The other members of the barberry family
are herbs. One of them, the blue cohosh, is found in shaded
woods, growing a foot or more in height and resembling, to
some extent, the meadow-rue. But when the cohosh fruits
it produces clusters of blue berries which are in reality seeds,
for they burst the thin fruit wall when young and mature
outside of it. The other, known as the may-apple or wild
mandrake, has, at the base, large shield-shaped leaves almost a
foot in diameter, while the upper leaves are deeply lobed, lighter
green above than below. The flowers are white, somewhat
butercup-like, nodding from the axils of the leaves and one or
two inches wide. A true fleshy berry of a yellow color is pro-
duced, two inches long and edible. This plant occurs in damp
woods along the flood plains of streams flowing into the Mis-
sissippi, in the extreme southeastern portion of the state.

Moonseeds. The moonseeds, represented in Minnesota by
a single form, are characterized by the disk-shaped or coin-
shaped seeds, hence the popular name. The Minnesota moon-

Minnesota Plant Life.

275

seed is a common vine,with leaves shaped a little like the leaves of
the wild grape, though not so deeply angled. The underground
portion is yellow and Indians use it for medicine. The flowers
are of two sorts, developed on different plants. The fruit con-
tains a stone which is curved into a circle, marked by clefts and
strongly flattened on the sides. The bunches of fruits are blu-
ish-black in color and resemble
a little the fruits of the wild
grape. They are easily distin-
guished, however, by the pres-
ence in each of the flat stone,
very different from the pear-
shaped seeds which are found
in the berries of the grape.
Calycanthuses and laurels, where the sassafras,
bays and spice-bushes are grouped, do not pro-
duce any Minnesota varieties.

The sixteenth order includes the poppy fam-
ily, where the blood-roots, Dutchman's breeches
and fumitories are classified; the mustards,
among which may be mentioned the water
cresses, rock cresses, whitlow-grasses, pepper-
grasses and shepherd's purses ; the caper family,
with the clammy-weeds and spider-flowers; the
mignonettes, and two other families not repre-
sented in the United States.

Blood-roots. Besides the common poppy,
which in some parts of the state has escaped
from cultivation, the blood-root is a common
form throughout the greater portion of Minne-
sota. Blood-root flowers are to be seen in the
spring in open woods, where their white petals
and great abundance make them attractive ob-
jects. The plant is named from the red juice
which exists in its horizontal underground rootstock. On the
latter, branches arise, bearing leaves— those at the base scale-
shaped and the upper ones large, heart-shaped or kidney-
shaped, with several lobes. The flowering stem displays usually
but a single flower in which there are two sepals that early fall

FIG. 130. May-ap-
ple,or mandrake,
in flower. After
Atkinson.

FIG. 131. Clammv-weed. After Britton and Brown.

276 Minnesota Plant Life.

to the ground. The pet-
als, eight to twelve in
number, inclose the nu-
merous stamens. At the
center the rudimentary
fruit appears as an ob-
long, narrow, one-cham-
bered pod, made up of
two carpels and ripening
into a .capsule with nu-
merous seeds. The later
leaves of the year grow
much larger than those
formed at the time of
flowering and by their ac-
tivity create considerable
reserve food material
which is packed away in

the underground part ready for use by the buds of the next
season.

Dutchman's-breeches. The Dutchman's-breeches or squirrel-
corn, of which two species occur
in Minnesota, are delicate and in-
teresting plants of the woodland,
where they grow on shaded
banks. The leaves are com-
pounded repeatedly on the plan
of three and the slender flowering
stem bears several nodding flow-
ers flattened laterally in a peculiar
manner. The shape of the flower
gives occasion for the common
name. Below the ground, in the
Dutchman's-breeches, a number
of bulbous scales may be discov-
ered. When fresh they are speck-
led with red dots. In the squir-
rel-corn, the flowers of which are
not so bifurcated as those of the

FIG. 132. Blood-root. After Britton and
Brown.

Minnesota Plant Life.

277

Dutchman's-breeches, the slender rootstocks bear a number of
little spherical tubers. The common bleeding-heart of flower-
gardens is a relative of these two native species.

Fumitories. The fumitories, with yellowish or pinkish, two-
sided flowers, occur in Minnesota in four different forms. Among
the more common is the pale fumitory with whitish-green leaves
compounded on the plan of three. This plant is most abun-
dant in the northern part of the state, where it grows often on
sandy beaches. The golden fumitory, frequent in the southern
part of the state along railway embankments and in woods, is
a smaller, darker green plant, with golden yellow flowers ar-

ranged in terminal ra-
cemes. Another variety,
the yellow, not so com-
mon as the golden fumi-
tory, may be recognized
by its paler leaves, like
those of the pink-flow-
ered northern form; but
this species has yellowish
flowers, not so bright as
those of the golden fumi-
tory, and quite different
from the pinkish type of
the pale fumitory. Still
another, found at the ex-
treme southern edge of

FIG. 133. Water-cress. After Britton and Brown.

111 11 C

smaller flowers than the others and foliage much like that of
the pink species.

Mustards. The mustard family is distinguished, for the mos
part, by a pungent peppery sap, so that after one has tasted
water-cress or pepper-grass he can usually determine, by c
ing the foliage, the relationship of other plants of the fam
A variety of mustards occur in Minnesota, about fifty spe
in all. Besides this, several are cultivated, such as the cabl
the cauliflower, the radish and the turnip. Mustards are :
ognized botanically by their pods, flattened lengthwise or en
wise to the partition which runs along them. In some po

278

Minnesota Plant Life.

the partition is evanescent, as in the garden radishes. Very
common forms are the pepper-grasses with little circular pods,
the shepherd's purses with heart-shaped pods, the hedge-mus-
tards with their long and slender pods, the rock-cresses grow-
ing upon cliffs and along gorges, the water-cress abundant in
cold streams issuing from springs, and the other cresses, some
in the fields, some in the woods and others in marshes or
swamps. In a great many of the mustards of Minnesota the
leaves are narrow and deeply lobed along the sides. A number
bear, at the surface of the ground,
rosettes of leaves from which the
slender flower-bearing axis arises.
The flowers are usually arranged in
racemes and are commonly white
or yellow in color, constructed on
the plan of four. Four sepals, four
petals, six stamens and two carpels,
united into a single pod, constitute
the parts of the normal mustard
flower. One of the smallest of the
land-flowering plants in Minnesota
is the whitlow-grass, a cress which
produces a tiny rosette of leaves and
a little stem an inch or two in
height, on which a few minute white
flowers are borne.

Pitcher-plants. The seventeenth
order includes the pitcher-plants, FlG- 134- etcher-plant. After Britton

and Brown.

grouped in two families, to one of

which belongs a common Minnesota variety, and the sundews
and Venus' fly-traps. All of these plants are carnivorous and
are very remarkable for the skillful devices by which they catch
the insects that form a part of their food. The Venus' fly-trap,
which in conservatories is sometimes cultivated, from its Car-
olina home, is a little herb with leaves built upon the general
plan of a steel trap. The base of the leaf is somewhat elongated
and provided with wings of green tissue. Above the middle
there is a strong constriction, and the end of the leaf is almost
round, with a longitudinal rib separating it into two halves.

Minnesota Plant Life.

279

On the upper side are some sharp-pointed hairs, and when an
insect alights upon a leaf and irritates the hairs a couple of times
the two sides of the leaf snap together with a movement suffi-
ciently sudden to catch the insect, after which its body is di-
gested by the plant. A little less sensational but none the less
accurate are the fly-catching habits of the common Minnesota
pitcher-plant which grows in abundance throughout the tama-
rack swamps of the state. The leaves of this plant are hol-
lowed out as vase-like structures, and are usually half full of
water. The margin of each pitcher is protected by a flap on
which are arranged a number of hairs pointing downwards.
Within, the surface of the pitcher is very smooth. Inquisitive
insects which alight upon the flap find it easy to walk in the
direction in which the hairs are pointed, but difficult to move
in the other direction. Thus they are guided to the smooth
rim of the vase and tumble in. Digestive ferments are secreted
by the action of glands or of bacteria which inhabit the water
in the pitcher, and the bodies of the insects are converted into
food-material for the bacteria, and directly or indirectly find
their way into the tissues of the pitcher-plant itself. The flower
of the pitcher-plant, standing on its slender, erect stalk, is con-
spicuous by its purplish petals and by a very extraordinary um-
brella-shaped stigma which arches over the short stamens, pro-
tecting their sensitive pollen-spores from the cold of the bog
where these plants select their abode. Besides, this umbrella-
shaped stigma serves as preventive against the flower being
pollinated by its own pollen. The pollen spores germinate on
the points at the angles of the umbrella. The fruit is made up
of five fused carpels and contains numerous small seeds.

Sundews. Related to the pitcher-plants are the sundews,
which are found throughout the state in deep tamarack swamps
or peat-bogs. There are four varieties, distinguished by the
shapes of their leaves, to be looked for in Minnesota. The
round-leafed sundew is as common as any. In this the leaves
are almost round, on slender stems, spreading out in a little
circle at the base of the delicate, erect flowering axis. The
leaves are half an inch or so broad and covered over with prom-
inent red glandular hairs. Another variety has the leaves ovate
or spoon-shaped. In still another, the leaves are long-ovate,

280

Minnesota Plant Life.

four or five times as long as broad, while in yet another the
leaves are shaped almost like grass leaves, one to three inches
long and slightly spoon-shaped toward the tip. In all the dif-
ferent species the glandular hairs are present. When a small
insect alights upon one of the leaves the sticky secretions of
the hairs interfere with its movements, while the hairs at the
edge of the leaf bend inward and push the insect down into a
helpless position. The whole leaf then seems to close around
the unfortunate ant or fly, and after a time, by means of di-
gestive ferments, its body is converted into nutriment for the
plant. In Portugal and Spain a variety
of sundew is by the inhabitants com-
monly employed in place of fly-paper.
Another foreign variety lives in the wa-
ter, has leaves much like the Venus' fly-
trap and snaps up little water insects.
These plants do not depend for food en-
tirely upon the insects they catch. They
are all provided with leaf-green and de-
vour insects only in an incidental way.

The eighteenth order includes the
riverweeds; the orpines; a family of
West Australian pitcher-plants ; the sax-
ifrages, to which the hydrangeas, goose-
berries and a number of herbs belong;
the witch-hazels ; the sycamores ; and the
roses. In the last-named family are in-
cluded the spiraeas, apples, quinces,

mountain-ashes and June-berries, the roses, strawberries and a
number of related herbs, the raspberries, blackberries and bram-
bles and the plums, almonds, peaches and apricots. Further-
more, in this eighteenth order is included the great pulse family
with the acacias, the sensitive plants, the tamarinds, the red-
buds, the sennas, the honey-locusts, the lupines, brooms, la-
burnums, clovers, indigo-plants, locust-trees, ground-peas, pea-
nuts, beans, peas, and all the allied varieties in which the type
of pod known as the legume is formed. Besides, there are some
smaller families classified here, so that this is one of the largest
and most important of all the orders of flowering plants.

Minnesota Plant Life.

281

Riverweeds. Of the rivenveed family there is a single Min-
nesota species which grows attached to stones under water in
strong rapids or cataracts. The riverweed belongs to a family
of herbs best developed in the tropics and very remarkable for
marvelously perfect adaptation to the submerged life. The
plant-body of many of the riverweeds resembles that of an
alga, the leaves being poorly distinguished from the stem on
which they are borne. The flowers and fruits are produced
entirely under water and are surrounded by involucres resem-
bling the spathes of the arum family. In the Minnesota va-
riety— the only one common in North America — the flowers

are sessile, there is no perianth
and there are two stamens united
together at the base. The fruit-
rudiment is ovoid, with two short
stigmas. The general appearance
of the plant is that of a dense tuft
of finely divided leaves attached
to the stones at the bottom of
the water. The flowers are small
and easily recognized by the two
partly fused stamens, standing
like a little fork beside the ovary.
In the fruit arise a number of
small seeds with straight embryos
and without albumen. The
riverweed has been collected in
Brown. Minnesota on the International

boundary, in the Granite lake rapids, at Minnehaha falls and at
Lake Pepin. The most interesting thing about the riverweed
is its entire abandonment of terrestrial methods of flower-pro-
duction and pollination. While pondweeds are compelled to
lift their spikes of flowers above the surface of the water to
accommodate themselves to the persistence of ancient methods
of wind-distribution in vogue during the days when their an-
cestors were dwellers on the land, the riverweeds have freed
themselves from this necessity and have the ability to main-
tain themselves quite submerged in deep water, as if they wei
algae Some other varieties of flowering plants flower under

FIG. 136. River-weed. After Britton and

282

Minnesota Plant Life.

water, as, for example, the marine eel-grass, so common along
seashores around the world. This plant is famous for its de-
velopment of thread-shaped pollen-spores — a form more favor-
able for aquatic pollination than the ordinary round spores
common in most other plants. There are no flowering plants,
however, which are so strongly adapted to the aquatic life as
are the riverweeds. Even the tiny duckweeds, floating like
green specks at the surface of quiet pools depend upon the wind
for the distribution of their pollen and produce their pollen sacs
and stigmas in the air as did their terrestrial progenitors.

Stone-crops. The orpine family is represented in Minnesota
by the native stone-crop
and the introduced uhen-
and-c hick ens." The
stone-crop, which grows
in ditches and swamps, is
a slender, erect plant with
smooth leaves and stem.
The flowers are produced,
at the tip of the stem, in
cymes on recurving
branches from one to
three inches in length.
The flowers have five se-
pals, ten stamens, usually
no petals, and five rather
imperfectly fused carpels
in each of which a num-
ber of seed-rudiments are produced. Many of the orpine fam-
ily are rock-dwelling plants and belong to the adaptational
group known as leaf-succulents. The "hen-and-chickens" is an
example of this group. Its leaves are very fleshy and thick, often
grayish-green in color and arranged in rosettes, from the centre
of which the erect, central flowering stems are developed. Such
plants inhabit little crevices in cliffs, and the fleshy character of
the leaves is doubtless in response to the difficulty of obtaining
sufficient moisture for the roots. The ditch stone-crop, how-
ever, prefers moist places, and has leaves of quite ordinary ap-
pearance.

FIG. 137. American alum-root. After Britton and
Brown.

Minnesota Plant Life.

283

Saxifrages. The saxifrage family includes in Minnesota the
gooseberries and currants, of which there are nine species ; the
saxifrages, with four species, one of which, the swamp saxifrage,
is found in peat-bogs and tamarack swamps throughout the
state; a single species of Sullivantia; two species of alum-root;
two miterworts ; one false miterwort ; and one golden saxifrage.
The swamp saxifrage has large, rather whitish green, long
ovate leaves and a central hollow stem, somewhat thick at the
base, upon which cymes of flowers are arranged in an open pan-
icle. Another saxifrage found on dry rocks along the north shore

of Lake Superior, has
rather succulent leaves,
forming a thick rosette at
the base of the flowering
stem* This plant propa-
gates by little offsets like
the hen-and-chickens.

Alum-roots. The al-
um-roots, common on dry
hills or rocks, have leaves
shaped somewhat like
those of the gooseberry
and erect panicles of flow-
ers at the end of a slender
axis. The flowers are
whitish-green or purplish
and inconspicuous. There
are five stamens. The
ovary is one chambered,
with numerous seed-rudiments and ripens into a two-valved pod
which splits from the end, curving the tips away from each
other. The two varieties in Minnesota are distinguished by
the appearance of the flowers. In the American alum-root the
calyx of the flower is bell-shaped and regular. In the rough
alum-root the calyx is bell-shaped and very oblique with un-
equal lobes. Both plants are sometimes found in dry woods
but are more abundant as rock plants on high ledges or as
crevice plants on barren islands. The miterworts and golden
saxifrages are delicate little herbs with leaves shaped some-

FIG. 138. Marsh Parnafsia. After Britton and Brown.

284 Minnesota Plant Life.

what like those of the gooseberry and with the general saxifrage
type of flower. In the common miterwort or bishop's cap the
five petals are shaped like tiny feathers.

Parnassias. The Parnassias, of which one species is com-
mon throughout the state while the other two grow especially
on the north shore of Lake Superior, are swamp plants with
entire, broadly spoon-shaped, strongly ribbed leaves and ter-
minal solitary flowers of a white or creamy yellow color, aris-
ing at the end of a slender erect axis. Usually a single sessile
heart-shaped leaf is displayed one-third of the way up the
flowering axis. The flowers of Parnassia may be recognized
by the little clusters of imperfect stamens produced at the base
of each of the five petals.

Gooseberries and currants. The largest genus of saxifrages
in Minnesota is the one to which the gooseberries and cur-
rants belong. There are probably six gooseberries in the state,
and the different sorts are recognized by the shape of the leaves
and the character of the fruit. One, the prickly gooseberry,
is common everywhere, and in this species the fruits are
covered with prickles. Of smooth gooseberries there are four
or five sorts distinguished by characters of the flowers and
leaves. Of currants there are four sorts, among which, one, the
flowering-currant, is not native. The other three are the skunk
currant, with its prostrate branches and disagreeable odor, com-
mon in the northern part of the state; the wild black currant,
abundant throughout the state; and the red currant, most
abundant north of a straight line connecting Fergus Falls with
Duluth. The gooseberries have the flowers arranged for the
most part in small clusters or they are solitary, while the cur-
rants produce racemes of flowers ripening into bunches of fruit.
The fruits are spherical berries, having a somewhat different
taste in the gooseberry division of the genus from that char-
acteristic of the currants. Each berry contains a few seeds
with slimy or gelatinous outer and hard inner coats. The
flowering-currant, with its bright yellow flowers, is a native of
the western plains and is abundantly introduced in Minnesota.

Witch-hazels. The witch-hazel family is represented in Min-
nesota by a single species, the well-known witch-hazel of the
southern part of the state. This is a shrub superficially re-

Minnesota Plant Life. 285

sembling the hazel in some respects, but with bright yellow
flowers in the axils of the leaves. The flowers are remarkable
for blooming during the autumn of the year as the leaves
are falling. The petals are very slender and elongated, and
there are four perfect and four imperfect stamens, while the
capsule opens by two valves. The witch-hazel is much used in
the production of an extract reputed to have healing virtues
similar to those of arnica, but by some believed to have no
medicinal value whatever.

Sycamores. Sycamore trees scarcely occur spontaneously in
Minnesota, the state being too far north for their development.

Chapter XXX.

Roses, Peas and their Relatives,

The rose family is represented in Minnesota by from sixty-
five to seventy species, among which are herbs, shrubs and trees,
while all unite in the general character ot the flower.

Meadow-sweets. Here are to be grouped the Spiraeas,
meadow-sweets or ninebarks, of which there are three varieties
in the state. The most common is the willow-leafed Spiraea
a frequent and abundant meadow plant in every district. All
of them are shrubs with alternate leaves — in the ninebark some-
what lobed and shaped a little like the leaves of the currant, but
in the meadow-sweet or Spiraea, with the outline of willow leaves.
The flowers are borne in terminal panicles, or large clusters,
and in two of the species are of a white or slightly purplish
color, while in the third they are of a handsome pink. The
meadow-sweets are common plants in swamps and swales as
well as in meadows, and one variety is very abundant on the
rocky shores of northern lakes, growing often partly submerged
under water. While much smaller, the flowers of the Spiraeas
are in their general appearance much like apple blossoms.

Crab-apples and chokeberries. The apples and mountain-
ashes, with the June-berries and hawthorns, constitute a very
clearly defined series of the rose family. Of apples and quinces,
which together with the pears form a characteristic series, there
are five sorts in Minnesota — three wild crab-apples and two va-
rieties of chokeberries. There is no difficulty in recognizing these
plants, because they have the typical apple fruit. The common
crab-apple is a small tree with ovate to triangular leaves,
distinguishable from the western crab-apple or chokeberry,
which also occurs in the state, by the general outline of the
leaves. In the western crab-apple the leaves are oblong or
ovate, but not so triangular. Still another form of crab-apple
has somewhat larger oval leaves with shallow notches at the
margin.

Minnesota Plant Life.

287

The chokeberries are shrubs ordinarily to be looked for in
swamps or damp woods. The flowers are considerably smaller
than those of the crab-apples, but decidedly similar. The
fruits, too, are not different in essential particulars from those
of the crab-apples, but are not so large, averaging about the
size of a well-grown gooseberry. In one of the chokeberries
the fruit is bright red when ripe, while in the other it is almost
black.

June-berries. Of June-berries there are four or five species
growing in Minnesota. These are all shrubs or trees with flow-
ers resembling those of the apple, but with more berry-like
fruits, smaller on the whole than the fruits of the apples. In
the common June-berry
the fruit is spherical,
sweet to the taste and of
a reddish color. The
shad-bush, a variety of'
June-berry, may be dis-
tinguished by the white,
woolly appearance of the
foliage when young,
changing to smooth when
older. In both of these
varieties the leaves are
somewhat elongated, like
plum leaves. In the
round-leaved June-berry,
the leaves, as the name
indicates, are almost round, while in the alder June-berry the
leaves are oval, notched more deeply towards the tip than
towards the base.

In all the varieties so far discussed the fruits are more
less apple-shaped. One other, which occurs at the extreme
northern edge of the state, in cold bogs, is a low shrub, smooth
throughout, with a purple pear-shaped fruit, half an inch or s

in length.

Hawthorns. Neither the apples nor the June-ben
thorny, and by this character they may be distinguished fron

FIG. 139. Hawthorn. After Britton and Brown.

288

Minnesota Plant Life.

the hawthorns, which have somewhat similar fruits. Haw-
thorns are commonly furnished with slender, pointed branches,
giving to the twigs a peculiar spurred appearance. Between
the different varieties it is exceedingly difficult to discriminate.
About six species exist within the state, and they are to be class-
ified by the shapes of the leaves and the outlines and surfaces
of the fruits. The flowers are borne in flat-topped clusters,
reminding one of the flat-topped elder inflorescences. The
fruits are never large,
being in all the species
about the size of choke-
berries. Sometimes
hawthorn trees fail to
produce thorns or form
them but sparingly. It
is not then easy to dis-
tinguish them from the
June-berries or choke-
berries; but in such
instances the flower
clusters are usually dis-
tinctive, for while those
of the hawthorn are, for
the most part, flat-
topped, the lower flow-
ers having longer stems
than the upper, the clus-
ters in June-berries and
chokeberries are pan-
icled or but slightly flat-
topped.

Mountain-ashes. The mountain-ashes are very close to the
apples and hawthorns. Indeed, they may be regarded as
apples with diminutive fruits and compound leaves. Two
sorts of mountain-ash may be looked for in the Minnesota
woods. They are both low trees with compound, feather-
shaped leaves and small white flowers in terminal, compound,
flat-topped cymes. The fruits are little red berries, quite like
the apple fruits, except that the core has not the papery walls

FIG. 140. Apple-blossoms. After photograph by
Williams.

Minnesota Plant Life.

289

of the apple. They may be distinguished from all the other
apple-like plants by their compound leaves. The American
mountain-ash is discriminated from the western mountain-ash
by the shape of the leaflets. In the first named species they
are slender and willow-like, while in the other they are elon-
gated-oblong and not so sharply pointed. The fruits in the two
varieties are very similar but average larger in the western
mountain-ash. Both varieties are very ornamental as lawn
trees, but the western mountain-ash is more desirable for culti-
vation in Minnesota than the other, on account of the larger
and handsomer flat-topped
clusters of fruits.

Strawberries and fivefingers.
A group of herbs, including
the strawberries, fivefingers
and avens, should be men-
tioned here. There are a num-
ber of varieties of them, some
sorts abundant in meadows
and fields, others distributed
in swamps and along the
shores of lakes. The straw-
berries in particular are abun-
dant and easily recognized by
their three-compounded leaves,
by their habit of producing
runners for propagation and
by their clusters of little seed-
like fruits upon the swollen

conical axis of the flower. This axis becomes red and fleshy as
it matures, and is the edible portion of the strawberry. The
other herbs, such as the fivefingers, closely resemble the straw-
berries in the character of the flower, but do not form fleshy
axes for their fruits. The avens is an erect herb, rather easily
mistaken by the casual observer for some kind of anemone in
fruit. One sort which is common in Minnesota produces fruit
clusters quite similar in appearance to those of the clematis,
having the same plumy appendages on the nutlets. None of
these herbs, except the strawberry, is of any particular economic
importance. They are all, however, throughout the state, com-

FIG. 141. Marsh fivefinger. After Britton
and Brown.

290 Minnesota Plant Life.

mon objects in open woods and along the edges of moist
meadows. The way to distinguish an anemone from a five-
finger or avens is this : the flowers of the fivefingers have appar-
ently a double calyx formed by the uniting in pairs of the stip-
ules at the bases of the calyx leaves. The anemones have no
such double calyx. Besides, the stamens in the anemones and
buttercups are arranged in spirals, while those of the fivefingers
and avens are arranged in whorls.

Agrimonies. Two curious little herbs, known as agrimonies,
have leaves resembling rose leaves, the flowers in narrow, spike-
like racemes and the calyx swollen up around the fruit and fur-
nished with a number of hooked bristles. The little fruits which
become attached to one's clothing in the woods in autumn, if
they are conical in shape and if the base of the cone is barbed,
are those of the agrimony. The bristles do not really belong
to the fruit, but arise from the calyx, illustrating how the plant
may use the same areas for different purposes. In apples,
mountain-ashes, June-berries, and chokeberries the calyx grew
up around the fruit and became fleshy. That is to say, the real
fruit of the apple is the core, the flesh which is eaten being the
outer portion of the flower and not the central ovary or group
of ovaries. The agrimony fruits, like those of the apples, pears,
quinces and hawthorns, are adapted to animal distribution ; but
the method of distribution is different. In the apples, calyx-
leaves become an inducement to animals to eat the fruits and
thus the seeds, remaining uninjured, are distributed. But in
agrimonies the calyx is so constructed that with its inclosed
fruit and seeds it attaches itself to the fur of animals and in this
manner obtains dissemination.

Raspberries and blackberries. Very closely related to the
fivefingers and strawberries are the brambles, including here
the varieties with edible fruits known as raspberries and black-
berries. About ten species occur in the state. The different
flavors in the fruits give occasion for the classification into rasp-
berries and blackberries, and there are no important structural
differences, since both plants belong to the same genus. They
are shrubs or herbs with characteristic fruitlets like miniature
plums aggregated together upon a fleshy swollen axis devel-
oped from the centre of the flower, and somewhat like the
conical base of the strawberry nutlets. One difference between

Minnesota Plant Life.

291

blackberries and raspberries is in the texture of this axis In
raspberries it becomes drier and the cluster of fruitlcts sepa-
rates from it, but in blackberries it remains fleshy and there
3 no separation of the fruit cluster from the receptacle Of
raspberries there are in Minnesota five varieties, including the
red and black raspberries, two dwarfed species, and the sour
raspberry, in which the fruit is less pleasantly flavored than in
the others. Of blackberries there are four sorts,— two varieties
of high blackberry, one low blackberry and one swamp black-
berry.

In all these plants the stems are shrubby. In the Arctic

dwarfed raspberry the plant-body
is herbaceous, unarmed, and only
three to ten inches in height, but
not creeping. Another peculiar
little creeping raspberry, seldom
found in Minnesota, has leaves
like those of the violet, and might
even be mistaken for a violet un-
less seen in flower or fruit.

Rose-bushes. The roses are
shrubs with large and conspicu-
ous flowers which cannot well be
mistaken for those of any other
variety. The different sorts in
Minnesota may be distinguished
by the shape of the leaflets, the
presence or absence of prickles,
the shape of the fruit, and the

stipules on the leaves. The common prairie rose, for example,
has distinct stipules and the leaves are disposed along a prickly
stem. There are usually from seven to nine round-ovate leaf-
lets in each leaf. The smooth, or meadow rose, is at once
known from the prairie rose by the scarcity of prickles, only a
few of which ever occur upon the stem. Neither of these
varieties climbs. A climbing rose is found, however, in thick-
ets in the southeastern portion of the state. In this there are
often three or five leaflets to the leaf. Yet another sort is rec-
ognized by the prickly midribs of the leaves. The swamp rose
and the pasture rose may be known by the presence of a pair

FIG. 142. Roses. After photograph by
Williams.

2Q2

Minnesota Plant Life.

of extra large prickles just below the stipules at the base of
each leaf.

This description does not extend over all the wild roses of
the state, but without going into technical details gives an idea
of their differences. All the roses are marked by a special
type of fruit which may be compared, perhaps, to a strawberry
turned inside out ; that is to say, the nutlets or fruits are aggre-
gated not upon a convex, but upon a concave receptacle. The
calyx grows up around this concave end of the flower, and the

FIG. 143. Sand-cherry in fruit. After Bailey. Bull. 70, Cornell Ag. Kxpt. Station.

nutlets are inclosed within its red and fleshy substance. Some
roses have the fruits, or hips, as they are called, protected by
a growth of prickles, while in others they are smooth.

Plums, peaches and cherries. A well-marked sub-family of
roses includes the plums, cherries, peaches, apricots and al-
monds. These are all trees or shrubs with bitter bark and
foliage. The bark, leaves, and seeds contain small quantities
'of prussic acid, — a substance which has, when chemically pre-
pared, about the same odor as the kernel of a peach stone. The
flowers are of the ordinary rose type, except that there is only

Minnesota Plant Life.

293

a single carpel instead of five or more as in other roses. Thi>
single carpel, or pistil, at the centre of the flower, contains one
or two seed-rudiments and the fruit matures as a stone fruit.
The outer wall of the pistil becomes fleshy, while the inner grows
hard and produces the stone. Inside, the one or two seed-
rudiments mature into the kernels. Plums have a smooth or waxy
outer surface for their fruits, while peaches and apricots have
this surface downy. In almonds the fleshy tract does not de-
velop and the nuts may be described as peaches with dry pulp.
Of plums there are two principal varieties,
—the plums proper and the cherries. In
Minnesota there are one or two species
of plum, including the very
common wild plum, a tree
ten to twenty feet in height,
with red, purplish or yellow
fruits. The stone is flat-
tened, with one edge sharp
and the other grooved. Be-
sides this common variety,
at the extreme northern
edge of the state are trees
of the Canada plum, aver-
aging somewhat larger than
the ordinary sort, with
broader leaves and larger,
longer fruits. In addition
to these two varieties of true
plums there are six sorts of
cherries. Almost the only
difference between the plums and the cherries is the flavor of
the fruit, though cherries as a class have rather more globular
fruits than plums. The Minnesota varieties are the dwarfed
or sand-cherry, common on sandy beaches, especially in the
northern part of the state ; the wedge-leafed cherry with fruits
four or five lines broad; the western sand-cherry, resembling
the wedge-leafed cherry in its foliage but with fruits nearly
twice as large, found on prairies in the western part of the state ;
the pin-cherries with sour small fruits, without bloom, with

144. A cluster of choke-cherry
flowers and a single flower dis-
sected. After Atkinson.

294 Minnesota Plant Life.

spherical stones and arranged in clusters of three or four; the
choke-cherry, with fruits of a red color or sometimes nearly
black, in clusters like those of the currant ; and the black cher-
ries, forming their fruits in clusters similar to the last men-
tioned, but always dark purple or black in color and somewhat
flattened vertically. The choke-cherry can be distinguished
from the black cherry by the very astringent taste it possesses.
The fruit of the black cherry is sweet and not so astringent.

Comparison of different types of rose fruit. The fruits in
the various sorts of roses appear to be quite dissimilar, while
in reality they are but different elaborations of the same gen-
eral types. It may serve to explain them if they are briefly
compared with each other and described as modifications of
some common fundamental form. In the first place it should
be noticed that the number of carpels in the flower varies
from one in the plums and peaches to fifty and more in the
strawberries. These carpels are generally separate from each
other, forming independent pistils; but in the spiraeas, apples,
mountain-ashes and their relatives, the small number of carpels,
ordinarily four or five, are produced close together, so that they
seem almost to blend in one body. In other instances the
carpels are quite distinct and separate, as in the strawberry.
An apple may be compared to five almond nuts placed close
together and surrounded by a thick fleshy layer. Each seg-
ment of the apple core is a ripened carpel containing one or
two seeds. A strawberry may be compared to an apple core
with the flesh removed and the number of carpels increased to
fifty or more, very much diminished in size and situated on the
surface of a swollen fleshy axis. A plum, or cherry, or peach,
may be compared to one segment of an apple core with the
papery membrane greatly thickened and converted into two
layers, the outer soft and pulpy, the inner hard and stony. A
blackberry may be compared to a strawberry in which all the
nutlets have matured after the fashion of plums or cherries.
A raspberry may be compared to a strawberry with a dry pulpy
centre and plum-like nutlets which separate from their axis in
a group. The curious bur-like fruit of the agrimony may be
compared to an apple of conical shape with the fleshy part
modified into a layer on which are arranged numerous prickles

Minnesota Plant Life. 295

with hooked ends. The clematis-like fruit of the avens may
be compared to a strawberry in which the pulpy part is dry
and the ends of the nutlets are prolonged into plumes, enabling
each nutlet to be distributed by the wind.

The majority of the rose fruits are adapted to animal distri-
bution, but the fivefingers and the avens depend rather upon
the agency of the wind. The rose hip, as has been said, may
be compared to a strawberry turned inside out, with an apple-
like pulp growing up around it. One can easily see at the end
of an apple opposite the stem, and at the end of the rose hip
more clearly still, the five points of the five calyx leaves, which
have become fleshy and assist in the distribution of the seeds.
The colors, perfumes, essences and sugars of the ripe fruiting
areas, whether these areas be the axis of the flower, as in the
strawberry, the swollen calyx leaves, as in the apples, haw-
thorns, pears and rose hips, or the ovary walls, as in the plums
and cherries, are in all instances adaptations for the attraction
of birds and animals. So that, in being eaten, such fruits
accomplish their own ends and are not to be regarded as un-
fortunate, like the fruits of wheat and corn that never "intended"
themselves to be eaten, but stored up their food materials en-
tirely for the benefit of their own enfolded plantlets. From
this point of view it is apparent that there are two classes of
edible fruits, those made edible by the plant for animal distri-
bution, and those adapted to the nourishment of the seedlings,
but seized by animals contrary to the well-being of the plant.
Of the former class apples are examples, of the latter, the cereal
grains.

The pea family. Related to the roses is the great pulse
family in which the pod-bearing plants of the world are classi-
fied. ' The lower genera of pulses have more or less regular
flowers with radial symmetry, but the higher genera form but-
terfly-shaped flowers like those of the sweet peas, and of a shape
distinct from that of any other flowers in the plant kingdom.
There is never any doubt whatever about the classification of
a plant if it shows the butterfly-shaped blossom. The pulse
family as a whole, however, is a group based rather upon fruit
than upon flower structure, for all the species are marked by
the production of pods or legumes. The legume is a fruit

296

Minnesota Plant Life.

developed from a single carpel, with from one to many seed-
rudiments produced in a row along one side, in the interior.
The forms of pods are very various. Sometimes they are shaped
quite like the familiar pea-pods or bean-pods. Again they are
broken up into joints, each joint containing a single seed. Often
the pods are coiled like snail shells. Some varieties have small
pods, reminding one, in their appearance, of the nutlets of the
strawberry, but differing in their almost universal habit of
opening down both edges to release the seed. About 7,000
species are included in the
pulse family, making it al-
most three times as large as
the rose family. The lower
division of pulses, in which
the flowers are not of the
true butterfly shape, though
sometimes approaching it, is
represented in Minnesota by
two trees — the redbud and
the Kentucky coffee-tree—
and four herbs, including
three sennas and a desman-
thus.

Redbud trees. The red-
bud, or Judas-tree, is re-
ported as occurring in the
extreme southern portion of

the State, but the Only Speci- FlG- 145- Kentucky coffee-tree. After Britten and
. , T , Brown.

mens that I know of are

cultivated, and it is probably not native to Minnesota. The
flowers have the look of the butterfly flowers of the higher
genera, but the broad petal, known as the standard, is inclosed
by the wings in the bud. In the true butterfly flowers the
reverse condition obtains. The leaves of the redbud are heart-
shaped and the flowers are pink and borne in short lateral clus-
ters. The fruit matures into a flat, oblong pod which opens
like the pod of a locust. The wood is heavy, coarse-grained,
dark brown or red, with lighter colored sap-wood.

Minnesota Plant Life. 207

Kentucky coffee-trees. The Kentucky coffee-tree is a large
forest tree indigenous, but somewhat infrequent, in the southern
part of the state. It is especially abundant near Mankato, in
Nicollet county. The leaves are doubly pinnate and the flow-
ers are produced in racemes and are regular in appearance.
Some of them are staminate, others pistillate, while still others
are provided with both stamens and pistils. The pod when
fully grown is from five to ten inches long and two inches wide,
somewhat flattened, of a dark brown color, with several seeds.
These pods hang unopened on the branches throughout the
winter. In the following spring they split along the edges and
reveal the large brown beans, which are remarkable for their
exceedingly hard coats, their albumen and the orange-colored
seed-leaves of the embryo. The wood of the tree is light brown
tinted with red and of some value in cabinet-making. The
coffee-trees select rich deep woods as their habitat, and are
beautiful forms under cultivation. They cannot be mistaken
for any other of the native Minnesota varieties, since their large,
thick pods are altogether distinctive.

Sennas. The sennas are also known as sensitive pe.as or
wild sensitive-plants. The three varieties which grow in Min-
nesota produce yellow flowers, almost regular, — that is, rose-
like and not two-sided in appearance. The American senna
has curved, rather smooth pods, three to four inches in length.
The large-flowered sensitive pea has for the most part straight
and slightly hairy pods, while the small-flowered has shorter
straight pods and flowers considerably less than half the size
of the other. The desmanthus is one of the pod-bearing plants
in which the pods are clustered together in heads. It is a
small herb with doubly pinnate, fern-like leaves, regular flowers
aggregated in spherical heads, and short curved pods clustered
together in dense heads, each pod containing from two to five
seeds. These plants would not be mistaken for clovers, in
which the pods are also clustered, on account of their fern-like
leaves and regular flowers. Besides, the pods are very much
larger.

Of the pulses, with butterfly-shaped flowers, there arc be-
tween 75 and 80 species in the state, including the false indigos,
the wild peanuts and wild beans, the vetches, prairie clovers

298

Minnesota Plant Life.

and tick-trefoils, the wild licorices, the ground-plums, locust
trees, pommes de terre, sweet clovers, lucernes, alfalfas, red,
white and yellow clovers, lupines and rattle-boxes. Most of
these are herbs. A few, like the false indigos or lead-plants,
are shrubs, and one, the locust, is a well-known tree.

Herbaceous false indigos and rattle-boxes. There are two
different kinds of plants belonging to different genera, known
under the general name of false indigo. Some of them are herbs
with creamy or white flowers in conspicuous racemes. Three
kinds of herbaceous false indigos are known to occur in Min-
nesota. The pods in these
plants are inflated and ovoid
in shape. The flowers of the
white false indigo turn black
in drying. The leaves consist
for the most part of three leaf-
lets and the plants are large,
averaging from two to four
feet in height. Related to
these false indigos are the rat-
tle-boxes. The Minnesota
species has apparently simple
leaves with prominent stipules
at the base of some. The
pods are ovoid and inflated
and the seeds rattle in them,
giving the occasion for the
common name.

Lupines, sweet clovers and clovers. Lupines, of which
one species is common in Minnesota, have the flowers arranged
in terminal, conspicuous racemes like the herbaceous false
indigo flowers. The leaflets, however, are seven to eleven in
number, growing out in radial fashion from the tip of their
common stem. The flowers are generally blue and the whole
plant is of an erect habit, from one to two feet in height. The
pods are not much inflated, but flattened and leathery. By
means of the leaves there is no difficulty in distinguishing these
plants from other pulses. The lucerne, or alfalfa, has violet
or purple flowers aggregated in loose clover-like heads or
racemes. The pod in this variety is twisted up like a snail shell.

FIG. 146. Wild lupine. After Britton and
Brown.

Minnesota Plant Life. 299

The sweet clovers are represented in Minnesota by two
varieties, the white sweet clover and the yellow. These are
bushy, branching herbs sometimes eight or nine feet in height.
The small flowers are arranged in slender racemes. The pods
are short-ovoid, and often — unlike most legumes — fail to open.
The peculiar fragrance of the flowers indicates adaptation to
insect pollination.

Six or seven kinds of clover, only one of which is native,
occur throughout the state. These are plants with leaves com-
posed of three leaflets, and flowers aggregated on short pedicels
in more or less globular or elongated heads. The flowers at

FIG. 147. Sweet-clover bushes. After photograph by Williams.

the edge of the head mature first, and, as they are pollinated,
often curve downwards, leaving the field clear to the unpol-
linated flowers to attract insects. The pods of the clovers, like
those of the sweet clovers, often fail to open, and, when they do,
separate along only one of the margins. If it were not for the
butterfly-shaped flowers such plants might escape classification
as pulses. The three most common clovers in the state are the
prostrate, with branches lying upon the ground, the common
white, and the red clover. The flowers of the prostrate clover
are yellow. Besides these, there are a few other introduced
clovers, one of which may be known by its oblong heads

3°°

Minnesota Plant Life.

Rather closely connected with the clovers are the little herbs
known as lotuses — no relatives, however, of the water-lily
lotuses, for this is an instance where common names are con-
fusing. In these plants the pods are more elongated. They
occur singly and hang down in a limp position when mature,
while the flowers are small, rose colored and with darker stand-
ard. The leaves are for the most part made up of three leaflets.
A lotus may be known by its solitary drooping pods.

Indian turnips. The pomme de terre, or prairie-turnip, or
Indian turnip, is an herb somewhat branched, of robust habit,
and arising from a tuberous root. The flowers are in hairy
ovoid spikes and the leaves are
made up of five radiating leaf-
lets. The pod is oblong,
smooth and inclosed in the
calyx. Two other plants of
this genus are abundant in the
state. One is conspicuous for
its silvery leaves and is known
as the silver-leafed prairie-
clover. The silvery appear-
ance, as in the buffalo-berries,
is given by hairs on the sur-
face of the leaves. There are
from three to five leaflets to
each leaf and the flowers are
of a blue color, sessile and in small clusters. Another variety,
the many-flowered prairie-clover, has leaves similar in form to
the silver-leafed variety, but without the hairs which give them
the metallic lustre. In this variety there are a number of small
blue flowers aggregated in loose racemes.

Shrubby false indigos. The shrubby false indigos occur in
Minnesota in three varieties. These plants are remarkable for
the modification of the butterfly-shaped flower, for all of the
five petals, except the standard, have disappeared, so that the
flower has but one petal. This is of a purplish, violet or blue
color. The leaves are pinnate with from twenty to fifty leaflets,
arranged opposite each other on their common midrib. The
large false indigo is from five to twenty feet in height, with

FIG. 148. White clover. After photograph
bv Williams.

Minnesota Plant Life. -»oi

spike-like purple racemes of flowers from three to six inches
in length. The pods are short, usually with two seeds, and the
surfaces are covered with little oil glands. It is common along
the shores of lakes. The low false indigo is a smooth shrub,
not over a foot in height. The flowers are arranged in spicate
racemes, usually solitary. They are of a purple color and sweet-
scented. The plant is at home in the southwestern districts,
preferring the prairie to the forest.

The lead-plant, which is one of the most abundant prairie
shrubs in the Minnesota valley, is covered with white hairs and
averages from one to three feet in height. The leaves develop
twice as many leaflets as in the other varieties, sometimes twenty
or more on each side of the common midrib. Several blue
racemes of flowers generally occur close together. The pods
are hairy and not markedly glandular.

Prairie-clovers. Of the true prairie-clovers there are three
Minnesota species, — the purple, the white, and the silky. These
plants have leaves made up, in the silky variety, of from ten to
twenty leaflets, and in the other two, of from five to nine. The
purple prairie-clover has commonly from three to five leaflets
and in all the varieties they are small and slender. The flowers
are arranged in dense spikes, and very often such spikes will
be found with girdles of flowers blooming around their middles,
while above the buds are still unopened and below the fruits
have set and the petals withered. By this habit, together with
their other characters, they may be recognized.

Locust-trees. The locust, or false acacia, is a handsome tree
and is noted for its beautiful pendulous racemes of large white
flowers, very fragrant and opening in the late spring. The
trunk, farther south, is sometimes three or four feet in diameter,
but rarely exceeds a foot in the colder climate of Minnesota.
The leaves are made up of from eleven to fifteen leaflets pin-
nately arranged. The pods are much flattened, with winged
edges, and the seeds ripen in separate chambers, and, when the
pod opens, remain adherent, some of them to one side of the
pod and others to the other. The halves of the thin pod serve
the seeds as wings for their distribution by the wind. Young
twigs of the locust tree have thorns at the bases of the leaves,
but the older branches are unarmed.

302 Minnesota Plant Life.

Ground-plums. The common ground-plum of the prairies
is one member of a little group of pulses including about ten
species in Minnesota. Most of them have slender, purplish,
lilac or whitish flowers in rather loose racemes. The leaflets
are much like those of the smaller shrubby false indigos ; that
is, they are composed of numerous small oval leaflets on each
side of a slender axis. In the ground-plum the pod, when it
matures, is fleshy and may be eaten when cooked. Not all of
the Minnesota varieties of ground-plum have this fleshy pod.
In others the pod is quite dry.

Two plants closely related to the ground-plum may be dis-
tinguished from it by the longer, more conspicuous racemes
of showy flowers. One of them in particular, which grows in
the western part of the state, has bluish-purple flowers on a tall,
central, erect stalk and is a very prominent flower of the prairie.
This plant is sometimes called loco-weed or loco-vetch. The
other member of its genus is of a beautiful silvery lustre, owing
to the soft white hairs that cover the leaflets and their axes.
In neither of these loco-weeds is there a branching plant-body
above ground, but the leaves seem to spring in a tuft from the
roots, while in the centre the erect flowering axis lifts itself
above their tips. The pods are incompletely divided into two
chambers by a deep partition extending lengthwise through the
pod almost to the back.

Wild licorice. A common herb of the Minnesota prairie is
the wild licorice. This plant may always be recognized when
in fruit by the ovoid pods covered with hooked bristles. No
other Minnesota pulse has just this sort of pod, which is, indeed,
not unlike a small cockle-bur head. The flowers, produced in
rather dense spikes, are of a cream color varying to white. In
these plants the roots are thick and sweet to the taste and are
sometimes used as a substitute for licorice. The flavor, how-
ever, is different from that of the true licorice and is scarcely
so agreeable. The leaves are of the same general character as
those of the last plant mentioned, except that they are not sil-
very in color, and are marked by minute glandular dots.

Tick-trefoils. The tick-trefoils are characterized by their
pods which are constricted between the seeds and separate into

Minnesota Plant Life.

303

pieces, each pod appearing to be made up of joints. One kind.
rare in Minnesota, and limited to the north shore of Lake
Superior, has the flowers in rather dense, violet-colored, ter-
minal racemes. The pod consists of from three to five smooth
joints shaped somewhat like eggs. The other tick-trefoils, of
which there are eight or nine reported to grow within the con-
fines of the state, have much less noticeable flower clusters, and
the flowers are small and loosely arranged on their axes. Some-
times they are terminal and sometimes produced in the angle

above the leaves. The pod is
very flat and usually separat-
ed into a number of joints.
Sometimes the pod is
straight along one edge,
while the other edge is in-
dented like the teeth of a saw ;
but in other instances both
sides of the pod are indent-
ed. The different kinds of
tick-trefoils cannot be dis-
tinguished from each other
without a critical examina-
tion ; but it may be said that
their principal differences
are in the shapes of the leaf-
lets, the arrangements of the

FIG. 149. Tick-trefoil. After Britton and Brown, pods in clusters, the SlirfaCCS

of the pods and their methods of jointing. They are found for
the most part in woodlands and usually stand up from two to
six feet in height. In most of them the pods are provided with
hooked bristles, by means of which they cling, either as a whole,
or broken up into their joints, upon the fur of passing animals,
or upon the clothing of their human visitors.

Bush clovers. Seven species of bush clovers are reported
from Minnesota. Several of these are known as wand plants ;
that is, plants which stand up slim and tall without any lateral
branches. One of them, the bushy headed or round headed
bush clover, is a common object with its brown, pod-bearing

304 Minnesota Plant Life.

heads aggregated in coffee-colored clusters at the top of a
slender stem from two to five feet high. The stems bear a
number of three-compounded leaves in which the leaflets are
shaped somewhat like those of the willow. One of these bush
clovers has a creeping stem and might be taken for a true clover
were it not for the egg-shaped pods which are larger and dis-
similar to those of the true clovers.

Vetches and beach peas. The vetches and beach peas may
be recognized, wherever they occur, by the formation of tendrils
at the tips of their leaves. There are about ten species in
Minnesota. They are found in woods and swales and one
variety is very conspicuous on sandy and gravelly beaches
throughout the northern part of the state, being particularly
abundant at Lake of the Woods and Red lake. This variety,
which is known as the beach pea, is seen at its best on the sea-
shore. The differences in the vetches lie in the shapes of the
leaves and pods, the colors and sizes of the flowers and the
development of the tendrils. In general, however, they are
supplied with pinnately compounded leaves with one or two
tendrils taking the place of the terminal leaflet or pair of leaflets.

Wild peanuts and wild beans. Not far removed from the
beach peas are the groundnuts, wild peanuts and wild beans.
In these there are commonly from three to five broad leaflets
to each leaf. The stems are slender and twine or climb over
the vegetation near them. The flowers are small, blue, pink
or violet, and are generally gathered together in rather small
clusters. These plants are abundant in the edges of woods.
The wild peanut forms two kinds of flowers, small purple or
white, ordinary butterfly-shaped flowers on lateral racemes, and
peculiar little flowers without petals, on certain slender pros-
trate stems which trail along the ground. By means of these
two kinds of flowers there is no difficulty in recognizing the
wild peanut. The wild beans resemble the wild peanut in their
general appearance, but are devoid of the curious inconspicuous
flowers. The groundnut usually displays five leaflets in each
leaf instead of three, but has the same slender vine-like habit
of growth that characterizes the others. All these plants will
be found in thickets and underbrush, trailing or climbing over
the bushes and thus exposing their own foliage to the light.

Chapter XXXI.

From Geraniums to Maples and Touch-me-nots.

if

The nineteenth order includes the geraniums, the wood-
sorrels, the nasturtium vines, the flaxes, the rues and prickly
ashes, the polygalas, the spurges, castor-beans, and tapiocas, the
water-starworts and several families not represented in North
America. A variety of interesting plants in this order are
cultivated, or are employed for various economic purposes.
For example, the coca tree, from which the well-known anes-
thetic, cocaine, is manufactured, should be grouped here; also
the oranges, limes and lemons, and the ailanthus tree, introduced
from China. To the spurge family, too, of this order, there
belong a number of singular cactus-like plants most abundant
in South Africa. Several of the families are represented in
Minnesota, but most of them by only a few species.

Geraniums. Four varieties of geranium occur wild in Min-
nesota. These all have regular flax-like flowers and slender
capsules which open by five clefts running lengthwise of the
pod. A peculiarity of the geranium pod is that, when it opens,
it does so suddenly, splitting from the base upward. Five
pieces, each carrying a seed at its lower end, split off in this
manner from a central column and the seeds are projected some
distance into the air as if thrown from a catapult. The differ-
ent kinds of wild geraniums may be distinguished by their
leaves. The common spotted-leafed geranium has rose-colored
flowers and leaves palmately divided and spotted. The red-
robin has much smaller leaves without the conspicuous spots.
The Carolina geranium has its leaves cut up into finer seg-
ments than the others and the flowers are of a pale, whitish hue.

Wood-sorrels. The wood-sorrels are well-known for their
three-leafleted leaves, not unlike those of the white clover, but
with a distinct acid taste. There are at least three varieties

21

306 Minnesota Plant Life.

in Minnesota and probably a fourth. In one, the white wood-
sorrel, found only in the northern part of the state, the flowers,
in general appearance like those of the flax, are white and the
flowering stems and leaves arise from a slender, scaly rootstock.
At the base of the plant are borne, on recurved pedicels, curi-
ous small flowers which do not open, but mature their fruits,
after close-pollination, from stamens developed side by side
with the fruit-rudiment. The other wrood-sorrels have violet
flowers in one species and yellow flowers in the other. The
violet-flowered wood-sorrel comes from a brown bulb not un-
like the bulbs of certain lily-like plants. For some reason
bulbs are but rarely produced by plants belonging to the high-
est class. The violet wood-sorrel is, however, one of the excep-
tions. The yellow wood-sorrel is much more branched above
ground than the others. Its leaflets are sensitive to the touch
and if rubbed for a moment with the fingers they will close.
The yellow wood-sorrel forms slender pods; the white wood-
sorrel produces short and rounded pods, while the pods of the
violet wood-sorrel are ovoid.

Flax. Of flax there are in Minnesota three wild species not
very easy to distinguish from each other. In one, the flowers
are blue like those of the cultivated flax, which sometimes
escapes as a weed. The wild blue flax may, however, be known
by the capsule which in fruit is much longer than the calyx.
Besides this variety there are two wild flaxes in which the flow-
ers are yellow. They may be distinguished by the length of
their capsules. In the grooved yellow flax the capsules are
from one to one and a half lines long, while in the stiff yellow
flax they are from two to two and a half lines long. Further-
more, in the grooved yellow flax the upper part of the stem
is clearly grooved, while in the stiff yellow flax the grooving
is not distinct. Flax is cultivated for fibre and for seeds. From
the seeds linseed-oil is manufactured, and from the fibre linen
is made.

Nasturtiums. Nasturtiums, with their pretty, round, shield-
shaped leaves, are favorite plants in borders and window-gar-
dens in all parts of the state. The plant, however, is not a
native. Perhaps the most interesting thing about it is the great
sensitiveness of its leaves to the direction from which they are

Minnesota Plant Life.

illuminated. A plant placed in a window will within a short
time incline all its leaves so that their surfaces are perpendic-
ular to the rays of sunlight. If the pot is now turned around,
in a short time the leaves will slowly swing back and accom-
modate themselves to the new direction from which the light
is shining.

Prickly ashes. The rue family is represented in Minnesota
by two shrubs. One, the prickly ash, is abundant throughout
the southern part of the state, extending as far north as Leech
lake. The other, known as the three-leaved ash, three-leaved
elm or hop tree, is reputed to occur in southeastern Minnesota.
The prickly ashes sometimes grow into small trees. Their
leaves are alternate, resembling those of the common ash trees,
and there are from five to eleven leaflets in each leaf. The
flowers are borne in little clusters, appearing in the early spring
before the foliage, or while the leaves are beginning to emerge
from the buds. The flowers are green and of small size. They
mature into black, egg-shaped capsules, each containing one
or two black and glistening seeds. The twigs of this plant
are armed with thorns. Prickly ashes are common on hillsides,
along rivers and at the edges of oak woods.

Three-leaved elms. The three-leaved elm has a fruit very
similar in appearance to that of the slippery elm, though the
plants are not particularly related to each other. The leaves
are made up of three leaflets, and the fruit has a decidedly bitter
taste, quite different from that of a true elm fruit.

Milkworts. The polygala family produces some small herbs
known as polygalas, milkworts and snakeroots. The Seneca
snakeroot is gathered in quantities on account of the medicinal
value of the rootstock. These plants may be recognized by
their flowers, generally in racemes or spikes, but in some in-
stances becoming condensed into heads, and by the three petals
united into a tube which is deeply cleft on one side. Two of
the sepals are larger than the other three and there are usually
eight stamens. The fruit is a small capsule and the seeds have
peculiar appendages.

Spurges. Fifteen species of spurges occur in Minnesota.
Most of them are mat-plants, forming disks of much branched
vegetation similar in appearance to the carpetweeds and purs-

308 Minnesota Plant Life.

lanes. Some of them, however, are erect, as, for example, the
very beautiful "snow-on-the-mountains," famous for the pure
white borders of the leaves. This is also known as the white-
bordered spurge. Many of the mat spurges which have been
alluded to are common along railway tracks and roadsides. All
of them have a milky juice, and in Minnesota, a mat-plant with
a milky juice is pretty certain to be a spurge. The different
kinds of spurges are marked by the different sizes and shapes
of the leaves, the smoothness or hairiness of the stem, and the
surface of the seeds. One erect type, rather common in the
western part of the state, is known by its red seeds sculptured
over with a fine network marking. Another, the flowering
spurge, is a very deceptive plant to the amateur botanist. It
seems to have clusters of flowers about the size of flax flowers,
arranged in loose, flat-topped terminal clusters. But each of
the flower-like areas is in reality itself a cluster of flowers and
the four or five white petal-like leaves are not really parts of
the flower, but are bracts surrounding the clusters. Like the
other spurges, this plant may be recognized by its milky juice.
It cannot well be mistaken for other milky-juiced forms, such
as milkweeds or wild lettuce, but it might be mistaken for
one of the dogbanes, from which it differs, however, in the
whorl of leaves standing at the base of the flowering area of the
stem. Besides, the real structure of the flowers is altogether
different, as may be learned by close observation.

Water-starworts. The water-starworts or water-fennels are
very small, insignificant herbs found growing on mud-flats, or
submerged in flowing water, or in ponds. Three varieties occur
in Minnesota, all of them with low slender stems and opposite
leaves with flowers in their axils. In one kind, which grows in
flowing water, the leaves are linear and about half an inch long.
In another, which may grow in the water or upon the mud,
the leaves are ordinarily spoon-shaped, while in still another they
are ovate. In all of them, however, the linear type of leaf may
prevail and it is then very difficult to tell them apart. Tiny
green plants found growing on mud-flats or submerged in the
water may be classified as water-starworts, if they have opposite
leaves with an inconspicuous bud-like flower in the axil of
each.

Minnesota Plant Life.

309

The twentieth order includes the crowberry family; the
sumacs, poison-oak and poison-ivy; the false mermaids; the
horse-chestnuts, maples, box-elders; and the touch-me-nots,
together with the hollies, bittersweets, wahoos and bladdernuts
besides some other families not represented in Minnesota.

Crowberries. Crowberries are heath-like shrubs and re-
semble diminutive yews. Their branches are generally not
more than eight to twelve inches in length. Each branch
is covered with densely crowded leaves of an evergreen as-
pect and with the margins rolled over toward the under side.
The plants generally grow in tufts, forming large mats. The
crowberries are
rather rare in
Minnesota, but
are known to
occur on the
north shore of
Lake Superior
and in Aitkin
county and
along the in-
ternational
boundary. The
flowers are in-
co nspicuou s,
developed
in the axils of
some of the
leaves toward

the tips of the branchlets. The fruit is a black stone-fruit, less
than half an inch in diameter. This curious little shrub is
unlike any other in the state. It cannot be mistaken for a yew
because in that the fruits are scarlet.

False mermaids. The false mermaids are odd little herbs
with pinnate leaves and deeply lobed fruits cleft into from two
to five nutlets. They are marsh plants and grow as slender,
more or less prostrate herbs, with solitary white flowers, trian-
gular in shape. No other plant in Minnesota resembles the
false mermaid.

FIG. 150. Sumac bushes, with golden-rods in foreground and
pies in background. After photograph by Williams.

3io

Minnesota Plant Life.

Sumacs and poison-elders. The sumacs include seven va-
rieties and are met with pretty commonly throughout the state.
With one exception — the fragrant sumac — they are abundant.
They are shrubs with pinnate leaves and invite attention by
their large panicles of small stone-fruits, bright red in color in
some of the varieties, and gray or white in others. The innoc-
uous varieties of sumac, of
which there are four or five
in the state, may be recog-
nized when in fruit by the
massive red clusters. The
leaves are made up of from
nine to thirty one leaflets,
except in the fragrant su-
mac, which bears three-
leafleted leaves and much
smaller clusters of stone-
fruits. The poisonous va-
rieties may be avoided by
noting their gray or white
stone-fruits. There are two
of these, the poison-elder
(poison-sumac, poison-dog-
wood, poison-ash or poison-
oak) and the poison-ivy,
both extremely unpleasant
to come in contact with.
The poison-elder grows for
the most part in swamps
and is pretty abundant
among tamarack through-
out the northern and central

FIG. 151. Poison-sumac. After Chesnut. F. B. 86, portions of the State It
U. S. Dept. Ag. . '

becomes more rare in the

southern and western districts. When in fruit it is easily rec-
ognized by the production of panicled currant-bunch-shaped
clusters of gray stone-fruits. The leaves are composed of about
seven leaflets arranged in pinnate fashion. From the shape of
its leaves this plant is also called the poison-ash, and it is known

Minnesota Plant Life.

in some localities as the poison-dogwood. Farther south the
plants reach a height of twenty to twenty five feet and are
small trees, but in Minnesota the poison-elder rarely exceeds
from eight to twelve feet. This plant is much more irritating
than the poison-ivy and is the cause of many of the severe cases
of skin-inflammation in the autumn — the season when it is most
virulent.

Poison-ivy. The poison-ivy, with currant-bunch clusters of
gray fruit, like those of the
poison-elder, differs from the
latter in being a low bush or
woody vine, in one variety
climbing, but bushy in another.
The leaves are made up of
three leaflets, resembling
somewhat the leaves of the
wake-robin or trillium. Poi-
son-ivy in fruit should not be
mistaken for any other Minne-
sota plant, but careless observ-
ers sometimes take for it the
woodbine, a member of the
vine family in which the leaves
are made up of five leaflets.
Both the poison-elder and the
poison-ivy secrete a highly
poisonous volatile oil which
rises in an invisible mist from
the foliage of the plant. It is
often not even necessary to
have handled the plant for
symptoms of poisoning to de-
velop. Merely approaching within a few feet of it will often
suffice. One can understand how this is possible by noticing
the distance at which he can smell the perfumes arising from
sweet-scented foliage or flowers, as for example, from the worm-
woods or the magnolias. Just as the air is permeated in the one
instance by the perfume, may it in the other be filled with the
poisonous exhalations. Among the antidotes for ivy or elder

FIG. 152. Poison-ivy. After Chesnut. F. B.
86, U. S. Dcpt. Ag.

312 Minnesota Plant Life.

poisoning are the acetates of lead or zinc, made into concen-
trated solutions and applied with a cloth or sponge as a wash
for the affected parts. Salol is also a specific.

The ordinary innocuous sumacs are, from their brilliant
autumnal tints, very beautiful shrubs of the Minnesota copses
and hillsides. The poisonous varieties do not show the rich
hues of their harmless relatives.

Hollies. One sort of holly bush is not uncommon in the
state. It is a shrub, usually six to twelve feet in height in Min-
nesota, with leaves shaped like plum leaves, but rather thick,
dark green and smooth above, turning black in autumn. Hence
the bush is sometimes called black alder. In late autumn, clus-
ters of red stone-fruits, spherical in shape, are found at the bases
of the leaves. The flowers are of two sorts, staminate flowers
devoid of pistils and perfect flowers with both stamens and pis-
tils. The Minnesota variety of holly has not the spiny leaves
of the Christmas holly, but its stone-fruits are of the same
brilliant red, though rather smaller. Another kind of holly,
the mountain holly, with grooved stone-fruits or capsules and
smaller smooth-margined leaves, occurs in the southeastern part
of the state. The deep longitudinal grooves in the fruit serve
to distinguish it from the swamp holly. Hollies and poison-
elders very commonly grow close together among the trees of
tamarack swamps, and those gathering holly berries in the au-
tumn will do well to observe any suspicious elder-leafed shrubs
that are near by, and avoid them.

Climbing bittersweets and wahoos. One species of bitter-
sweet and two wahoos represent their family in Minnesota.
The bittersweet is a twining vine, often climbing up the trunks
of small trees in the woods and displaying its stem along their
branches twenty feet or more from the ground. The leaves
are alternate and shaped somewhat like plum leaves. The flow-
ers are produced in racemes and mature their fruits as orange-
colored, spherical capsules, half an inch or less in diameter.
These fruits split open by three clefts in autumn and show a
red, pulpy structure inside.

The wahoo or spindle-tree, sometimes known also as burn-
ing-bush, is a shrub from six to twelve feet in height in Min-
nesota. The leaves are plum-shaped, the flowers are purple,

512

Plant Lif

ll

00,

3 »
Str

l

II

Oj 0

cr^

S-S
ft- 1

S E

fr a

»

e cr

e a

Ba

n is als< -lie.

e, from their
ibs of the Minnesota
• poisonous varieties do not show the
tnless relatives.

e sort- of holly bush is not uncommon in
lally six to twelve feet in height in .
ves shaped like plum le ather t'

smooth above, turns;

times called black a ... ,

• fruits, spherica'

The flowers are of t aate flo-

and perfect flo\vers with both stamens and
;a variety of holly has not the spiny leaver
. but its stone-fruits are of the same
1, thougl. uller. Another kind of holly,

iin holly, wii :its or capsules

>oth-margine<
. The deep
ish it from i
common

bittersweets e species of bitter-

nt their family in Minnesota.
e, often climbing up the tru
displaying its stem along their
i'rbm the ground. The le;
:at like plum lea

sture their fruits as orange-
inch or less in diameter.
in autumn and she

n also as bv
heigfht in Iv;

Minnesota Plant Life. ->,-,

borne in axillary cymes, the fruits are singular, deeply-lobed,
three or four-parted capsules. When the capsules split along
the sides, a red, fleshy mass is shown within similar to that
observed when the bittersweet capsules open. The cliinl .in-
habit of the bittersweet serves, however, at once to distingui>h
it from the common wahoo. A rare species of wahoo is a
trailing shrub.

Bladdernuts. Bladdernuts are branching shrubs with pe-
culiar, large, deeply three-lobed bladdery capsules. The leaves
are made up of three leaflets and the clusters of flowers arise
in their axils. These plants may be readily recognized by the
capsules which resemble three small pea-pods blended together
by their backs and separate at their tips. They are not uncom-
mon in the southern part of the state, where they inhabit the
edges of woods.

Maple trees. Seven kinds of maple, including the box-elder,
occur in Minnesota. These are the soft maple, the red maple,
the sugar or hard maple, the black maple, the moosewood
maple, the mountain maple, and the ash-leaved maple or box-
elder. All of these plants may be known by their production
of two-lobed fruits provided with wings. The fruits separate
into halves when ripe and each half, furnished with its wing,
obtains distribution by the wind. The box-elder is the only
Minnesota maple with pinnate leaves. In this plant each leaf
is made up of from three to seven leaflets. The other maples,
in which the leaves are simple, may be distinguished by their
flowers, leaves, bark and fruits. The soft maple and the red
maple display their flowers before the leaves emerge from the
buds and are among the earliest flowering Minnesota species.
The flowers of the common soft maple have no petals and are,
therefore, rather inconspicuous, while the flowers of the red
maple have showy red or yellow petals. The sugar-maple,
or hard maple, and the black maple form the flowers on long
drooping stalks and at the same time that the leaves unfold.
The leaves of the sugar-maple are smooth on the under side,
while in the black maple they are hairy below, usually over the
whole surface and always on the veins. The moosewood maple
and mountain maple open their flowers in terminal racemes after
the leaves have unfolded. In the moosewood maple the ra-
cemes are drooping, while in the mountain maple they are erect.

3*4

Minnesota Plant Life.

Of these plants, the soft, red, hard and black maples are large
and handsome trees, while the moosewood and mountain maples
are small trees or shrubs. The black maple has a rough black
bark. The sugar-maple is utilized in the manufacture of sugar,
obtained by boiling down its copious sap in the springtime.
The red maple has scarlet or crimson bark on the younger trees.
The soft maple has whitish bark with leaves more notched than
in the hard or black varieties. The moosewood maple has
leaves with two deep notches making three sharp lobes toward
the end. All the lobes are about equal in size. The mountain

maple has leaves
similarly three-
lobed,but the middle
lobe is much the
largest.

Soft maples. The
soft maples are
abundantly planted
in Minnesota for
shade trees, for
which purpose, how-
ever, they are not so
valuable as hard ma-
ples. Under favor-
able conditions they
grow to be large
trees, over a hun-
dred feet in height. The branches are brittle and many of them
are markedly pendulous like the branches of the weeping wil-
lows. The leaves are five-lobed, bright green above and whit-
ish or silvery below. In autumn they turn yellow. The flowers
are produced in little heads on short lateral branches, and there
are two kinds, staminate and pistillate, often borne on the
same, but sometimes on different trees. The fruits hang on
slender, drooping stems, and very often one side of the fruit
fails to mature. As soon as the seeds fall to the ground, or
the next season, they may germinate, and the seedlings develop
their first leaves and terminal bud during June. Maple wood,
from this species, is hard and is used in the manufacture of

FIG. 153. lyeaves and flowers of the sugar-maple. After
Atkinson.

Minnesota Plant Life.

315

woodenware or furniture. Soft maples are abundant through-
out the southern part of Minnesota and extend north to Bel-
trami county.

Red maples. The red maple commonly occurs in Minne-
sota as a bush or low tree, but may, under the best conditions,
reach a height of over a hundred feet. The bark is of a dark
gray color. The leaves are whiter below than above, and in
autumn exhibit beautiful hues of scarlet and orange. The
flowers are borne much as in the soft maple and the fruits some-

Fio. 154. A grove of sugar-maples. Near I^ake Minnetonka. After photograph by Mr. E. C.

Mills.

what resemble those of the latter species, though the wings are
more incurved. The red twigs, brilliant autumnal color, and
more conspicuous flowers distinguish easily this maple from the
soft maple. Its wood is heavy and one variety of it, known
as curly maple, when polished is very beautiful. In Minnesota
the red maple is one of the earliest trees to assume the autumn
tints, and, with the sumacs, gives a vivid color to hillsides
before the deep red of the scarlet oaks appears.

Sugar-maples. The sugar-maple is a large, round-headed
tree, sometimes growing in Minnesota to a height of seventy

Minnesota Plant Life.

five or eighty feet, and, under the most favorable conditions,
to nearly twice this height. On the trunk the bark is of a light
gray color, while on young twigs it is orange or yellow-brown.
The leaves are darker green than those of the soft maple and
assume a variety of colors in the autumn, some trees turning
scarlet, others crimson, others yellow, If a particular tree is
yellow one year it will be yellow the next, the tint of the autumn
foliage being apparently an individual habit. The pistillate
flowers are more commonly borne towards the tips of their

branchlets, while the staminate
flowers are on the sides, and lower
down. The wood is strong and
tough, more valuable than that of
any other common maple. It is
useful for fuel and is employed in
the manufacture of flooring, furni-
ture, tool-handles and portions of
machinery. Bird's-eye maple and
a form of curly maple are obtained
from diseased trunks of the sugar-
maple. It is this species which sup-
plies the greater part of the maple
sugar, though that is also made
from the black maple and from the
moosewood by the Indians of north-
ern Minnesota. The sugar obtained
from the sugar-maple is of a some-
what better quality, however, than
that derived from the other species.

Black maples. The black maple is very closely related to
the sugar-maple and is possibly only a variety of it.

Moosewood maples. The moosewood maple occurs in Min-
nesota as a small and bushy tree with red-brown twigs and
striped bark of a brown color. The leaves are smooth on both
sides, turning yellow in autumn. The flowers open in late
spring, the sterile and the fertile being produced on the same
plant, but in different clusters. The wood is light and soft.
The name "moosewood" is applied from the habit which the
moose have of chewing the young twigs on account of their
sweet juices.

FIG. 155. Moosewood maple. After
Britton and Brown.

Minnesota Plant Life.

317

Mountain-maples. The mountain-maple in Minnesota is a
rather low shrub. The leaves turn scarlet or orange in autumn
and the flowers are of two sorts, generally produced in the same
cluster, the staminate towards the tips and the pistillate toward
the bases. The wood is soft, light, and of little commercial
value.

Box-elders. The box-elder grows as a small tree, thirty or
forty feet in height, though farther south it becomes larger.
The bark is of a brown or gray color; the twigs are purplish
with a white bloom. The leaves do not show any brilliant
autumn coloration. There are two kinds of flowers, staminate
and pistillate, always borne on separate trees. The staminate
flowers hang in clusters on
thread-like stalks, while the
pistillate droop in loose ra-
cemes. The fruits mature
in autumn and often cling
to the trees throughout the
winter. When they fall in
autumn, as they more com-
monly do, the stems on
which they were produced
remain until the succeeding
spring, attached to the twigs
that bore them. The wood
is soft and weak, but is em-

i i • ,1 f „ FIG. 156. Touch-me-not. After Britton and Brown.

ployed in the manufacture

of some woodenware and for wood-pulp. This is a favorite
shade tree along the streets of Minnesota towns. When grow-
ing wild it is to be looked for especially beside streams and in
low woods.

Buckeyes. The horse-chestnut family is represented in Min-
nesota by the buckeye, a plant which is probably introduced into
the state by the agency of man and is nowhere abundant, though
it occurs as if native in a few southeastern localities. It is a
small tree with long-stemmed leaves made up of about five
willow-leaf-shaped leaflets. The flowers, borne in terminal
panicles, are of a yellow color, not so striking in their appear-
ance as those of the horse-chestnut. The fruit is a spiny, spher-

318 Minnesota Plant Life.

ical capsule, an inch or so in diameter, becoming smoother with
maturity. The seeds, of which one or two are produced in a
fruit, are large and have glistening coats. The wood is soft
and white and, in Ohio and Indiana where the tree is more
abundant than farther northwest, is used in the manufacture
of woodenware.

Touch-me-nots. There are two species of touch-me-nots in
Minnesota. Both of them are shade-loving plants, and grow
in swamps, damp woods and ravines, where the light is not too
strong. Their stems are translucent and one can see the fibrous
threads through the skin. The leaves are very thin, of ovate
shape, and with toothed margins. They wilt almost immediately
if removed from their stem. The flowers are colored — in one
variety, orange speckled with brown, in the other pale yellow—
and two-sided, looking a very little like snapdragon flowers,
to which, however, they are not related. The fruit is an ob-
long or slender capsule of a bright green color and succulent
when ripe. If pressed gently between the thumb and finger,
or if brushed against, the fruit splits violently into strips
which coil together, ejecting the seeds with explosive force.
The touch-me-nots are perfect examples of the adaptational
group of plants known as shade plants. They are pale in color
throughout, with thin, rather large leaves and an abundance of
moisture in their tissues. They do not secrete purple coloring
substances in marked quantities either in their leaves or in their
stems. They are very abundant in Minnesota near rivulets, in
wooded ravines, in tamarack swamps and around springs.

Chapter XXXII.

From Buckthorns to Prickly-pears.

The twenty first order includes two families, the buckthorns,
of which there are two species, and the vines, with four grape-
vines and one Virginia creeper.

Dwarf alders. The alder-leafed buckthorn, or dwarf alder,
is a shrub found growing in swamps and recognized by its
plum-shaped alternate leaves, in the axils of which small flowers
arise. There are no petals, and the calyx is urn-shaped with
four or five teeth at the margin. The stamens are borne on
the calyx between its notches. The fruit is berry-like, contain-
ing three nutlets within. The character of the fruit and the
structure of the flower easily distinguish this shrub from others
which might be mistaken for it.

New Jersey teas. Besides the buckthorn, there are two
varieties of New Jersey tea or redroot, one of which is pretty
abundant throughout the state, while the other is less com-
mon. These plants are small shrubs, the two species be-
ing distinguished by the shapes of the leaves. One, the
American redroot, has ovate, while the other produces lance-
head-shaped oblong leaves. In both varieties the flower is very
similar to that of the buckthorn. The calyx-parts are fused
together at their base and have five notches at the margin.
Between these notches the stamens are borne, five in number,
while under each stamen arises a curious ladle-shaped petal of
a white color. The black fruits are dry and deeply three-
grooved, and when mature they separate longitudinally into
three hard nutlets. The American redroot is more abundant
in dry woods, while the smaller redroot prefers rocky places,
barren soil, dry hillsides or bluffs, or the tops of knoJls in the
rolling prairie. The name, "New Jersey tea," arises from the
use of the plant in place of tea by American soldiers during the
Revolution.

20

Minnesota Plant Life.

Wild grapes. The wild grapes can scarcely be mistaken for
any other plants, except, perhaps, the moonseeds, from which
they are known at once by their more or less pear-shaped seeds.

FIG. 157. _Tree covered by grape-vine. After photograph by Williams.

They are all of them tendril-bearing, climbing, shrubby vines,
with characteristic maple-like leaves. The flowers are either
altogether separated, or of two sorts on the same plant. It

Minnesota Plant Life.

is not usual to find among grapes what are known as perfect
flowers, with both stamens and pistils. The fruit is a spherical
berry of a blue or purplish-black color, edible and containing
from two to four seeds. The four varieties of grapes in Min-
nesota are the fox-grape, the summer grape, the frost-grape,
which is the common one, and the riverside grape, which is
likewise abundant except along the north shore of Lake Supe-
rior. The different grapes may be discriminated from each
other by certain structural characters. The fox-grape and the
summer grape have leaves with cottony under sides. The other
varieties have leaves with smooth, or only slightly hairy under
sides. In the fox-grape the berries are rather large, with a
strong musky fragrance, and the cotton on the under sides of
the leaves is of a brownish color. The summer grape has small
berries without the musky fragrance; and the cotton on the
under side of mature leaves is almost white. The riverside
grape may be distinguished from the other smooth-leafed va-
iety by the bloom on its berries and by its trailing or low habit
of growth, while the frost-grape climbs high, often swinging
itself on the branches of trees, and produces black shining
berries, ripening after frost and not possessing the distinct
bloom of the riverside grape. In all of these vines the fruits
hang in panicles and droop from the weight of the berries.

Virginia creepers.. The Virginia creeper or woodbine, is an
abundant plant in most sections of the state. The tendrils
of this vine often form little sucker-like disks by which they
attach themselves to walls or fences, making the plant a desir-
able climber in dooryards and about houses. The leaves are
composed of from five to seven leaflets, five being much the
more common number. The fruits are grape-like, with from one
to four seeds, and are borne in forking clusters that stand erect
owing to the strong pedicels and smaller weight of the whole
as compared with a bunch of grapes. The berries are not
edible.

The twenty second order includes six families not represented
in Minnesota, and in addition to these the basswoods, and the
mallows to which the hollyhock of country gardens belongs.

Basswoods. One variety of basswood, known also as the
American linden or whitewood, is native within the borders of

22

322

Minnesota Plant Life.

the state. It is a handsome tree, reaching a height of seventy
feet or more, very abundant in the hardwood belt throughout
Minnesota, and only less common along streams and on hill-
sides in the northern woods. Its range extends to Thunder
bay, Lake Superior, and along the international boundary to
Lake of the Woods. The trunk is rather slender, not more
than two feet in diameter in the northern portions of its range.
The leaves are large and broad, unevenly heart-shaped at the
base and turning yellow in autumn. The flowers are produced
in cymes upon a stem that bears at the base a remarkable

FIG. 158. Virginia creeper on tree trunks. After Schneck in Meehan's Monthly.

wing-shaped bract which is coherent until about its middle with
the flowering stem. The fruit is a hard berry, and within it
are one or more seeds. Two or more of the berries are ma-
tured in a cluster and the stem of the cluster with the adher-
ent wing-shaped bract separates from the tree. The centre of
gravity of the cluster and the shape of the wing are so exactly
coordinated that the whole affair whirls through the atmos-
phere, making of itself a little parachute. By this means the
berries are often distributed to a considerable distance. The
wood is pale brown in color, light, and rather weak. It is

Minnesota Plant Life.

323

employed principally in the manufacture of wood pulp or paper
and in the production of some kinds of furniture and wooden-
ware. The inner bark, which is papery, is used by nur-<
men to tie buds into scions. The basswood is a very desir-
able shade tree and is frequently planted in dooryards and
along streets. The European basswood or linden, which ^ives
the name to the famous street ''Untcr den Linden" of the Ger-
man capital, is sometimes planted in the United States, but
is not particularly abundant in Minnesota. Unlike the Amer-
ican species, it has no scales at the base of the petals in the
flowrer.

Mallows. The mallowr family includes a little group of herbs,
mostly introduced from Europe, such as the hollyhock, the
creeping-charley or cheese plant, the velvetleaf, the ketmias or
rose-mallows and some others. There are a few native species,
none of which is very common. Among them are the Collir-
rhoe and false mallow of the southwestern corner of the state,
the glade-mallowr, a rare plant of the southwestern section, and
the halberd-leafed rose-mallow, found occasionally along the
Mississippi river in the vicinity of the Twin Cities.

Mallows may be distinguished from other plants by the devel-
opment in the flower of large numbers of stamens all blended
together by their bases into a tube which surrounds the fruit-
rudiment. The latter has several compartments and encloses
one or two seeds in each. The embryo is curved and con-
tains albumen. Sometimes the flowers are large and shuwy.
as in the hollyhock, while in other varieties they are rather
small. The common round-leafed mallow or creeping-charley,
also known as cheese plant, from its disk-shaped little fruit-
bodies, sometimes eaten by children, is a common plant in
dooryards and waste places. The flower is like that of the
hollyhock, only much smaller and of a pale blue color. The high
mallow is an erect plant of biennial growth, with fruits quite
similar to the creeping variety and leaves shaped like those of
currants. The crisp mallow has the margins of the leaves crisped
like some varieties of lettuce, while the general shape of the
leaves reminds one very much of the high mallow. The Cul-
lirrhoes, of which at least one variety, and probably two. are to
be found in Minnesota, are known also as poppy-mallows. They

324

Minnesota Plant Life.

are herbs of the prairies and should be looked for particularly
in the far southwestern portions of the state. One of them
is occasionally found along railways as far east and north as
Minneapolis. The two varieties of Callirrhoe are distinguished

FIG. 159. Basswood trees. Shore of L,ake Calhoun. After photograph by Hibbard.

by the shape of their leaves. The triangular-leafed poppy-
mallow has the lower leaves somewhat halberd-shaped, while
the other puts forth deep-lobed round leaves. The flowers in
each of these varieties are rather large and showy, purple in

Minnesota Plant Life.

o D

color, verging towards red. The prairie mallow resembles
closely in general appearance the poppy-mallows, but may be
distinguished by the silvery foliage and the red flowers. 'The
glade-mallow displays rather small white flowers in terminal
clusters. The leaves are shaped very much like those of the
soft maple, only smaller. The whole plant is an erect, slender
herb from four to eight feet in height. It has been found in
damp woods in Goodhue county, and occurs in such localities
as far west as Mankato. The native rose-mallow is an herb,
three to five feet in height, with leaves heart-shaped or three-
lobed on the upper side, velvety to the touch. The flowers are
large and of a pretty pink tint, growing darker toward the
centre. In fruit, the calyx is inflated into a bladdery sheath
not unlike that of the ground-cherries. The ketmia is a low
herb with deeply-cleft leaves. The flowers are large and yellow,
with purplish centre, and remain open but a few hours ; hence
the plant is also known as the flower-of-an-hour. Like that of
the halberd-leafed rose-mallow, the calyx in this variety inflates
itself into a little balloon-shaped bag around the fruit. Another
name for this plant is black-eyed Susan. It is rather abundant
in waste fields and vacant lots in the vicinity of St. Paul and
Minneapolis.

Velvetleafs, The velvetleaf, which is sometimes encountered
in the southern part of the state, is a large herb, often six feet
in height, with leaves in size and shape like those of the linden.
They are, however, of a soft velvety texture ; hence the common
name applied to the plant. The flowers are yellow and are
borne in the axils of small leaves toward the ends of branches.
The twelve or more carpels which make up the fruit are sep-
arated from each other by deep longitudinal grooves, and the
appearance of the whole fruit-body is something like that of a
circle of milk-pitchers set close together with their lips point-
ing outward.

None of the mallows is of any particular economic impor-
tance. The hollyhock and the ketmia are cultivated for orna-
ment, and it is in this family that the marshmallow — a plant with
mucilaginous root, used in the manufacture of a popular con-
fection— is grouped.

The twenty third order includes twenty six families of plants
without any Minnesota representatives and but three families

326 Minnesota Plant Life.

of which Minnesota species are known. Many of the families
are small exotic groups of plants, but among them are some
important economic varieties. The tea-plant, a member of the
tea family, cultivated in Japan, China and Ceylon, is classified
here, — also the camphor plant, the marcgravias, the tamarisks,
the passion-flowers and the begonias. The families represented
in Minnesota are the St. John's-worts, with about a dozen
species, the rock-roses, with three or four species, and the vio-
lets, with about twenty species.

St. John's-worts. The St. John's-worts are herbs with oppo-
site leaves, which are always marked with glandular dots or
small black specks. The flowers are borne in panicles or cymes
at the apex of slender stems. In each flower there are five sepals
and five petals, with a number of stamens sometimes united
into clusters. The ovary is one-chambered, with from three to
five interior longitudinal ridges, along which the numerous seed-
rudiments are attached. At the top of the capsule, which is
generally pyramidal-ovoid in form, from three to six separate
stigmas are borne. In some of the Minnesota varieties the
longitudinal interior crests of the fruit-rudiment project clear
to the centre, thus making a three- to five-chambered capsule.
The flowers are regular in appearance. The different varieties
of St. John's-worts may be recognized by their general habit
of growth ; by the sizes and shapes of the leaves ; by the char-
acter of the flower-cluster, which, as has been said, is either
flat-topped or panicled; and by the cross section of the fruit,
which is, when mature, in all instances a dry capsule — some-
times one-chambered, sometimes three-chambered and some-
times five-chambered. In all these the leaves are ovate, slender
or elongated. One variety, the marsh St. John's-wort, is found
only in swamps. It may be recognized by its three-carpeled
red capsule.

Rock-roses. The rock-roses include three or four plants, of
ledges or barren soil, known as frostweeds, Hudsonias, pin-
weeds, beach heathers or false heathers. The frostweed, which
is a pretty common plant throughout the state, is a woody herb
one or two feet in height with two kinds of flowers, — some with
petals and clustered in terminal cymes, the others much smaller,
without petals, almost sessile in the axils of the leaves. The

Minnesota Plant Life.

327

leaves are shaped like small willow leaves and are covered with
a gray growth of hairs. The petaled flowers are light yellow,
with hoary sepals. The fruit is a capsule ovoid in shape and
divided into three chambers, in each of which is a lar-e number
of seeds.

Beach heathers. The Hndsonia, or beach heather, is a plant
of local occurrence in Minnesota, abundant on rocky islands at
Rainy lake ; on Sable island at Lake of the Woods ; on sand
dunes in Ancka, Sherburne and Wright counties ; and on rock
ledges in the Minnesota valley, along the St. Croix and lower
Mississippi. It is a densely
tufted herb, with very small,
oval leaves, covering each
other like shingles on a roof.
The flowers are small, yellow
and sessile, produced in clus-
ters towards the ends of the
branches. The whole plant
has a hoary aspect, from the
minute white hairs with which
its stems and leaves are cov-
ered. It is an abundant dune
and crevice plant along the
international boundary, more
frequent north than south,
but found on high rocks even
to the southern border of the
state.

Pinweeds. The pinweeds grow in great abundance along
the St. Croix river, in open woods or by the roadside, but are
less common elsewhere in the state. Minnesota has one or
two varieties, which may be known by their small simple leaves,
in most instances less than half an inch in length, and by their
large numbers of green or purple flowers gathered in terminal
panicles. The common Minnesota variety is about a foot in
height, slender and usually unbranched below the region of the
flowers. The fruits, when they mature, are capsules with three
longitudinal furrows marking the three carpels of which they
are constructed.

FIG. 160. Beach heather. After Britton and
Brown.

Minnesota Plant Life.

Violets. Violets, of which there are several species in Min-
nesota, are well-known as flowers of the springtime and are
remarkable for a number of structural peculiarities among
which may be mentioned the development of their flowers singly
upon slender, almost leafless stems; for the upper- and under-
sidedness of the flower, which in this respect superficially re-
sembles the flowers of larkspurs or of orchids; and for the
production in many varieties of small flowers, close to the sur-
face of the ground, incapable of opening, and, therefore, pol-
linated by their own pollen. The violets of Minnesota may be
divided into the stemless
and stemmed varieties.
Actually they all have
stems, but in the so-called
stemless sorts the leaves
and flower-bearing axes
arise from short, erect or
prostrate underground
stems, so that the leaves seem
tufted at the root, while in the
stemmed varieties, so named,
there is more or less branching
of the above-ground portion of
the plant-body. The stemless
varieties have, for the most
part, purple, lilac or white
flowers, while in the stemmed FlG" 16L Sweet ^ B.^*' After Britton
violets, yellow, white or cream-
colored flowers are also to be found. Among the violets of
the state, which are abundant and easily distinguished, are the
larkspur-leafed or prairie violet, with deeply-cut leaves, appar-
ently made up of seven or eight incised leaflets; the meadow
violet, with heart-shaped leaves; the arrow-leafed violet, with
leaves shaped like arrow-heads; the bird's-foot violet, similar
in general appearance to the prairie violet, but distinguished
from it by the beardless petals; the round-leafed violet, with
abundant closed flowers, developed later in the year than the
open ones; the marsh-violet, with its pale lilac petals marked
with darker veins; the sweet violet, with small, white, sweet-

Minnesota Plant Life.

scented flowers, abundant in two varieties in the tamarack
swamps of the state ; the kidney-leafed violet, with leaves of a
broad kidney shape and longer than the flowering stem; the
lance-leafed violet, with leaves shaped like those of the wil-
low. All these belong to the stemless group. Among the
stemmed forms are Nuttall's violet, a prairie variety, with elon-
gated, lance-shaped leaves; the halberd-leafed violet, with
leaves shaped like arrow-heads and yellow flowers like those of
the preceding species. Here, also, is the common yellow violet
of the woods, with heart-shaped and kidney-shaped leaves and
hairy stems, usually solitary. Very similar to this is the smooth,
yellow violet, with narrower heart-shaped leaves, smooth stems
and foliage, and clustered growth. Related to these yellow-
flowered species is the Canada violet of rich woods, with its
violet or whitish flowers and heart-shaped leaves, and the very
similar striped violet, with cream-colored, white or blue flowers.
Both the latter have stems five to fifteen inches in height and
not tufted. The Labrador violet, with smaller heart-shaped
leaves and purple or white flowers, may be distinguished by its
tufted growth and its production of closed flowers later in the
season than the ordinary open ones. The sand violet is known
by the strongly notched, slender stipules of the leaves. The
flowers are of violet color, the stems are tufted and the leaves
are kidney-shaped or heart-shaped, on stems longer than their
blades. The long-spurred violet of the Isle Royale and Grand
Marais region may be recognized by the slender spur of the
flower, in length equaling or exceeding the petals. Besides
the native forms the common pansy has escaped from flower-
gardens in the southern part of the state and sometimes occurs
as a dooryard weed.

Violets show in their two-sided flowers an adaptation similar
to that seen lower in the series in the two-sided flowers of the
pulse family and of the larkspurs, dr, still lower, in the flowers
of orchids.

Prickly-pears. The twenty fourth order includes but a single
family, the cacti, to which belong three species of prickly-pears
and the purple cactus — rock-plants of southern Minnesota.
The cactus family is a very extraordinary group, in which stems
have become fleshy and consolidated, while leaves have been

330

Minnesota Plant Life.

modified into a defensive armor. These plants indicate a strong
adaptation to desert life. Their massive, leafless stems — leaf-
less in the sense of producing no ordinary foliage leaves — sug-
gest the scantiness of the soil-moisture which they are able to
absorb, and because it is so- hard to obtain, they have abandoned,
as far as possible, their evaporating surfaces. Some of them,
like the melon-cacti, have not only lost their foliage, but have
shortened their stems into spherical or ovoid melon-shaped
bodies. They have large roots, usually extending to a con-
siderable distance in all directions from the base of the stem.

The strong defensive armor of
spines, which most varieties
possess, suggests a danger to
which the plants of an arid
region are exposed, owing to
the absence in such districts of
abundant forage for herb-eat-
ing animals. The three Min-
nesota species of prickly-pear
are all of them wanderers from
the southwestern plains, where
they developed their peculiar
characters, and now that they
have entered the more favor-
able northern region they re-
tain the organization best
adapted to their original home.
After They are not infrequent in the
Minnesota valley, on ledges of

rock near New Ulm and Redwood Falls. One variety occurs
at Taylor's Falls, in the valley of the St. Croix, while two are
abundant on the rocks in Pipestone county, in the vicinity of
the old Indian quarry. Perhaps the Indians have had some-
thing to do with their introduction from the southwest. The
three species may be distinguished by their spines and fruits.
The western prickly-pear produces a fleshy edible fruit, free
from spines, from one to two inches long, shaped somewhat like
a pear, borne upon the flat, sinuous joints of the stem. In this
variety the spines on the stem are not numerous. They occur

Minnesota Plant Life.

in groups of from one to four. The flowers are yellow with
a red centre. The other two prickly-pears have smaller fruiu.
covered with spines and drier in texture. The many-spined
prickly-pear bears on the flattened stems little masses of bristles
in tufts, with from five to twelve spines in a group. They are
slender, from half an inch to two inches in length. The brittle
prickly-pear produces, on the more egg-shaped joints of the
stem, from one to four central spines, varying from a half to
one and a half inches in length. Each group of central spines
is surrounded by from four to six lateral shorter prongs. The
spines in this species are gray, becoming black toward the tips,
while in the many-spined prickly-pear the thorns are whitish
and not black toward the tips.

The purple cactus is known by its almost globular, warty
and thorn-covered stem, from one to five inches in height,
arising either singly or in tufts. The flowers are terminal and
solitary, and are purple or purplish-red. This species is re-
ported only from the vicinity of Ortonville, and probably does
not grow elsewhere in the state.

Chapter XXXIII.

From Leatherwoods to Dogwoods.

The twenty fifth order comprises eleven families that are not
represented in Minnesota and five that are. Among the exotic
species are the pomegranate, the mangrove, the myrtles and
eucalypti, the melostomas, the Brazil-nuts and a number of
forms peculiar to South Africa. In Minnesota there are found
one species of the leatherwood family, three species of buffalo-
berries and silverberries, four species of the loosestrife family,
eighteen or twenty evening primroses and about six varieties
of water-milfoil.

Leatherwoods. The leatherwood is a shrub from two to
six feet in height, not uncommon along streams in woods and
thickets throughout the greater part of the state. It is most
abundant from Duluth to Lake of the Woods and is not to
be expected in the southwestern portion of the state, although
it extends to New Ulm and Blue Earth county. The leather-
wood has yellowish-green twigs, with alternate, broadly oval,
entire-margined leaves. The flowers are disposed in clusters
of three or four, appearing while the leaves are emerging from
the bud. The perianth is bell-shaped, with eight stamens borne
upon its inner surface and protruding from the mouth. Every
alternate stamen of the group is longer, while the intermediate
ones are shorter. The fruit is oval in outline, red in color, and
about half an inch in length. The bark is poisonous, acting
as a violent emetic. This shrub may be known by the yellow-
ish color of the flowers and bark, the stamens alternately longer
and shorter, and the red stone-fruits.

Buffalo-berries. The three species of buffalo-berries are sil-
very shrubs, particularly abundant in the Red river valley, in one
variety extending as far east as the north shore of Lake Supe-
rior. They may all be recognized by the curious scurfy growth

Minnesota Plant Life. „-

on the leaves, which gives to them a silvery lustre upon both
sides in the silverberry and silver buffalo-berry, but upon the
under side alone in the Canada buffalo-berry. In this latter
species a few scurfy shield-shaped hairs develop on the upper
sides of the leaves. The silverberry has alternate, oblong
leaves, while buffalo-berries have opposite oblong leaves. The
flowers are bell-shaped, without corolla. The stamens are four
or eight in number, borne on the inner surface of the perianth.
The silverberry, which is a most attractive and beautiful shrub,
is silver-colored, not only with respect to the leaves, but over
the young twigs as well. The fruit is oval in shape, silvery in
color, with a grooved stone. It ripens in August and is edible.
The two varieties of buffalo-berries have the same general
appearance as the silverberry, but are distinguished by their
opposite leaves. In the Canada buffalo-berry the leaves are
green on the upper side, silvery below, and the twigs are not
thorny. In the silver buffalo-berry the leaves are bright silver-
colored on both sides and the twigs are generally thorny. The
fruit of the Canada buffalo-berry is harmless, but flat and taste-
less, and is either of a red or yellow color. The fruit of the
silver buffalo-berry is of a delicious flavor and is used by house-
wives in the Red river valley in the manufacture of jellies and
preserves.

Loosestrifes. The loosestrife family includes some insignifi-
cant herbs with opposite leaves and small axillary flowers, soli-
tary in the Rotala, aggregated in axillary clusters in the swamp
loosestrife, solitary again in the true loosestrife. The Amma-
nias and water-purslanes strongly resemble the water-starworts
in their superficial characters, but may be distinguished by their
flowers. They are, like the water-starworts, small aquatic or
mud-dwelling herbs, with opposite leaves and axillary flowers.
The water-purslane, indeed, has often been mistaken for the
water-starwort or water-fennel. In the water-purslanes and
Ammanias the calyx is bell-shaped with four notches at the
margin, but in the water-starwort there is no perianth what-
ever. The fruit of the water-purslane is a globular capsule with
two chambers, but that of the water-starwort is flattened and
deeply grooved on the flattened surfaces, dividing it into two
distinct portions. The Ammanias are larger herbs than the

334 Minnesota Plant Life.

water-purslane, but resemble the latter variety in general char-
acters. One variety of Ammania occurs in the state, and it
may be recognized by the opposite linear leaves, with clasp-
ing bases and sharp tips. From one to five flowers, the petals
of which soon fall from the bell-shaped calyx, are produced
in the axils of each leaf. In the water-purslane the flowers
are solitary in the axils of the tiny, opposite, slender leaves
and are very small, green and inconspicuous. The Rotala
resembles an Ammania in its larger size, varying from two to
six inches in height, but has the small axillary flowers of the
water-purslane. Unlike those of the water-purslane, they are
furnished with four small petals between the four lobes of the
bell-shaped calyx. The swamp loosestrife, which occurs in the
St. Croix valley, has stems from three feet to ten feet in length
and with whorls of willow-shaped leaves. The flowers are
nearly an inch in breadth and are clustered in purple cymes
in the axils of the whorled leaves. The Ly thrum, or purple
loosestrife, is a plant of low moist ground, with alternate, stem-
less, lance-shaped or oblong pointed leaves and purple flowers,
solitary in the upper axils. These plants are not uncommon
along low lake shores throughout the southern part of the
state. A most remarkable peculiarity of the loosestrifes is
the formation of very extraordinary structures in the cells of
the outer seed-coats. In some of the varieties each cell of the
layer which makes up the surface of the seed is provided with
a curious cork-screw-like apparatus, developed in its cavity and
capable of being turned out into the ground, where, together
with hundreds of other bodies of the same nature, it assists in
drawing the seed into the soil.

Evening-primroses and fireweeds. The evening-primroses
— the family to which the cultivated fuchsia belongs — include
two species, known as false loosestrifes, from their resem-
blance to the true water-purslanes. They have the same op-
posite leaves, axillary flowers and general habits of growth.
There are, however, four stamens, and capsules with four com-
partments instead of two. These false loosestrifes are rather
unusual plants of ditches, swamps and muddy banks in the
southern part of the state. To the evening-primrose family
belongs also the fireweed or willow-herb, abundant in two va-

Minnesota Plant Life. 335

rieties, especially in the northern part of the state on burnt-over
tracts. The fireweed is an erect herb, with purple flowers in
broad terminal racemes and willow-shaped leaves arranged alter-
nately upon the stem. The capsules split into four sections and
release the numerous seeds, covered with cottony hairs, by
means of which they are distributed abundantly in the wind.
Closely related to the fireweeds are three or four species of
willow-herbs with slender capsules packed full of small tufted
seeds. Here, too, should be classified the evening-primroses
and Ganras, with their fuchsia-like yellow flowers. Five or six
varieties of evening-primroses occur in different parts of the
state. The white evening-primrose is limited to the western
portion. The shrubby prairie evening-primrose is common
over the prairie district. The most abundant is the ordinary
evening-primrose of roadsides, known by its yellow flowers,
with four large petals and calyx growing up around the fruit-
rudiment and adherent to it The Gauras are rare herbs, or
half-shrubs, not abundant except in the southwestern districts.
They may be known by the fuchsia-like flowers, red in one
species — the scarlet Gaura — and pink in the other. The flow-
ers are smaller than those of the evening-primroses, but rather
larger than those of the willow-herbs.

Enchanter's nightshades. Two herbs of woodland districts,
known as enchanter's nightshades, are grouped in the evening-
primrose family. They are low herbs with the habits and
appearance of shade plants. Their leaves are opposite and
are more or less triangular. The small white fuchsia-like flow-
ers are borne in loose terminal racemes, and the capsules,
when they mature, are covered with hooked prickles. The
little pear-shaped burs that are found upon one's clothing after
an autumnal ramble in the woods will probably be the fruits
of the enchanter's nightshade. The two varieties of nightshade
may be distinguished by their size, one of them varying from
a foot to two feet in height, while the other is seldom over five
inches tall.

Water-milfoils. The plants known as water-milfoils include
five or six Minnesota species, of which the so-called mare's tail or
jointweed is the most striking in form. It is a slender, erect,
unbranched plant, found growing on wet mud or in the water.

336 Minnesota Plant Life.

and has a stem composed of joints like those of the well-known
scouring-rushes. At each joint, however, is a whorl of from
six to twelve green, lance-shaped leaves. The plant cannot,
therefore, be mistaken for a scouring-rush, for it has functional
foliage leaves. Another kind of water-milfoil is the mermaid-
weed, with two sorts of leaves. If the plant has grown partly
submerged, the leaves below the surface of the water will be
like feathers, while the leaves above will be oval and only slightly
notched. The flowrers are borne in the axils of the leaves above
the water and the fruit is triangular in cross section, with three
deep grooves. The true milfoils are exceedingly abundant in
the lakes and ponds of Minnesota. They may be recognized
by their jointed pale-reddish stems, with whorls of feather-
shaped leaves each with fine thread-like dissected lobes. The
flowers are borne in the axils of small, oval leaves, toward the
end of the stem, where it emerges from the water. The flow-
ering stem protrudes above the surface like the spike of a pond-
weed. No pondweed, however, has these whorls of feather-
shaped leaves. Three or four different varieties of water-mil-
foils occur within the state, and the plants need not be confused.
For the most part milfoils prefer deep water and are found grow-
ing along with pondweeds outside the lily-pad zone and on bars
or sandy bottoms.

The twenty sixth order includes three families, each of which
is represented by Minnesota forms. These are the ginsengs,
the parsleys and the dogwoods. The Minnesota forms of the
ginsengs and parsleys are all herbs, while the dogwoods are all
of them shrubs — one, the dwarf dogwood or cornel, being only
three or four inches high. The others, however, are shrubs
of good size.

Spikenards, wild sarsaparillas and ginsengs. To the ginseng
family belong five Minnesota species — the spikenard, the wild
sarsaparilla and wild elder, together with the ginseng or "sang"
and the dwarf ginseng or groundnut. The first three are char-
acterized by leaves made up of leaflets arranged as in the ash,
that is, the leaflets are pinnately grouped. In the last two the
leaflets are arranged as in the Virginia creeper — that is, pal-
mately grouped. The spikenard is a large herb, from three to
six feet high, with thick, sweet-scented root. The leaflets, ar-

Minnesota Plant Life.

337

ranged in pinnate groups, are developed in such manner as to
form one large three-branched leaf, of which there are several
upon the branching stem. The flowers are arranged in the
kinds of clusters known as umbels, characteristic also of the
parsley family. In the spikenard the umbels are massed to-
gether into a large panicled inflorescence. The fruits, forming
very large and ornamental bunches when ripe, are of a red-
purple color, globular in shape and not edible.

The wild sarsaparilla is not furnished with an erect, branch-
ing stem, but the leaves and flowering axes arise from a long,
underground rootstock. The flowers are produced at the apex
of the flowering axis in a
group consisting usually of
three umbels, arranged so as
to form a flat-topped cluster.
The fruit is purplish-black,
nearly spherical, and long-
itudinally grooved. The
wild elder has leaves like
those of the elder bush.
The umbels are numerous
and simple, aggregated to-
gether in groups towards
the end of the leafy, erect
stem, and the fruits are dark
purple, five-grooved when FlG" 1(

dry. The whole plant is more or less beset with slender bristles.
The two varieties of ginseng may be distinguished by their
leaves. In the true ginseng the leaves are made up of five
stalked leaflets, while the leaflets in the dwarf ginseng are ses-
sile and vary from three to five in number. In both plants the
leaves are arranged palmately, and in each there is a swollen
root — almost globular in the dwarf ginseng, and ovoid-tuberous
and sometimes branched in the true ginseng. The dwarf gin-
seng rarely exceeds six inches in height, but the true ginseng
may reach the height of a foot and a half. The flowers and
fruits are arranged in small umbels. In the true ginseng the
fruit is crimson, while in the dwarf ginseng it is yellow. Gin-
seng roots are commercially valuable on account of the use
which the Chinese make of the plant in their pharmacopoeia.
23

338

Minnesota Plant Life.

By American or European physicians the plant is not consid-
ered to be of any medical value whatever.

The parsley family. The parsley family in Minnesota in-
cludes about thirty-five species of herbs, very difficult to dis-
criminate without a technical examination of their peculiari-
ties. In all of them the flowers are produced in compound
or simple umbels, with the exception of the curious button-
snakeroot, which resembles in its appearance a one seed-leafed
plant much more than it does the other members of the pars-
ley family. In this the leaves are parallel-veined and grass-
like and the flowers are clustered in heads. Among the varie-
ties of parsley found in
Minnesota are two sorts
of pennyworts, two sorts
of black snake-roots, the
cow-parsnip, the hog-
fennel, the cowbane, the
w a t e r-h e m 1 o c k , the
meadow-parsnips and wa-
ter-parsnips, the hone-
worts, poison-hemlocks
and the sweet cicelys.

The plants have in this
family, for the most part,
compound leaves, but in
a few species the leaves
are simple, as in the button-snakeroots, the introduced hare's-
ear, the Zizias, and the pennyworts. In most of the forms the
leaves are compounded like those of the well-known water-
parsnips or wild parsnips. In all the varieties the fruit is dry
and consists of two carpels, which are at first united but finally
separate from each other along their faces, so as to produce two
half-fruits, in each of which a single seed is inclosed. There
are usually oil-tubes in the fruit, so that the odor of caraway
seeds is a peculiarity of most of the fruits in the family. It is
upon the characters of the mature fruit that the specific descrip-
tions are based, rather than upon those of the flower or of the
vegetative tract ; for the flowers, and to some extent the plant-
bodies, are very similar throughout great numbers of species
and genera.

FIG. 164. Water-parsnip. After Britton and Brown.

Minnesota Plant Life.

In the sweet cicelys the fruits are adapted for animal distri-
bution. They are elongated, pointed, armed with barbed hairs
and grouped in very loose umbels. These are common plant,
in the woods throughout the state, and the slender, pointed
seed, which attaches itself to one's clothing during a forest
ramble, is generally the half-fruit of one or the other species
of Minnesota sweet cicely. The snakeroots form little bur-

FIG. 165. Wild parsley. After photograph by Williams.

•

like fruits in loose, few-flowered umbels. These are, like those
of the sweet cicelys, intended for animal distribution ; but most
parsley fruits have smooth or ribbed surfaces and do not attach
themselves to animals. In some the fruits are winged to a
degree, and probably obtain distribution through the agency
of the wind. The roots of certain plants of the parsley family
are very poisonous, and to children eating those of the pois«m-

340

Minnesota Plant Life.

hemlock or of the wild parsnips or cowbane, they often prove
fatal. To the parsley family belong some garden vegetables,
such as carrots and parsnips. Here, also, are the plants fur-
nishing coriander and caraway seeds. The perfume, myrrh, is
obtained from a European variety.

Dogwoods. There are eight varieties of dogwood in Min-
nesota, all of them rather closely related. In dogwoods the

flowers are rather incon-
spicuous and borne in heads,
to be regarded as compact
umbels. In some of the
varieties about four large
white, petal-like leaves are
produced just below the
head of flowers, so that, as
in the sunflower family, the
whole head resembles a
single flower. Two Minne-
sota species have these
handsome white leaves be-
low the flower heads. One,
the dwarf cornel, or bunch-
berry, is a little shrub from
two to eight inches in
height, with the upper part
of the stem herbaceous.
The above-ground branch,
which is generally simple,
arises from a prostrate, slender rootstock. The leaves are ovate,
with several strong longitudinal ribs, and are clustered in a
whorl below the pedicel of the flower-head. In fruit the dwarf
cornel produces from each flower a little ovoid or spherical
stone-fruit of a scarlet color. The fruits are aggregated in
heads as the flowers were, and form characteristic red bunches,
giving occasion to one of the common names.

The other dogwood, in which conspicuous, white petal-like
leaves are clustered below the flowering head, has these leaves
very large, an inch or more in length, strongly notched at the
tip. Sometimes in this variety, known as the flowering dog-

FIG. 166. Water-hemlock. After Chesnut.
F. B. 86, U. S. Dept. Ag.

Minnesota Plant Life.

34i

wood, the petal-like leaves are pinkish, but more commonly
they are white. The bush occurs rather sparingly along the
Mississippi river, from Stearns county to the Iowa line. Its
fruits are very similar to those of the dwarf cornel but are a
little more elongated. They have the same scarlet color ami
cherry-like structure. In the rest of the Minnesota dogwoods,
including the shrubs known as red osiers and kinnikinics, the
flowers are larger and looser, cymose or paniculate, and not pro-
vided with the large, petal-like bracts beneath. The shrubs are
distinguished from each other by their foliage, the shape of their
flower clusters, the color of their twigs and the stones of their
fruits. The round-leafed dog-
wood, very abundant through-
out the state, is a bush from
three to ten feet in height,
much branched and furnished
with broadly ovate, entire-mar-
gined leaves. The fruit is of a
light blue color and has an al-
most globular stone. Closely
related to the round-leafed
dogwood is the silky cornel or
kinnikinic, distinguished by its
silky-haired twigs, quite differ-
ent from the green, smooth
twigs of the round-leafed dog-
wood. The fruit is of the same
light blue color, but the leaves
are somewhat slender, approaching in their shape ordinary plum
leaves. The rough-leafed dogwood grows a little larger than
either of its relatives which have been mentioned and may be
recognized by the reddish-brown, hairy twigs, the rough, hairy
upper surfaces of the leaves and the spherical, white fruits, in
which the stone is but slightly furrowed and not much flattened.
Bailey's dogwood is very similar in appearance, but has rather
narrower lance-shaped leaves and white fruits, in which the
stone is flattened and furrowed along the edge. The red osier
or kinnikinic is one of the most frequent varieties through the
northern and central portions of the state. It is a shrub from
three to fifteen feet in height, with bright red or purple. >mooth

FIG. 167. Dwarf cornel. After Britton and
Brown.

342 Minnesota Plant Life.

twigs, sometimes slightly hairy towards the tips. The leaves
are broadly ovate and the fruits are white, with stones of a
generally globose shape. This variety, together with the silky
cornel, is utilized by the Indians — under their name of kinniki-
nic — as an adulterant of tobacco. The inner bark of the twigs
is collected and dried, mixed with the tobacco and believed by
the Indians to improve its flavor. It should be mentioned that
the Indians apply the same name to other materials which they
use in a similar manner, as for example, sumac leaves. The name
of the Redwood river is said to be derived from the red osier.

The panicled dogwood is, perhaps, the most abundant species
in the southern and through the central portions of the state.
It is, like its relatives, a branched shrub, and has smooth, gray
twigs. The leaves are lance-shaped, with slender tips. The
fruits are white in color and have slightly furrowed stones.

All the dogwoods which have been described are character-
ized by opposite leaves. One other kind, the alternate-leafed
cornel, is not uncommon in Minnesota, except in the region
of the international boundary. As its name indicates, the leaves
are alternate. The fruit is of a blue color and has a channeled
stone. In the southern portions of its range this variety some-
times becomes a small tree, but in Minnesota it remains of
shrubby habit. The wood is heavy, close-grained and of a
reddish-brown color.

Most of these varieties of dogwood grow best in damp woods
or thickets and along the shores of lakes. The dwarf cornel,
however, is by preference an inhabitant of tamarack swamps,
where it is found along with wintergreens and lady's-slippers.
It is abundant, too, in the pine woods, particularly in shaded
places. The dogwoods are exceedingly beautiful shrubs when
disposed along broad lake beaches, where they select the back-
strand or mid-strand and often form handsome hemispherical
plant-bodies ten feet or more in height and fifteen feet in
breadth, growing regularly and looking as if they had been
trimmed by some careful gardener. Together with certain va-
rieties of willows which have the same habit of growth, they are
among the most noticeable plants of level lake shores, especially
in the northern part of the state. They abound, too, around
meadows and in the edges of woods or along streams.

Chapter XXXIV.

High Types and Low Types of Flowers.

There have now been passed in review the twenty-six orders
of two seed-leafed plants which agree in showing no fusions of
the petals of the flower into corolla tubes. Indeed, some of
them have no petals. But in such forms as produce flowers
with petals, the typical honeysuckle tube or morning-glory
funnel is not developed. A number of differences in flowers
and fruits have been recorded, and it may not be amiss, before
passing to the consideration of succeeding orders, to note briefly
the general law under which flowers vary from lower types to
higher. There is a distinction, pretty clear in the mind of the
botanist, between lower or simpler sorts of flowers and higher
or more complex kinds. The distinction does not, however,
consist in showiness, size, color, perfume or abundance. Con-
sidered botanically, some large and beautiful blossoms are lower
in type than other tiny, inconspicuous flowers that might almost
escape the observation of the amateur.

In order to understand the distinctions which have weight
with botanists it is necessary to remember from what sort of
structures flowers are believed to have developed. A proto-
type of all flowers is the pine cone — an aggregate-body is fore-
shadowed even among flowerless plants, notably by the club-
moss cones. It will be recollected that in club-mosses the
ends of many of the stems gathered their leaves more closely
together than elsewhere, and on the upper side of each of such
leaves was placed a little spore-containing sac. The cone of
the club-moss is an axis upon which spore-bearing leaves are
distributed. As has already been suggested, in the discussion
of the club-mosses, the primitive type of spore-bearing leaf had
also, as part of its duty in the plant economy, the starch-making
work of an ordinary leaf. But by a division of labor, some

244 Minnesota Plant Life.

leaves, especially toward the tips of branches — therefore raised
higher from the ground — devoted themselves particularly to
spore-manufacture, leaving the starch-making to lower leaves
on the stem. Naturally it was more important for the plant
to use, for spore-production, those leaves farthest from the
ground, because if produced at a height the spores could be
distributed over a wider area.

When the habit of making two kinds of spores became fixed
among the distant ancestors of modern seed-bearing plants, the
clusters of spore-bearing leaves or cones came, in the pines and
their allies, to be specialized, so that one cone devoted itself
to the manufacture of the small-spores while another produced
only large-spores in the little cases on its leaves. Thus there
originated the very different pollen-bearing and seed-bearing
cones, which may be observed in such plants as the white pine,
tamaracks and junipers. Probably, however, in some varieties
there was not this separation, upon their special axes, of the
two sorts of leaves; but one sort arose toward the tip of the
axis, while the other appeared lower down, so that mixed cones,
with carpels or large-spore-bearing leaves toward the tip, and
stamens or small-spore-bearing leaves toward the base of the
axis, originated. After the seed-habit had become fixed, it
is apparent that the same advantage which club-mosses de-
rived from having their spore-producing leaves highest on the
stem, would now be derived from having the seed-rudiment-
producing leaves, or carpels, highest on the stem. The advan-
tage of height above the substratum which was manifest in the
distribution of spores would be retained as favorable to the dis-
tribution of seeds. The primitive higher flowering plants no
doubt had their seeds distributed by the wind, and it was,
therefore, important, from the plant's point of view, that the
carpels should stand higher in the flower than the stamens.
This will account for the central position of the pistil and the
peripheral position of the stamens.

The crowding together of the leaves of the flower, which
became possible when they abandoned their starch-making
functions, may be seen foreshadowed even in the cones of the
club-mosses. It becomes still more marked in the pines, while
in flowering-plants the great majority have the cone or flower-

Minnesota Plant Life. ~*c

axis so short that it is actually flat or even depressed in the
centre, as in roses. To this rule, however, there are a number
of important exceptions, as for example, the little mousetail,
a member of the crowfoot family, with its elongated axis, upon
which the nutlets are produced. The anemones, also, and
some of the rose family, like the strawberry, have conical or
cylindrical floral axes upon which the carpels are distributed.
These elongated axes may not, indeed, in such instances, be
really primitive, but may rather be secondarily adaptive. Yet
the highest types of flowers do not have such long axes, but are
flat, with the carpels central and the stamens in encircling rings.
If, now, one can imagine a pine cone, the tip of which is com-
posed of seed-bearing scales, while at the base are disposed the
pollen-scales or stamens, and then imagine further that the tip
of this axis is pressed down with the thumb until the whole
becomes flat and saucer-like, it is apparent that the seed-bearing
scales will now be at the centre, while the pollen-bearing scales
will form a ring around the outside of the saucer. Precisely
such change in shape of the ancestral cone is believed to have
taken place in the plant world under the slow workings of
structural improvements through the ages. Many advantages
in flowers might be derived by the passage from the elongated
to the flattened type of axis. If, for example, the flower came
to depend for pollination upon insects, the flattening of the axis
might make the work of the insects surer, or if the flower
depended upon its own pollen for pollination, the bringing of
the stamens and the stigmas into the same plane would, per-
haps, facilitate the process. Of course the ancient prototypes
of flowers could not be expected to have these flattened axes,
because in them the division of labor between spore-producing
and starch-making leaves had not arisen, and each leaf on the
axis had to stand in such a position that it could get light for
itself from the sun without shading too much the other leaves
near by. Elongated flower-axes, like those of the pines, remind
one of earlier days, in which such axes had, in addition to their
production of spores, also a starch-making work to perform. Any
flower which retains in its structure the marks of earlier, less
improved conditions, is conceived in this respect to be of lower
type than one which has lost these marks, and this is the true

Minnesota Plant Life.

criterion of rank among flowers. Precisely the same thing is
apparent in human society, for a civilized man who retains char-
acteristics which may have been valuable to the savage but have
been outgrown during the progress of civilization, is regarded
as of lower grade than his fellows.

The flattening of the axis of the flower into a disk is pos-
sibly the most fundamental evidence of improvement; that is,
of passage from a lower to a higher type. Connected with
this flattening arose a rearrangement of the parts of the flower.
In the pine cone the scales are arranged spirally, just as if they
were foliage leaves, but in apples the stamens and carpels are
produced in whorls. A spiral arrangement of stamens and
carpels, because it is more like the fundamental grouping of
foliage leaves upon a stem, is believed to indicate a lower type
of flower than when whorls are substituted — a grouping not
so common among foliage leaves, but quite unobjectionable for
spore-producing leaves. Even among the pines the tendency
to gather the leaves of the flower into more compact clusters
may be seen in such plants as the junipers and red cedars.

Again, as flowers came to be blocked out as definite spore-
producing tracts, made up of leaves arranged on a shortened
axis, the leaves below the stamens became modified from their
proximity to the true floral parts. Thus the area known as
perianth came into existence. By a further specialization peri-
anth came to consist of outer perianth — that is, lower perianth,
or calyx, and inner — that is, upper perianth, or corolla. Under
such conditions what may be known as a typical flower ap-
peared, and such a typical flower may be described as an axis,
bearing essential leaves, viz., carpels and stamens, surrounded
by the accessory leaves of the calyx and corolla.

In all the four regions of the typical flower modifications
and improvements are possible. The carpels, for example, may
blend together into a single fruit-rudiment or pistil. Thus the
fruit of the lily is regarded as made up of three carpels blended
together. Such a blending would be regarded as an improve-
ment over the separate condition of the scales in the cones of
the pine. It is certainly farther removed from that primitive
arrangement in which, on account of their starch-making duties,
the leaves were necessarily separate. After having thus be-

Minnesota Plant Life.

come blended, conditions might arise, when, by the deep groov-
ing of the pistil, the carpels would again be separated and such
'a secondary separation won1-1, mark a higher type than the orig-
inal blended condition. It is sometimes difficult to tell whether
a separation of the carpels is primitive or secondary. In the
region of the stamens the separate leaves indicate a primitive
type, while the blending of the stamens into a tube, as in the
mallows, is regarded as an improvement, and consequently indi-
cates a higher type. Likewise the blending of the parts of the
calyx into a tube .is regarded as a modification of that original
condition in which the calyx leaves were separate.

Not only may parts of the same group blend with each other,
but they may also blend with the group next to them. Thus the
production, in orchid flowers, of stamens apparently springing
from the surface of the pistil is regarded as evidence of the
blending together into one body of what were originally sepa-
rate stamens and pistils. For this reason the orchid flower, in
which such a condition has arisen, is regarded as higher in type
than the lily flower, for in the latter the blending of stamens
and pistil has not been effected. A great many such blend-
ings exist. Sometimes the stamens are produced upon the
petals or upon the calyx leaves. Sometimes both the petals
and stamens seem to arise from the calyx, indicating a fusion
into one body of all three regions of the flower — a condition
evidently remote from the primitive type, and, therefore, indica-
tive of higher rank. Especially is the blending of the calyx
with the surface of the pistil regarded as an improvement over
the condition in which these two areas are quite distinct. Apple
flowers, for example, develop petals and stamens upon the
calyx and the latter is blended with the surface of the carpels,
giving an additional protective layer to the seeds and permit-
ting the important function of assisting in seed-distribution to
be borne by a part of the flower below the essential organs.
In willow-herbs, too, or fireweeds, the calyx is blended with
the pistil, and when the capsule is mature it consists of two
protective layers around the seeds instead of one. All these
blendings of parts indicate higher rank.

Another way in which flowers become modified from prim-
itive forms is by the development of differences between the

348 Minnesota Plant Life.

parts of the same area. The violet flower, with one of its petals
spurred, is conceived to be higher in rank than the linden flower,
in which all the petals are alike. Irregularity of the flower
marks some improvement over regularity, and it should always
be remembered that the irregular flower is irregular for a pur-
pose. The irregularity may be, and usually is, an adaptation
to the habits of the insects which effect pollination. There-
fore, the strongly irregular flowers of orchids, beautifully
adapted to the sizes, shapes, weights and feeding-habits of bees
or moths, are improvements over the regular flowers of tulips,
blue flags and trilliums. Irregularity may arise in a variety
of ways. A very common type is two-sidedness of the flower and
the substitution of the two-sided symmetry for the radial sym-
metry. Just as man, whose body can be divided into approxi-
mately equal halves by only one plane, is on this account a
higher structural type than the starfish, the body of which may
be divided into several approximately equal portions by planes
radially disposed, so the two-sided flower of an orchid, or that
of the pea or larkspur, must be regarded as structurally higher
than related radially-symmetrical forms, such as lilies, acacias,
lindens or buttercups.

Along with the development of upper- and under-sidedness
in the flower go a number of changes in the shapes, positions,
numbers and sizes of the floral organs. Thus in the pea flower,
one petal is larger than the others, and forms the so-called
standard. The other four petals, grouped in pairs, constitute
the so-called wings and keel of the flower. The stamens are
blended together into a tube, but one stamen in the plane of
symmetry stands distinct from the rest. The carpels, too, in
the pea flower become reduced in number and the pod is often
flattened in the plane of the symmetry.

There should be no difficulty in comprehending how a flower
that manifests in its whole structure a great departure from
the primitive type should be considered as higher than a flower
that approximates in its structure more closely to the early
conditions. It must be observed, moreover, that the different
orders of flowering plants do not constitute a single series of
advancement. One order may show improvement along one
path, while another shows improvement in quite a different

Minnesota Plant Life. 349

direction. In the same order the lower families may have reg-
ular flowers, while the flowers of the higher families have
acquired more specialized irregular shapes. The proper ar-
rangement of the orders is not one of sequence, but rather the
kind of arrangement that is seen in genealogical charts, or in
the trunks, main branches, secondary branches and twigs of a
tree. Grasses and sedges, for example, represent the perfection
of certain lines of development. Orchids represent the per-
fection of another line of improvement, and dogwoods occupy
relatively another terminal position. Yet it is possible in a
general way to regard the plant with two-leafed seedlings as
showing a higher type of embryo-structure than the plant with
one-leafed seedlings, and when the orders of plants are discussed
in sequence, the former group is considered, as a whole, subse-
quent to the latter. On this account, however, it should not
be supposed that willow flowers are of higher structural type
than orchid flowers, for orchids are among the most perfected
of plants with the lower type of embryo, while willows are
among the least perfected types with the higher kind of embryo.
In general, that higher class in which the petals are blended into
corolla tubes marks, in this respect, an advance over those plants
in which such blending does not exist. But it would be a
mistake to suppose that the flower of the cranberry is struc-
turally more complicated than the pea or the violet flower.
As in the case of the willows and the orchids just compared,
the cranberry belongs to one of the lowest orders of corolla-
tube-producing plants, while the peas and violets are relatively
high types of the generally lower series, in which no corolla
tubes are formed.

With this explanation of a somewhat difficult point — look-
ing toward an answer to the question, why is one flower con-
sidered of higher type than another? — there may now be dis-
cussed the eight remaining orders of two-seed-leafed plants
in which corolla tubes rather than separate petals are almost
universally the rule.

Chapter XXXV.

From Wintergreens to Choffweeds.

The twenty-seventh order includes six families, two of which,
the wintergreens and the heaths, are represented in Minnesota.
About twenty two species of heaths are native to the state.
Here are classified the huckleberries, cranberries, blueberries,
snowberries, bearberries, trailing arbutuses, checkerberries,
leatherleafs, Cassiopes, rosemarys, laurels, Menziesias, and Lab-
rador teas. To this family belong also the azalias, rhododen-
drons and heathers.

Wintergreens. The wintergreen family in Minnesota com-
prises nine or ten species of true wintergreens; the one-flow-
ered wintergreen, two pipsissewas or spotted wintergreens, the
pine-drops, the Indian-pipe or corpse-plant, and the pine-sap
or false beechdrops. The last three plants named do not
exhibit leaf-green but absorb their food from the humus of the
forest floor, taking up organic substances and manufacturing
no starch of their own. The others are green plants with
somewhat the appearance of the heaths, except that they are
not so shrubby. The wintergreens, from branched under-
ground rootstocks, produce upright stems usually less than a
foot in height. The flowers are commonly grouped in a single
slim terminal raceme, each flower nodding or erect in the
axil of a small bract or scale. In some of the varieties the flow-
ers have the stigmas and stigma-stalks bent down, while in
others the stigma projects in the centre of the flower.

The round-leafed wintergreen, very abundant in pine woods,
throughout the northern part of the state, has rounded or
broadly oval leaves, of a leathery texture, shining and ever-
green, and spreading out at the base of the straight, tall flower-
bearing axis. The flowers are white, rather large and sweet-
scented and are arranged, eight or ten together, in their ra-

Minnesota Plant Life. 35I

cemes. The green-flowered strongly resembles the round-
leafed wintergreen, except that the leaves are of a dull green
color above and the flowers are greenish-white with slight
fragrance. The shinleaf, unlike the two preceding species,
has papery rather than leathery leaves, and these are broad
and rounded with blades rather longer than their stems. The
flowers in this variety are greenish-white and very sweet-
scented. The bog wintergreen, found in cold peat-bogs, has
the leaves of the green-flowered wintergreen — that is to say,
they are broadly oval, leathery and of a dull green. The flow-
ers, however, are purple, thus easily distinguishing
this variety. The pink-flowered or heart-leafed
wintergreen is very similar to the bog wintergreen,
but may be recognized by the heart-shaped bases
of the leaves. The flowers are rose-pink or some-
times purple.

All the wintergreens mentioned have the stigma
depressed towards the under side of the flower.
The remaining varieties have central stig-
mas. The lesser wintergreen resembles
in most of its characters the green-flow-
ered, but has the thin leaves of the shin-
leaf wintergreen. The stamens do not,
as in the previous varieties, diverge from
the fruit-rudiment, but close around it in
the open flower. The serrate-leafed win- Fic.ies. wintergreen plant

n in flower. After Atkin-

tergreen has flowers very much like those son.

of the lesser wintergreen, but the leaves

are almost plum-leaf shape with teeth along the margin.

Besides the forms already noted, there are two others that
are but slightly different from the typical varieties. The round-
leafed wintergreen sometimes produces leaves red-veined or
red instead of shining green, and in this form it is known as
the red-leafed wintergreen. The serrated wintergreen, which
is usually from four to ten inches in height, with a number
of flowers in a one-sided raceme, may exist as a low plant,
less than four inches high, with from three to eight flowers
and rounded leaves. It is then known as the low serrated
wintergreen. The leaves of all the species are rather pleasant

352 Minnesota Plant Life.

to the taste. The fruits they mature are five-grooved spherical
capsules which split into five sections to release the small
seeds.

The one-flowered wintergreen has the same evergreen leaves
that characterize the ordinary varieties, but is peculiar for the
production at the end of a slender axis of a single, rather large,
drooping, white or pink flower, about six inches or less in
height. The leaves are almost round, with short stems, and
are gathered in tufts at the base of the flowering axis. This
variety of wintergreen is limited to the northern portion of the
state, where it occurs among the moss in deep balsam, spruce
or tamarack woods.

Pipsissewas. The two kinds of wintergreen known as pip-
sissewas or spotted wintergreens, if they are found in fruit can
be distinguished at once from the preceding forms. In the
other wintergreens, when the capsules open, the clefts are woolly
at their edges, but in the pipsissewas the clefts in the capsules
are not at all woolly. The rarer variety of spotted wintergreen
may also be known by its more willow-shaped leaves with
remote notches in the margins and by the disposition of the
white or pinkish flowers in cymes rather than in racemes. The
leaves in this variety are spotted with white along the veins,
but the commoner pipsissewa has bright, shining leaves without
spots, considerably shorter and broader than those of the rarer
kind. The flowers are clustered four or five in a group, in a
somewhat flat-topped inflorescence at the tip of their axis.
Both of these plants prefer drier woods and are sometimes abun-
dant under the pines. They appear also in hardwood timber,
but rather more sparingly.

Pine-drops. The pine-drops is a rare herb of the northern
part of the state. It forms an upright, unbranched slender stem
from six inches to three or four feet in length. This stem is
of a reddish or brown color, with a few scaly leaves which are
not green, since they make no starch. At the end of the stem
are numerous, nodding, bell-shaped white flowers, each arising
in the axil of a little scale. Each seed has a small thin wing
on the end. The root area is unusually small.

Indian-pipes. The Indian-pipe, otherwise called the corpse-
plant, is of very striking appearance. Several stems usually

Minnesota Plant Life.

353

grow together in a tuft, and the whole plant-body is commonly
of a snow-white color, with yellowish or reddish scales. At the
tip of each stem is a single, nodding flower, around which the
bracts are white. This variety is not uncommon throughout
the state and is to be looked for in deep woods where a rich
layer of decaying leaves has collected.

Pine-saps. The pine-sap, more abundant in the pine woods
and extending south to Gull lake and Taylor's Falls, resembles
the Indian-pipe or corpse-plant in almost all particulars, but it
may at once be identified by its having several flowers clustered
at the tip of each stem, instead of the single flower of the more
common variety.

The three plants last mentioned are quite fungus-like in their
habits of food-collection. Unlike most flowering plants, they
do not produce leaf-green. They may be described as plants
which have lost the power of making their own starch, and
have learned, through the cooperation of root-fungi, to take
their food in complex form from the decaying remains of other
vegetation. Structurally they are not very different from the
wintergreens, and so must be classed with them rather than
with the fungi, which physiologically they resemble. Winter-
greens are not the only kind of flowering plants that have
given rise to such types of fungus-like forms. Among the
orchids it will be remembered that the coralroots showed the
same tendency to take their food "ready-made" rather than to
manufacture it independently from carbonic-acid gas and water.

Labrador teas. An abundant variety of Minnesota heath
growing in bogs, especially through the northern part of the
state, is the Labrador tea. It is an evergreen shrub with leaves
shaped very much like those of the willow, green upon the upper
side and covered with a soft, rust-brown wool below. The
margins of the leaves are somewhat curled over toward the
under side. The flowers, borne in umbels, are white, and each
matures a five-chambered, oblong dry capsule, that splits from
the base into five segments. The plant abounds especially in
spruce swamps and among tamaracks. It is scarcely ab-
sent from a single spruce swamp in the state. A form, known
as the narrow-leafed Labrador tea, with much slenderer leaves
than the common species, grows along the Pigeon river in
24

354 Minnesota Plant Life.

Cook county. From this plant, which is fragrant if crushed, the
oil known as Leduin oil is manufactured.

Menziesias. The Menziesia is a small shrub, three or four
feet in height, with obovate deciduous leaves and pretty, nodding
umbels of bell-shaped, purplish flowers. The calyx and corolla
are generally four-lobed and there are eight stamens, while the
fruit is a spherical or ovoid capsule, splitting into four segments.

Kalmias. The laurel or Kalmia, occurs in cold peat-bogs as
far south as Gull lake. It is a little shrub, usually not more

FIG. 169. Kalmia flowers. After Atkinson.

than eighteen inches high, with opposite, linear, evergreen, pale
green leaves. The flowers, borne in terminal umbels, are purple
and broadly bowl-shaped, with five marginal notches and ten
stamens. The shape of the flower will serve to distinguish this
plant from the rosemary, which somewhat resembles it. On
the under side the leaves are white.

Moss-plants, The Cassiope or "moss-plant," is found along
the palisades north of Duluth, extending, doubtless, to Grand
Portage. It looks like a moss, being densely tufted, evergreen,
and only from one to three inches in height. The leaves are
very small and crowded, and the flowers are borne singly at the
ends of leafless pedicels arising from the tips of branches or

Minnesota Plant Life.

355

from the axils of the leaves. The flowers are white and nod-
ding, and each matures a spherical capsule with a large number
of small seeds. No other plant in Minnesota resembles, in
general habit, this tiny shrub.

Rosemarys. The rosemary, found in cold peat-bogs through-
out the northern part of the state, is a shrub one or two feet in
height, with few branches. The leaves are slender, willow-
shaped, darker above than those of the Kalmia, but with the
same white under sides and incurved margins. The flowers,
however, are nodding and vase-shaped, rather than erect!
spreading and bowl-shaped, as in the Kalmia. The capsule is
more nearly spherical than that of the Kalmia.

Trailing arbutus. The trailing arbutus is a rare plant in
Minnesota, occurring,
however, near Duluth
and on the Kettle river
and in the valley of the
St. Croix. It is a pros-
trate, trailing, branching
shrub, with alternate, ob-
long, leathery, evergreen,
entire leaves. The blos-
soms are pink, borne in
clusters toward the ends
of the branches. They
are sweet-scented and mature into spherical, furry, five-cham-
bered capsules.

Checkerberries. The checkerberry, an abundant plant in
the pine woods throughout the northern part of the state —
rarely extending, also, as far south as Lake Pepin — is a little
shrub with slender, prostrate or underground stems, from which
erect branches arise to a height of from two to six inches. Its
leaves are oval, slightly toothed, evergreen and shining, dark
above and paler beneath. The flowers nod in the axils of the
leaves and are white, broadly vase-shaped, and with five mar-
ginal teeth. The fruit is bright red and of a distinctive agreeable
flavor. This plant is also known in Minnesota as wintergreen
and partridgeberry.

Bearberries. The bearberry, growing best on sandy soil, is
abundant through the northern part of the state and extends

FIG. 170. Moss-plant. After Britten and Browi

356 Minnesota Plant Life,

south very sparingly to Winona county. It is a little trailing
shrub, with leathery entire, evergreen, spoon-shaped leaves and
a few small, white, vase-shaped flowers in terminal racemes.
The berries are red and rather tasteless.

Leatherleafs. The leatherleaf occurs in cold bogs from the
north shore of Lake Superior to Lake of the Woods, and south
into the valley of the St.. Croix. It is a branching shrub,
usually about two feet in height. The leaves are evergreen,
oblong, ovate in shape, and when young provided with scurfy
hairs or scales on both sides. The flowers are produced in large
numbers towards the ends of the branches. Each flower nods
in the axil of a leaf, is white and urn-shaped and produces a
spherical, deeply five-grooved fruit.

Blueberries and cranberries. The blueberries and cranber-
ries, of which there are about eleven varieties in the state,
include some well-known forms. Here are to be classified the
bog huckleberry, the dwarf bilberry, the thin-leafed bilberry,
the tall bilberry, the tall blueberry, the Canada blueberry, the
low blueberry, the mountain cranberry or cowberry, the deer-
berry, the small and the large cranberry. Most of these are
found only in the northern part the state, especially along the
international boundary and the north side of Lake Superior,
extending, as so many northern plants do, down the valley of
the St. Croix, through which in early days Lake Superior
drained into the Mississippi river.

Blueberries. The different kinds of blueberries or bilberries
are to be discriminated by their foliage and by the flavor of the
berries. The one most common is the dwarf or low blueberry,
gathered in large quantities for the market. Its fruits are
blue with a whitish bloom and are of very pleasant flavor,
enjoyed alike by the Indians and the whites. The plant is a
low shrub, with pale green leaves, not evergreen. Its flowers
are vase-shaped, small, and white or pink.

The deerberry, which resembles the blueberry in some re-
spects, is considerably larger — three or four feet in height. The
berries, shaped like the blueberries, are greenish or yellow and
not edible. This variety is also called the squaw huckleberry.

The Canada blueberry, found growing in much moister soil
than the ordinary form, has smaller berries, of a blue color, with

Minnesota Plant Life.

357

a bloom. It may be distinguished by the entire margins of
the leaves, quite different from the notched margins of the low
blueberry. The bog blueberry has pink flowers and small ovate
leaves. The cowberry may be recognized by the sour red
berries and the evergreen leaves. The flowers and fruits are
in structure altogether similar to those of the blueberries.

Cranberries. The two kinds of cranberries found in the
state are both bog plants, with very slender creeping stems,
having small thick evergreen leaves apparently disposed in
two rows along the
branches. In the small cran-
berry the berry is almost
spherical, while in the large
cranberry an oblong or
ovoid berry is produced. In
the flowers the corolla lobes
are turned backward toward
the stem. By this character
the cranberries can be dis-
tinguished from the cow-
berry, which has a bell-
shaped flower. Both spe-
cies of cranberry are red
or spotted, and acid to the
taste.

Snowberries. The snow-
berry has a plant-body which reminds one of that of the cran-
berries, but the flowers are ovoid vase-shaped, and the fruit is
of a pure white color. Like the cranberries, they are found in
cold peat-bogs and in tamarack swamps. This plant is partic-
ularly abundant in the region about Duluth.

Huckleberries. One variety of huckleberry is found between
the Kettle river, Cass lake, and the international boundary.
The plant-body reminds one of the blueberry, but the fruits are
black, without a bloom, sweet to the taste and clustered in
erect or nodding racemes.

Primroses. The twenty-eighth order comprises three fami-
lies of plants, of which only one, the primrose family, is repre-
sented in the state. Of primroses there are fourteen or fifteen

FIG. 171. Small cranberry. After Britton and
Brown.

358 Minnesota Plant Life.

Minnesota species, including two varieties of primrose, one An-
drosace, one water-pimpernel, two loosestrifes, the curious little
sea-milkwort, the poor man's weather-glass, and the chaffweeds.
Besides, there is a plant known as the starflower and another
as the shooting-star, both to be classed in this family. The
true primroses are found only along the north shore of Lake
Superior. They are small plants, with a tuft of rather long,
willow-shaped leaves, from the centre of which a stem arises,
bearing at the tip a little umbel of pink flowers.

The Androsace is a tiny plant, often not more than an inch
in height. It is of about the same size as the little whitlow-
grass of the mustard family. The leaves are produced in
rosettes. From these slender flowering axes arise, usually more
than one, and at the end of each of them is an umbel of small
white flowers. This plant may be distinguished from the whit-
low-grass by its umbels in place of racemes. It is more com-
mon on prairies in the western part of the state.

The water-pimpernel grows near springs and in the edges
of brooks. It is from six to eighteen inches in height, some-
what branched, with membranous oval leaves. The flowers
are tiny and bell-shaped, produced numerously in loose racemes.
The calyx is blended with the base of the fruit-rudiment and
the seeds are very small. The loosestrifes and the false loose-
strifes grow for the most part in wet places or in fields, and
may be recognized by their bright yellow, primrose-like flow-
ers. In some of the varieties the leaves are in whorls, while
in others they are opposite. The flowers in some sorts are
solitary in the axils of the leaves, but in others they are in
terminal racemes or flat-topped clusters. In one kind, the
tufted loosestrife, a swamp plant abundant throughout the state,
the yellow flowers are grouped in dense racemes which stand
in the axils of the opposite, willow-shaped leaves.

The starflower grows in deep woods along with the dwarf
cornel and the wintergreens. It is a little plant with prostrate
rootstock from which a slender stem rises to a height of about
six inches or less. Two or three white star-shaped flowers are
produced from the tip of this stem and directly under them are
from five to ten willow-shaped, slender leaves, all standing in
a circle.

Minnesota Plant Life.

The sea-milkwort is found in some saline marshes in the Red
river valley. It is a small, branched herb, with opposite, fleshy
leaves, in the axils of which small, stemless, pink or white flow-
ers are produced. Each flower is broadly bell-shaped.

The poor man's weather-glass or scarlet pimpernel is intro-
duced from Europe, in some waste fields. It has the opposite
leaves and open tubular flowers of its family, but the color of
the flowers, which are produced singly on the stems in the axils
of the leaves, is scarlet or pink with a darker centre. They
open only in the sunshine, hence the common name.

The chafrweed, to be met with at the Pipestone quarry in
Pipestone county and probably elsewhere on rocks in the Min-
nesota valley, selects moist depressions and grows as a little
branched, insignificant herb with small, alternate entire leaves,
in the axils of which little pink, stemless flowers are produced.
The capsule, when it matures, splits by a circular cleft, cutting
off its upper portion as a lid, recalling the purslanes.

The shooting-star may be recognized at once among all the
other flowering plants of the state by the curious position
which the petals take in the open flowers. The young flowers
are erect, but as they grow older the flower is inverted. When
they open the petals turn completely back, so that while the
stamens point downward, the petals, which are of a purple or
whitish color, have their tips directed upward. When this plant
begins to set its fruits, the stems of the flowers straighten again,
so that the tips of the young capsules point upward. The petals
of the open flower are often twisted, giving to the plant a
peculiar and characteristic appearance.

Chapter XXXVI.

From Ash trees to Verbenas*

The twenty-ninth order includes four families, none of which
is native to Minnesota. Here are grouped the persimmon trees
of the south, the benzoin gum trees, the gutta-perchas and the
butter seeds, and the ebony tree, the hard black wood of which
is capable of taking a high polish and is much prized.

The thirtieth order includes the ashes, the gentians, the dog-
banes and the milkweeds, all represented in the Minnesota flora.
There are also two other families without Minnesota represent-
atives, in one of which is classified the strychnine plant.

The ash family, besides the common ash trees, comprises
also the lilac bushes, the olive trees and the jasmines. Lilac
bushes, with their handsome panicles of fragrant tubular flowers,
are well known as dooryard shrubs throughout the state. They
are not, however, natives of North America.

Of ashes there are five species in Minnesota, namely, the
white, the red, the green, the blue and the black. Ash trees,
botanically considered, are noteworthy as being the highest
type of trees native to the state. In all of them the leaves are
compound, consisting of several leaflets arranged pinnately
upon a common axis. The fruit in all the varieties has a strong
terminal wing, by means of which it is distributed in air cur-
rents. The different kinds of ashes may be known by the
foliage, the character of the wing on the fruit, and the appear-
ance of the young twigs.

White ashes. The white ash is a tree, reaching under fa-
vorable conditions a height of 120 feet, but not growing so
strongly in Minnesota. The bark is dark brown and the wood
is heavy, firm and tough, universally employed in the manu-
facture of tool handles and agricultural machinery. The leaves
are composed usually of seven leaflets, somewhat broadly willow-

Minnesota Plant Life.

shaped, dark green above and light green and often hairy below.
The body of the fruit is cylindrical and the wing is terminal,
not at all or but very slightly extended down the sides.

Green ashes. The green ash is a smaller tree than the white
ash, and its wood is somewhat inferior in quality, though strong.
The leaflets are similar to those of the white ash, but rather
broader. The fruit is commonly winged down the sides. The
twigs and the flower stems are smooth or only very slightly
hairy.

Red ashes. The red ash is a tree of about the same height
as the green ash, not exceeding thirty or forty feet in Minne-
sota. The twigs and flower stalks are covered with velvety
hairs and the fruit is generally winged down the sides.

Blue ashes. The blue ash may be recognized by the four-
sided young twigs, the smooth foliage and the leaflets — num-
bering from seven to eleven, — slender and of a more willow-
shaped outline than in the preceding varieties. The fruit is
broader, shorter and heavier in appearance than that of the
white ash, and is winged down the sides.

Black ashes. The black or elder-leafed ash, unlike the oth-
ers, is a swamp tree, occasionally growing also in low, wet
woods along streams. There are from seven to eleven leaflets
in each leaf, but the twigs are cylindrical, not four angled. Both
the blue and the black ash are large trees, sometimes reaching a
height of a hundred feet or more. The bark in both varieties
is of a gray color. The wood of the black ash is heavy but not
very strong, and the tree is noticeable for the stemless character
of the lateral leaflets, in which respect it differs from all the
other ashes. This tree is often affected by an insect which pro-
duces large "witches-brooms" or galls.

Ash flowers are rarely perfect. Usually they are separated,
the staminate flowers blooming on one tree and the pistillate
on another, though in other instances both separated and per-
fect flowers are found on the same tree. The calyx is small,
or it may be altogether wanting. The corolla, too, is some-
times lacking. There are usually two stamens inserted below
the fruit-rudiment, or on the base of the petals when they are
present, and the stigma is two-cleft, so that the fruit-rudiment
has two chambers, in each of which a couple of seed-rudiments

Minnesota Plant Life.

are produced. Only one of the seed-rudiments ripens, so that
when the fruit is mature it ordinarily contains but a single seed,
supplied with albumen, and inclosing the straight embryo plant-
let. The flowers are borne in panicled clusters and are of a
greenish color. All five varieties, except the blue ash, are pretty
common in Minnesota. The white ash and the green ash are
the most abundant. The red ash abounds particularly down
the upper Mississippi to the White Earth reservation, and on
the Rainy river. The blue ash is found only in the far northern
portions of the state along the international boundary and

near the sources of the Mis-
sissippi.

Gentians, The gentian
family includes in Minne-
sota about ten species of
gentian, one spurred gen-
tian, one buck-bean and one
f 1 o a t i n g-heart. The two
plants last named are either
aquatic or denizens of wet
bogs, but the others are
terrestrial. The gentians
proper are noted for their
beautiful blue flowers,
blooming late in the year.
Two of the ten varieties are
known as fringed gentians,
because the edges of the
lobes of the corolla tubes are frayed out into a blue fringe.
The larger fringed gentian has opposite, stemless, broad-based
leaves. The smaller fringed gentian has leaves slender at the
base and narrower, of willow-shaped or linear outline. The
other gentians are not fringed. In some the flowers open
into little blue bells, but in one, known as the closed gentian,
the corolla does not open at all, or only by a small pore.
Of those that open, the northern gentian may be recognized
by the row of ragged threads which arise just below and in-
side the notches of the corolla tube. The leaves are oppo-
site and lance-shaped. The stiff gentian and the oblong-leafed

FIG. 172. Yellow gentian. After Britton and
Brown.

Minnesota Plant Life.

gentian are very similar, but have not the shredded filaments
in a circle within the lobes of the corolla. The oblong-leafed
gentian has between each of the five notches of the corolla
tube a little ragged, toothed appendage. The plant-body is
smooth. The downy gentian is quite similar to the oblong-
leafed, but may be known by its solitary stems, while those of
the oblong-leafed gentian are clustered. In all the sorts that
have been mentioned the stamens are distinct and spreading.
In the remaining varieties the stamens bend together and co-
here by their tips into a ring around the fruit-rudiment. The
soapwort gentian is a form with the flowers of the closed gen-
tian and opening but slightly at the tip. The leaves are oppo-
site, but in the closed gentian they are in whorls around the
clustered flowers. The yellow gentian produces its bell-shaped
flowers at the ends of stems or in the axils of upper leaves,
quite after the mode of the closed gentian, but they are of a
greenish or yellowish white instead of blue. The narrow-leafed
gentian somewhat resembles the downy variety, but may be
distinguished by the coherence of the stamens in a tube. The
leaves are slender and willow-shaped. The red-stemmed gen-
tian is like this, with broad-based, lance-shaped leaves.

Many of the gentians are found in bogs or in moist meadows.
In the autumn of the year, together with Parnassias, they form
extensive beds in the low wet meadows along river valleys. The
spurred gentian has a spur at the base of each of the corolla
lobes, making the flower somewhat of the shape of a colum-
bine. They are rather smaller, however, and of a purplish or
white color. This plant is found along the north shore of Lake
Superior and throughout the northern part of the state to Lake
of the Woods.

Buck-beans. The buck-bean is a pretty common plant on
floating bogs and among the reed-grasses along the shores of
lakes. From a thick, scaly rootstock stems arise, bearing leaves
in shape somewhat like large clover leaves and of a pale green
color. The flowers are borne in panicles and are white or
purple, decidedly attractive in appearance. This plant is fre-
quent in the Chisago lakes and generally throughout the state.
In the northern lakes it becomes very abundant and is often

364 Minnesota Plant Life.

found growing luxuriantly in great beds almost to the exclu-
sion of other vegetation.

Floating-hearts, The floating-heart is an odd little water
plant with a rootstock that creeps in the mud at the bottom
of ponds. There are two sorts of leaves. Those which are
submerged are grass-like and clustered around the base of the
stems, which are thread-like and sometimes ten feet in length.
At the surface of the water there is borne a single broadly heart-
shaped floating leaf, a little umbel of yellow flowers, and a clus-
ter of curious tubers. No other plant in the Minnesota flora is
anything like the floating-heart in appearance. The grouping
of a bunch of tubers, an umbel of yellow flowers, and a single,
broad heart-shaped floating leaf at the end of a slender stem aris-
ing from the bottom of a pond will serve at once to designate it.

Dogbanes, Three species of dogbanes exist in the state.
One of them is known as Indian hemp. All of them have
a milky juice, so that they are often mistaken for milkweeds.
They may be recognized, however, by their flowers, which are
somewhat bell-shaped and do not have the five singular, horn-
like appendages of the petals distinctive of most milkweed-
flowers, and connected with the remarkable pollination-con-
trivance of that family of plants. One of the dogbanes — more
abundant in the northern part of the state — has a spread-
ing, generally forked stem, with opposite broad leaves, and,
in loose terminal cymes, white flowers which mature slender
cylindrical pods. In these are enclosed a large number of seeds
with tufted flying-hairs at their ends. The Indian hemp sends
up erect branches, but not broadly forked at the summit like
those of the spreading dogbanes. The flowers are produced
in rather thick clusters at the apex, or arise from the axils of
the leaves. Still another variety of dogbane, with clasping
leaves, occurs in the southern part of the state.

Milkweeds. The milkweeds form a family of plants with pods
and seeds like those of the dogbanes, but with most extraordi-
nary flowers, gathered in most instances in umbels, and fitted for
pollination by insects. These are captured by the flowers, as if
in a trap, after which pollen masses shaped like the old-fashioned
saddle-bags are attached to their legs. In Minnesota there are a
dozen species of ordinary milkweeds and five green milkweeds.

Minnesota Plant Life.

365

Each milkweed flower consists of a five-parted calyx, usually
small. Within, there appear the five corolla lobes, turned back
around the pedicel of the flower when it opens. Next are five
curious hood-shaped appendages of the corolla, known as the
corona. Inside of each hood is a horn-shaped process, while
the stamens fuse together into a tube around the central
fruit-rudiment. When an insect visits the flower in search of
honey, it catches its legs in grooves between the hoods of the
corona, and in attempting to escape must drag its feet over a
part of the stamen where a viscid forked body is located, and this
with a couple of pollen-masses attached to it is pulled out of
the flower. By means of a bit
of silk thread any one can, with
proper care, extract the little
saddle-bag, thus imitating the
work which the flower exacts
from its insect visitor. Often
bees are not strong enough to
jerk their legs free from the
cleft in which they are caught,
and they may sometimes be
seen hanging head-downward
from the milkweed flower, de-
spondent or dead.

The different sorts of milk-
weeds in Minnesota may be
identified by the shapes of
their leaves, the colors of their
flowers and the surfaces of their pods. One milkweed, com-
mon on prairies, has bright orange flowers, and this sort is
known as the butterfly-weed. Its leaves are alternate and hairy
and the pods stand erect and are covered with fine hairs.
Another group of milkweeds has the flowers purple and the
leaves opposite. Here are classified the purple milkweeds,
with stout, smooth stems two feet or more in height and leaves
of an elongated, pointed oval shape. They are found in dry
fields. The swamp milkweed is similar in appearance, but has
smaller clusters of flowers and slenderer willow-shaped leaves.
usually quite smooth. It is to be looked for in swamps or

FIG. 173. Swamp milkweed,
and Brown.

After Britton

;65

Minnesota Plant Life.

marshes. The hairy milkweed is similar to the swamp milk-
weed and is found in similar stations, but has very hairy leaves.
In all varieties the umbels of flowers are crowded toward the
top of the plant and are erect, as are the pods.

Sullivant's milkweed and the blunt-leafed milkweed are
smooth, pale green plants with stout stems and rather broad,
blunt leaves. The capsules in Sullivant's milkweed are borne
on straight erect stems, but in the blunt-leafed milkweed the
downy, slender capsules stand on stems curved downward like
the letter "S." The tall milkweed, or poke milkweed, has
lance-shaped leaves and the capsules stand erect upon pedicels
which grow diagonally downward. The four-leaved milkweed

is recognized
by the leaves
toward the mid-
dle of the stem,
standing in
whorls of four.
Two m i 1 k -
weeds, known
as the common
milkweed and
the showy milk-
weed, are dis-
tinguished by
the pods, the
surfaces of

which are covered with short, soft, somewhat elongated tufts
or warts. The common milkweed has oblong leaves, while the
showy milkweed, named on account of the large purplish-green
flowers, has broad, ovate leaves. Both these are very prolific
in fields along roadsides and in damp places throughout the
state. The oval-leafed milkweed is a plant of the southern and
western prairies. It is recognized by its smaller, greenish
flowers arranged in few or in solitary umbels toward the tip
of the stem. The leaves are rather broadly willow-shaped and
cottony on both surfaces. When quite mature the upper sur-
faces of the leaves become smooth. The whorled milkweed
has very narrow leaves in whorls of from three to seven. The
pods are slender, two or three inches long, and smooth.

FIG. 174. Brookside vegetation. Milkweeds in foreground. After
photograph by Williams.

Minnesota Plant Life.

36?

The green milkweeds may be distinguished by this character:
The hoods of the corona do not inclose spur-like projections.
Otherwise the flowers, flower-clusters and pods are very much
like those of the true milkweeds. Here are classified the broad-
leafed green milkweeds, with lance-shaped or broad willow-
shaped leaves; the Florida milkweed, with slender, willow-
shaped leaves, difficult to distinguish from the two varieties of
the broad-leafed form — in one of which the leaves are really
grass-shaped, while in the other they are lance-shaped. The
broad-leafed milkweed and its varieties have, however, sessile
umbels of flowers, while the Florida milkweed displays each
umbel on a stem of its own. Besides the varieties of green
milkweed which have been mentioned, there is another known
as the woolly green milkweed. It is characterized by a solitary
terminal umbel and woolly or hairy leaves, and is found on
prairies.

The thirty-first order includes a number of families, most
of which are represented in Minnesota. Here are the morning-
glory family, to which the morning-glories, sweet potatoes and
dodders belong ; the phloxes ; the waterleafs ; the borages ; the
verbenas; the mints; the nightshades, including the ground-
cherries, capsicums, potatoes, tomatoes, tobaccos and petunias ;
the figworts, with the snapdragons, mulleins, hyssops and fox-
gloves ; the bignonias, with the catalpa trees ; the broom-rapes,
a curious group of parasitic plants ; the Gesneras, to which the
Gloxinias belong; the bladderworts ; the Acanthuses; and the
lopseeds. Several families, including some of those mentioned,
have no species native to Minnesota. The following, however,
present Minnesota forms : The morning-glories, phloxes, wa-
ter-leafs, borages, verbenas, mints, nightshades, figworts, broom-
rapes, bladderworts and lopseeds.

Morning-glories. The morning-glory family is represented
in Minnesota by three species of morning-glory or bindweeds
and five species of dodder. The morning-glories are recog-
nized at once by their familiar funnel-shaped flowers. In two
of the varieties the stem is twining or trailing, while in the erect
morning-glory it stands independently and does not twine.
except sometimes very slightly at the tip. One of the climb-
ing morning-glories has arrow-head-shaped leaves and pink

368

Minnesota Plant Life.

flowers about two inches long. The other variety has ovate,
blunt-pointed leaves, often very large and somewhat heart-
shaped at the base. The form with the arrow-head-shaped
leaves is much more common and is found trailing over shrub-
bery in thickets or in the edges of woods.

Dodders. Dodders are very curious parasitic plants, closely
related to the morning-glories. They may be considered as
twining morning-glories which have acquired the habit of suck-
ing up their food
from the bodies
of the plants
upon which they
climb. As a
consequence of
this habit their
leaves have been
reduced to tiny
scales, being no
more employed
in starch-mak-
ing, and their
stems, no longer
green, have be-
come yellow or
white in color.
Dodder often
produces great

FIG. 175. Dodder in flower; the parasite is seen to be clutching

tightly the stem of its host plant. After Atkinson. of threads, like

so much yellow

yarn, looping over the herbs or shrubs from the tissues of which
they extract their nutriment. Another variety of dodder that
grows on the stems of sunflowers, goldenrods and asters, looks
like three or four turns of rope around the axis of the host plant.
The relationship of the dodders to the morning-glories may
be seen in their capsules and seeds which strongly bring to
mind the well-known pods of the ordinary cultivated morn-
ing-glory. In Minnesota the following varieties of dodder may
be distinguished: The field dodder, with sepals of the calyx

Minnesota Plant Life.

369

united into a tube, sessile flowers, fringed corolla scales and
obtuse calyx lobes, the stems pale yellow and thread-like, with
the flowers in little clusters ; the smartweed dodder, most abun-
dant on smartweeds, similar to the field dodder, but with the
thread-like stems of an orange-yellow color and the calyx lobes
acute; Choisy's dodder, developing stemmed flowers with dis-
tinct corollas, the lobes of which are curved in over the capsule ;
the hazel dodder, growing mostly upon hazel bushes, with cap-
sules capped by the shriveling corolla ; the button-bush dodder,
with corolla lobes spreading, not curved over the capsules, and
the capsule flattened and globular in form ; and Gronovius'
dodder, found, like the button-bush dodder, on a variety of
herbs and shrubs, but with pointed capsules. In all these dod-
ders the flowers are in rather loose clusters, when compared
with the remaining variety, known as the massive dodder. In
this species, occurring mostly on goldenrods, asters, sunflowers
and other herbs of the composite family, the flowers are borne
in very large numbers and very close together, quite concealing
the stem. The little dodder flower-clusters, therefore, give the
appearance of a coil of rope, turned three or four times around
the axis of the host-plant.

The stems of all the dodders have sucking organs which
are driven through the skins of their host-plants and expose
their surfaces in the soft tissues. Through them the juices of
the host-plant are absorbed for the benefit of the dodder. This
kind of parasitism is derived from the habit of twining orig-
inated by those prototypes of the dodders, the morning-glories.
It is interesting to notice just how the parasitic habit probably
arose in this instance, because, in others, parasitism began in
quite different ways.

Phloxes. The phlox family includes the Greek valerians,
phloxes, Gilias and Collomias. In all the Minnesota varieties
the flowers are tubular, with the lobes of the corolla spreading.
The fruit-rudiments are three-chambered, maturing into three-
chambered capsules. Four sorts of phlox occur in Minnesota:
The wild sweet-william, the downy, the blue, and the smooth
phlox. They are distinguished by the shapes and textures of
their leaves and by the colors of the flowers.
25

370

Minnesota Plant Life.

In the blue phlox the flowers are blue and each petal lobe
is notched at the end. The other phloxes have pink, white
or purple flowers. Of them, the downy phlox is soft, velvety,
hairy or downy to the touch. The smooth phlox is quite
smooth with pink flowers and the lobes of the corolla are longer
than the tube. The wild sweet-william, or common phlox,
looks like the smooth phlox, but has flowers in which the lobes
of the corolla are considerably shorter than the tube. In all
the phloxes the leaves are simple, not lobed. The Polemonium
has the flowers of a phlox, blue in color; but the leaves are
pinnately compound like those of the ash. It is an herb

about a foot high, with weak
ascending stem arising from a
short rootstock. The Collomia
has flowers of the phlox type,
ag"gre§"ated in clusters at the
tips of the stem. They are
purplish or white, but the
leaves are alternate, not oppo-
site as in the phloxes. The
little Gilia of the western edge
of the state, where it is found
on high prairies near Lake
Benton, is a tufted plant with
flowers in dense heads, each
provided with a calyx, the
lobes of which are awl-shaped
and come up around the co-
rolla like five stiff bristles. The leaves are small, pinnate and
spiny.

Waterleafs, The waterleaf family includes two waterleafs,
one Ellisia and two Phacelias. The waterleafs are herbs with
large, pinnately cleft leaves and violet or purplish flowers devel-
oped in umbels or cymes. They are exceedingly abundant on
the level, damp floors of woods along streams through the south-
ern part of the state. The Virginia waterleaf has the stamens
a good deal longer than the corolla and the stamen-stalks are
hairy. The other waterleaf, called the appendaged waterleaf,
has stamens but very little longer than the corolla. Another

FIG. 176. Virginia water-leaf
and Brown.

After Britton

Minnesota Plant Life. .

way of distinguishing the two varieties is by the calyx which
in both is five-notched, but in the appenclaged waterleaf a
little scale grows out of each of the calyx notches, while this
scale is absent in the Virginia waterleaf.

The Ellisia is an herb, four inches or so in height, with leaves
a couple of inches long, deeply pinnately-lobed, shaped some-
what like those of the shepherd's-purse. The flowers are borne
singly on their stems, and are white and bell-shaped. In fruit
the calyx enlarges and looks like a small paper star, in the
middle of which the globular capsule is attached. The two
Phacelias, both very rare plants in Minnesota, have leaves some-
what like those of the Ellisia, but with purple or blue flowers
in clusters. One sort has them in terminal racemes, on both
sides of which the flowers are borne. In the other kind the
flowers are all grouped on one side of the raceme.

Borages. The borage family includes the comfreys, false
gromwells, puccoons. lungworts, forget-me-nots, stickseeds,
hound's-tongues and mudworts. Several of the varieties are
introduced from Europe. There are, in all, about twenty-five
varieties growing wild within the limits of the state. Borage
flowers, in outward appearance, are a good deal like those of
the phlox, though often very much smaller. The stamens are
borne upon the tube of the corolla and the fruit-rudiment, made
up of two carpels, is deeply grooved, so that when the fruit
matures it has the appearance of four one-seeded nutlets stand-
ing close together within the calyx. The leaves are generally
alternate. The stems are rarely square, but in almost every in-
stance cylindrical. The whole plant-body is commonly hairy,
sometimes very much so. Plants with the sort of tubular, flaring-
topped flowers, found in the sweet-william, and accustomed
to ripen four little hard nutlets from each flower, may pretty
safely be put down as borages, unless their stems are square,
in which instance they should be looked for in the mint family.

Hound's-tongues. The hound's-tongue is a weed of waste
places and woods, with stems from one to three feet in height.
The flowers are blue or reddish-purple and occur in somewhat
flat-topped clusters. Another sort of hound's-tongue, with
much slenderer, almost willow-shaped leaves, is an immigrant
from Europe. Its flowers are arranged, in most instances, in

372 Minnesota Plant Life.

one-sided racemes, and these clusters show a tendency to bend
over like a shepherd's crook.

Stickseeds. The stickseeds are very abundant plants in the
Minnesota woods. Four or five varieties exist, distinguished
by the shapes of their leaves and the character of the flower-
clusters. In all of them the four nutlets, which constitute each
fruit, separate from each other, and on their backs carry a num-
ber of barbed hairs, or thorns, by which they attach themselves
to the fur of animals, or to the clothing of man, thus obtaining
distribution. Among the various little fruits and seeds which
anchor themselves to one's clothing, in the woods, those of the
stickseeds may always be known because they are shaped
something like the quarter of an apple and come in groups of
four. The tip of each of the thorns along the backs of these
nutlets is barbed just like a harpoon, so that when the burs
affix themselves to clothing it is difficult to remove them.
Of the Minnesota varieties, two are very rare and are known
to occur only in the extreme northwestern corner of the state.
The others, however, are abundant throughout all portions.

Lungworts. The lungworts are also called bluebells, but
they are not to be confused with the Canterbury-bells, which
belong to quite a different family. They are erect, smooth or
downy herbs and have blue, bell-shaped flowers with somewhat
narrowed tubes. The flowers are borne in large terminal,
hemispherical clusters, sometimes flattened out and loose in
appearance. The tall lungwort possesses rough leaves, while
the Virginia lungwort has its foliage quite smooth.

Forget-me-nots. Two sorts of forget-me-nots occur in the
state. They are little, low, rough-leaved plants, in one variety
with small blue flowers, and in the other with white. They are
annual or biennial and produce tufts of leaves near the base,
from which the leafy flowering stem arises. The flowers are
borne in one or two-sided racemes, often bent over like a shep-
herd's crook.

Puccoons. The puccoons are known by their yellow flowers,
varying towards orange or white. One of the commonest early
spring flowers — the hoary puccoon — is classified here. In this
plant, at the end of the stem, six inches or more in height, a
little cluster of orange yellow flowers is developed. When it

Minnesota Plant Life.

373

fruits, four white, hard, smooth and shining nutlets are pro-
duced, protected by the five-lobed, green and hairy calyx. The
yellow puccoon, a form that is abundant on prairies, has trum-
pet-shaped flowers of a lemon or bright yellow color. Its leaves
are slenderer than those of the hoary puccoon and have not
the same white-hairy appearance, though they are rough to the
touch. This plant, later in the season, produces much smaller,
pale yellow, closed flowers, which, after pollination by their own
pollen, mature fruits. The broad-leafed puccoon has ovate or
ovate-lanceolate leaves and may be thus distinguished. Its
flowers are yellowish-white or
yellow. The European puc-
coon has yellowish-white flow-
ers scattered along the ends of
its branches, but it matures
the same white hard nutlets
that characterize its American
relatives.

False gromwells. The two
species of false gromwell may
be known by their extra-
ordinarily rough and hairy
foliage, strong-veined leaves
and inconspicuous white or
greenish flowers, produced in
leafy one-sided racemes. There
are four nutlets begun in the
flowers of the false gromwell, but only one of them is
likely to mature, so that if ripened fruiting specimens alone
were at hand, it would be difficult, at first sight, to include these
plants in the borage family. The nutlets are white and hard,
like those of the puccoons.

Bonesets. The comfrey or boneset has purple or yellow flow-
ers, brown nutlets, lance-shaped leaves, hairy foliage and thick

roots.

Verbenas. The verbena family includes, in Minnesota, six
varieties of wild verbena and one variety of fogfruit, or
These are all herbs, with, ordinarily, opposite leaves and
very much like those of the borages, but collected in spikes or

FIG. 177. Blue verbena. After Britton and
Brown.

374 Minnesota Plant Life.

heads, and not in one-sided racemes. The fogfruits have two-
lipped flowers, and it is doubtful whether any of them actually
occur in Minnesota. The fruits of the verbenas, when mature,
separate into four nutlets, just as do the fruits of the borages.
If there is any question whether a plant is a verbena or a borage
it may generally be decided by opening the corolla tube and
counting the stamens adherent to its inner surface. If there
are four, the plant is a verbena ; if there are five, it is a borage.
Of course there are a great many other kinds of plants with
four stamens, but the combination of four stamens on the corolla
tube, flowers in racemes, spikes or heads, and fruits consisting
of four nutlets, pretty distinctly indicates a verbena.

The six verbenas of Minnesota may be distinguished as
follows : One of them is a mat plant, growing in waste
fields along roadsides and on prairies. The whole plant-body
is prostrate and often spreads out over a circle a yard in
diameter. The flowers are purplish-blue and borne in spikes.
The leaves are of various shapes, but some of them, at least,
are likely to be cut, from the margin toward the midrib, by
deep notches. The hoary verbena is recognized by the soft,
hairy leaves, of an ovate form, almost stemless, with the edges
sharply notched. The blue flowers stand in dense leafy spikes.
No other verbena has this soft hairy leaf-surface. The nettle-
leafed verbena and the wild blue verbena also have ovate cr
oblong leaves, but in these varieties each leaf has a distinct stem.
The nettle-leafed verbena has usually white flowers or pale
blue, while the blue verbena, as its name indicates, produces
bright blue flowers. The other two verbenas have different
foliage from the erect forms that have been mentioned. The
narrow-leafed verbena ~has very slender, or at most, willow-
shaped leaves with blue flowers in slender, dense spikes. The
European verbena, with an erect habit, has, at least on the lower
part of its stem, leaves deeply toothed to the midrib, like those
of the prostrate verbena. The flowers are purple or white,
produced in numerous, very slender spikes, three to six inches
in length.

Chapter XXXVII.

From Peppermints to Plantains.
if

The mint family in Minnesota includes about forty species,
among which are the pennyroyals, mints, peppermints, bugle-
weeds, basils, calamints, horse-
mints or bergamots, Blephilias,
catnips, anise plants, hyssops,
dragon's-heads, skull- caps,
hedge-nettles and dead-net-
tles.

Mints may be recognized by
characters as follows: Their
stems are almost always four-
sided with opposite leaves and
aromatic foliage. The flowers
are usually strongly two-
\ lipped, though in some Minne-
sota varieties they are nearly
regular. The stamens, borne
on the inner surface of the
corolla tube, are generally four
in number, two of them longer

than the other two; but sometimes the short ones become
reduced to thread-like appendages. The fruit, as in borages
and verbenas, consists of four one-seeded nutlets. It is almost
always possible to identify a mint by rubbing a little of the
foliage between the fingers and noticing the fragrant odor, like
that of catnip or peppermint. The presence of the scent, even
if the flowers are regular instead of two-lipped, will serve to
indicate the mint, especially if its stem is four-sided.

Wood-sages. Among the mints some varieties may be iden-
tified by characters not too minute. The wood-sages and

FIG. 178. Wild mint. Aftei Briitou and
Brown.

376

Minnesota Plant Life.

false pennyroyals have the fruit-rudiment lobed into four sec-
tions, but not fairly divided into four nutlets as in the rest of
the mints. The wood-sage is a slender herb from one to two
feet tall, and is to be looked for in thickets through the southern
part of the state and in the Red river valley. The flowers are
distinctly two-lipped. The false pennyroyal is of similar habit,
six inches or more in height. The flowers are small, blue,
almost regular, and disposed in flat-topped clusters arising from
the axils of the leaves.

Skullcaps. Of those mints which separate their fruit-rudi-
ment into four
nutlets, the
skullcaps may
be known by
the curious lit-
tle bulging pro-
tuberance upon
the back of each
flower. Skull-
caps are, for the
most part, small
herbs, with
leaves of vari-
ous shapes, and
strongly two--
lipped flowers,

generally Ol a FlQ 17g clump Of horse-mint (in middle of picture). After
blue COlor. photograph by Williams.

Four kinds occur in Minnesota.

The rest of the mints may be divided into two series. In
one the corollas are two-lipped, and the upper lip is con-
cave. Here are included the catnips, the dragon's-heads,
the heal-alls, the false dragon's-heads, the hedge-nettles and
hemp-nettles, in all of which there are four stamens with pollen
pouches. The sages, horsemints and Blephilias have the same
kind of corolla but only two of the stamens produce any pollen
pouches. The other series of mints includes those forms in
which the corolla tube is nearly regular, or, if two-lipped, has
the upper lip flat or but very little concave. Here are to be

Minnesota Plant Life.

377

grouped the pennyroyals, the basils, the hyssops, the mountain-
mints, water-hoarhounds and peppermints, in all of which the
flowers are clustered in small dense whorls in the axils of the
leaves. Sometimes, when many of these whorls arise close to-
gether, near the end of the stem, they become confluent into a
spike.

Horsemints and dragon's-heads. Of the various mints several
are decidedly handsome plants. The horsemint, for example,
with its heads of two-lipped flowers, is an abundant and beau-
tiful herb of the woods. There are two sorts in Minnesota,
one with a yellowish flower and the other with pinkish or
purplish heads. The dragon's-
heads, with their light blue
flowers in close clusters and
the false dragon's-heads with
rose-colored flowers are inter-
esting plants of the northern
and central portions of the
state. The water-mints, found
in great abundance in springs
and along the edges of brooks,
present a variety of forms,
many of which, except by mi-
nute characters, are difficult to
distinguish from each other.

Some mint flowers are very
interesting mechanisms for the
utilization of insects in the
work of pollination. In the

sages, for example, the two stamens are hung on levers and
rest under the arched upper lip of the flower. When a bee
visits the flower it stands upon the lower lip and thrusts its bill
down towards the base of the flower, as it does so, striking with
its head the short arms of the levers. The two long arms
bearing the pollen pouches are thus brought down on the back
of the insect like hammers, leaving there a couple of patches
of pollen spores, several hundred spores in each patch. After
this mechanism of the flower has been set in motion by the
visit of a bee, the slender stigma-stalk of the pistil drops down

FIG. 180.

Horse-mint. After Britton and
Brown.

378

Minnesota Plant Life.

from the hood where it was resting and takes such a position
that its end will be dragged across the back of a bee that sub-
sequently visits the flower. In this way bees going from flower
to flower commonly carry pollen from one plant to stigmas
of another.

Mint extracts, as is well known, are of considerable excel-
lence for a variety of purposes. They are used in perfumery
and confectionery, and in some medical preparations. Many
of them are gathered as household remedies.

Ground-cherries. The nightshade or tobacco family includes
about fifteen Minnesota varieties, of which only eight are native.
Here are the ground-cherries, plants known also as ground
tomatoes, and recognized by the much inflated bladdery calyx,
which incloses the little tomato-like berry. The name ground-
cherry is given because, in the common species, the berry is
about the size of an ordinary cherry. Several different kinds
occur in Minnesota. The various sorts may be known by the
presence or absence of underground stems, by the smoothness
or hairiness of the leaves, and also by the shapes of the leaves,
by the color and sizes of the flowers, and by the shape of the
calyx in fruit. The most common species in Minnesota are the
clammy, the leaves of which are clammy and viscid to the touch ;
the Virginia, with smooth leaves, sometimes more or less hairy ;
the prairie ; the long-leafed, and the Philadelphia ground-cherry,
all of which have underground rootstocks. Besides, there occur
the low, and the cut-leafed, in the first of which the leaves are
ovate and entire, while in the second the margins are strongly
notched. In neither of these plants is there any underground
rootstock and the plants are therefore annual, springing up each
year from the seed.

Nightshades. Besides the ground-cherries there are three
varieties of nightshade — herbs with flowers resembling those
of the potato and arranged in cymes. The black or deadly
nightshade is an annual, smooth, unpleasant-smelling herb, with
entire or slightly notched ovate leaves, and black, spherical,
smooth berries, without a bloom, hanging on nodding stems.
The cut-leafed nightshade, which in its fruits resembles the or-
dinary variety, may be known by the pinnately-lobed leaves and
the greenish-black or green colored fruits. The prickly night-

Minnesota Plant Life. 379

shade, or potato-bug plant, is covered over with prickles both
upon the leaves and upon the stem. Even the berry is very
prickly. This plant, having been introduced from the west,
is sometimes found along railway tracks, and it has the unen-
viable distinction of being the original food of the potato-bug.
From it, a few decades ago, when potato cultivation began to
be undertaken in Iowa and Nebraska, this destructive insect
migrated to the fields. The climbing nightshade has stems
from two to eight feet long. The leaves are heart-shaped, often
with two leaflets at the base. The flowers are bluish in appear-
ance and like those of the potato or tomato, while the berry is
red and as large as the end of one's thumb.

Jimson-weeds. The jimson-weeds, which occur sparingly as
introduced forms in the southern part of the state, are tall,
unpleasant-smelling herbs, usually three or four feet high. The
flowers are large, sometimes two inches broad, shaped rather
like morning-glory flowers, but more deeply notched along the
edge. The capsule, an inch in length, is prickly and bursts
irregularly.

Wild tobacco. Wild tobacco is found in the vicinity of In-
dian reservations, having escaped from their fields. The flow-
ers are petunia-like and the leaves are broadly ovate and smooth
along the edge. A many-seeded capsule, splitting longitudi-
nally into two halves, forms the fruit.

Figworts. Nearly fifty different varieties of figworts are
known to occur in Minnesota. Here are classified the mulleins,
the toad-flaxes, the turtle-heads, the monkeyflowers and snap-
dragons, the false pimpernel, speedwells, Gerardias, Indian pinks,
cow-wheats, louseworts and yellow-rattles. Figworts may be dis-
tinguished from mints, for which they might be mistaken, by
their generally cylindrical stems and their two-chambered, or
rarely one-chambered capsular fruits, different in appearance
from the deeply four-lobed, or four-nutleted fruits of the mints.
Mullein fruits are, in their structure, typical of the figwort
family. The flowers, however, are, for the most part, strongly
two-lipped, recalling those of the mints, but the aromatic,
minty odor is absent.

Mulleins. Mulleins — common plants in fields and pastures
— are well-known on account of their woolly leaves, which

380

Minnesota Plant Life.

have much the feeling of flannel. A careful examination of
a mullein leaf will show that its surface is covered with little,
much-branched hairs, standing close together like so much
miniature shrubbery. In the spring of the year the leaves
form dense rosettes at the surface of the ground, and later an
erect, tall flowering axis is developed, from two to six feet in
height. At the end of this a spike of yellow, almost regu-
lar flowers is borne. In each flower there are five stamens.

FIG. 181. View in Minnesota lake district. Shows in center two mullein plants in character
istic positions. After photograph by Williams.

The leaves are alternate. In these characters the mulleins
differ from the rest of the figworts, in none of which are there
five pollen-bearing stamens, and in most of which there are
two-lipped flowers and opposite leaves, though the latter char-
acter is by no means universal.

Toad-flaxes. The toad-flaxes are recognized at once by their
snapdragon-shaped yellow or blue flowers, provided with a
spur like that of a larkspur flower. The common toad-flax
of roadsides and fields blooms in the summer and autumn.

Minnesota Plant Life.

381

The flowers are yellow and are arranged in a <len-e raceme at
the end of the slender stein, not usually more than a foot in
height. The leaves in this variety are linear. The Canada
toad-flax, not an abundant plant in Minnesota, rf^-mbles the
ordinary sort except in the color of its flowers, which are bluish
or white.

Pileworts, turtle-heads and snapdragons. The figwort or
pilewort is a tall herb, often five or six feet high, with a large
terminal panicle of small purplish, two-lipped flowers of curious
shape. There are five stamens, but only four of them produce
pollen sacs. The fifth is reduced to a little scale. The stems
are somewhat four-sided, but the plant has the typical figwort

capsule,with two chambers, open-
ing along the partitions. The
turtle-head is a swamp plant,
with white or pink flowers, large
in size and borne in the axils of
the upper leaves, or in terminal
spikes. The flower is shaped
somewhat like a turtle's head,
hence the common name. The
seeds in this variety are provided
with wings. The snapdragons,
known also as beardtongues, and
the monkeyflowers have usually
bell-shaped or mouth-shaped

Fio.182. Monkey flower. After Bntton flowers. Several different kinds
and Brown. of beard-tongues occur and they

are especially abundant on dry banks or high bluffs in the
prairie region of the state. The monkeyflowers, of which
there are two sorts, have the flowers on distinct stems in the
axils of the leaves. Each flower seems to have an upper and
lower jaw, closed together like a mouth. One variety has blue
flowers and the other has yellow. Both are found in swamps
or along streams,— not, however, in peat-bogs or tamarack
swamps, or only very sparingly.

Hedge-hyssops. The hedge-hyssops are mint-like in their
appearance, but lack the fragrance of the mint. There are two
or three varieties, one of which occurs in peat-bogs. The
flowers are considerably smaller than those of the turtle-head,

382

Minnesota Plant Life.

beardtongue or monkeyflower, but have a strongly two-lipped
aspect. There are four stamens, in one variety all pollen-bear-
ing, and in the others only two with pollen.

Speedwells. The speedwells, of which there are several
species, have only two stamens. They are usually provided
with capsules of a heart shape, caused by the deep lobing of
the typical figwort fruit. Many of them are found in wet
places along the muddy shores of ponds or in woods. One
of them is a tall herb, often six feet in height, with willow-
shaped leaves in whorls of from three to nine, and several dense,
spike-like racemes of flowers, the central one of which develops
first. The flowers are small,
and white or blue. In this
variety the capsule is not
heart-shaped. The plant is
common in the edges of
woods.

Gerardias. The Gerar-
dias, with about ten Minne-
sota species, are abundant
in various localities, but are
most often found among
sedges along the shores of
lakes or on dry prairies.
The flowers are not dis-
tinctly two-lipped, but are
almost bell-shaped, usually
of a pink color, varying
towards violet, purple or yellow. The leaves are commonly lin-
ear, or at most lance-shaped. The showy flowers, slender leaves
and capsules of the figwort type, half inclosed in the calyx, or
almost surrounded by it, will serve to distinguish these plants.

Indian pinks. The Indian pinks, or painted-cups, form their
two-lipped flowers in leafy spikes. Many of the leaves in each
spike are themselves colored scarlet or yellow, giving to the
whole structure a much more ornate appearance than would be
produced by the flowers alone. One painted-cup has scarlet
leaves ; another has yellow leaves, while yet another is supplied
with green leaves to accompany the flowers.

FIG. 183. I^ousewort. After Britton and Brown.

Minnesota Plant Life.

383

Cow-wheats. The cow-wheats, louseworts, yellow-rattles and
eyebrights are remarkable for their partial parasitism upon
neighboring plants. If a turf containing one of these varieties
is dug up and the earth very carefully removed by washing, it
will be found that the rootlets of the figwort attach themselves
to those of neighboring plants and in this way extract food
material from the bodies of their hosts. Such plants are called
root-parasites. The dependent habit of these root-parasites
is not, however, so thoroughly fixed that they derive the
principal part of their nutriment in such an irregular manner

They are all of them green
plants with well developed
leaves. The flowers are two-
lipped, have strongly con-
vex upper lips, and are of
various colors — white in the
cow-wheat, yellow in the
rattlebox, cream colored in
the louseworts, and lilac or
purplish in the eyebright.

Catalpa trees. One tree
related to the figworts, and
belonging to the bignonia
family, is cultivated in Min-
nesota, especially in the
southern part of the state.
This is the catalpa, a very

FIG. 184. Bladderwort. After Britton and Brown, beautiful trCC with large

leaves shaped somewhat like those of the linden and handsome
purple-mottled, bell-shaped, two-lipped flowers, produced in
loose clusters. The pods when full-grown are a foot or more in
length, cylindrical and slender. In every pod a large number
of winged seeds are matured and the wings stand out on each
side of the seed like the wings of a bird. Catalpa seeds have
their center of gravity very nicely balanced between the wings,
so that they lie flat in the air, and if there is a current of wind
they soar in circles like hawks, and are often carried to great
distances.

384 Minnesota Plant Life.

Bladderworts. Relatives of the figworts are certain very
extraordinary aquatic plants known as bladderworts. In Min-
nesota all the forms live in the water, except a little plant called
the butterwort, which grows upon rocks along the north shore
of Lake Superior. In the tropics, however, a number of blad-
derworts grow as perching plants upon tree trunks. For the
most part, true bladderworts have no roots, but extend in the
water their much-branched, floating body, from which slender
stalks arise, bearing yellow, snapdragon-shaped flowers. The
leaves of these plants are decidedly compound and consist of
thread-like divisions, upon which are produced, usually in large
numbers, little, clear, flattened, shrimp-shaped bladders. Each
bladder contains generally a bubble of gas along with some
liquid, and by aid of the bubbles the plants are enabled to float
free in the water. Being surrounded by liquid, they have little
need of roots, and have therefore abandoned them. The blad-
ders are not, however, employed solely as floats, but each one
has an aperture, guarded by a trapdoor, which opens inward
but not outward. Small aquatic insects find their way into
these bladders, but cannot escape, since the door of the bladder
cannot be opened from within. Digestive glands are present
on the inner surface of the bladders, and the bodies of the little
animals are used by the plant as part of its nutriment. Blad-
derwort stems resemble somewhat those of the water-milfoils,
but the latter are not free floating plants and are attached to
the bottom, nor have they the remarkable shrimp-shaped blad-
ders on their leaves. Bladderworts in flower are immediately
recognized, for no other free-swimming plants produce two-
lipped flowers. Each corolla is provided with a spur like that
of the toad-flax flower and is visited by insects which effect
pollination. The fruiting capsule is like that of the figworts,
with numerous small seeds. In Minnesota there occur five va-
rieties of bladderworts — to be discriminated by minute differ-
ences in the flowers, leaves and bladders.

Butterworts. A close cousin to the bladderworts is a curi-
ous little plant known as the butterwort. It grows in the
crevices of rocks along the north shore of Lake Superior, reach-
ing in such stations a height of three or four inches. The
leaves are oblong, clustered at the base of an erect axis that

Minnesota Plant Life.

385

bears a single nodding, two-lipped violet flower. Each leaf
has a greasy feeling and is provided with a viscid secretion in
which insects are caught. In the greasy substance digestive
ferments are elaborated, and by means of these the bodies of
the insects are converted into food for the plant. Through
the rennet-like ferments secreted by their leaves butterworts,

FIG. 185. Cancerroot. After Jellett in Afee/iati's Monthly.

if placed in it, will curdle milk. They are actually thus em-
ployed in the domestic cheese-making of Lapland and north-
ern Scandinavia.

Cancerroots, The broom-rapes, including plants known as

cancerroots, beechdrops and squawroots, are represented in

Minnesota by three, and probably more species. They may

be regarded as derived from the cow-wheats and louseworts,

26

386

Minnesota Plant Life.

just as were the dodders from the morning-glories. They are
strongly parasitic by their roots and have lost their green color,
becoming whitish or pale like the Indian-pipes or corpse-plants.
They have not, however, the dead white color of the corpse-
plant, and their flowers are bent in the middle and are, in one
variety, slightly two-lipped, and in the other two, strongly. The
one-flowered cancerroot sends up several slender, erect stems,
from three to eight inches high, at the end of each of which
a single whitish-violet flower is borne. A few little scales of
a pale color appear at the base of the flowering axis. The stem
of the plant is subterranean and sends out a number of roots
which attach themselves to the
roots of neighboring plants. The
clustered cancerroot pushes its
main stem out of the ground
from two to four inches. On this
several single-flowered axes are
developed. The flowers in both
varieties are about an inch in
length. A third species, the
Louisiana broom-rape, may be
recognized by the production of
numerous short-stemmed flowers
in a terminal spike, upon which
also several scaly leaves arise.
The whole plant stands up from
four to eight inches in height.
The flowers are purplish, and the stems and scales are of a pale,
yellowish-green color.

Lopseeds. The lopseed family is represented in Minnesota
by its only species, a plant with the general aspect of a nettle,
but bearing two-lipped flowers in slender spikes from three to
six inches long towards the tip of the plant. After the flowers
have been pollinated they turn downward and lie flat against
the axis upon which they were borne, giving a curious barbed
appearance to the spike. From this habit the name "lopseed"
is given.

Plantains. The thirty-second order includes but a single
family, that of the plantains, one variety of which is a common

FIG. 186. Rugel's plantain. After Brit-
ton and Brown.

Minnesota Plant Life.

and troublesome weed in lawns throughout the state. The
stems of the plantains are very short, situated underground,
commonly in an erect position. A cluster of leaves with prom-
inent longitudinal veins are borne on this short stem and fn.m
the center of the tufts of leaves an axis arises, in the plantains
proper prolonged into a dense spike of flowers. In the related
shoreweed, not known to occur in Minnesota, the flowers are
solitary on the erect axes. Each plantain flower is provided
with a four-lobed corolla and calyx and there are ordinarily
four stamens, though the number in some species is reduced
to two. The fruit-rudiment matures into a two-chambered
capsule that splits by a circular cleft, thus removing the tip
as a lid and allowing the seeds to escape.

In Minnesota there are six or seven varieties of plantain.
The common plantain of dooryards has broad, smooth or
slightly hairy leaves, arising from a thick, short rootstock.
The spikes are long, slender and many-flowered. The pod
opens by a ring around the middle. Rugel's plantain resembles
this closely, but has fewer flowers in a spike and the pods split
below the middle, so that the lid is the larger portion. The
rib-grass, or rib plantain, is introduced from Europe and is
recognized by its slightly hairy, lance-shaped, or broadly grass-
like leaves, and its pod splits at about the middle. The salt-
marsh plantain, known from the saline soils of the Red river
valley, has oblong, lance-shaped leaves and pods splitting below
the middle. The heart-leafed plantain has broad, heart-shaped
leaves of a purplish-green color with smooth surfaces. The
spike is not continuous but is interrupted by short, flowerless
areas. The pod splits at about the middle. The woolly plan-
tain, found on prairies in the Minnesota valley, especially
upon high knolls, has silky or woolly, very slender grass-like
leaves. The whole plant, from the hairs, has a white aspect.
The pods split at about the middle. The bracted plantain lias
grass-like leaves, but is not furnished with silky hairs and the
spike is clothed with slender green bracts or scales which pro-
trude considerably beyond the ends of the flowers. The p«»d
splits below the middle.

Chapter XXXVIII.

From Bedstraws to Lobelias.

The thirty-third order includes the madder family, to which
the exotic coffee and cinchona plants belong. From the latter
quinine is manufactured. The Minnesota species are all herbs
but one — the button-bush — and include about ten kinds of
bedstraw, the partridgeberry and two Houstonias. In addition
to the madders, the thirty-third order includes the honeysuckle
family, with the honeysuckles, twinflowers, snow-berries, high
bush cranberries, arrowwoods, elders and horse-gentians; the
adoxa family, with a single small herb known as the musk crow-
foot or moschatel; and the valerian family, with two valerians
and two lamb-lettuces. The teazel family, to which the fuller' s-
teazel belongs, is not represented in Minnesota.

Bedstraws. Of the madder family the little bedstraws of the
woods are well-known forms. Their stems are four-sided, their
leaves are apparently in whorls and are mostly slender or wil-
low-shaped. The stems are armed with recurved barbs, so that
they cling to one's clothing. The flowers are small, white and
clustered in flat-topped cymes, often aggregated in com-
pound panicles. Each flower exhibits a four-lobed calyx and
a four-lobed corolla, upon which four stamens are borne in
the notches. The fruit consists of two nutlets, side by side,
and in each of them a single seed is formed. The different
kinds of bedstraw are distinguished by the character of the
nutlets, the color of the flowers, and a number of minute pecul-
iarities which can scarcely be recognized without the use of a
microscope. Most of the Minnesota varieties have fruits pro-
vided writh hooks, but in some the fruits are quite smooth.
The slender, trailing, clinging stem, whorled leaves, four-lobed
flowers and two-nutleted fruits will serve to identify these
plants. One variety is a common prairie flower.

Minnesota Plant Life.

389

Partridgeberries. The partridgeberry is a slender, creeping
evergreen plant with opposite leaves. It is easily mistaken for
a heath, from which it must
be distinguished by its white,
sessile, four-lobed flowers, each
with four stamens and four-
lobed stigmas. The flowers are
borne in pairs at the ends of
the stems. The fruit is a berry-
like body, red in color, and con-
sistingof two fused stone-fruits,
in each of which there are
four seeds. In fruit this plant
is easily mistaken for a cran-
berry; but the berries, while
edible, have a flavor different
from that of true cranberries.

Button-bushes. The but-
ton-bush is a Shrub With Op- FiG.187. Bedstraw. After Britton and Brown.

posite leaves of the familiar plum-leaf shape and with spher-
ical heads of white flowers. The cluster of flowers is about

an inch in diameter
and all over its surface
the slender stigma-stalks
of the pistils protrude like
so many short threads.
The flowers themselves
are crowded together
very tightly, but upon be-
ing removed show the
four-lobed corolla and ca-
lyx of the madder family.
This plant is found in
the St. Croix valley and
along the Mississippi, be-
low the confluence of the

FIG. 188. Partridgeberry. After Britton and Brown. ~ Croi\

Bluets. The Houstonias, or bluets, are erect herbs with op-
posite leaves, usually tufted, and not over ten inches in height.

390

Minnesota Plant Life.

The flowers are funnel-shaped with the four calyx and corolla
lobes and the four stamens of their family, but the stigma is
two-lobed. The flowers are blue or lilac or almost white, and
are arranged in flat-topped clusters. The fruit is an almost
spherical capsule. The fringed Houstonia has a fringe of hairs
along the margins of the leaves, while the long-leaved Houstonia
has none.

Elder-bushes, The honeysuckle family comprises a group
of shrubs, vines and herbs, with opposite leaves and tubular,
generally five-parted, flowers, the calyx of each of which adheres

to the surface of the
fruit-rudiment, so that
the corolla tube and
the calyx seem to
spring from the top of
the undeveloped fruit.
Here are included the
elders, of which there
are two varieties in
Minnesota, the one
forming a flat-topped
cluster of flowers from
each of which a purple
or black stone-fruit is
produced, and the
other, panicle-clusters
and stone-fruits of a
scarlet or red color
when ripe. The berries
of both varieties are edible. The leaves are compound like
those of the ash, and when bruised have a curious strong smell.
Elder flowers have five-lobed corollas with five stamens, each
placed in a notch.

Black haws and high bush cranberries. Related to the elders
are the bushes known as black haws, sheepberries, arrowwoods,
high bush cranberries, or Viburnums. There are seven or eight
varieties in Minnesota. The high bush cranberry is a shrub,
eight to twelve feet in height, with opposite leaves shaped some-
what like those of the maple. The white, honeysuckle-like

FIG. 189. High bush cranberry. After Britton and
Brown.

Minnesota Plant Life. 391

flowers are produced in more or less flat-topped clusters, and
each one matures into a stone-fruit with much the flavor and
appearance of the cranberry. The maple-leafed arrowwood has
the same maple-shaped leaves seen in the high bush cran-
berry, but the stone-fruits are nearly spherical and black.
This variety does not grow more than six feet high. The
downy-leafed arrowwood, with elm-shaped leaves, has black,
oblong stone-fruits. Another sort, very similar in the foliage,
has almost spherical fruits of a dark blue color. Both these
arrowwoods have coarsely notched leaves. The withe-rods and
sheepberry Viburnums have plum-shaped leaves with fine teeth
along the edge. In the withe-rod the fruits are of a pink or
blue color and the stone is round, or slightly flattened. In the
sheepberry the fruits are blue or black, with flat disk-like stones.

These various Viburnums are found in moist woods or
swamps. Some of them, like the sheepberry, the downy arrow-
wood and the high bush cranberry, are not uncommon through-
out the state, especially toward the north. The others are rarer
or local in their distribution.

Horse-gentians. The horse-gentian, or feverwort, is a com-
mon herb in rich woodland, especially throughout the southern
and central portions of the state. The leaves are opposite,
entire and in most instances blended by their bases around th<
stem, so that the stem seems to grow through the leaves,
flowers arise in the axils and are of a purplish hue.
fruits are orange-red, hairy, and have three nutlets.

Twinflowers. The twinflower, not uncommon through
the wooded portion of the state, grows among moss and might
be mistaken for the partridgeberry. The slender branches trail
over the ground, producing small opposite leaves, and
sional side stems, at the ends of which pairs of nodding flowers
are borne. The flowers of the partridgeberry are erect a
four-parted, but those of the twinflower are five-parted,
are usually, however, but four stamens. The fruit is nearly
spherical, with a single ripened seed.

Snowberries. The snowberries are little shrubs not ovei
feet high, and in one variety rarely over six inches. They have
white berry-like fruits produced in clusters in the axils of t
leaves, except in one species in which the berry is red.

392

Minnesota Plant Life.

leaves are ovate, smooth-margined, opposite and honeysuckle-
like. The flowers are small, with four or five teeth to the corolla
and the fruits have two seeds each. The different varieties may
be recognized as follows : The red-berried form, known also
as the Indian currant, is at once distinguished by the color of
its fruit. Of the three with white fruits the wolfberry protrudes
its stamens and stigma-stalks slightly from the flower, while the
other two do not. Of the latter, the snowberry is an erect
shrub one to four feet in height, while the low snowberry
branches diffusely and averages from six to ten inches. All
four varieties are to
be found in the
edges of woods,
along lake shores
and in rocky places.
Honeysuckles.
Of the honeysuckles,
some are climbing
vines while others
are spreading
shrubs. The flowers
are produced in lit-
tle spikes and are
themselves generally
large and conspicu-
ous. The hairy
honeysuckle^ the
smooth honeysuckle,
Sullivant's honeysuckle, and the yellow honeysuckle, all have the
leaves near the flower clusters grown together by their bases
around the stem. Those just mentioned are vines. The blue
honeysuckle, the swamp-honeysuckle, the fly-honeysuckle and
the involucred honeysuckle are shrubs, varying in the different
species from one to ten feet in height. The hairy honeysuckle
is known by its hairy leaves. The smooth-leafed honeysuckle
has red berries. Sullivant's honeysuckle has yellow berries and
yellowish-green flowers. The yellow honeysuckle has bright
orange-yellow flowers, that are sweet-scented. The blue or
mountain-honeysuckle is a shrub one to three feet in height,

FIG. 190. Snowberry. After Brittoii and Brown.

Minnesota Plant Life. 393

with oblong leaves, pairs of yellow flowers and bluish-black
berries. The swamp-honeysuckle has red or crimson berries.
The fly-honeysuckle has bright red berries, and the involucrcd
honeysuckle, with yellow flowers and black berries, may be
distinguished by the production of bractlets surrounding the
fruit.

The bush-honeysuckle has the flowers and general foliage of
the true honeysuckles, but the fruit is a capsule, not a berry.
The Minnesota species is a shrub from two to four feet in height,
with plum-shaped leaves the margins of which are finely
notched. The flowers are yellow, produced on stalked umbels
in the axils of the upper leaves. This plant is very abundant
in open pine woods throughout the state.

Moschatels. The Ado.va, or moschatel, otherwise known as
musk crowfoot, is a little herb with the appearance of a small
anemone. It is not more than six inches high. The leaves are
compounded on the plan of three, each of the three leaflets being
again compounded or deeply lobed. Three or four leaves of
this sort are borne at the base of the flowering axis — which is
slender and erect, carrying a pair of three-parted leaves oppo-
site each other and a little above the middle. At the end of the
flowering axis is a small head of from three to six flowers, all
of them five-parted with a forked stamen produced in each
notch. The fruit is a green stone-fruit, with from three to five
nutlets. This little plant, the only one of its family, has been
found in Winona and Goodhue counties. It is to be sought
among the rocks in dark ravines and is an arctic-American form,
reaching its southern limit in Minnesota and northern Iowa.

Valerians. The valerian family includes four Minnesota
species, two valerians and two lamb-lettuces or corn-salads.
They are strong-smelling herbs with the characteristic odor of
the drug valerian. The two species, known respectively as
tobacco-root and swamp valerian, have pinnately divided leaves,
with slender leaflets, and erect stems from one to four feet in
height, bearing panicles of tubular flowers with opposite bracts.
The calyx is fused with the fruit-rudiment and consists of from
five to fifteen bristly teeth, which stand out like little feathers
around the mature fruit. The fruit has but one chamber and
is strongly ribbed. In the tobacco-root the flowers are of a

Minnesota Plant Life.

yellowish-white color and are often separated. The root of
this plant is edible. The swamp valerian has flowers of a pink
or whitish color and the stem-leaves consist of a larger number
of leaflets than in the tobacco-root. Valerian flowers are, in
structure, very similar to those of honeysuckles, from which
they can be known by their slight irregularity and by their
stamens, from one to four in number. The fruit also contains
but a single seed and is not, as in honeysuckles, a stone-fruit
with pulpy exterior.

The two corn-salads are rather low herbs, from one to two
feet in height, with opposite, smooth-margined leaves and small
flowers, clustered in heads that are loosely arranged on the
forked, flat top of the main axis. The fruits are somewhat
triangular in outline, smooth and enclosed by the calyx, grow-
ing closely around' the fruit-rudiment. There are three sta-
mens and the stigma is three-lobed. These plants can be dis-
tinguished from members of the honeysuckle family by the
number of their stamens, and from the valerians by the absence
of feathery appendages on the top of the fruit.

The thirty-fourth and highest order of plants comprises the
gourd family, to which belong such common garden plants as
melons, citrons, cucumbers, squashes, pumpkins and bottle-
gourds. Only two varieties, the wild cucumber and the star-
cucumber, are native to Minnesota. In this thirty-fourth order
are grouped also the bluebells and lobelias, three small families
not represented in the United States by native species, and the
large and important sunflower family, to which a great variety
of herbs known as "Composites" belong. The three Minnesota
families of the thirty-fourth order are known by the fusion, or
close approximation to each other, of their stamens. In the
gourd family the flowers are for the most part regular — as they
are also in the bluebells. In the lobelias the flowers are strongly
two-lipped, reminding one of mint or snapdragon flowers, while
in the sunflower family the flowers are always aggregated in
dense, flat-topped, spherical or cylindrical heads and are either
all tubular like honeysuckle flowers, all two-sided and strap-
shaped like dandelion flowers, or partly tubular and partly strap-
shaped in the same head, as is the case in sunflowers. In the
latter instance the tubular flowers are centrally disposed in the

Minnesota Plant Life.

395

head, while the strap-shaped flowers form one or more marginal
rows and are then called ray-flowers, because they radiate from
the center of the disk.

Gourds and cucumbers. The plants of the gourd family are
almost always provided with tendrils by which they climb, and
they belong to the highest group of climbing plants which
exists. The leaves are alternate and are generally large and
palmately divided like maple leaves. The calyx is fused with
the surface of the ovary and the petals arise from the calyx. The
corolla is often so deeply notched that it is broken up into five
separate petals, returning thus to the condition of the flowers
in a lower series. There
are from one to three sta-
mens. The fruit-rudiment
is from one to three-cham-
bered, commonly three-
chambered, as may be no-
ticed on the dining table
when sliced cucumbers are
served. The seeds are for
the most part flattened and
contain no albumen. Ex-
tremely large fruits with
great numbers of seeds are
produced by some of the
species of this order. The
well-known prize pumpkins
of the fairs, and the Georgia
watermelons furnish abun-
dant proof. Generally the fruits do not open, but release their
seeds by decay or after they are eaten by animals, but in some
varieties explosive fruits are known. From these the seeds are
ejected as from a catapult, or are shot out into the air as from
a gun or mortar.

The star-cucumber is an herbaceous vine with palmately-
lobed leaves shaped like those of the moonseed. The flowers
are separated, both kinds being borne on the same plant. The
fruit is one-chambered and matures but a single seed. Three
or four of such fruits are borne together in a little bunch at

FIG. 191. Blue-bells. After Britton and Brown.

Minnesota Plant Life.

the end of a short nodding stem. The surface of the fruit is
spiny and it does not open to release the seeds. This form of
wild cucumber is not very common in Minnesota, but occurs
throughout the southern part of the state.

The wild cucumber, or balsam-apple, like the star-cucumber
is a climbing herbaceous vine with rather deeply lobed leaves,
shaped somewhat like those of the hard maple. The flowers
are separated, both kinds occurring on the same plant. The
staminate flowers are numerous in conspicuous slender racemes,
but the pistillate flowers are generally solitary, and each one
ripens an egg-shaped green fruit covered with weak spines and
containing from two to four
seeds, that are released by the
opening of the fruit at the end.
The number of seeds in the fruit,
the opening of the fruit, and its
ordinarily solitary character, will
generally serve to distinguish
this plant from the star-cu-
cumber.

Bluebells. The bluebell fam-
ily includes four bluebells, one
little herb known as the Venus'
looking-glass, and six species of
lobelia, all of which, except the
V e n u s' looking-glass and the
water lobelia, are rather common
in Minnesota. The bluebell, or
harebell, is an abundant plant in
rocky places and meadows

throughout the state. Its beautiful, blue, bell-shaped flowers
are borne in a slender raceme, with several very narrow bract-
leaves at the bases of their stems. The root-leaves of the plant
are in most instances rounded, or heart-shaped, but sometimes
all of the leaves are slender. A variety of this plant, with soli-
tary erect flowers crowning the stems, occurs in the northeast-
ern part of the state. The marsh-bellflower has very slender
stems, with narrow alternate leaves, and the flowers, often
almost white, are smaller and paler than those of the harebell.
The shape of the flower is more open. The tall, or wood-bell-

FIG. 192. Blue lobelia. After Britton
and Brown.

Minnesota Plant Life. 397

flower, is a wand plant of the woods, varying from two to six
feet in height. The leaves are lance-shaped and the flowers —
generally of a brilliant blue color, but sometimes pale or white
— are crowded in a loose, terminal spike with numerous leaves
intermingled. In this variety the bell-shape of the flower is
lost and the five notches of the corolla stand out in a plane,
making a wheel-shaped flower an inch or so in breadth. In
all these plants the fruit is a capsule with from three to five
chambers. There are several seeds, and the calyx comes up
over the fruit or fuses with the lower end of it.

Venus' looking-glass. The Venus' looking-glass is known
by the small, strongly clasping, shell-shaped leaves, in the axils
of which the violet or blue flowers are gathered. The plant is
uncommon but may be looked for in the edges of woods.

Lobelias. Lobelias, as has been said, might from the shape
of their flowers be mistaken for mints or figworts. Their cap-
sular fruits are, however, quite different from the four nutlets
which the mint develops and the flower may always be dis-
tinguished from that of a figwort or mint by the blending with
each other of the stamens. One variety of lobelia — rare in
Minnesota — is aquatic, commonly rooting in the mud at the
border of lakes or ponds. It has hollow, quill-shaped sub-
merged leaves, clustered around the base of a slender stem from
six to eight inches in height, and at the end of this the pale blue
flowers are gathered in a loose raceme. The cardinal-flower,
or red lobelia, to be found in swamps or rich soil along the
lowrer Mississippi, is recognized at once by its conspicuous
scarlet flowers, arranged in a many-flowered raceme. The
leaves are willow-shaped and the whole plant is generally over
two feet in height. The flowers are about an inch long. The
large blue lobelia, common throughout the southern part of the
state, much resembles the red lobelia, except that its flowers
are bright blue. In both these varieties white flowers are
sometimes produced. The pale blue lobelia is a slender plant
of dry soil, abundant in the southern part of the state and rec-
ognized by its smaller flowers, four or five lines in length. The
leaves are rather thick, of an oblong shape, with short stems,
but the stem-leaves are generally sessile. The flowering raceme
is very long and slender, reaching a maximum length of two

398 Minnesota Plant Life.

feet and, commonly, of eight to fifteen inches from the tip to
the lowest flower. The Indian-tobacco lobelia, not so frequent
as some of the others, may be identified by its broadly plum-
shaped, pointed leaves and its light blue flowers in rather loose,
spike-like racemes. Kalm's lobelia, the commonest of all the
varieties in Minnesota, is especially abundant in peat-bogs, on
banks of lakes and streams and in meadows. It is a slender
plant, with light blue blossoms in loose, few-flowered racemes.
The flowers are about the size of those of the pale lobelia, or
rather smaller, but they are not exhibited in the long slender
clusters, characteristic of the other varieties. The fruit of the
lobelias is a capsule, usually with two chambers, and to its sur-
face the calyx-tube is closely attached.

Chapter XXXIX.

Dandelions, Ragweeds and Thistles.

The last and highest family comprises the plants known as
Composites. It includes some 11,000 species of herbs and
shrubs, with a very few trees, well distributed over all regions
of the world, and is characterized by the aggregation of the
flowers into composite heads. These heads are subtended by
groups of bract-leaves to which is given the name of involucre.
The involucre is a green, closely packed series of scales, such
as may be seen below the head of a sunflower or thistle. In
some plants, such as the burdocks or cockleburs, the involucre
produces bur-like, hooked or barbed groups of bristles, by
means of which all the fruits of a head are distributed as a unit.
There are two main series of composite plants, one of which
is distinguished by the presence of a milky juice, while in the
other no milk exudes on the breaking of the stems or foliage.
Dandelions, lettuce, sow-thistles and chicory serve to illustrate
the first series, while asters, goldenrods, burdocks, sunflowers,
thistles, cockleburs and ragweeds are examples of the second.
The composites with milky juice develop what are known as
strap-shaped corollas for all the flowers of a head. Such strap-
shaped corollas may be conceived to arise by the splitting of
a tubular corolla — like that of a honeysuckle — down one side,
near to the fruit-rudiment. Very often, as in dandelion flowers,
five little notches will be found at the edge or tip of the strap.
These represent the five fused petals of the original tubular
flower. Those members of the composite family which have
no milky juice produce, in many instances, at the margin of
the head, the strap-shaped flowers ; but some, and often all the
flowers in a head are tubular, like miniature honeysuckle flow-
ers. The sunflower or the daisy furnishes an example of a head
in which strap-shaped flowers are produced laterally and tubu-

400

Minnesota Plant Life.

lar flowers centrally, and the thistle furnishes one in which all
the flowers are tubular.

In composite flowers the stamens generally have their pollen-
bearing portions fused to-
gether into a ring, while their
^^^^^^^ stems are free. The fruit-

«- ^; rudiment is composed of two

*> 1«* carpels, with a single cham-

ber in which a single seed
matures. The calyx is always
fused with the surface of the
fruit-rudiment, and in a great
many varieties the calyx pro-
duces a bristly or scaly series
of appendages for distribut-
ing the fruits in air currents.
The well-known parachutes
of the dandelion are such
areas, with the margins frayed
out into circles of little bris-
tles. Sunflower fruits are
provided with a pair of scales
similarly derived from the
calyx. When the fruits are
enclosed in burs, the calyx
sometimes, as in the cockle-
burs, develops this flying ap-
paratus but poorly, while in
other instances, as in the bur-
docks, flying appendages are
produced upon each fruit,
probably reminiscences of an
earlier condition when the
bur-method of distribution
had not been perfected. The
modified, aeronautic calyx of

FIG. 193. Chrysanthemum in flower. After 4-Ue r n m n O m' t P flower k
Miller. Bull. 147, Cornell Ag. Expt. Sta-

tion- known as pappus.

Minnesota Plant Life.

401

There are in Minnesota between 240 and 250 species of
composites, including the ironweeds, the blazing-stars, the thor-
ough worts or bonesets, the asters, the fleabanes and Boltonias,

FIG. 194. Dandelions in flower. I<ake Calhoun. After photograph by Hibbard.

the goldenrods, the rosimveeds or compass-plants, the cone-
flowers, sunflowers, tickseeds, bur-marigolds or beggar-ticks,
sneezeweeds, chrysanthemums, tansies and yarrows, cudweeds,
everlastings, ragworts, thistles, burdocks, ragweeds, cockleburs,

27

4<D2 Minnesota Plant Life.

marsh-elders, chicories, hawkweeds, rattlesnake-roots, wild let-
tuces, dandelions, sow-thistles and corn-flowers. In some of
these groups there are a large number of Minnesota species.
For example, there are six sorts of blazing-stars, six thorough-
worts, nine or ten fleabanes, thirty goldenrods and about forty
asters, besides eleven or twelve wormwoods or sage-brushes,
ten or eleven thistles and fifteen sunflowers.

The composite family may for convenience be divided into
three sub-families, the dandelions, the ragweeds and the sun-
flowers. To the dandelion family about thirty Minnesota

FIG. 195. Dandelions in fruit. After photograph by Williams.

species belong. The characters by which they are classified are
minute and it is not possible to go into them in detail. A few
of the common forms may, however, be described.

Dandelions and their relatives. The dandelion is known by
its broad flat head of yellow flowers, becoming closed in the
early stages of fruiting. In later stages the head opens again
and the disk of the flower-cluster becomes convex. On this
the little spindle-shaped nutlets are situated. Above each
nutlet the calyx is prolonged into a rigid thread at the end
of which the pappus-hairs diverge in an umbrella-shaped
circle.

Minnesota Plant Life.

403

The sow-thistles have small, yellow dandelion-like flower-
heads, arranged in panicles or in flat-topped clusters. The
pappus, as in thistles, stands in a tuft on the top of the nutlet.
The meadow salsify has flowers and fruits very much like those

of the dandelion, but the leaves are
all more grass-like in appearance.
The autumn dandelion has a few
leaves clustered about the base of a
rather slender, erect stem, at the end
of which a dandelion-like flower is
borne. The fruit is slender and the
pappus-bristles are brownish in color
and on close observation are
seen to be like little feathers.
The dwarf dandelion has gen-
erally two kinds of pappus
bristles, an outer row of short
brown scale-like bristles and
*an inner row of slender, erect,
stiff, barbed bristles. The
hawk's-beards, with flowers
decidedly similar to those of the dan-
delion, have a copious pappus of slen-
der bristles, arising in a spreading tuft
from the top of a many-furrowed fruit.
The closely related hawkweeds can
scarcely be distinguished by any but
very minute characters. The wild
lettuces look much like some of the
hawkweeds, but the flowers are more
often blue than yellow. The prickly
FIG. i96. wild lettuce, a compass- lettuce, a compass-plant, may be dis-

plant; the fruits stand in heads, . 1-1 i_- i

and each fruit is provided with tinguislied from the sow-thistle, which
ItkCon111" °f briStlCS' After * somewhat resembles, by the dande-
lion-like fruits, with the pappus ele-
vated above the tip of the nutlet on a slender prolongation of
the calyx. Its leaves are prickly, and those on the stem may
twist so that their edges point up and down. The whole plant
is generally flattened by the twisting of its leaves, and the ends

404

Minnesota Plant Life.

FIG. 197. Rattlesnake-root,
and Brown.

of the leaves show a tendency to point either north or south.

One observing the plant carefully can easily see that the leaf-
area as a whole exposes its sur-
face toward the east and toward
the west. The blue-flowered va-
rieties, some of them wand-plants
from three to twelve feet in
height, are known by the copious
heads of small blue flowers ar-
ranged in compound panicles.
They are common at the edges of
woods.

A curious little flower, known
as Lygodesmia, is a desert plant
with rigid branching stem about
a foot in height, and with small,
After Britton awl-shaped leaves and flowers in
pink heads of from three to

twelve, giving to the whole cluster quite the appearance of a

small carnation. It is a wanderer from the plains of the south-
west. The Not/iocalais and

its relatives are prairie

plants with grass-like

leaves and dandelion-like

heads. The rattlesnake-
roots, some varieties of

which are abundant in the

Minnesota woods and in

shaded ravines, may be

known by their heads of

flowers, nodding in the

common forms, arranged

in panicles and of a pink

or purplish color. One

of these with curiously

triangular leaves is abun-
dant in deep woods, flow-"

ering in autumn, and with

its mature fruits surmounted by a deep brown tuft of pappus

hairs.

FIG. 198. Cocklebur. After Britton and Brown.

Minnesota Plant Life.

405

Ragweeds and cockleburs. The ragweed family, with six
or seven native species, includes the ragweeds, cockleburs and
marsh-elders. The cocklebur, of which two varieties occur in
Minnesota, is known by the conversion of the involucre of each
pistillate head into a two-pronged, many-hooked bur in which
two fruits are enclosed. A striking peculiarity of the cockle-
bur is that one of its two fruits will germinate the first season,
while the other ordinarily lies dormant for a year. The marsh-
elder is, in Minnesota, a tall roadside weed with leaves shaped
like those of the cocklebur. The panicled heads of green statn-

inate flowers are intermixed
with small pistillate flowers
without corollas. The rag-
weeds, of which three species
are common in Minnesota, are
also known as "hay-fever
plants," because their copious
pollen-spores produced in the
autumn will, if inhaled, some-
times germinate in the nostrils
and the little thread-like male
plants will then irritate the
nasal membranes of persons
subject to the disease. The
tall ragweed, which sometimes
grows fifteen feet in height in
low ground along roadsides,
has three-divided leaves and
numerous slender racemes of heads. The other ragweeds have
pinnately divided or compounded leaves, and are a foot or two

tall.

Sunflowers and their relatives. The sunflower family has
about 200 native species. Here are classified the ironweeds,
herbs of moist soil with willow-shaped leaves and purplish small
heads, arranged in flat-topped clusters; also the thoroughworts,
distinguished from the ironweeds, which in outward appearance
they much resemble, by the pappus. In thoroughworts this is
composed of numerous slender bristles, while in the ironweeds
it is double, the inner whorls alone being constituted of bristles,

FIG. 199. Ragweed. After Britton and
Brown.

406

Minnesota Plant Life.

while the outer is made up of short scales. Related to the
thoroughworts are the blazing-stars of the prairies and thickets,
some sorts being also very prominent in open pine woods.
These are wand-plants, with handsome pink or purple heads,
of massive appearance in ordinary varieties, all arranged in a
spike-like cluster at the end of the upright stem. The leaves
are very narrow, like short grass leaves. The gum-plant or
Grindelia, may be known by its sticky leaves and heads, — the
latter with yellow rays and yellow disk flowers.

FIG. 200. Autumnal vegetation of marsh border. Thoroughwort or joe-pye weed. After

photograph by Williams.

The goldenrods are, for the most part, wrand-plants with
densely panicled small yellow heads. In many varieties the
heads are arranged in one-sided racemes and these are aggre-
gated together in paniculate clusters, in three varieties becom-
ing flat-topped. Some goldenrods, found in prairie districts,
have rather narrow leaves, while others, natives of deep woods,
have them very 'broad, ovate or oblong. The different kinds
of goldenrods may be known by the sizes of the heads, by the

Minnesota Plant Life.

407

Boneset or thoroughwort.
Brown.

After Britton and

arrangement of the heads in compound flower-clusters and by

the texture and shape of the leaves. Daisies and oxeye daisies,

asters and Boltonias are

kindred to the golden-
rods. The asters, which

bloom so abundantly

in the autumn of the

year, may be known by

their generally purple

or whitish ray-flowers,

their pappus, consist-
ing of a single series of

hair-like bristles, and

their disk flowers of a

red, purplish or brown-
ish color. Some asters

which live in the forest

have very broad and

heart-shaped leaves, FlG m

while others, at home

in the open, produce leaves that are slender or even awl-shaped.

The flowers are ordinarily arranged in compound panicles

or flat-topped clusters, very
numerous in some species,
in others fewer. The one-
sided, racemed inflorescence
aggregates of the golden-
rods are found in a few spe-
cies. Asters are to be dis-
tinguished from each other
by the same characters men-
tioned for the goldenrods.

Fleabanes have commonly
very slender, thread-like ray
flowers, usually of a white
color, shading often into
violet or purple. The ever-
lastings, to which the com-
mon little Indian tobacco belongs, are for the most part woolly
plants with separated flowers. The staminate flowers are pro-

FIG. 202.

Blazing-star. After
Brown.

Britton and

408

Minnesota Plant Life.

duced on one plant and the pistillate on another, or they may
both arise on the same plant. The rosinweeds include three
rather marked varieties, among which is the Indian cup, in

FIG. 203. Autumnal composite vegetation. In foreground golden-rods, sunflowers and
asters; in background, on brow of cliff, wormwood or sage-brush. After photograph
by Williams.

which the bases of the large leaves are grown together around
the stem, forming deep cups, through which the four-angled
stem seems to grow. Water is caught in these cups and they

Minnesota Plant Life.

409

are often filled with the dead bodies of insects. It is probable
that the plant is partially carnivorous like the pitcher-plants.
The flowering heads are yellow, like small sunflowers. The
compass-plant rosinweed produces near the surface of the
ground a number of leaves a foot or more long, with very deep
lobes running from the margin to near the midrib. These
leaves stand upright and arrange themselves with their edges
north and south. A third variety, known as the prairie-dock,
displays large, long heart-shaped leaves, a foot in length and
six inches or more in width at the base. They compose a large,
loose rosette and do not
stand erect like those of the
compass-plant. In each va-
riety the flower heads are
yellow, both in the disks and
in the rays. The related
oxeyes or sunflower herbs,
as their name indicates, re-
semble sunflowers closely.

In the coneflowers the
disk is hemispherical, con-
ical or columnar in contour.
One variety, the long- i
headed coneflower, has the
disk flowers arranged in a
cylindrical, pointed cone, of
a brownish color when ma-
ture, with a few large yel-
low ray flowers at the base. The sunflowers are mostly upright
herbs, with heads consisting of numerous tubular disk flowers
surrounded by conspicuous yellow rays. The ray flowers con-
tain neither stamens nor pistils and are purely for the purpose of
attracting insects to the less ornamental stamen- and carpel-bear-
ing flowers of the disk. Such a division of labor between the
different flowers of the head marks a very high degree of special-
ization. In some sunflowers the foliage leaves are opposite
while in others they are alternate. Some have sessile leaves,
while in others they are stemmed. In some the foliage is
smooth, while in others it is rough, and in some the disk

FIG. 204. Early golden-rod.
Brown.

After Britton and

Minnesota Plant Life.

flowers are purple, while in others they are yellow. The shapes
of the leaves and of the flower heads differ in the different kinds ;
and the arrangement of the flower heads varies slightly, though
ordinarily they are either solitary or in flat-topped clusters.
To this genus of plants belongs the artichoke, the rootstock of
which bears tubers.

The tickseeds are little yellow-flowered composites, with the
pappus much reduced, appearing commonly as a couple of small

FIG. 205. Asters and golden-rod. Banks of the Mississippi. After photograph by Williams.

teeth at the end of the somewhat winged nutlet. The bur-
marigolds produce yellow flower heads, from the disk flowers
of which arise fruits with two or more strongly barbed bristles
upon each, for in these plants the pappus has lost its aeronautic
characters and is adapted to fasten the fruits to the bodies of
wandering animals. The little flattened, pitchfork-like seeds
which stick to one's clothes in the autumn are those of the bur-
marigold or beggar-ticks. The several different varieties are
known by the shape of the nutlets, by the foliage and by the

Minnesota Plant Life.

411

flowering heads. One, the highest type of aquatic vegetation
in Minnesota, is called the water-marigold, or Beck's marigold,
and is found in ponds and brooks. Its submerged leaves are
all dissected into thread-like lobes. The flowering heads, dis-
tinctly composite in their appearance, are thrust out of the
water, and just below them a few willow-shaped leaves are borne.
The nutlets produce from three to six barbed bristles and are
fitted for attachment to the plumage of birds or the fur of
animals.

The yarrow is an erect herb, a foot or two in height, with
leaves of strong, tansy-
like odor, dissected pin-
nately into numerous tiny
segments. The heads are
very numerous, borne in
dense terminal flat-topped
clusters. The ray flow-
ers are white or pink.
Tansy, a common herb
escaped from cultivation,
is known by the highly
aromatic foliage and the
pinnately divided leaves.
Wormwoods, of which
there are several sorts,
contain the peculiar bitter
principle used as a flavor-
ing substance in the man-
ufacture of absinthe.
Many of them are very

white or silvery, from the numerous hoary hairs with which the
leaves and stems are covered. The heads are small and aggre-
gated in dense spikes, compound racemes or panicles, and the
foliage exhales a characteristic aromatic odor. Colts'foots, to
be found in marshes, may be known by their thick horizontal
rootstocks, by their scaly stems on which, in flat-topped clus-
ters, a few heads are borne, and by their large root-leaves — in
one variety palmately divided like the leaves of some anemones,
and in another of a broadly arrow-head shape. Related to the

FIG. 206. Rosinweed compass-plant,
and Brown.

After Britton

4I2

Minnesota Plant Life.

colts'foots are the arnicas, fireweeds and Indian plantains.
Three varieties of the latter occur in Minnesota. In one of
these the leaves are similar to those of the dooryard plantain,
while the small flowering heads are borne in large flat-topped
clusters at a height of from two to six feet. In another form

the leaves are kidney-
shaped, while in still
another they are trian-
gular, deeply toothed
and provided with a
white bloom on the un-
der side. The ground-
sel, ragworts, squaw-
weeds and butterweeds
or Senecios, are rela-
tives of the Indian
plantains. The eight
or nine varieties which
are found in Minnesota
have somewhat the ap-
pearance of y e 1 1 o w-
flowered asters. I n
most of them there are,
as in mustards, rosettes
or root-leaves different
in shape and appear-
ance from the stem-
leaves, and the flowers
are commonly borne in
flat-topped clusters.
These plants cannot be
mistaken for the hawk-
weeds and their allies
because they have no

milky juice. One variety, the marsh fleawort, or marsh
groundsel, is an abundant swamp plant with a beautiful flat-
topped cluster of yellow heads borne on a very stout, hollow
stem from six inches to two feet in height. In some of the
groundsels the leaves are deeply pinnately divided, while in

FIG. 207.

Cone-flowers.

Williams.

After photograph by

Minnesota Plant Life.

413

others they are more nearly entire. The root-leaves in all
instances, with perhaps one or two slight exceptions, differ in
appearance from the leaves on the flowering stems and are gen-
erally larger.

The burdocks are herbs with very large ovate leaves, cottony
on the under side, but becoming dark green above. Two
varieties occur in Minnesota, the large burdock and the small.
The flowering heads in each are surrounded with involucres,
the scales of which become hooked at the end and barbed so
that the whole flower head separates when in fruit and is dis-
tributed on the fur of animals.
The seedlings of the burdock
spring up, therefore, in little clus-
ters, one from each of the numer-
ous enclosed fruits. Both species
are locally known as "wild pie-
plant" on account of their large
leaves like those of the rhubarb.

Thistles are stout herbs of
wand-like habit, often ten feet or
more in height and with hand-
some heads made up of pink or
purple tubular flowers. The foli-
age and the involucre is pro-
tected by spines and the fruits
are provided with abundant pap-
pus, sometimes of plumy and
sometimes of hair-like bristles. FIG. 208. prairie cone-flower. After Brit-
Related to the thistles is the
bachelor's-button or corn-flower,
flowers of a head are not strap-shaped, but are overgrown
tubular flowers, blue or purple in color.

Summary statement. There have now been passed in re-
view a considerable number of Minnesota plants, sufficient to
illustrate all the important groups. The lower groups are
marked by relative simplicity of structure, increasing in com-
plexity to the highest. Such plants as the thistles and sunflow-
ers occupy in the plant kingdom a position similar to that of
man in the animal kingdom. Structurally they are the most

ton and Brown.

In this variety the marginal

Minnesota Plant Life.

improved. Especially in the
composite family should it
be observed that the ftower
cluster has become an area
perfected under somewhat
the same laws that were seen
to govern the perfecting of
the flower. It will be re-
membered that the flower
itself is supposed to have
originated from groups of
leaves arranged on a slender
axis. As this axis aban-
doned itsstarchmaking
work, the leaves were gath-
ered into a more compact
structure by the shortening
of their general stem. Thus FlG' m- Water bur-marisold- After Britton

and Brown.

from cones like those of the

pines arose the flatter aggregates of spore-bearing leaves known
as "flowers" in the higher plants. These flowers were essentially

branches of the stem and in
the lower families such
branches more commonly
maintained their primitive po-
sition with reference to each
other, so that the flowers were
arranged loosely upon the
plant. In higher forms defi-
nite flower clusters of particu-
lar shape came into existence
and the law of condensation
finally permitted the produc-
tion of the flat-topped cluster
of the sunflower in which hun-
dreds of flowers are gathered
together on a broad circular
disk. Among these flowers of

FIG. 210. Corn-flower. After Britton and

Brown. the disk a division of labor

Minnesota Plant Life. 4 1 5

arose so that some flowers abandoned their stamens and pistils
and became converted into neutral ray flowers, useful in adding
to the attractiveness of the cluster, thus possibly inducing in-
sects to visit it more freely. The heads of flowers came them-
selves to stand in definite compound clusters, so that just as
there was a spike of flowers in the plantain family there later
came to exist a spike of flower-heads, as in blazing-stars, and
just as the flowers of the high bush cranberry learned to stand
in flat-topped clusters, so in the thoroughworts and asters, heads
of flowers were arranged in similar inflorescences.

Each flower of the composite head shows a high degree of
fusion between its parts. That is to say, it is a flower of high
rank. The originally separate carpels are blended in pairs into
the fruit-rudiments, one to each flower. The stamens in all
Minnesota genera of composites except one are fused. The
petals of the corolla are blended into a tube which in some of
the flowers becomes split, to make the strap-shaped corolla of
the dandelion or the strap-shaped ray flower of the daisy. The
calyx parts are blended together into a calyx tube and this be-
comes fused with the surface of the fruit-rudiment, developing
in many of the genera a distributing apparatus made up of
bristles, variously arranged and of various structure. The
leaves below the flowering head, in such forms as the burdock
and cocklebur, become modified to assist the distribution of the
seeds.

Three types of higher plants may be regarded as terminal,
the orchids standing at the top of the series of plants with one
seed leaf, the dogwoods at the top of the lower series of two
seed-leafed plants, and the sunflowers, dandelions and thistles
at the top of the highest series. Among orchids, the flower
cluster was not highly improved as such, but the perfecting
tendencies worked rather toward the production of a much
complicated floral mechanism, irregular in shape, reflecting the
strong influence of those forces which develop bilateral sym-
metry, and very exact in its adjustment to the habits of the
insects which co-operated in its pollination. The clusters of the
dogwood, although not so fully perfected as those of the sun-
flower, showed, in the arrangement of their flowers, some tend-
ency towards the perfection of the flower cluster as a unit.

4i 6 Minnesota Plant Life.

Especially in the flowering dogwoods and dwarf cornels, with
their conspicuous bracts below the heads of flowers, did there
arise an adaptational response to the tastes and habits of insects,
equivalent to that secured in sunflowers by the specialization of
the ray flowers. In the bunching of the edible fruits of dog-
woods and in their high coloration, the fruit-cluster, as such,
became a definite factor in the mechanism of seed distribution ;
for the aggregation of the fruits made them more attractive to
birds and animals, therefore more likely to be disseminated than
if they had been scattered loosely over the general surface of
the plant. In composites, winged distribution has, for the most
part, been adopted, and in this family highly colored, pulpy and
edible fruits do not exist. The aggregation of the flowers, how-
ever, is perfected and the co-operation of the calyx, from which
the pappus is formed, makes the distribution of the fruits quite
as certain as among the dogwoods.

A sunflower head may, upon the whole, be regarded as the
most perfect structural response to the static conditions of the
plant world, just as the human head, with its wonderfully per-
fected brain and sense organs, may be regarded as the highest
structural response to the dynamic conditions of the animal
world and of animal life.

Chapter XL.

Adaptations of Plants to their Surroundings.

if

It has already been remarked that plants which resemble each
other in external form must not for that reason alone be con-
sidered as related. Indeed, quite the opposite is often true, and
plants that are outwardly very dissimilar are found upon careful
examination to bear the marks of kinship. Thus, the locust
tree and the pea vine are really connected with each other much
more intimately than are locusts and ashes, although the latter
are similar in size, in habit of growth and even in the production
of such special types of starch-making organs as pinnately-com-
pounded leaves. Plants may, however, for purposes of investi-
gation be arranged in groups according to their adaptations to
the various conditions of life and growth. Such adaptational
groups will include plants of widely different genealogy, but
throughout there will be discovered certain similarities of struc-
ture and habit. Thus, for example, among aquatic plants there
are often striking likenesses in structure between comparatively
unrelated forms, and it is in many instances a puzzling problem
to determine just which structural resemblances are indicative
of true relationship and which are indicative of similar adapta-
tions to similar conditions. The submerged leaves, for illustra-
tion, of the water crowfoot or water buttercup are in general
appearance not particularly different from the submerged leaves
of the bur-marigold, in both plants those leaves produced un-
derneath the surface of the pond in which they live are dis-
sected into fine, threadlike portions. Again, the quillworts,
plants belonging to the fern alliance, bear the same type of
cylindrical hollow leaves that is distinctive of the water lobe-
lia— a member of one of the highest families of flowering plants.
Or, passing to plants of a different habit of growth, it may be
noted that the curious, compressed forms of vegetation charac-
teristic of cacti are almost exactly reproduced in members of

28

4i 8 Minnesota Plant Life,

the unrelated spurge family at the Cape of Good Hope. The
pitcher-plant and sundew have developed apparatus for catch-
ing small insects and converting them into food for their own
uses, and somewhat similar contrivances are met with in the
bladdcrworts and butterworts ; but the two groups of plants, so
far as true relationship goes, are very widely separated. With
such facts in mind, it is apparent that, if genealogical connection
be ignored, plants may be grouped according to their adapta-
tions. By this means certain interesting truths may be em-
phasized concerning the influence, upon plant structures and
habits, of the surroundings. Before entering upon any discus-
sion of the various adaptational groups of plants represented in
Minnesota, such as water plants, desert plants, carnivorous
plants, perching plants, mat plants, wand plants, shade plants,
sun plants, rock plants, marsh plants and a number of others, it
may be briefly noted what are the principal external conditions
to which plant structure and habits are adapted.

Gravity. A plant, like any other natural object, must main-
tain itself under the constant influence of the force of gravity,
and it is, therefore, necessary that it should be architecturally
well constructed. An imperfectly constructed tree trunk could
not bear the weight of its branch-system, nor of its thousands
of leaves and possibly of fruits, unless — precisely as in works of
man, such as elevators, aqueducts or bridges — the laws of en-
gineering had been obeyed. Certain necessary ratios exist,
therefore, between the thickness of tree trunks, the tenacity of
the wood, the height of the tree, the number of branches, and
the angles at which they stand upon the main axis. For this
reason a limit is fixed for the height of land vegetation, beyond
which it is extremely difficult to pass. If, however, in the life
of the plant some method is found by which support can be
obtained from without, much longer stems can then be produced
and they can remain of slenderer habit. Thus the climbing
bittersweet, the wild grape vine, the trumpet-creeper, the pipe-
vine, or the bean, are enabled to produce stems much longer in
proportion to their thickness and strength than would be pos-
sible if they did not utilize neighboring vegetation to help bear
the weight of their leaves, twigs, flowers and fruits. The sup-
port that is obtained by a plant stem need not necessarily con-

Minnesota Plant Life.

419

sist of the vegetation around it, but the stem may lie flat upon
the ground, as does the strawberry runner. Thus supported, it
can remain slim and fragile, but it could not do this if it main-

FIG. 211.— Bur oak and bracken fern. Illustrates relation between strength of stem and the
weight to be borne. After photograph by Hibbard.

tained an erect habit. Again, water surrounding the stem and
leaves of a plant may furnish the necessary support, and the
plant is free to produce slender organs which collapse when

420 Minnesota Plant Life.

removed from the water that buoys them up. Thus, in the
pipewort, which, from the bottom of a lake, lifts a thread-like
stem ten feet or more in length, an organ is formed that could
not be thus developed under ordinary terrestrial conditions.

A great many other adaptations besides these simple ones of
length and thickness of shoots might be discussed at this point.
For example, it is necessary that seeds or fruits, borne at the
tops of trees, should not be of such structure that they would be
broken and injured by falling to the ground. Cocoanut seeds,
therefore, which are heavy and are produced at a considerable
height, have thick, hard shells and are not injured by their fall.
A definite relation commonly exists between the stem of a leaf
and the blade, or flat portion, so that the leaf is extended in a
position such that its leaf-green can do the work of starch-mak-
ing under the influence of sunlight. So the stems of large
leaves are generally strong and often of a half-cylindrical shape,
giving the strength of an arch to the lower surfaces. The net-
work of the large leaf is stronger than that of the small leaf, just
as a large umbrella must have a stronger frame than a child's
parasol. If leaves or fruits are produced close to the ground
they may become larger, while remaining more delicate in struc-
ture, than if they were produced at a considerable height. In
the one instance the fall would be harmful, while in the other
the influence of the wind would enter as a factor.

Mechanical forces. Besides being exposed to the force of
gravity acting constantly upon its structure, and consequently
rendering due attention to strength of materials a prime requi-
site in plant architecture, the organism is subjected to various
forces which would tend to demolish it unless it met them with
properly constructed areas. As examples of such agencies, there
might be mentioned currents of air, which if violent are often
known to damage the bodies of plants; currents of water, to
which plants growing in rapid streams are particularly exposed ;
the action of waves, to which the various surf plants must adapt
themselves ; and the pressure of soil, air and water, by which the
different parts of plants are constantly affected. In erect ter-
restrial vegetation elasticity is to a certain degree a requisite of
structure. This is particularly true of such stems as are slender,
unsupported, and exposed to the influence of wind or surf.

Minnesota Plant Life.

421

Beautiful examples of elastic plant organs are furnished by any
field of grain over which a gust of wind is passing. The stems
with their heavv heads of fruit, under the breeze bend almost to

FIG. 212.— Willows and bulrushes. The latter are typical surf-plants. After
photograph by Williams.

the ground, then as the air becomes calmer elastically swing back
again into the erect position. Or, when it is blowing a great

422 Minnesota Plant Life.

gale along the lee shore of some Minnesota lake, one may see
the bulrush stems beaten into the water by the wind and surf,
only to rise again erect and unharmed when the waves are
calm. Such elasticity is procured by special structural areas
in the stem, disposed in highly accurate fashion so as to take
up the lateral strains evenly and effectively. The cross-section
of a bulrush stem shows it to be as cunningly constructed as the
finest bridge-truss, with girders, flanged in the regulation style,
made up of the so-called "tension pieces" and "compression
pieces" of the architect, and constituting an altogether admi-
rable piece of structural engineering. Such contrivances are
not needed by plants growing under other conditions and will
not be found. Elasticity, for example, is not a noteworthy char-
acteristic of the stem of submerged aquatic plants living in
quiet pools ; but if the stem grows in running water it is some-
times more elastic. Roots, in general, being underground in
their habit, are not so much exposed to occasional displacing
forces as are stems and, therefore, are by no means so elastic.
It is easy to compare, in these regards, a grass stem and a grass
root. If the living erect stem of a rye plant is bent down it
quickly resumes its original position ; but if the root is bent to
one side the resumption is but slight, or there is no resilience.

In certain parts of the world, where heavy falls of snow occur,
a weight is in this way piled upon the branch system, and the
plant perhaps responds to such a climatic state by growing in
the form of a flat, prostrate shrub, as many of the heaths have
done. Or, if it be a tree, it learns to produce strong drooping
lateral branches like those of the spruces. When grown in a
lawn, these trees retain the droop of their branches or branch-
lets — originally a structural device for shedding masses of snow,
that might otherwise break the branches by their weight.

Plants that produce abundant and heavy fruits must, if they
support the weight of these fruits, develop strong branch sys-
tems, or otherwise the body of the plant will be broken. Of
this the apple trees of orchards furnish good examples. The
branches of the apple are pulled into a more horizontal posi-
tion by the increasing weight of the fruit and many of them
actually droop. The main branches will, however, be found to
be strong and well buttressed against the trunk. Very often,

Minnesota Plant Life.

423

under a heavy branch the trunk of the tree is especially strength-
ened to bear the weight. And so, too, against the massive
roots of a tree, the trunk is often buttressed because it is against
these points that the pressure is exerted, when the tree top is
pushed laterally by the wind. Plants with comparatively slen-
der branch systems may mature large fruits if they let these
fruits lie upon the ground. This is the device adopted by the
gourd family, and the gigantic pumpkins and squashes which
are so often exhibited could scarcely be borne, except under
very exceptional conditions, upon plants that carried the whole
weight of such enormous bodies themselves. Some plants, it
is true, manage to suspend extremely heavy fruit areas. Thus,
the banana forms a bunch of fruits weighing in the aggregate
some scores of pounds. But it is borne close to the main trunk
and is hung in such a way that the strain is not unbearable.
Cocoanuts, which form heavy fruits at a considerable height,
have them placed close to the center of the tree, not out near
the tips of the branches like those of the apple.

The relation between the sizes of leaves and their exposure
to the winds has already been mentioned. It is not possible for
large, thin and delicate leaves to maintain themselves under
climatic conditions in which heavy winds are prevalent. If large
leaves occur in windy districts, their edges are strengthened by
special adaptations of the leaf network. Very beautiful ex-
amples of strengthening devices for the edges of leaves may be
seen in milkweeds, basswoods or catalpas. In the latter tree,
especially, the edges of the large, heart-shaped leaves are faced
by arch after arch of network, making the margin of the leaf
very strong against any lateral tearing agent.

A consideration of the points which have been thus briefly
presented will show how reasonable it is that the longest
stemmed plants in the world should be oceanic, for such stems
have water on every side to support them. It will be equally
apparent how reasonable it is that the most massive plant struc-
tures and the strongest should be the trunks of trees on land,
for these, of all plant organs, have the greatest need of strength
if they are to perform their work and meet the forces to which
they are subjected. The difference of elasticity between differ-
ent plants growing under different conditions, or between two

Minnesota Plant Life.

differently conditioned organs of the same plant, will appear
altogether comprehensible. After such facts have become
familiar it should not be difficult to infer something of the his-
tory of a plant from its general architectural construction. The
droop in the branches of a spruce tree comes to have its sig-
nificance, and the prostrate bodies of the cranberry or par-
tridgeberry tell a similar story of the flattening effect produced
by heavy falls of snow.

Heat. Another natural force to which plants must necessa-
rily adapt themselves is that of heat. Therefore, under different
temperatures different forms and habits of vegetation may arise.
The range of temperature under which dormant life can be
maintained is apparently a pretty wide one — between 400 and
500 degrees centigrade. The spores of some bacteria can en-
dure boiling for an hour or more and, for a short time, a dry
heat somewhat higher, while certain seeds have been exposed
for a season, without killing them, to the low temperature of
liquid aid. But the limits of plant growth, so far as regards tem-
perature, are considerably narrower. A few blue-green algae
are able to maintain themselves in hot springs, the waters of
which would burn the hand, while the little red-snow plant
grows upon snowdrifts on mountain tops. Between these limits
— scarcely 100 degrees centigrade — are the temperatures at
which active plant, life and growth is possible.

The form of plants is quite different under an average low
temperature from that which is developed in areas of greater
warmth. So, therefore, a very characteristic arctic vegetation
arises in contradistinction to that of the tropics. A comparison
of polar with tropical vegetation will serve to indicate what are
the influences upon plant form and structure of relatively high
and relatively low temperature. For the most part the vege-
tation of the polar regions is dwarfed, consisting of low, tufted
plants, little shrubs, stunted herbs, mosses and lichens. In such
regions the great luxuriant trees and herbs of the tropics are
unknown. So, in the matter of size, the poles and the tropics
favor just the opposite sorts of plants. In polar regions there
is only a short growing season and during the rest of the year
the temperature is so low, and the illumination so poor, that
plants, like many of the animals, are compelled to pass into a

Minnesota Plant Life. 425

dormant condition. Not all of them hibernate in the same way.
A few polar species are annuals, shooting up from the seed dur-
ing the short polar summer, rapidly maturing their flowers and
fruits, and passing the long cold winter as little plantlets,
wrapped up in their protective seed coats. There are, however,
a greater number of biennial and perennial polar plants. Some
of these are shrubs, like the poplars and willows, which grow a
very little from year to year, quickly mature their flowers and
fruits, and pass the winter in a leafless, dormant state. Such a
rhythm in the plant, established to meet the rhythm in the outer
world, results, as has been previously noted, in that general
habit of shedding the leaves which characterizes so many plants
of the polar and temperate regions.

Besides their dwarfed size and their various habits of hiberna-
tion, plants of cold regions exhibit numerous protective devices
against the cold. The seed coats are thick, and sometimes the
seeds are inclosed in warm fruits ; the leaves and stem are often
clothed with hairs ; the young twigs are covered over with pro-
tective scales, forming the well-known object that is called a
bud; and "warming-up colors" are developed, especially where
there is need for them to protect the delicate portions of the
plant. The ends of the shoots are particularly rich in the warm-
ing substances. Peat-mosses are good examples of this, for in
a great many of them the ends of the branches are violet, red
or purple, while lower down they remain green. Bud scales
are commonly purple, and alpine and polar flowrers are more
likely to be blue or violet than yellow or red. By this means
the temperature of a flower in which the delicate pollen spores
are formed, or the temperature of a young twig, surrounded by
its purple bud scales, is raised somewhat, and the unfavorable
influence of the cold is, to some extent, counteracted. The
efficiency of the "warming-up color" may be tested experiment-
ally by any one who cares to take the trouble. If two similar
thermometer tubes are selected and around the bulb of one of
them a green leaf is tied, while around the bulb of the other a
purple leaf, such as that of the beet or of certain begonias, is
wrapped, and the two thermometers are then laid in the sun,
after a short time it will be found that the one with the purple
leaf is registering from six to ten degrees higher than the other.

426 Minnesota Plant Life.

So, too, if a thermometer bulb is imbedded in a bunch of violets
and laid in the sun, while another is imbedded in a bunch of
primroses, the one in the violets will register a higher temper-
ature after both have been lying together in the sunlight. The
recognition of the warming-up color of plants as a heat-pro-
ducing substance gives a basis for the explanation of a great
many facts that would otherwise be difficult to understand.
Autumn foliage can be understood to be a definite response of
the plant to the falling average temperature, by the development
of a heat-producing area of its own. The purple bud scales, so
common in trees that grow outside the tropics, purple tints
in bark and in leaves, and the purplish or reddish colors of
flowers, are all recognized as having the same general signifi-
cance.

At this point it is possible to understand how, in a great many
species, the color of flowers may have originated. As has already
been explained, the flower is essentially the end of a branch, and
the coloring substances which it contains are possibly to be
attributed to protective heat-producing substances present in
the race-history long before flowers were developed as such.
When flowers came to be formed it was important that their
pollen should be protected against cold, and the heat-producing
colors were not abandoned but accentuated. In many blue,
violet and red flowers it is possible to read a story of defence
against cold. Hence is made clear the reason for so many
very early flowers, like the pasque flower, maple flowers, violets
and anemones, being purplish in color, and for late flowers,
such as the gentians, having the same blue or purple hue. It
is also easy to understand how flowers on the mountain tops
should be so often blue and that flowers of the polar regions
should show the blue, violet or reddish tints. With such facts
in mind it is possible to recognize violets and anemones as, for
the most part, northern plants, while goldenrods and evening-
primroses indicate a southern origin.

Another useful habit of plants in polar regions is their tend-
ency to form stores of reserved food-material, such as under-
ground fleshy roots, stems or tubers, or subterranean bulbs. A
great variety of plants with such habits are common in Minne-
sota. On account of its provident behaviour the plant is able

Minnesota Plant Life. 427

to begin the development of its flowers and fruits immediately
after the cold of winter is past. When the growing season is
short, it is particularly important for plants to ripen their fruits
speedily, or they will not be able to ripen them at all, and under
such stress, in the plants of cold countries, very rapidly growing
flowering stems are produced. Arising from a fleshy root, a
starch-packed tuber or a solid bulb, they open their first flower
perhaps within a week after the snow has gone, finishing their
fruits before the end of spring. Such unnecessary haste in a
climate like that of Minnesota indicates an adaptation to a
colder region ; and the willows and poplars, for example, which
scatter their fruits in the spring or early summer, may be found
abundantly distributed far to the northward, even to the barren
lands of arctic Canada. More leisurely plants which do not
ripen their fruits until the late autumn, such as the grapes, the
gourds, the goldenrods and the asters, by this very fact show
their southern ancestry, and they will be found better developed
in the south than in Minnesota. The colors of flowers, the meth-
ods of hibernation and the presence or absence of reserve organs,
such as bulbs, are all of much value in determining the probable
climatic history of a plant.

Some movements in plants are significant as indicating an
adaptation against loss of heat. A great many flowers close
at night. This is particularly true of the flowers of northern
plants, though it is a device which is common enough in many
species growing in regions where the nights are cool. By
the closing of the flower nocturnal radiation of heat is dimin-
ished and thus the pollen spores are protected against unde-
sirable chills. Sometimes the flowers do not close, but place
themselves in peculiar sleep-positions. Thus a pansy flowrer,
which is erect in the daytime, bends over and faces the ground
at night. Such new night attitudes are not limited to flow-
ers, but may be adopted by leaves as well. At night the
leaves of the clovers and locust trees will be found in quite differ-
ent positions from those which they maintain during the day.
The nocturnal position is probably a device for limiting the
radiation from the plant body. Incidentally it is useful in pre-
venting the condensation of dew. Such modified positions are
sometimes taken suddenly, as by the leaves of the sensitive

428

Minnesota Plant Life.

plant, an instance for which no doubt other and special reasons
must be assigned. In general the so-called sleep of leaves and
flowers is an adaptation to the falling temperature after the sun
has set.

When plants grow in warm regions they often manifest a
number of characters which are the reverse of those to be
looked for in plants whose home is nearer the poles, or at a
greater elevation. Thus in many tropical plants the produc-
tion of special reserve storage organs is less considerable than
among related species of colder climes. Buds are not so care-
fully protected. Furry coats on the leaves or twigs are not so
abundantly formed — except, it should be said, by desert plants
in which furry or hairy coatings arise as a protection against
the too ardent rays of the sun. In the tropics, since hiberna-
tion is unnecessary, the various hibernating habits fail to ap-
pear, and plants do not so commonly grow as biennials. The
foliage is not shed at the end of a definite growing season, but
normally drops only when exhausted or when shaded out of
existence by younger foliage between it and the sun. The
heat-producing qualities, as manifested by color, are not so
marked a feature, and a great many white, yellow and mottled
flowers occur, like those of most tree-top orchids in the equa-
torial forests. Evergreen plants, such as the live-oak, flourish
in the south; in temperate regions the oaks are deciduous,
though retaining the character of trees, while in the far north,
oaks, which would be trees in more southern ranges, become
stunted into little shrubs. It is possible, in view of such facts,
to understand how dwarf shrubs may occur in certain genera,
as, for example, the dwarf cornel among the dogwoods; the
dwarf snowberry, among the honeysuckles ; or the dwarf willow,
among the willows. It is possible to understand, too, how very
hairy varieties may develop under climatic conditions different
from those which favor the production of smooth varieties of
the same plant. The silky dogwood may thus be regarded as
a species showing in its foliage a response, either to the lower
average temperature, or to more direct illumination by the sun
than the smooth-leafed dogwood.

Light. Another form of energy, which has a strong effect
upon the structure and habits of plants, is light. Some plants are

Minnesota Plant Life.

429

so constructed that they can exist with much less illumination
than others. This is particularly the case if they are devoid
of leaf-green, and certain fungi are able to grow and mature
their fruit-bodies in absolute darkness. The ordinary green
plant must, however, be supplied with illumination sufficient
for the use of the starch-making machinery, — for leaf-green may
be described as a variety of light-engine. Hence there arise,
especially in the leaf-areas of plants, a variety of adaptations by
means of which the leaves are spread out to the sun. If a plant

FIG. 213.— Elm tree growing in the open. I^ight is received on all sides. After
photograph by Williams.

is growing where it is not shaded by other plants, it may assume
the mat or carpet habit of growth ; but if it is shaded by other
plants it must become taller in order to get its share of illumina-
tion. The positions of leaves on the plant body are, in the
economy of the plant, often very carefully adjusted, so that one
leaf fits quite exactly into the spaces between other leaves.
Thus, what are known as leaf-mosaics are formed. The leaves
sometimes make a rosette at the base of the fruiting stem, a
condition that may be seen in a dandelion, in the evening-

430

Minnesota Plant Life.

primrose, or in the mullein. In other plants the shapes of the
leaves are modified by their mutual relations to each other upon
the general stem tract. Thus the one-sidedness of elm or
hackberry leaves will be found to be dependent upon the rela-
tive positions of the leaves upon the twig. The side of the leaf
which is less protuberant is the one that is shaded by the leaf
above. The sizes of leaves vary considerably with their illumina-
tion. Thus the leaves of plants in shady places are generally
larger than those of plants growing in the sun. The trillium
and jack-in-the-pulpit leaves, for example, are considerably

FIG. 214.— Two-leafed wood-lilies. These plants have the broad leaves of shade plants and
the white, conspicuous flowers. After photograph by Hibbard.

broader than the ordinary leaf of their class. Some grass leaves
belonging to species growing in the deep woods are decidedly
broader than ordinary, and the forest-dwelling asters and gold-
enrods are conspicuous for their broad leaves, quite different in
shape from the willow-like or linear leaves of the sun-loving
varieties.

It is well known that light retards that actual increase in
size of plant organs which alone should be called growth. It
is well to distinguish between growth, meaning by this, increase

Minnesota Plant Life.

43'

in size, and nutrition, meaning by that, increase in substance.
Plant stems usually become more extended in the dark than in
the light. Thus, if potatoes are allowed to sprout in the cellar
the stems produced under such circumstances are quite different

FIG. 215. — Jack-in-the-pulpit. A shade plant. After photograph by Hibbard.

in appearance from those grown in the ordinary way. Con-
sequently, the principal hours of growth are those of the night,
and corn-stalks, if carefully measured, will be found to increase
in length most rapidly between midnight and morning.

432

Minnesota Plant Life.

While light has a retarding influence upon the growth in
length of stems, it has a strong directive influence upon organs,
so that they tend to place themselves parallel with the rays, or
transverse to them, as their nature may be. It is well known
how the leaves of geraniums growing in the window turn to-
ward the light. Nasturtium vines turn very quickly and if
one of these plants be put in the window, it will in a short time
stretch out its leaves toward the light and place them vertically
to the rays, thus securing a maximum illumination for the
starch-making apparatus. Some plants are not thus sensitive

FIG. 216.— Reaves of the sensitive fern, a shade-loving variety. After photograph by Hibbard.

to light. For example, such climbing plants as the ivy or
the woodbine do not instinctively bend toward the light, because
to do this would tear them from their supports ; therefore, they
remain either insensible to the directive influence of light, or
they actually turn from it, as do most roots.

Where the light is strong and abundant, there are often de-
veloped purple layers on the under sides of leaves to utilize the
surplus light by converting it into heat and employing it for
the growth-energy of the plant. This is true of such large

Minnesota Plant Life. 433

floating leaves as those of the water-shield, in which the upper
side of the leaf is green and the lower is purple. The giant lily
of the Amazon, sometimes cultivated in aquatic gardens of parks
in Minnesota, has great shield-shaped leaves, two feet or more
in diameter, and fitted to float upon the surface of the water.
The edge of the leaf is turned up to prevent ripples from break-
ing over the surface. While the upper side is green the under
side is violet or purplish. The surplus light, not used in starch-
making, is, in such a leaf converted, by the purple coloring mat-
ter, into heat, and is not lost.

When leaves form rosettes an adaptation for saving the sur-
plus light is often noticeable. Thus, the under sides of dande-

FIG. 217.— The Virginia creeper on the walls of the old round tower, Fort Snelling. This
plant does not turn towards the sun, but clings to the shaded wall. After photograph
by Williams.

lion leaves are commonly purple; and in a great many other
rosette-forming plants the leaves of the rosette will have the
color scheme which has been described. Hanging or swing-
ing leaves that are swayed by the wind, for reasons that
are sufficiently obvious, do not so often have the two sides
colored in this manner.

Protection of the leaves against an illumination strong
enough to injure the starch-making machinery within, is of
various types. Sometimes the leaves are covered with scales,
or hairs, thus tempering the light. Sometimes they are
capable of changing their positions, so that when exposed to

direct sunlight they shift from the transverse to a more ver-
29

434 Minnesota Plant Life.

tical position. This is true of leaves in the compass plant and
many leaves on a variety of herbs. In some of the Austra-
lian blue-gum trees the leaves stand with their edges ver-
tical, and similar positions are very often maintained by
grasses of the prairie. When a plant has adopted the mat
habit of growth, indicating the absence of shade around it, it
commonly shows very small leaves, and no Minnesota mat
plant, lying exposed to the full glare of the sun as it does, has
large leaves.

Moisture. The adaptations of plants to moisture are vari-
ous. Some plants live quite submerged in water, and others find

FIG. 218. — " Gallery woods," near Minnesota Falls, valley of the Minnesota, in the prairie

district. Dependence of trees upon moisture is illustrated by their grouping

in declivities. After photograph by Professor R. D. Irving.

their most congenial home in deserts, or on the surfaces of inhos-
pitable rocks ; while between these two extremes of station there
are a great number of intermediate conditions worthy of care-
ful and extended investigation. All plants need some moisture.
Usually this moisture is absorbed by a special area of the plant
known as the root system. But leaves are, in some varieties,
able to absorb moisture, and aquatic plants characteristically
absorb over their whole surface. There are sometimes pres-
entations of liquid to the plant which it finds undesirable. For
example, foliage guards itself by a variety of devices against
the heavy rains of the tropics. Many of the same contrivances

Minnesota Plant Life. 435

may be seen in plants of northern regions. If leaves are ex-
posed to a heavy rainfall the surfaces are often lacquered or
waxy, and, by means of the coating, rain is diverted and there
can be little danger of the tissues becoming water-logged.
Upon such leaves grooves or furrows may be developed.
Through these the water is quickly drained and is not allowed
to accumulate. Slender points are distinctive of leaves upon
which too much moisture accumulates for the good of the
plant, and especially in tropical forests are these rain-tips, as
they are called, ordinary characters of the leaf. It has even been
shown that trees growing in the spray of waterfalls develop
leaves slightly different in shape from the ordinary leaves of
the species and marked both by furrows on the upper side
and by elongated tips. Because of the danger of rain or dews
clogging the air pores of leaves these tiny apertures are in most
instances assembled on the lower surfaces of leaves, where
they are protected. Or, if they occur on the upper surfaces
there are hairs, or pegs of cell wall substance, or blooms of wax
or shellac, which guard them and make it difficult for them
to be wet. Such protections against moisture are particularly
common in flowers, where it is essential that the pollen should
be kept dry. The shapes of the petals, the positions of the
stamens, and a variety of other adaptations make the wetting
of pollen by rain improbable. Many fruits are furnished with
blooms of wax or with hairs by means of which they easily
shed water. No such contrivances are to be looked for in the
root system, or on the leaves or stems of submerged plants.
In water-lily leaves and other floating varieties, where the air
pores are all upon the upper surface of the leaf, decidedly waxy
coatings are often developed to keep the water from the
pores. In some varieties, as, for instance, the oleander, the
pores open into special chambers or depressions, on the under
sides of the leaves, and the mouths of these are guarded by
"non-wettable" hairs, thus affording absolute protection to the
air pores. Many of the different positions, shapes and textures
of leaves and flowers are to be ascribed to such adaptations
against unfavorable moistening.

The root tract of plants, which in most instances is the spe-
cial absorptive area, is fitted by structure and position for the
\vork it has to do. The young roots are furnished with in-

436 Minnesota Plant Life.

numerable delicate hairs and these are thrust between the crev-
ices of the soil to collect whatever moisture there may be
present. If, however, the roots are immersed in the water and
hang down like the little balancing roots of the duckweeds, root
hairs are not then so abundantly produced because moisture is
plentiful everywhere around the root and no special arrange-
ments for its collection are necessary. Moisture, after having
been collected by the plant through the activities of the absorb-
ing surfaces, is evaporated, and the residue is left in the plant,
either to be combined with other substances in the plant chem-
istry or to remain as a useless by-product. Evaporation and
transpiration of water vapor are the ordinary methods by which
plants rid themselves of the superfluous water they have ab-
sorbed ; but some varieties exude it in drops from special water-
excreting glands. Thus, fuchsia leaves, if well supplied with
water at the root, will excrete it in little drops from each tooth
of the leaf margin.

There are at least three conditions under which plants
find it undesirable to excrete or transpire water rapidly. One
condition is that of the desert, where there is very little
water to be obtained, and its rapid transpiration by large
evaporative surfaces would result in the wilting of the whole
plant. Another condition under which rapid evaporation is
undesirable is that of bogs and marshes, and the reason is just
the opposite. Here there is such an abundance of moisture
that the rapid evaporation of it might maintain an unneces-
sarily strong stream through the plant tissues. A third con-
dition is where the soil-water is impregnated with salts, and
if rapidly evaporated it would be as rapidly absorbed, and the
salts would accumulate in the plant tissues to such an extent
that they might interfere with vital processes. Consequently
there are three groups of plants so situated that, while they
permit water to evaporate from their leaves and stem, their
adaptations of structure are for slow transpiration. The cacti,
with their solid stems and reduced leaf surfaces, are examples
of one class. The tamaracks and spruces, with their small
needle-shaped leaves, are examples of another, and the sea-
blites and glassworts of the salt marshes furnish examples of
the third.

Minnesota Plant Life. 437

A variety of contrivances have been devised by plants to
retrench their evaporation. A simple one is the reduction of
the evaporating surface. Thus, leaves become small or are
altogether abandoned, as in the cacti and glassworts, or the
leaves may become thick and succulent, as in the purslanes and
claytonias. Sometimes the skins of the leaves are greatly thick-
ened and the air pores are reduced in number, as in the leather-
leafed wintergreens and heaths. Often the margins of the
leaves are rolled in so as to cover the air pores and protect them
from the rays of the sun, as in many prairie grasses, or in the
crowberries. Sometimes the leaves are covered with scales or
scurf, as in the buffalo-berries. Sometimes strong ethereal oils
are produced. These form a "scent-vapor-sheath" around the
plant, and thus temper the rays of the sun. For such a reason
many desert plants are strongly perfumed, as are wormwoods
or sage-brushes. The positions of the leaves upon the stem,
and their shapes, are often automatic, regulative devices, con-
nected with the evaporation of moisture. Good examples of
leaf-position unfavorable to rapid evaporation are furnished by
the cat-tails, flags and sweet-flags of marshy places. In these
the ribbon-shaped leaves stand erect and their surfaces are not
exposed to the strong illumination of the sun. Hence the
evaporation is slight.

Electricity and magnetism. The adaptations of plants to
the forces of electricity and magnetism are not well understood,
nor have they yet been fully studied. It has been suggested
however, that points on leaves, and spines or thorns, may in some
instances be devices for the collection of atmospheric electricity.

The soil or substratum. The relations of plants to the soil
are somewhat various. The texture of the soil may be either
loose or firm. Good examples of loose soil are furnished by
sand dunes, and there are a variety of special sand dune plants,
the underground parts of which, meeting with little resistance,
branch copiously in every direction. The low fertility of drift-
ing sand makes such a broad expansion of the root area essen-
tial, and as a consequence the plants that are able to grow
on sand dunes commonly bind the sand by their extensive root
systems, and may even, if they have become sufficiently estab-
lished, stop its drifting. In very resistant soils, such as hard

438 Minnesota Plant Life.

clays, less copiously branched root systems are produced. The
temperature of the soil, as well as its texture, has a variety of
well-marked effects upon root areas, as has also the consist-
ency, the chemical constitution and the aeration. Soils which
are very poorly aerated, such as those disposed underneath
sheets of water, often make it necessary for roots developed in
them to send up aerating tubes or organs. The well known
"knees" of the swamp cypresses of the Atlantic region are ex-
amples of such organs. A greater or less percentage of nitrog-
enous substance, lime, magnesium, iron or silica, in the soil
has a distinct determining effect upon the forms of plants.

Especially interesting is the soil known as humus, a type
which contains a large percentage of decaying organic material.
In such a soil many plants without leaf-green are enabled to
grow, and upon the humus of the forest floor a wealth of mush-
rooms, club-fungi, cup-fungi, slime-moulds and various related
forms are displayed. Some seed-producing plants, such as the
pine-drops, the Indian-pipe, and the pine-sap, together with the
coralroots and others, have learned to abandon their leaf-green
and have adopted the habits of life similar to those of the fungi.

Other living things. The proximity of other living things
is a condition of the surroundings that cannot be disregarded in
the discussion of plant adaptations. These neighboring crea-
tures may be either plants or animals. In response to their
presence a large variety of curious structures and habits have
come into existence. The carnivorous plants catch and eat
small insects with which they come in contact. Parasitic fungi,
such as the caterpillar fungus or the fly-cholera fungus, attack
certain small animals and use their bodies for a soil in which
to grow and mature. The roots of louseworts, toad-flaxes, and
cancerroots, reach out and attach themselves to the roots of
neighboring plants, in some instances deriving their whole
sustenance in this manner. A great variety of little fungi
develop upon the leaves, twigs, flowers or fruits of other plants,
having become accustomed to eke out an existence in this
dependent manner. Many plants perch upon other plants;
thus, the Spanish moss of the south hangs in festoons from the
live-oaks, and the orchids of South America sit in rows, like so
many partridges, upon the branches in the forest. The lichens

Minnesota Plant Life.

439

of more northern regions similarly perch themselves upon the
trunks, or branches, of trees ; and with these, too, a number
of mosses and liverworts will be found. Sometimes the perch-
ing-plant adroitly selects a position where it will receive more
moisture than elsewhere. So, many mosses grow around the
bases of tree trunks, — for the tree with its branches serves as a
drain, by which the water of rains is brought to the position
pre-empted by the moss. Lichens and mosses alike select the
degree of illumination that they prefer, and in northern lati-
tudes arrange themselves on the southern sides of tree trunks
if they require stronger illumination, but on the northern sides
if their requirements lie in the other direction. Some perching
plants acquire the habit of driving their roots into the branch
upon which they stand. Thus originated the parasitism of the
mistletoe and related plants, — quite a different method of its
development from that shown by the cancerroots, which learned
to clutch the roots of neighboring plants and drive little suck-
ing organs into their soft and nutritious tissues.

Another result of the mutual proximity of plants is the
development of climbing or twining species. Some climb by
means of prickles, thorns or hooks, and thus the brambles or
tear-thumbs lift themselves upon surrounding vegetation.
Others, like the scouring-rushes, brace themselves by means
of lateral branches and lift their slender stems farther into the
air than they could without assistance. The clematis vines
twist their leaf stems around twigs that chance in their way and
thus show a tendency toward tendril production. Other vines,
like the smilaxes, the grapes, or the wild cucumbers, develop per-
fected tendrils, and by aid of these lift themselves high up on the
stems or branches of neighboring trees. The bittersweets,
morning-glories and hops learn to roll spirally their slender
stems around the shrubs that stand near them, thus twining
to a considerable height.

All such habits must have arisen by degrees, and each of
them, when accentuated, might encourage dependent habits
of nutrition, finally resulting in parasitism. Thus, the twining
habit of some morning-glory vine may have given, in some
earlier epoch, opportunity for the production of the parasitic
dodders.

440

Minnesota Plant Life.

Intra-specific adaptations. A last group of adaptations
that may be considered here are those connected with spore
distribution and seed distribution. It is necessary for the well
being of the species that new individuals should be given an
opportunity to develop. Thus arose such simple primitive
adaptations as the elongation of the spore-bearing plant in
mosses and liverworts, so that the spores could be distributed
over a wider area. More perfected apparatus enabled the
spores to be distributed under conditions of moisture such that
they would most certainly germinate. As spores assumed a
division of labor, devices were adopted by which the two sexual
plants might be produced close together, thus insuring fecun-
dation of the eggs. The ancestors of the seed-bearing plants
originated methods of keeping the young embryo close to the
vegetative areas of the preceding individuals in the species line.
In this manner there arose in the plant kingdom such complex
structures as flowers and seeds. With the added complexity
of structure it became possible for a great number of slight
differences in detail to exist and thus the highest division of
the plant world, that of the seed-bearing plants, is also the one
in which the greatest number of different species are described.
A vast number of intricate adaptations for pollination, embryo-
nursing, and seed distribution came into existence. In some
families of plants wind pollination, or wind distribution of seed,
became the rule, while in others the seeds are distributed by
animals and the pollen spores are planted on the stigma of the
flower by the same animate agents. All the manifold variety
of form in flowers and fruits may be regarded as due to adapta-
tions, more or less perfect, by which the two sexes of plants are
developed sufficiently near together, by which the young plants
may derive benefit from supplies of nourishment produced by
maturer individuals of their species, or by which they are placed
under conditions favorable for their growth and for the best
interests of the species as a whole.

Minnesota Plant Life.

441

FIG. 219. — Dandelion fruiting in shady spot. Shows the slender stems and erect root-leaves
of the shady habitat, and fruits adapted for wind distribution.
After photograph by Hibbard.

Chapter XLI.

Hydrophytic Plants.

The different adaptational groups of plants may be best
classified under three main divisions, according to the relation
between the structure of the plant and the moisture of sur-
rounding conditions. For one series of plants the moisture
of the surroundings may be considerable, for another it is ordi-
narily slight, while for the third a middle condition is main-
tained. Thus, there are three principal adaptational groups,
known respectively as hydrophytes, of which aquatic species
are typical; xerophytes, of which desert inhabitants are char-
acteristic forms ; and mesophytes, in which group may be classi-
fied the common herbs of meadow and forest, growing under
medium conditions of moisture. It should be noted in pass-
ing that while the essential structural adaptation of desert
plants is toward the slow evaporation of moisture, there are
also other conditions, besides those of desert life, that make
rapid evaporation undesirable. Hence plants growing in
peat-bogs, such as tamaracks and spruces, or plants grow-
ing in saline localities are said to have the xerophytic type of
structure and, like true desert plants, are slow to transpire
moisture. A number of different subdivisions of the three
main classes may be described, and one should regard the marsh
and swamp varieties, and those living in saline soil, as furnishing
the transition to the true middle group, that of the mesophytes,
which will here be discussed after a brief account of the other
two.

Out of fourteen classes of hydrophytic plants described by
Eugene Warming, in his classic work upon adaptational groups
of plants, eight are represented in Minnesota. Those unrep-
resented are either arctic or alpine, such as the snow plants,
or marine, such as the seaweeds, and the mangrove swamps
of oceanic coast lines.

Minnesota Plant Life.

443

Plankton. The first class of hydrophytic vegetation is that
known under the technical term of plankton vegetation. By
this is meant the passive, free-floating vegetation, not rooted
or attached to the soil in any way. To this type, no doubt,
belong the earliest forms of life that appeared upon the crust
of the earth. Here are to be classified many algae — such as
the familiar water-flower of Minnesota lakes, which, as will be
remembered, is a type of blue-green algae. A number of Min-
nesota varieties belong to the algal plankton, for here are in-
cluded not only the water-flower, but such forms as the sphere-
alga, the pond-scum, the desmids and diatoms, the rolling alga
and a number of others. Some of these plants are characterized
by the production, between their filaments, of interlocked gas
bubbles, by which they are enabled to float at or near the sur-
face of the water, and thus to receive the sunlight. In many
of them there are formed reproductive bodies provided with
swimming lashes, and by the aid of such little motile cells the
plant may be distributed throughout the water of a lake or pond.

Another group of plankton vegetation is constituted by the
bacteria that live in water. A great many different sorts are
known ; not only from fresh water, but from the sea. Any drop
from a Minnesota lake or river, if carefully examined by the
proper methods, would be found to contain great quantities of
the bacterial organisms.

Still another group of plankton vegetation is what may be
called derived, or secondary plankton. This group is composed
of passive, free-floating plants which are, from their structure,
evidently derived from ancestors that were rooted. To this divi-
sion belong the little water fern Azolla, the duckweeds, form-
ing such abundant scums on stagnant pools, and the bladder-
worts, together with some varieties of liverworts, such as the
swimming Riccia and the floating Riccia. A number of pecul-
iar adaptations exist in plants of the derived plankton. Often
in their bodies there are air chambers by means of which they
float. These may be seen in cross sections of duckweed plants
or Riccias. Sometimes the air chambers are developed as spe-
cial pouches or bladders, as in bladderworts, where they also
fulfill another function — that of capturing small animals for
food. If the plant floats on the surface of the water, with its

444 Minnesota Plant Life.

upper side exposed to the air, as do the duckweeds, certain
special structures are necessary. First of all, proper counter-
poises must be carried to prevent the plant from being turned
upside down by the ripples. In the duckweeds these counter-
poise areas are readily seen to be roots, or groups of roots, but
in the smallest of the duckweeds no counterpoise exists as a
special organ, since from the very small size of the plants they
are able to ride the waves without their upper surfaces being wet.
In one of the water ferns — the little Salvinia plant, common in
greenhouses, where it grows in tanks — twro rows of leaves on
the floating stem are thrust down into the water and act as
counterpoises; but in the wild water fern— the tiny Azolla—
just as in the duckweeds it is the slender roots that perform
this function. Sometimes skillful combinations of counter-
poises and floating apparatus are effected, as in the handsome
water-hyacinth of conservatories — a species which has become
a great pest in the rivers of Florida. In these plants the bases
of the leaves, which arise in rosettes, are swollen into spongy,
spherical floats, an inch or more in diameter. Below such a
circle of floats a tuft of roots hangs down into the water, and it
is quite impossible for any ordinary gust of wind to turn the
plant upside down.

A second group, also, of adaptations are interestingly de-
veloped in the free-floating higher plants by means of which
the upper surfaces of natant organs are protected against wet-
ting. Sometimes the surface is very smooth and glistening
and the water rolls from it in the spheroidal form just as it
does from a buttered plate. This is the condition to be ob-
served in the larger duckweeds. The upper surface of the small
disc-like stem of these plants is somewhat convex and very
smooth. If water is poured upon a group of duckweeds as they
float upon the surface of a pool it will roll off as from the pro-
verbial duck's back, and will leave the little plants as dry and
glistening as before. One of the duckweeds, the three-cor-
nered variety, is a partially submerged plant and therefore has
not this power of shedding water. Another arrangement is
seen in the water fern, Salvinia. The upper surfaces of the
floating leaves are provided with curious tufted hairs, the tips
of which spread out in three or four branches If one of the

Minnesota Plant Life. 445

Salvinia plants is taken between the thumb and finger and
thrust under the surface of the water, air is imprisoned between
the tufted hairs and the whole plant glistens as it is submerged.
If it is released it rises instantly to the surface, buoyed up by
the air chambers in its leaves and stem, and when it emerges
the upper sides of the leaves will be found perfectly dry.

Of the planktonic flowering plants of Minnesota, some de-
pend upon the wind for pollination, as do the duckweeds, while
others, such as the bladderworts, are adapted to insect pollina-
tion. The flowers, therefore, of the duckweeds are extremely
inconspicuous, while those of the bladderworts are pretty, yellow,
snapdragon-like and elevated upon steins some inches in length,
so that they become noticeable objects and are easily found
by wandering bees or flies. Some free-floating or plankton
plants are particularly protected against the attacks of small
aquatic grazing insects or animals, while the bladderwort actually
catches and eats the little insects that gather in its vicinity.
The Salvinia plant is provided, on its submerged counterpoise
leaves, with sharp-pointed hairs, and these stand out on every
side in bristling defence. The sharp-pointed hairs are par-
ticularly useful because the fruits of the Salvinia are borne
under water, on the submerged leaves, and it is important that
they should be protected. The under sides of the floating
leaves have also a defence of sharp-pointed hairs, but the hairs
on the upper side, since they have a different purpose — that of
keeping the surface dry — are of different structure.

Swimming plants. Closely related to the plankton, or free
floating vegetation, are the animal-like little plants that swim
about in the water seeking decaying organic substances upon
which to feed. They are abundant in stagnant water where
there is sufficient organic food material. A Minnesota plant,
known to botanists by the name of Euglena, is an example of
this class of hydrophytes. It is able, by means of its green color,
to assimilate carbonic-acid gas in the presence of sunlight. It
takes up its nitrogenous food from the organic substances dis-
solved in the stagnant water and is, therefore, in its method of
nutrition, partially dependent. The Euglena plants are of
microscopic size and countless myriads of them in stagnant
pools often form dense green scums of a granular appearance.
Zoologists consider them animals.

446 Minnesota Plant Life.

Rain-water plants. A little class of obscure plants are re-
garded as of hydrophytic character, since they live on rain-
water. The green slime that forms upon mud flats, the
bacterial skins that arise upon soil highly charged with or-
ganic substances, the blue-green algae that thrive between the
particles of sand upon a moist beach, and the curious algal or
bacterial organisms that live under the surface of damp sand-
stone cliffs, looking like cobweb threads when a bit of the cliff
is chipped off, might be given as examples of this class.

Attached water plants. Another adaptational class of hydro-
phytes is furnished by those species which live attached to
stones, either at the bottom of streams or lakes, or upon the
surfaces of wet cliffs, or those of bowlders exposed to spray.
Several algae are found in such localities. On \vet cliffs a variety
of green algae are to be looked for, and here, too, especially
near waterfalls, will be found the very few kinds of red algae
which occur in Minnesota. Sometimes a dark brownish-purple
skin of slimy algae may be seen on cliffs wet by the spray of
waterfalls, and this may be a growth of red algae. In similar
localities, and on stones in rapidly running streams, the wire
like, reddish-brown algae of the Minnesota flora are to be
sought.

Some higher plants select similar localities — for example, the
river moss so common in swift, rock-bottomed streams, where
it grows attached to stones and lies in tufts with the cur-
rent. The very curious riverweed, of which one variety exists
in Minnesota, affixes itself to stones in waterfalls, and closely re-
sembles an alga. It is remarkable because it is the only kind
of Minnesota flowering plant that opens and pollinates its
flowers entirely below the surface of the water. A character-
istic structure of attached rock plants in rapid water is the
holdfast, an organ which has more the office of an anchor than
of an ordinary root. In the river moss the ordinary slender
root hairs characteristic of mosses are gathered together in
strands, thus giving additional strength, and by means of these
little cables entwined around the rough corners of the stones
the plant holds itself in place. Plants of this sort with hold-
fasts and with submerged vegetative tracts naturally do not
have abundant air chambers as in the floating1 varieties. On

Minnesota Plant Life.

447

the contrary, air chambers are often entirely absent. Where,
too, the plant is anchored and free to undulate its branches
with every ripple of the water there is little occasion for strong
mechanical tissues, and no need for air pores or any of the
devices for protecting- them. Elastic tissue is, however, some-
what useful, and in many plants of this class it is formed. A
great number of the submerged plants are slimy to the touch,
especially in the ocean. This is well known to be true of sea-
weeds and it is also the case with river moss and riverweeds.
Such slime-coverings may be useful as protections during
periods of low water, or they may reduce the friction, upon the

tissues of the plant, of the
flowing water.

Still another class of water
plants are attached under
water to loose soils, sand or
mud. The water eel-grasses
may, perhaps, be taken as
examples of this group.
Holdfasts are not here de-
veloped simply as anchors,
but there may also be
branching root systems
upon which, however, root
hairs are often wanting.

Shore and bar plants.
The most important class of
water plants that are of
genuine aquatic habit, so
far as developed in Minne-
sota, are those which may
be known as the shore
plants and bar plants. These are attached or submerged vari-
eties, growing upon loose soil, generally in communities, with
the plant body either entirely submerged or with the leaves
floating. The flowers are entirely aerial and pollination cannot
go on under the water. It is difficult to distinguish this class of
aquatic plants from the related swamp plants that grow close
down to the water's edge; and in fact, sometimes the same

FIG. 220. — Vegetation of ravine. The home of
mosses and liverworts. The plants in
front are touch-me-nots. After photograph
by Williams.

448 Minnesota Plant Life.

kind of plant appears both as a lake-border and as a marsh
plant, as, for example, the common yellow pond-lily, which
may grow upon mud flats, or more ordinarily out a little dis-
tance in the pond. Of the shore and the bar plants a number of
different varieties belonging to various groups occur in Min-
nesota. Among the algae, the bass-weeds, so common as the
outer zone of shore plants in almost every Minnesota pond or
lake, are most prominent. In some ponds, especially the
smaller ones of swales, prairies or meadows, the water mosses
are abundant. These have a different adaptation from the
river mosses. They do not have strong holdfasts by which
to maintain themselves in rapidly flowing water, but are spongy
masses of vegetation and evidently near relatives of the carpet

FIG. 221.— Stream-side vegetation. Ironweeds, thoroughwort, mullein, sedge, speedwell and
shrubbery. Hydrophytic vegetation in water's edge. After photograph by Williams.

mosses of the woods. When they fruit, the spore cases are
sometimes thrust above the surface of the water, but often
the spores are shed below the surface. To this group of
plants may be referred also the water lobelias, pipeworts, quill-
worts, the four-leafed water fern and others, including a variety
of flowering plants, such as the eel-grass, the water buttercups,
starworts, water-lilies, water smartweeds, floating arrowheads,
pondweeds and water milfoils.

A number of different and interesting adaptational charac-
ters exist among the shore plants. Commonly, when alto-
gether submerged, they have very much divided leaves, as do
the water milfoils or water buttercups. If part of the plant

Minnesota Plant Life. 449

is submerged and part exposed, the leaves of the submerged
portion may be finely dissected, while the leaves of the emerg-
ent area are simple and but slightly notched. Of this the
water bur-marigold is an example. Again, the leaves are all
submerged and ribbon-shaped, as in the water eel-grass, or
they may be quill-shaped, with air chambers, as in the quill-
worts and water lobelias. When some of the leaves are float-
ing and others are submerged, the floating leaves are often
larger and broader than the submerged. Thus, in the float-
ing arrowhead the natant leaves are arrowhead-shaped, while
the submerged leaves are grass-like; or, as in the water-shield
(not, however, the Minnesota variety), the floating leaves are
shield-shaped and the submerged leaves are finely dissected.

In other instances,
as in the water-lilies,
the difference be-
tween the submerged
and floating leaves is
not so great, but a
slight variation in
texture is not hard
to observe. The fine
dissection of the sub-
merged leaves of so

FIG. 222.— Birch trees along a lake shore. Bar vegeta- mailV aOUatic floW-

tion in background. After photography by Williams.

ering plants is evi-
dently an adaptation, by which a considerable absorptive power
is added to the ordinary starch-making function of the leaf. Such
finely dissected leaves are easily maintained under water, but
they would be likely to shrivel on account of too rapid evap-
oration if developed in many land forms. The floating leaves,
like those of the planktonic vegetation, have adaptations against
moistening, so the upper side of the shield-shaped leaf of the
Minnesota water-shield will be found to be waxy and difficult
to wet. The generally oval or circular shape of floating leaves,
or floating stems like those of the duckweeds and swimming
Riccias, may be regarded as a response to the equal lapping of
the waves against the edges of the leaf from all directions.
These floating leaves, or stems, are very often purple on the
under side, so that the surplus light is converted into heat.
30

450 Minnesota Plant Life.

Ribbon-shaped leaves are not so common, but are found as
the submerged variety in those arrowheads which have two
sorts of leaves, and in some of the pondweeds, as well as in
the ordinary eel-grass. More frequent are small, numerous,
narrow leaves, or leaves cut up into small and narrow divisions.
A number of the pondweeds have such submerged leaves, as
also the water milfoils, the waterweed, the mare's-tail and the
water starworts. Least usual is the quill-shaped leaf, found
however, among Minnesota species in the quillworts and in the
water lobelias. Some of the pondweeds have broad, thin,
papery leaves, crisp like lettuce, in some varieties, but of a
texture different from that of land forms. In general, sub-
merged leaves have no air pores, or these are very sparingly
produced. The epidermis or skin of the leaf is not as strongly
developed as it is in the case of terrestrial leaves that are
fitted for evaporation. Such leaves are decidedly more absorp-
tive than are those of land plants, this function being favored
by the thin walls of the skin cells. In originating the forms
of aquatic leaves the illumination had probably something to
do, and the elongated, ribbon-like leaves on submerged por-
tions of arrowhead plants may be considered, perhaps, to be
extended on account of the semi-darkness caused by the water.

The stems of these water plants are as various in structure
as the leaves. Sometimes, especially where the soil is loose,
the stem becomes a creeping, branched rootstock. This may
be embedded in the soil at the bottom, as in pondweeds and
water-lilies, or it may creep along the bottom, as in water but-
tercups and water milfoils. Sometimes the stem is short with
the leaves arranged in rosette fashion — for example, the water
eel-grass and the quillwort. In all of these plants the stem is
perennial. A few annual water plants, however, exist, such as
the naiads. In such, the stems die when the water freezes and
the plant comes up from the seed the following spring*. By
far the great majority of water plants are perennial. The mass-
ive storage organs of bulbous land plants such as the jack-in-
the-pulpit, or the onion, are not typical of aquatic vege-
tation. In general their stems are characterized by a consid-
erable development of the cortical region, together with a poor
development of the vascular region. Mechanical tissue is not

Minnesota Plant Life. 451

at all abundant in the greater number and most of the stems
and leaves are limp when taken from the water. In the cortex
of the stems and leaf-stocks air chambers are common.

A variety of propagative processes are characteristic of water
plants. Sometimes they pass the winter in an evergreen state
at the bottom of ponds under the ice. The eel-grasses and
water starworts do this. Sometimes their leaves are destroyed
by the winter's cold and new ones are produced from storage
areas of the rootstock, from buds, or from special propagative
bodies. The special propagative bodies of water plants are
very interesting. The pondweeds sometimes form little buds,
that are separated from the plant body and become distributed
to a distance. The bladderworts are remarkable for their pro-
duction of green winter buds, known as hibernacida, which, in
the autumn of the year, or in the spring, may be seen at the
end of bladderwort stems. In such buds the leaves are very
densely crowded together into a diminutive green cone and
the sections of the stem with crowded leaves may be sepa-
rated from the general plant body and serve to propagate the
species. The calla, — rather a marsh than a water plant, but
often living in the water, — has a similar habit of separating win-
ter buds as propagative organs.

The distribution of different kinds of shore and bar plants
depends upon a variety of conditions, — the character of the soil,
the depth of the water, its quiet or agitation, and its tempera-
ture. The bass-\veeds form the deep water zone. Warming
states that they may grow in 75 feet of water, but usually
they do not grow nearly as deep as this. The waterweeds pre-
fer shallower water, the pondweeds still shallower, while the
water-lilies grow close to the reed-grasses and bulrushes. The
latter are accounted also as marsh vegetation, because so much
of their starch-making surface is lifted above the water.

The reproductive processes of water plants of this group
retain the characters of the original land habitat, so far at least
as the flowering plants are concerned. Thus, the flower clus-
ters are always produced above the surface of the water, and
pollination is effected either by the wind, by currents of water,
by wind and water combined, or by insects. Where the flowers
are conspicuous, as is true of water-lilies or pond-lilies, insect

452 Minnesota Plant Life.

pollination is the rule. Where they are inconspicuous, as in
the pondweeds and water milfoils, wind pollination is the rule.
A peculiar case is that of the eel-grass, which produces its
pollen-bearing flowers in large numbers on submerged spikes.
Each pollen flower separates from the spike and rises to the
surface of the water, where it opens. The pistil-bearing flow-
ers are produced singly on the ends of long, thread-like stems,
and open at the surface of the water. The little pollen-pro-
ducing flowers are blown about like so many tiny sail-boats,
either striking their stamens against the stigmas of the pistil-
late flowers, or giving the wind an opportunity to carry the

^FiG. 223.— Trees along a river bank. Soft maple and cottonwood. Minnesota river.
After photograph by Williams.

pollen from one flower to the other. In the naiads and in some
of the pondweeds, the pollen-spores are carried in the water,
by ripples on its surface, from one flower to the other. The
majority of these water plants retract their fruits under the
surface to ripen them. Sometimes the stem of the fruit-bear-
ing flower shortens spirally, coiling down into the water as in
the eel-grasses. Sometimes the stem curves and thrusts the
young fruit under the surface. A few water plants mature the
fruits above the surface of the water, and of such the Indian
lotus is an example.

Minnesota Plant Life. 453

The depth at which quondam land plants are able to grow is
in some instances very great. Thus Magnin is authority for the
statement that one variety of moss was found at a depth of
nearly 200 feet in an Alpine lake, showing on the part of an
originally terrestrial plant a very high degree of adaptation to
the aquatic life. Nothing of this sort is known to occur in
Minnesota, and beyond 25 feet only algae and bacteria are
likely to be discovered, while into such deep water pondweeds
and waterweecls rarely extend.

Abyssal vegetation and modified hydrophytes. The vari-
ous classes of hydrophytes which have been discussed may be
grouped under the general name of aquatic vegetation. Some
forms of aquatic vegetation are scarcely represented in Minne-
sota,— for example, hot spring vegetation, the various seaweed
classes, and snow7 vegetation. Those which have been discussed
comprise the bulk of Minnesota aquatic species. The class de-
scribed by Warming as abyssal vegetation occurs, however, in
the deep waters of Minnesota lakes from 50 feet below the
surface to greater depth. The darkness is so great in such
abysses that green plants scarcely exist, though blue-green algae
and diatoms are known to occur at depths from 250 to 300
feet, being able to utilize the extremely small amount of light
which penetrates to them. Most abyssal forms are bacteria.
These occur in the deepest waters, either suspended or in films
along the bottom, forming, in such depths, a living slime or ooze,
as may be determined by microscopic examination of deep lake
soundings. The bacterial vegetation occurs also in moist or-
ganic substrata, such as the bodies of animals, where a large
percentage of the substance is water. So the parasitic bacteria
of disease, either of plants or of animals, might possibly be
described as forms of hydrophytic vegetation. The bacteria,
too, which live upon decaying organic matter, such as the sul-
phur bacteria and the ferment-producing bacteria, may be re-
garded as constituting a sort of water-loving vegetation, and,
therefore, may be classified here.

Swamp vegetation. The remainder of the hydrophytic
classes may be included under the general term of swamp
vegetation. This is the plant group that shows itself typic-
ally in swamps, in bogs, in marshes, moors and tundras.

454

Minnesota Plant Life.

Several different classes exist, all of them characterized by the
development of the underground portions of the plant — that
is, the roots or rootstock — in moist soil, while the aerial por-

FIG. 224.— Marshy place at the edge of a wood. After photograph by Murdock.

tions, especially the starch-making areas, are exposed to atmos-
pheric evaporation. Like the majority of aquatic plants, most
of the swamp plants are perennial. A great many of them

Minnesota Plant Life.

455

produce underground or prostrate rootstocks. These organs
are underground in sedges, scouring-rushes, reed-grasses,
sweet-flags, cat-tails, some of the cranberries, brambles and
primroses. They are above ground and prostrate in many of
the heaths and club-mosses. The tissues of swamp plants are,
as those of water plants, likely, in a variety of species, to be
spongy. Thus, the rootstocks of the cat-tail, the rootstocks
and stems of the scouring-rush. the leaves of many sedges and
the leafless erect stems of bulrushes contain a great number
of air chambers, giving them a spongy consistency. Some

FIG. ±25. Ferns in tamarack swamp. Iyake Calhoim. After photograph by Hihbard.

swamp plants have special aerating organs, of which cypress
"knees" are examples. But these structures do not occur, so
far as I know, on any Minnesota species.

Most swamp plants have adaptations for limiting the tran-
spiration of water from their shoots and leaves ; that is to say,
they are in this character like the xerophytes of desert regions.
Among the various devices for reducing transpiration may be
mentioned the hairiness of many swamp plants, such as the
swamp-saxifrage. Sometimes special pegs are produced around

456

Minnesota Plant Life.

the air pores, as in many sedges and smartweeds. Sometimes
that region of the leaf where the air pores are the most abundant

FIG. 226.— Swamp saxifrages. The large root-leaves are adapted to the shade of the swamp.
The whole plant is hairy. Tamarack swamp, I^ake Harriet. After photograph by Hib-
bard.

is covered with a cottony or woolly coating, as are the under
sides of the leaves in the Labrador tea. Again wax coatings

aJL.

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456

Plant Life,*

letimes
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re the under

Minnesota Plant Life.

457

may be found on the leaves, as on those of the rosemary, the
cranberries, and the swamp blueberries. Sometimes the epi-
dermis of the leaf or stem is very thick, as in the bulrushes
and sedges. Sometimes the leaves are leathery, as in partridge-
berries, cranberries and Kalmias, and this is a common adapta-
tion among heaths. Sometimes the leaves are small, slender,
and with but little surface for evaporation, a character that
may be seen in many heaths and sedges. In some varieties the
leaves are greatly reduced, as in the scouring-rushes, the bul-
rushes, some of the sedges related to the cotton-grasses and
many of the true rushes. Or, if present, the leaves may be almost
cylindrical, as in the Scheuchzcrias. Again, the leaves may be
needle-shaped, as in tamaracks or spruces. If the leaves are
broader they often stand vertically so as to expose only their
edges to the direct rays of the sun. This is well illustrated by
the blue flags, the sweet-flags, the blue-eyed grasses, the yellow-
eyed grasses and the cat-tails. Where these broader leaves do
not stand vertically they are sometimes rather few in number.
This may be seen in the reed-grasses and wild rice. Broad
leaves of swamp plants are often rolled in along the mar-
gins— the same adaptation found among desert grasses. Thus,
crowberry leaves and many sedge and grass leaves in the
swamp-dwelling species, are rolled. Sometimes the air pores
are developed but very poorly on the upper surfaces where the
leaves are spread out to the sun. All of these characters may
be regarded as limiting the transpiration of the shoot and
leaves.

Special reasons may be given for the leaflessness of some
swamp plants, as for the bulrushes which belong to the cate-
gory of surf plants. Their leafless, whip-like sterns are adapted
to withstand the impact of surf. The temperature, also, of the
water has something to do with the appearance of the xerophytic
characters. They are more prominent where the water is cold.
So especially in peat-bogs and cedar swamps does one find a
variety of sedges, heaths, rushes and cone-bearing trees, all
characterized by slow evaporation.

Reed marshes. To the class of reed marshes belong a variety
of shore formations and swamp formations common in Min-
nesota. Here should be classed the wild rice beds and the beds

458

Minnesota Plant Life.

of rushes and reed-grasses. Here, too, should be included the
beds of cat-tails, of blue flags, of arrowheads, burweeds, callas,
sweet-flags and sedges. In such regions a variety of accessory
plants habitually develop, such as the swamp butterweed, the
buck-bean, the swamp-docks and several members of the pars-
ley family. These plants often arrange themselves in zones
dependent upon the relative moisture of the soil, or upon the
depth of the water that covers the rootstocks and roots. Thus,
along the borders of Minnesota lakes, bulrushes generally grow

FIG. 227. — A marsh-loving sedge, showing fruit clusters. After photograph by Hibbard.

outside of reed-grasses, and reed-grasses outside of sedges,
showing the exact adaptations of these kinds of plants to the
moisture-content of the soil and to the water covering their un-
derground portions. Most of the plants in reed swamps are
provided with rootstocks by means of which they propagate.
The strong rootstocks of bulrushes and cat-tails may serve as
examples. While pushing a boat through a bed of bulrushes a
careful observer will notice that the rushes stand in rows, and
these rows designate the position of the prostrate rootstock in
the bottom. From such branching rootstocks, common to

Minnesota Plant Life. 459

sedges, cat-tails, bulrushes and reed-grasses, the aerial or lateral
branches arise. The rootstock commonly bears scale leaves.
These may be well seen if a cat-tail plant is dug up and washed.
Among the perennial rootstock-forming herbs, which are the
characteristic plants of reed swamps, a few shrubs are often
found growing, such as willows and alders.

Wet meadows. A second class of swamp vegetation is known
as swamp-moor or wet meadow. In such regions there is a
high percentage of ground water, but under ordinary conditions
the subterranean portions of the plants are not directly covered
by standing water. Such meadows exhibit in Minnesota a variety
of plants, for the most part sedges, grasses and rushes, but with
a strong intermixture of other plants, including such varieties
as the shield-ferns, marsh-marigolds, the Parnassias, some gen-
tians, buck-beans, orchids, willow-herbs and parsleys. Here,
too, swamp-saxifrages and pitcher-plants are often to be found.
Mingled with the herbage which is the predominant vegeta-
tion of such wet meado\vs a variety of shrubs may grow, in-
cluding dogwoods, willows, dwarf birches, buckthorns, and
spiraeas or meadowsweets, and. in northern parts of the state,
heaths or crowberries. A considerable moss vegetation exists
in such wet meadows, including sometimes peat-mosses, but
also carpet mosses, hairy-capped mosses and others. Some-
times moss meadows occur, forming a transition to peat-
bogs and peat-tundras. In arctic regions such wet meadows
are inhabited often by lichens to the exclusion of other plants.
As is also true of aquatic vegetation these wet meadows are
tenanted for the most part by perennial species.

Peat-bogs. A particular type of swamp vegetation is the
peat-bog. It differs from the ordinary wet meadows in the
chemical character of its soil. Chalk and potassium are pres-
ent in peat-bogs in smaller quantities than in wet meadows,
and it has been shown that the nitrogenous content of peat-
bogs is less than that of wet meadows. Humus, therefore,
forms better in wet meadows than in peat-bogs. On account
of the low nitrogenous content of the peat-bog there is a
poorer development of bacteria and vegetable remains are,
therefore, better preserved if sunken in peat than if embedded
in the bacterial soil of a wet meadow. The distinctive plants

460 Minnesota Plant Life.

of peat-bogs are the peat-mosses, the most abundant and in
some respects the most remarkable of all the mosses. A con-
siderable number of different species occur in Minnesota.
They are extremely spongy and contain a large amount of
water in special cells of their leaves and stems. Besides the
peat-mosses a number of other mosses will be found in peat-
bogs, with a variety of liverworts. Here, too, is the favorite
home of many sedges, such as the cotton-grasses, of many grasses
and lilies, of rushes and of orchids. Heaths are a marked fea-
ture of peat-bogs and almost all the Minnesota varieties are to
be looked for in such localities, where one finds the Labrador
tea, the Kahnias, the rosemarys, the cranberries, the snow-
berries, the leatherleafs and the bilberries. Mingled with them
are a number of other peat-bog-dwelling plants belonging
to various families. Here one will find the sundews and
pitcher-plants, the dogwoods, brambles and sweet-ferns, the
myrtle-leafed willow, the tag-alder and the crowberry. Espe-
cially distinctive of such areas are spruces and tamaracks and
these are the most characteristic trees of peat-bogs in the Min-
nesota region. They are often very much dwarfed by the
cold water and by the low percentages of mineral salts which
these waters contain. Especially when growing in the wet
region of the bog are the trees diminutive; and spruce trees
75 years old and but little over an inch and a half in diameter
have been found in Minnesota peat-bogs.

It is probably on account of the low nitrogenous content of
the water that carnivorous plants, such as the pitcher-plant and
sundews, have developed particularly in peat-bogs. They are
able by their insect-catching habits to supply, from the bodies
of their victims, nitrogen to compensate for the scantiness of
this element in the soil.

Most of the species in peat-bogs are perennial. On account
of the open, meadow-like character of typical peat-bogs the
snow accumulates in heavy sheets and this will perhaps account
to some extent for the prevalence of prostrate shrubs like the
heaths. No doubt also the prostrate habit is resultant from
the necessity for slow evaporation. Since the heaths do not
lift their leaves into the air on erect shoots so abundantly as
do other kinds of shrubs, they avoid that agitation by the wind
which would promote evaporation.

Minnesota Plant Life.

461

Peat-tundra. The type of vegetation known as peat-moss
tundra is sparingly developed in Minnesota. It may be de-
scribed as a kind of dry peat-bog. I have seen isolated and

FIG. 228. A pitcher plant in flower; tamarack swamp. The leaves are converted into insect-
traps. After photograph by Hibhard.

limited peat-moss tundra formations at Lake of the Woods,
where, on some of the rocky islands near the Northwest Angle

462 Minnesota Plant Life.

Inlet, dry peat-moss turfs form in the depressions of the rock.
Mingled with the peat-moss were the reindeer-moss lichens
and the bluebells and juniper bushes, which are such distinctive
rock plants of this region.

Swamp underbrush. Another type of swamp vegetation de-
veloped in Minnesota is known as swamp shrub or swamp
underbrush. This consists for the most part of birches, wil-
lows, buckthorns, black haws, hollies, dogwoods, alders and
poison sumacs. Where a reed swamp or wet meadow has
grown up to underbrush this sort of formation appears. When
the swamp underbrush has arisen, sufficient shade is produced
to permit the development of certain accessory herbs that
would not otherwise be so abundantly present. In such re-
gions, for example, violets and touch-me-nots, gentians and
thoroughworts are often abundant. Such swamp underbrush
sometimes grows along the edges of peat-bogs and lakes and in
this situation willows and dogwoods particularly abound. Wil-
lows, also, very often form rings around the shores of small, low
islands, mud flats, or sand bars in lakes or streams, while the
higher land of the centre is occupied by elms, cottonwoods,
maples or basswoods. This is a very common example of
zonal distribution in Minnesota.

There have now been passed in review the principal types
of hydrophytic vegetation. Apparently the strong preponder-
ance of water in the substratum, as for the swamp plants, or
surrounding the plant body, as for aquatic vegetation, has a
number of definite influences not only upon the structure of
plants, but upon their grouping. The depth of the water, the
character of the soil, the chemical substances held in solution
in the water, the temperature, agitation, or quiet, and other
conditions, all have their influence and it is not at all an acci-
dental matter whether a particular moist region develops as a
peat-bog, as a reed swamp, as a wet meadow, or as 3. swampy
underbrush. In all the hydrophytic vegetation classes peren-
nial species are predominant. A great many of them are
herbs, while some are shrubs, and a few are dwarfed or spe-
cialized trees.

Chapter XLII.

Xerophytic Plants*

The plants classified under the general name of xerophytes
are, in their selection of habitats, just the opposite of aquatic
plants. They grow typically under conditions of slight mois-
ture and some of them are able to maintain themselves in the
most arid regions of the world. Thus, a distinctive desert
vegetation, such as may be found in the Sahara, or in the deserts
of Arizona, has come into existence. A number of plants,
although not inhabitants of the desert, find it difficult to obtain
sufficient moisture and assume the xerophytic type of structure.
Good examples of these are the orchids that live in tree tops
and dangle their roots in the damp air of tropical forests. Since
this is a slow way of accumulating moisture, such plants are
often cactus-like in form. Not being exposed to the attack
of grazing animals, as are the cacti, they do not become armed
with thorns and spines, but they have often the same massive
bodies that are found in true desert plants. A great variety
of secondary conditions serve to modify and regulate the ap-
pearance of xerophytic structural characters. Thus, some xero-
phytic plants living in sand differ decidedly from others living
upon rocks. Those developed in soil rich in nitrogen differ
from those that have but a scant supply of this element avail-
able for their roots. The saline substances present or absent
in the soil may modify the plants growing upon it. For this
reason a difference arises between the vegetation of limestone
and granitic regions and some plants are known to be indica-
tive of limestone soils just as others are of the presence of quartz.

Desert plants. A variety of devices are employed by xero-
phytic plants to regulate the evaporation or transpiration of
moisture. Sometimes during extremely dry seasons desert
plants abandon their leaf structures entirely, thus responding
to the arid conditions quite as plants of temperate regions re-
spond to the approach of winter. Trees in deserts often drop

464 Minnesota Plant Life.

their leaves after the short rainy season is over and pass into
a winter-like condition, during which they evaporate much less
moisture than would be necessary if their leaves were expanded
to the ardent rays of the sun. For this reason, too, a great
many desert plants are annual, and in the compact form of
seeds withstand the dry season of the year. When the rain has
come again the seeds germinate rapidly and in a short time the
flowering and fruiting processes are completed. It is remark-
able, in a desert, when the rainy days are at hand, to observe
the extraordinary rapidity with which plant organs of various
sorts appear upon what was before an arid waste.

Many desert plants develop underground bulbs and root-
stocks which persist without sign of life during the dry time
of the year and, when there has been a short season of rain,
suddenly put forth flowering stems and foliage. Another way
of meeting the aridity and dryness of the air is by the rolling
up of the leaves. This is well seen in the buffalo-grasses, in
some of the wormwoods or sage-brushes, and in a variety of
sedges, grasses and mosses. By means of this reduction of
the evaporating surface at the critical time, the desert plants
which employ these adaptations are able to prevent too great
evaporation. Another method adopted by plants in arid re-
gions is the modification of their leaf positions, and a number
of leaf-movements are regarded as protective against undue
evaporation of moisture. Many plants of the pea family in
desert regions have such special leaf-movements. Still another
method is the setting of the leaves on edge, as in compass-
plants; and the rosinweed compass-plant and the lettuce com-
pass-plant of the Minnesota flora, by twisting their leaves so
that only their edges are presented to the direct light, illustrate
such adaptations. Since the strongest illumination in the
northern hemisphere is from the south, these compass-plants
turn most of their leaves so that the flat sides face east or west,
and thus they are exposed to the least direct sunlight possible.

In the desert regions of the world, leaves sometimes hang
from the stems so that the light strikes them as little as pos-
sible during the day. Still another device for limiting tran-
spiration, common among desert plants, is the formation of leaf
structures that evaporate moisture but slowly. The prismatic

Minnesota Plant Life. 465

leaves of pine trees, the leathery leaves of heaths and hollies,
the scale-covered leaves of buffalo-berries and silverberries, the
slender cylindrical leaves of many rushes, the ribbon-shaped
leaves of many grasses and sedges are all examples of such
protective structures. Some leaves are fleshy and succulent,
like those of the live-forever, the purslane, the spring-beauty or
the portulaca. The leaves of century-plants are types of this
kind of adaptation.

Not only are leaves variously modified, but stem areas as
well, in the above-ground portions of xerophytic plants, re-
spond to the conditions around them. Thus, some stems are
leafless, as in certain of the cacti. Such leafless stems may be
somewhat flattened and may have green rinds by which they
carry on their starch-making. Sometimes the steins are cylin-
drical, as in the bulrush. Sometimes, as in the asparagus, the
leaves are absent from the plant body, or are reduced to scales
and their place is taken by little needle-shaped branches that
carry on the starch-making function. Sometimes the stem is
converted into a solid gourd-like body, as in the melon-cacti
and prickly-pears. By such forms and structures of leaves and
stems the transpiration of moisture is greatly reduced.

Another modification appears in those plants which have
coatings of one sort or another to protect the leaves and stem.
Thus, the bloom on the leaves of a century-plant, the hairs and
bristles on a mullein leaf, the clusters of dead leaves that are
retained by some plants for a year or more, the incrustations of
chalk, wax, slime, shellac or gum, all have their value in re-
ducing evaporation. The internal sliminess of the leaves of cen-
tury-plants is a familiar fact. Well known, also, is the resin-
ous matter so commonly seen to exude from the leaves of pines
and their allies. Various other adaptations exist which cannot
be discussed at all fully. The intimate structures of leaves,
the position of the starch-making bodies in the leaves, the
position and character of the air pores, all have a significance.

Some plants have glands the function of which is to secrete
salty deposits on the leaves. These salty deposits have a strong
affinity for moisture and may serve to collect it from the ex-
terior. Many desert plants are known by their pungent odor,
very perfect examples of which are the wormwoods or sage-
brushes. It has been shown that the vapor of the ethereal oils,
31

466

Minnesota Plant Life.

r

Minnesota Plant Life. 467

existing in such plants, when commingled with the atmosphere
reduces its permeability to heat, and thus the constant exhala-
tion of perfume from the body of a wormwood is to be regarded
as a device for tempering the heat of the sun. No doubt some
of these strongly scented substances are of value, too, as dis-
couragements to grazing animals. By all such adaptations in
the above-ground portions of a plant it is clear that a reduced
transpiration is effected. The below-ground organs, such as
the roots or rootstocks of desert plants, are often important as
reservoirs of moisture. Some varieties, like the wild morning-
glories, produce very large roots, and often the root system
of a desert plant is much greater in extent than the above-
ground portion.

A number of classes of xerophytic plants exist, many of them
represented in Minnesota. While the state does not include
any desert regions, yet there are numerous tracts upon which
xerophytic plants would find a habitat — for example, sandy
barrens, dry rocks, sand dunes and high sand beaches, high
prairies and meadows, or the dry branches of trees. Some of
the characters of these different classes may be discussed more
in detail.

Rock plants. Rock vegetation is well defined and includes
a number of species that are not common elsewhere. A large
portion of it is made up of mosses and lichens; and on dry
cliffs, exposed bowlders or crags, as well as upon ledges of
rock, a number of rock lichens and rock mosses are prolific.
These plants require but a small amount of water and are
often provided with several of the special adaptations against
transpiration. The common little black tufts of moss which are
found upon bowlders, under ordinary conditions look perfectly
dry and shriveled, but if wet they quickly revive and their green
color becomes more apparent. Many of the lichens growing
upon rocks have the same shriveled, dry appearance betokening
adaptations affecting evaporation. In order to attach them-
selves to the bare surfaces of rocks, lichens secrete, as has al-
ready been stated in the chapter on lichens, certain acids able
to corrode limestone or quartz. The plants cling closely to the
corroded surface and they cannot possibly be detached with-
out destroying them. Some algae are capable of living on

468

Minnesota Plant Life.

rocks and there pass into a dry, dormant condition, except when
the rock is wet \vith rain. In Minnesota a number of pinks,
rock-roses, purslanes and Canterbury-bells make their home
upon .rocky ledges or shores. Here, too, there are to be met
with a variety of ferns, such as the cliff-brakes, the polypody
and others. With them may be found numerous grasses, plan-
tains, verbenas, evening-primroses, ragweeds, capers, and saxi-
frages. Upon such rocky ledges may also be discovered, espe-
cially in the northern part of the state, the juniper bushes and
the ground-hemlock. Rock-succulents are not common in

FIG. 230. — Growth of hardwood trees upon a rocky island. Northwest angle, I,ake of the Woods.
After photograph by the author.

Minnesota; but the prickly-pear cactus of Pipestone and the
rock purslane of the Minnesota valley, are examples. More
often grasses with rolled up leaves, junipers with needle-shaped
or scaly leaves, saxifrages with hairy leaves and other adapta-
tional types will be present. The larger rock plants, needing
more soil for their root areas, grow in crevices and may be
found abundantly wherever the rocks have been split and soil
has formed in the clefts.

Moss heaths. Another class of xerophytic vegetation in-
cludes the moss heaths. These are dry, moss-covered stretches.

Minnesota Plant Life. 469

Mingled with the mosses there may sometimes be small shrubs
or herbs. Such moss heaths are to be found upon some of the
islands in Lake of the Woods and Rainy Lake.

Lichen heaths. A related class may be described as lichen
heath. The characteristic plants of this formation are the rein-
deer mosses ; and very beautiful examples exist along the north-
ern limits of the state. The dry, rounded, thin-soiled islands
in Lake Saganaga give perfect examples of lichen heaths. A
few trees and shrubs are present, but the characteristic and pre-
dominant vegetation is composed of reindeer mosses with
little heaths, grasses, rushes, verbenas, and vetches mingled with
them.

Shrubby heather. Another class not so extensively repre-
sented in Minnesota as elsewhere is the shrubby heather, in
which the ground is covered by little heath bushes, mosses,
club-mosses and junipers. Yet such heaths to a limited extent
exist in the northern part of the state. Mingled with the heaths
proper are a number of composites, such as those goldenrods.
asters, and fleabanes which prefer dry open localities.

All of these rock and heath groups of plants are strongly
xerophytic in their general features. They are, in many in-
stances, to be regarded as responses to sterility of soil rather
than aridity of climate.

Sand plants. Very closely connected with rock vegetation
is the sand vegetation of dunes, beaches and barrens. The sand
is lacking in moisture, which percolates through it readily,
lacking also in nitrogenous substances and, therefore, to some
degree not unlike a rock tract, hence naturally presenting
similar types. A great many plants which can grow upon rocks
can also grow upon sand dunes and, as a result, in the northern
part of the state, junipers, for instance, occur in about equal
frequency upon bare rock ledges and upon sand dunes. A
special type of sand vegetation is that of sandy beaches, where
the proximity of lake water makes the soil moister than it
would otherwise be. For this reason the plant inhabitants of
beaches are often mesophytic rather than xerophytic in char-
acter, while close to the water's edge true hydrophytes may
establish themselves. Dunes are particularly characterized by

470

Minnesota Plant Life.

sand-binding plants, such as the wild rye, the junipers, some
sedges, rushes and grasses. Mingled with the herbaceous
plants are a few shrubs and trees, such as the hackberries, choke-
berries, poplars, oaks and ashes, with brambles and roses as
underbrush. Sand barrens in Minnesota fall for the most part
into three classes, jack-pine-barrens, oak-barrens and sandy
wastes. The distinctive plant of the pine-barren, a common
formation in the central portion of the state, is the jack-pine.
Along with trees of this species, a number of underbrush plants,
herbs, mosses and lichens establish themselves. Here blueberry
bushes are abundant and other heaths. In such woods the de-

'

FIG. 231.— Vegetation of sand dunes, Isle saux Sables, I«ake of the Woods. In the foreground
is the sand cherry and scrub poplar, in the center, a juniper bush and in the background,
plums. After photograph by the author.

velopment of wand plants is common, and in the autumn the
forest floor is resplendent with the yellow heads of sunflowers,
the purple spikes of blazing-stars, and the white or blue inflo-
rescences of asters. Sandy wastes are characterized by the de-
velopment of mat plants, such as carpetweeds and spurges.
Mingled with these are to be sought many rosette plants like
the evening-primrose and the plantain.

Minnesota Plant Life. 471

The prairie. A most characteristic xerophytic formation in
Minnesota is the prairie — especially the high rolling prairie,
which differs considerably from ordinary meadow or pasture.
Much of the level prairie is mesophytic rather than xero-
phytic. Here a variety of grasses, pulses and composites grow
luxuriantly. Such a region is the home of tumbleweeds, com-
pass-plants and prairie turf-building varieties. Some strongly
xerophytic lilies, such as the onions, are found in profusion
upon the plains. Over unbroken prairie, between the plants
established upon it there exists a great competition. This
goes on not only between the under-ground portions, but also

FIG. 232. — The valley of the Minnesota river in the prairie district. Abundant grass vegetation.
After photograph by Professor R. D. Irving.

between the erect structures. Thus, some prairie plants grow
tall and strong in order to get the light that they require. Sun-
flowers, indeed, may be regarded as the kings of the prairie.
Their erect, vigorous, annual stems are like trees as compared
with the more humble grasses, and where they occur in abun-
dance they may, to the seeing eye, be regarded, perhaps, as in-
dicative of how the forests of the world will appear hundreds
of thousands of years in the future. One may look forward
and imagine sunflowers and their kind grown taller and
stronger, a hundred feet or more in height, and even able to
usurp the place of the trees that are now abundant in the woods.

472

Minnesota Plant Life.

A great many prairie plants are annual, but some of them
are shrubby and perennial. The shrubs are for the most part
low. This is no doubt in response to the moisture-condition,
because if they were high and loose, like the dogwoods and
willows of moister localities, their evaporation would be too
great.

All of the formations that have been described are distinctly
xerophytic and in all of them the moisture-content of the soil
is comparatively small, while its temperature may be high.

Pine forests. At this point it might be well to call atten-
tion again to the xerophytic characters of coniferous forests,
especially tamarack and spruce swamps, balsam thickets, and
river-bluff lines of junipers or red cedars. Probably the whole
pine forest may be regarded as xerophytic. The needle-shaped
leaves of the white and red pines are slow to transpire moisture,
and the pine forests reach their highest perfection along ridges
equivalent, in their topographical character, to the ridges of
rolling prairie. The moisture-content of such soil must be
below the average. Along with the pines a number of xero-
phytic mosses, such as the hairy-capped moss, of ferns, such
as the bracken ferns, and of flowering plants, including the
wintergreens, several heaths, and a variety of asters, are com-
mon. In such forests wand plants grow luxuriantly along with
the shrubby underbrush.

Air plants. When growing upon a substratum in which
nutritive substances required by the plant are lacking or small
in amount, the surrounding atmosphere is drawn upon for the
food supply. Plants that habitually do this are termed air-
plants. The Spanish moss, tree-top orchids and perching ferns
of the tropics afford typical examples. In temperate regions
the perching vegetation is composed principally of lichens,
mosses, liverworts and algae. Much of the rock vegetation
previously mentioned may also be included in this class, and
here, too, may be classified the lichens and mosses that attach
themselves to the bark of trees, to fence rails, to the walls of
buildings or to absolutely arid soil.

Chapter XLIII.

Halophytes and Mesophytes.

The adaptational type of vegetation known as salt vegetation,
or the halophytic group, is very sparingly represented in Min-
nesota. It reaches its best development in the mangrove
swamps of the seashore, and on salt-impregnated beaches or
marshes close to the ocean. A few salt plants are, however, to
be found in the state. In the Red river valley they are some-
times most prolific upon saline or alkaline soil. Here are en-
countered the sea-blites, the glassworts and the Russian thistle,
together with several salt-loving goosefoots, salt-loving purs-
lanes and grasses. One of the plantains is capable of growing
in salt marshes. The most general character of salt marsh
vegetation is its sparseness — a character presented, for example,
by a growth of Russian thistles. Such plants are usually some
distance apart, not close together as in most other formations.
Salt plants, like many bog plants, are stamped with the xero-
phytic structural adaptations. The succulence of the glass-
wort and the great reduction of its leaf surfaces is distinctively
suggestive of the cactus type. The fleshy leaves of the goose-
foots and purslanes call to mind similar characters of rock or
desert succulents. If the body of a glasswort is chewed a
strong saline taste will at once be recognized and will serve to
demonstrate that salts are carried from the soil, where they
exist so abundantly, into the juices of the plant. The typical
salt-succulents are not ordinarily armed with thorns or spines
as are the typical desert-succulents. This may be because there
is not such absolute sparseness of vegetation in the general
locality and they are, therefore, not called upon to bear the
brunt of attack by hungry animals.

Succulents in general. At this point it may be desirable to
bring together for comparison the different sorts of succulent
plants. They may be divided into two general groups, leaf-
succulents, such as the purslanes and century-plant, in which the

474

Minnesota Plant Life.

leaves are the principal succulent organs; and stem-succulents,
such as the cacti, in which the leaves are reduced to thorns and
the stems have become fleshy. Of adaptational types there
are the following: desert-succulents, generally armed with
thorns; rock-succulents, more commonly unarmed; salt-suc-
culents, like the glassworts, sometimes armed; and tree-top-
succulents, generally unarmed. Of the latter group tropical
orchids furnish illustrations. Some of the leaf-succulents de-
velop their leaves in rosettes and belong also to the class of

FIG. 233. Cottonwood trees on the Minnesota river. After photograph by Williams.

rosette vegetation; the century-plants, the live-forevers, and
the little hen-and-chickens are examples of this group. The
tree-top-succulents, also, of the orchid family, to be seen in
greenhouses, in a number of instances develop their leaves in
clusters upon short stems. Other leaf-succulents, however,
have the stems slender and branching. This is true of the
purslane, the rock purslane and the Russian thistle. Succulents
may have arisen through direct influence of the environment,
by the warming of the soil. This would tend to increase the

Minnesota Plant Life.

475

absorptive power of the roots, so that desert-succulents in par-
ticular might be regarded as plants that in a warm soil have
swollen themselves full of water and, during the course of gen-
erations, have adopted permanently the fleshy structure.

Mesophytic vegetation. A number of other plant forma-
tions remain to be catalogued under the general head of meso-
phytic vegetation. The term is applied to those plants which
are intermediate, in their reaction to moisture, between hydro-
phytes and xerophytes. The characteristic mesophytic forma-
tions of Minnesota are the hardwood forests, the meadows, the

FIG. 284. — A Minnesota meadow bordered by shrubbery and deciduous forest. After photograph

by Mr. W. A. Wheeler.

cultivated fields and gardens, the roadsides and the mesophytic
shrub, such as underbrush at the edges of forests, or the widely
distributed scrub, composed of little oaks, sumacs and maples.
In all these formations the plant-covering is thick and a large
number of perennial species exist.

Meadows. Meadows or pastures are composed for the most
part of grasses and accessory herbs, such as verbenas, flax, sor-
rels, buttercups, anemones and thistles. Here, too, gentians
and speedwells will be found, together with primroses and

Minnesota Plant Life.

thoroughworts. Occasional xerophytic plants enter such
meadows and one may find in them mulleins or scouring-rushes
growing among the typical mesophytic grasses and herbs. In
such localities plants of xerophytic tendencies may often be
distinguished by their rosettes of leaves. In the meadows
mosses and sometimes ferns occur. With the meadows should
be compared the broad expanses of mesophytic prairie, es-
pecially those of the Red river valley and the Minnesota.

Cultivated fields. Cultivated fields and gardens, where the
soil is stirred by the plow or spade, come to be occupied by a
group of vegetation classified by the farmer as crop and weeds.
This is, of course, a purely economic classification, and to get
the proper botanical idea of a cultivated field all thought of
human interest in the kinds of plants that grow must be elim-
inated. It will then be discovered that the field is occupied
by a dominant formation which owes its selection and abun-
dance to the distribution of its seeds or fruits through human
agency. A number of accessory plants are also developed, in-
cluding a variety of common grasses and herbs. Into such
fields some xerophytic forms, like the purslanes, introduce
themselves, but the majority of the plants will not show con-
spicuously the xerophytic adaptations of structure which have
been described ; that is, the weeds of a cultivated field are not
predominantly silky or strong-scented, or succulent, or plants
with the edges of their leaves rolled in together. In such
localities, rather, will be found the thistles, the fox-tail grasses,
the oxeye daisies, the amaranths, pigweeds and wild parsleys,
together with some kinds of buttercups and clovers. Such a
field in its general composition bears a close resemblance to
pastures or meadows. A particular kind of field is produced
when the soil is sandy or alkaline. Or, if the soil is very hard,
composed of clay closely packed together, the vegetation cov-
ering it will be different from that of ordinary cultivated fields.
Sand-loving plants or mat plants will come in and establish
themselves prominently along with carpetweeds, purslanes,
thistles and wild lettuce.

Roadside vegetation. With such wastes of weeds as have
been described, roadside vegetation may be connected and the

Minnesota Plant Life.

477

strong resemblance between it and that of a neglected field is
at once apparent.

Mesophytic shrub. Of mesophytic vegetation classes, in
which shrubby or woody plants are predominant, a number of

FIG. 235. — Roadside vegetation in summer. After photograph
by Williams.

special varieties might be described for Minnesota. Here
would come the oak scrubs, the sumac and maple underbrush,

1 1

FIG. 236. — Roadside vegetation in winter, St. Anthony Park. Oaks,
sunflowers and golden rods. After photograph by Williams.

the hazel scrub which is particularly abundant in Minnesota
and the poplar scrub in which the dominant plant is the com-

478 Minnesota Plant Life.

mon poplar. Dogwoods, roses, hawthorns, plums, ashes and
other shrubs are prominent as components of this general
formation. Along with these go usually a number of wand
plants, herbs that thrust their slender stems up between the
shrubs, thus getting illumination. Of these the goldenrods, the
willow-herbs, the evening-primroses and the asters are ex-
amples. Here, too, one will find a variety of climbing or twin-
ing herbs or vines, and the wild beans and wild peanuts, the
bindweeds and morning-glories, are to be expected. The floor
of the underbrush will be occupied by a number of little grasses

FIG. 237.— Autumnal underbrush, Mississippi river, between Minneapolis
and St. Paul. Golden rods, asters and sumac. After photograph
by Williams.

and low herbs, some of which may be vagrant xerophytes with
the rosette habit of growth or with other characters by which
they can be recognized.

Hardwood forest. The hardwood forest of Minnesota, espe-
cially as developed along river bottoms, where it is made up
of ashes, maples, basswoods, oaks and elms, furnishes an ex-
ample of what is meant by mesophytic forest. Upon sand bar-
rens where the bur-oak finds a congenial home the conditions
are almost xerophytic and, therefore, oak-barrens were men-
tioned under a previous topic.

Minnesota Plant Life.

479

Certain conditions of the forest floor arise, owing to the
decay of the falling leaves, that make such a region favor-
able for the development of humus plants, and a num-
ber of them are likely to be found there, as, for example,
the coralroots, Indian-pipes and wintergreens. Many shade
plants hide in the dense woods and one finds, in their
depths, the trilliums, the jacks-in-the-pulpit, the broad-leafed
asters and broad-leafed gol'denrods, and upon moister ground,
the touch-me-nots, the anemones and the clintonias. In such

woods a number of vines
have their growth, such as
the wild grape and the
climbing bittersweet, or, of
slenderer habit, the hop and
the clematis. A character-
istic of hardwood forest is
the remarkable luxuriance
with which spring flowers of
various sorts are produced.
Before the leaves have come
out upon the trees the forest
floor is covered with flower-
ing herbs. The autumn
flowers of the forest are not
so conspicuous as in the
prairie regions, perhaps be-
cause there is not so much
possibility of attracting the
attention of insects at a dis-
tance, owing to the prox-
imity of tree trunks and to the shadows thrown by the leaf
crowns. In the spring, before the leaves have appeared, such
conditions are minimized and the development of a conspicuous
flower might be of more advantage to the plant.

General considerations. It must not be supposed that every
plant formation in nature is purely hydrophytic, purely xero-
phytic, or purely mesophytic. On the contrary, mixed forma-
tions are exceedingly common. A little change in the topo-
graphical features of a region, a difference in illumination or in

FIG. 238. — Neglected corner in the Minneapolis
manufacturing district. Weeds and shrub-
bery. After photograph by Williams.

480

Minnesota Plant Life.

exposure to wind, a slight modification of the chemical or phys-
ical condition of the soil, or any one of innumerable other varia-
tions in the surroundings may suffice to alter the vegetation
which has become established. Thus, in a well-kept lawn,
where conditions are normally mesophytic, plantains and dande-
lions— both of them mesophytic in structure — will prob-
ably be among the most troublesome weeds. But let the
lawn be established on a soil -too porous and easily dried, or
let the season be below the average in rainfall, and very promptly
xerophytic mat plants, such as spurges and prostrate verbenas,
and xerophytic grasses, such as the sand-burs and other similar

FIG. 239. — Modern hardwood forest of the St. Croix valley, near Osceola. After photograph
by Professor W. R. Appleby.

vegetation, will begin to encroach upon the turf. Vegetation
coverings, wherever they are formed, are quite as sensitive to
changes in surrounding conditions as is a city lawn, and for
this reason the infinite variety of woods, fields, marshes, swamps
and prairies has come to exist.

A very broad classification of the influences which affect plant
adaptations is that made by the German authority, Schimper.
He distinguishes essentially — i, climate; 2, substratum, and 3,
neighbors. By climate he means the complex of atmospheric
and cosmic influences, including, for example, all the influences
of solar light and heat and those of atmospheric vapor and wind.

Minnesota Plant Life.

481

By substratum he means the soil, whether it be rich in calcium,
sodium or nitrogen. By neighbors he means the surrounding
plants and animals which by their proximity affect the habits
or structures of the plant in question. Thus, in accordance
with the origin of their most characteristic adaptations, he
divides vegetation into three fundamental groups, viz., climatic
formations, substratum formations, and neighborhoods. Desert
plants, for instance, may be grouped among the climatic, salt-
succulents among the substratum, and carnivorous plants among

FIG. 240. —View of Fort Snelling, showing midsummer vegetation. After photograph

by Williams.

the neighborhood formations. The further extension of such
a classification is perhaps sufficiently apparent without multi-
plying examples. Aquatic plants would form a special class.

Yet under even so general an analysis it must be evident that
very many plants — indeed, most of them — will appear in one
group or another, as attention is diverted to one or another
aspect of their adaptation. The tree-top orchid as an air-plant
falls into the group of climatic formations, but as a plant en-
abled through the cooperation of its root fungi to use decaying
32

482 Minnesota Plant Life.

materials for food, it comes within one of the neighborhood
formations. No adaptational classifications that have yet been
devised are altogether accurate, but those by Warming and
Schimper are the most practicable.

Chapter XLIV.

Maintenance of the Plant Individual.

Like every other living thing the plant must maintain itself
or die. For different kinds of plants the normal duration of
life may greatly vary. Thus, the microscopic females of cer-
tain orchids, hidden, as they are, deep within the rudimentary
seeds of their species, may exist for but a few days or weeks.
On the other hand, in the canons of the Sierra Nevada, there
still stand, challenging the winds and the winters of the cen-
turies, Sequoia trees that were saplings when the pyramids were
new, noble trees when Rome was in her glory, and already
giants of the western forest when Columbus set sail on an un-
known sea.

Whether the life of a plant be long or short, it may be de-
scribed as arising and continuing through a series of adjust-
ments, complex, subtle, immemorial, between the forces and
the substances of Nature. The materials of which the plant
is made are certain ordinary chemical elements. Their num-
ber and their character can be determined by recorded methods
of analysis. The energy manifested by the plant in its assim-
ilative processes, in its growth, and in its movements is but a
transformation of the energy with which it is supplied through
its food arid through the warmth and illumination of the sun.
Yet it is impossible to reduce the living plant to the terms
of an equation in chemistry and mechanics. That this cannot
be done is because the plant is really a microcosm. The
problem of its existence is as difficult and as profound as that
of the universe. There it stands beside one's doorstep, humble,
passive and inarticulate. Yet it responds to the forces of
light and gravitation reaching it from the depths of infinite
space. It is touched by terrestrial dews and breeze, and, after
its fashion, reacts to such local stimuli. It is moulded by the
inheritance which comes to it through an ancestral line reach-

484

Minnesota Plant Life.

ing down the dim and distant ages to the very moment when
the first living particle appeared on the surface of the earth.
Thus, the child of two infinities, it baffles interpretation ; for in
the heart of every flower is the riddle of the Sphinx.

From such a conception the poet may derive his inspira-
tion and the moralist may instill his lesson. But it is the duty
of the student of science to put aside all feelings either of ex-
altation or depression and to endeavor to collect such facts as
are attainable, even when he recognizes that ultimate explana-
tions lie far too deep to be reached by the plummet of human
thought. In such a spirit the plant has been questioned by
modern science and somewhat is known of the story of its life.
In very simple fashion I shall endeavor to picture it as an
organism at work.

Living substance. The essential groundwork of every living
organism is a material known as living substance, or protoplasm.
By no means all portions of an organism actually consist of
this living substance, although all portions have arisen through
its activity. It is as the spiders spin their webs, or as men
build their cities. The living substance is the organizing body
and the completed plant or animal is the resultant organiza-
tion. As long as the organism contains this living substance
it may be said to be alive; but when the living substance is
destroyed throughout its body the organism is then said to
be dead. No longer held together by the forces inherent in
its builder it may be resolved again into the elemental sub-
stances from which it was constructed. Just so, to continue
the illustration, will a city, if abandoned by its inhabitants,
fall into ruins and finally crumble into dust.

Death of an organism may be sudden or gradual. Thus
by fire, for example, a plant or animal may in a few moments
be converted from a living being into a handful of ashes and a
wreath of smoke. Again, death may be slow, creeping from
organ to organ, and even when the organism as a whole is no
longer living there may in some of its tissues still remain por-
tions of the living substance. The whelming of Pompeii by
the fires of Vesuvius might be taken as an illustration of the
first condition and the gradual but relentless march of a pesti-
lence might illustrate the other.

Minnesota Plant Life. 485

Since plants have no nerves by which shocks are transmitted
to a central system and thence to every portion of the body,
they die much more slowly than do animals.

Location of the living substance. Only in very lowly crea-
tures, such as the slime-moulds, does the greater part of the
body consist of living substance. The jelly-like masses de-
scribed for such organisms are among the best examples of
pure protoplasm. Generally the body of the plant consists,
for the most part, of wood, bark, cellulose, starch, oils, water,
sugar, ash and a great variety of other compounds manufac-
tured at different times by the living substance. One exam-
ining a tree or herb in the ordinary way can neither see nor
touch any of the living substance, whatever, but must lay his
hand upon leaf-skin, cork or some of the various other periph-
eral materials of the plant. It is not otherwise if an animal
be investigated in like superficial manner. The living sub-
stance lies concealed within the walls of the city it has built.
To see it and to study it most delicate manipulation is neces-
sary.

Certain portions of plants are transparent and at the same
time contain living substance. Such areas are favorable for
observation. If, for example, some of the hairs that grow
along the stem of a tomato-vine are carefully removed, placed
in a drop of water and examined under a sufficiently powerful
microscope, it will be discovered that they are composed of
cylindrical joints. Each joint has a \vall transparent as glass,
and, within, most of the interior is occupied by water. There
is also present, however, a pellucid slime, very conspicuous
when once identified. It keeps up a remarkable streaming
motion and tiny granules in it are carried along like boats in
a rapid current. The direction of the stream changes from
time to time. Eddies form in the current. Sometimes the
streams flow together from different parts of the cell interior
and a mound of slime is formed. Sometimes the streams fork
again and again, making a network within the cell. The mo-
tion may cease if the temperature is lowered or raised beyond
certain limits. It ceases, also, if the cell becomes dry or if it
is exposed to the vapors of ether or chloroform. A slight
electric shock stops the movement, but after a time it may

486 Minnesota Plant Life.

beg-in again. A strong electric shock stops it forever. This
streaming, pellucid slime is the living substance.

Not only in hair-cells does the living substance commonly
occur, but in many other portions of the plant. It is found
at the tips of all young roots and buds. In the green cells of
leaves it is always present. It will be found in certain of the
conducting-areas of the plant — in the leaf network and in the
young fibers of the stem. In trees and shrubs it occurs neither
in the mature bark nor in the mature wood of the trunk,
branches or woody roots. Between the bark and wood there
exists, however, in ordinary trees a thin layer — no thicker, in-
deed, than tissue paper — known as the cambium. In this layer
of cells the living substance will be found. It occurs in all
spores, eggs and spermatozoids, in all very young organs and
tissues, and in general in all growing parts of the plant.

Physical structure of the living substance. Years ago when
investigation of the living substance was in its infancy it used
to be described as a "structureless slime" or as "living jelly"-
these phrases indicating how little was really known of its or-
ganization. The researches, however, of the last fifteen years
in particular, have revealed that the intimate structure of the
living substance is extremely complex — so much so, indeed,
that a new science, the science of the cell, has developed, until
to-day libraries can be collected in this field alone. It would
appear that, just as the body of a plant or animal is composed
of cells and their products, so the particle of living substance
in each active cell is itself composed of smaller bodies and their
products, the whole constituting an organism of extreme com-
plexity. It may properly be said that there are now known
three hierarchies of life — social life, individual life, and cell
life. In the first of these man has his place as a component
body, in the second he exists as a self-sustained individual, while
in the third lies the living basis of his organization.

Modern research has shown that the motion seen in a living
cell lying under the microscope of the observer is by no means
disorderly or unrelated. On the contrary the kaleidoscopic
changes in the living substance are now known to have pro-
found significance in nutrition, growth and heredity. The dif-
ference between the old idea and the new may be suggested by

Minnesota Plant Life. 487

an illustration. Suppose some observer stationed in an air-
ship many miles above the battle-field of Waterloo. Per-
haps by the use of powerful glasses he could have made out a
vague commotion far below him, but he could scarcely have
distinguished what actually was happening. To an observer
on the hills near by, the battle would have presented a very
different meaning. Thus, the earlier students of living sub-
stance, because they could not see all that is revealed to the
observer of to-day, fell into the error of thinking that they had
under their microscopes a "structureless slime."

Living substance is by no means homogeneous. Sometimes
it shows a fibrous structure made up of innumerable meshes
and threads. Again it appears as a foam or emulsion consisting
of an intricate combination of larger and smaller bubbles. At
one time, when more saturated with water, it is liquid, plastic
and mobile. At another, when like a sponge it has expelled a
portion of its moisture, it seems almost solid and is passive
and immobile. Thus the living substance in the active cells of
a growing hair and in the dormant cells of an ungerminated
seed may seem very different. By the absorption or expul-
sion of water living substances may pass from one condition to
the other.

Chemical composition of living substance. The following
chemical elements are components of living substance : carbon,
oxygen, hydrogen, nitrogen, sulphur and phosphorus. In the
higher plants the following metals are also necessary for the
formation of living substance, although they do not become
essential components of protoplasm : iron, potassium, mag-
nesium and calcium. Numerous other elemental substances,
such as sodium, lithium, manganese, silicon, chlorine, bromine,
and iodine are frequently found in the bodies of plants; but
they do not appear to be everywhere either essential compon-
ents of the living substance or necessary reagents for its con-
struction.

It must not be supposed that all living substance is of exactly
the same chemical composition. To say that no two particles
are precisely alike would probably be nearer the truth. Al-
though the number of the essential elementary components is
so small, many atoms of each kind are present and the varia-

488 Minnesota Plant Life.

tions in their relative positions and combinations might be al-
most infinite. Certainly, however, the difference between one
piece of living substance, such as the egg of a fish, and another,
such as the egg of a fern, consists less in chemical composition
than in physical structure. Chemically, all living substance lies
within limits which have been just outlined.

Physiological character of living substance. The following
are the most important physiological characters of protoplasm :
i. Assimilation, the power of initiating and maintaining com-
plex chemical changes by which not-living matter is brought
into the living condition and into relation with the living sub-
stance. 2. Grozvth, a term here applied to the increase of living
substance in mass. 3. Irritability, the quality of responding,
after a manner determined by heredity, to impulses originating
within or without the body. 4. Reproduction, the power of
separating, from the body, portions of living substance that,
under the influence of heredity, may recapitulate the develop-
mental stages of the parent. Together with assimilation, in its
broad sense, goes on a variety of chemical processes. By these,
waste products are formed and excreted, accessory products
are combined and modified, and a variety of complex substances
are broken down into simpler forms, thus liberating energy that
is either used in growth and movement or reappears as body-
temperature, phosphorescence, electrical disturbances or some
form of mechanical work.

Requisitions made by living substance on its environment.
In order to maintain its physiological processes, living sub-
stance must have a supply of matter and a supply of energy.
The supply of matter, or the food of the organism, may be of
great variety, provided that it contain the necessary chemical
elements in assimilable form. The great primal source of
energy is the sun and upon its light and heat all living things,
in the final analysis, will be found depending. Some, however,
like the fungi and the animals receive much of this energy indi-
rectly. It is utilized directly by the green plants, the color of
which indicates the presence in their tissues of that extraordi-
nary accessory product of living substance — leaf-green, or chlor-
ophyll. This leaf-green that stains either the entire living sub-
stance of the cells that are set aside for starch-making, or cer-

Minnesota Plant Life. 489

tain specialized portions, is a form of "light-engine" by which
the energy of the sunlight is set at work building up starch
out of such simpler substances as carbonic-acid gas and water.

The food of plants. In general the diet upon which a plant
can live is simpler than that necessary for an animal. The
important elements are principally obtained from sources as
follows : Carbon is collected from the carbonic-acid gas of the
atmosphere ; oxygen both from the atmosphere and from water ;
nitrogen from salts in the soil, but not from the atmosphere;
and hydrogen from water. Sulphur, phosphorus and the
metals are obtained from soluble salts in the soil. In excep-
tional instances the sources may be other compounds than those
mentioned. Thus nitrogen and possibly hydrogen may be
taken from ammonia products, but this would be very unusual.
What has been stated refers to green plants alone, for plants
without leaf-green demand a much more complex diet. Their
carbon they may obtain from sugars and from proteids; their
nitrogen from proteids ; their oxygen and hydrogen from water,
from sugars or from proteids; their sulphur and phosphorus
from the soil, or perhaps from proteids ; and their metallic sub-
stances from soluble salts in their substratum.

The plant does not ingest solid particles of food as does the
animal — though to this certain carnivorous plants are quasi ex-
ceptions— but receives its nutriment either as gases, liquids or
solutions. The absorptive tract of the plant is often specialized
so that one area is fitted better for absorption of gases and
another for absorption of liquid solutions. Thus in the ordi-
nary green plant it is the foliage that characteristically absorbs
carbonic-acid gas and oxygen, while the root-system absorbs
water with nitrogen compounds and metallic salts in solution.
Aquatic plants are more generalized, as are also air-plants —
although the latter use their exposed root-system very much
as if established on a firm soil. Humus plants and parasites
obtain their food from the bodies of other plants or animals
or from decaying organic substances.

Partnerships for obtaining food. Some extraordinary part-
nership arrangements for securing food have been developed
in the plant world. Thus, in the lichen-body a fungus and an
alga live in partnership and obtain their food quite as if they

490 Minnesota Plant Life.

constituted an independent green organism. So, too, do many
humus plants, such as coralroots and pine-saps, depend upon
the presence, in their underground portions, of root-fungi. By
aid of these they can secure from the soil organic substances
that alone they could not collect. In return for such service
they harbor the fungus in their tissues.

Intra-specific partnerships. Among higher plants a remark-
able division of labor exists. By it the spore-bearing plants of
the species exist as the primary food-gatherers, while the egg-
producing and sperm-producing plants live dependently upon
them, having no original food-collecting capacity of their own.
Thus, among flowering plants the female, quite devoid of leaf-
green, lives upon substances stored up for her use in the rudi-
mentary seed borne by the spore-producing plant. The
male, also, among flowering plants, lives parasitically upon the
tissues of the immature seed or fruit. Similar conditions are
known to exist among certain ferns and club-mosses. Other
highly interesting inter-relations for nutrition are those between
the mother plant and the offspring, as in cone-bearing trees;
or between the twin embryos in seeds of higher flowering plants.
In the latter instance one of the twins customarily gorges itself
with food for the benefit of the other, and by the latter it is
ultimately devoured. In such a life-history as that of the sun-
flower, for example, only the ordinary green leaf-bearing plant
of the species is an independent collector of food. Upon it
depend the male and female plants, the albumen-plant of the
seed, and, for a time, the embryo-plant that is later to develop
into a new leaf-bearing individual.

Storage of food. After absorbing its food materials from
the air, soil, water or bodies of other organisms, these are re-
combined by the plant into characteristic products. In green
plants the first visible product of assimilation is starch. This
substance originates in the leaves and other green portions
under the influence of sunlight. It arises as little white gran-
ules. These may grow to a considerable size, but are ordi-
narily attacked by ferments, converted into soluble sugars and
conveyed along the conduction-paths of the plant either to
growing areas where they are used in construction, or to storage
areas, such as bulbs, tubers, fleshy roots, seed-albumen or bud-

Minnesota Plant Life. 491

cores in which they are deposited as starch or as oils. Proteid
substances, originating also in the foliage of the green plant,
may be carried away in the form of peptones to growing tracts,
or to storage organs, where they may take the shape of little
granules, known as farina grains or aleurone grains. Storage
layers commonly occur along the conduction-paths, while spe-
cial storage organs are produced in a variety of plants. Of
such storage organs an ordinary potato, onion, beet or carrot
may serve as familiar examples.

Ultimate disposal of the food. The materials taken into the
body of the plant and subjected to the elaborative processes
initiated by the living substances must be either retained as
part of the body or excreted. The high manifestation of energy
that characterizes the animal is by no means so characteristic
of the plant. In other words, constructive processes prepon-
derate in the plant-\vorld and a greater proportion of material
received as food remains in the body of the plant than in the
body of the animal. Excrements are, therefore, not so abun-
dant among plants as among animals. Indeed the principal
plant excreta are gaseous. From the leaves are given off
oxygen, a waste-product of starch-making, and water vapor.
Water in the fluid state is also rejected by many plants. Car-
bonic-acid gas, a waste-product of respiration, is excreted from
the surface of the plant, both in the area of the shoot and of
the root. Solid excreta, however, are not formed by plants.

When retained in the body of the plant, food materials may
assume a great variety of forms. A certain portion is utilized
in the production of new living substance, but by far the greater
.amount is stored as cellulose, bark-substance, wood-substance,
gelatine, crystals, organic acids, coloring material, tannin, alka-
loids, glucosides, oils, fats, resins, gums, reserve-food and cell
sap. Many thousands of plant products are known, so marvel-
ous is the chemical activity of the living substance.

Growth. The term growth is rather an ambiguous one, since
it is applied in several different ways. It should at least ex-
clude nutrition, and should generally indicate increase in size.
Sometimes, however, there may be an increase in mass without
a visible increase in size, and it seems difficult in such an in-
stance not to apply the term growth to the process of enlarge-

492 Minnesota Plant Life,

ment. For the sake of clearness at least three types of growth
should be distinguished: i, growth of living substance; 2,
growth of cells, and 3, growth of tissues and organs. The first
takes place as a result of constructive assimilative processes,
and may or may not be accompanied by a visible increase in
size. The second may go on without increase in mass either
of the living substance or of the organ to which the growing
cell belongs. The third may occur while mass of living sub-
stance and cells are increasing, but sometimes even while mass
is stationary or diminishing. Thus by change in shape of its
component cells an organ may elongate, though while it does
this there may be no actual increase in substance. Neverthe-
less such an elongation might appear as visible growth. Such
an analysis is somewhat disregardful of refined and technical
terminology, but is not seriously at variance with the truth.

Growth of living substance. The most important fact to be
kept in mind concerning the growth of living substance, is that
it is not simply an accretion of new material. Growth goes
on in varying degree among the innumerable component parts
of the living substance, each growing in its own way and at
its own rate. Thus results the growth in aggregate of the
whole. To illustrate this, let there be imagined a village full
of children. After a year or two had passed the children
would have grown and the total human weight of the village
would have increased. Some, however, of the children would
have grown more than others, — some, even, might not have
grown at all. The final result, however, a general increase in
weight, was not obtained by mere accretion. In such fashion
does a microscopic piece of living substance grow. It grows
as an organism, not as an office-building nor as a snow-drift.

For living substance, the limits of growth above which me-
chanical support, such as partition walls, strengthening beams,
and retaining membranes, becomes desirable, are generally be-
low the limits of unaided vision. For this reason most plant
cells are of microscopic size. The cell may, in a complex
tissue or organ composed perhaps of millions, be regarded as
resulting from the necessity of individualizing small pieces of
living substance. It is true, cells vary greatly in size. The
smallest are those of the bacteria. The largest are those of

Minnesota Plant Life. 493

certain oceanic relatives of the green felt — an alga belonging
to the bright-green group. Yet even in the latter, the body,
as large as a hen's egg, which exists without partition walls
cutting it in all the planes of space is equivalent rather to a
cell-aggregate than to a single cell.

Just why the limits between which cells vary in size should
be what they are, is a difficult question to answer. The cause
must be sought in the structure and qualities of the living sub-
stance and in the conditions of the outer world as they react
upon it. A proper comparison would be with the towns and
cities of the human species. These vary in size between mere
hamlets to cities like London, Paris and New York. Cities
with fifty million inhabitants, however, do not exist, because
with human society organized as it is they cannot be main-
tained. To explain exactly the causes that have fixed 6,000,-
ooo rather than some other number as a population limit be-
yond which human cities have not yet developed, would re-
quire a more exhaustive knowledge of anthropology and soci-
ology than any one possesses. Still more impossible is it to
state why the limits of cell size are precisely what they are. It
is, at the same time, clear that, as in the instance of the cities,
the reason lies essentially in the nature of the organism — that
is, the living substance which builds the cell.

The largest masses of living substance in which cell com-
partments have not appeared are the jelly-like bodies of the
slime-moulds. These aggregates of protoplasm, in patches
the size of a dinner plate, are sometimes found on decaying
timber. Because they are not provided with internal mechan-
ical support they lie flat and shapeless upon their substratum.

Origin of the cell as a structural unit. One is now in a
position to understand why living substance almost universally
displays itself in the microscopic individualized portions known
as cells. The cell is an adaptation fitted to enable the living
substance, under the stress of outward conditions, to perform
its physiological functions in a better way than if this adapta-
tion had not been called into being. There is reason to sup-
pose that mechanical support and protection against shock
might have been the principal necessities under which primal
masses of living substance came to develop the cell-habit. In

494 Minnesota Plant Life,

both plants and animals cell structure is almost universal and
both kinds of creatures are said to be composed of cells. It
must be observed, however, that the cells are not the funda-
mental units of structure, but are themselves individualized
areas arising through adaptation of the living substance to its
surroundings.

The growth of cells. Certain distinctions appear to exist
between the growth of cells and the growth of living substance.
When the living substance grows there is an actual increase
in its mass. A cell, however, may grow by distending itself
with water and there need be no absolute increase in its liv-
ing substance. A typical cell shows a delicate wall surround-
ing the living substance, and a portion of the latter is differ-
entiated from the rest as a complex body termed the nucleus.
Within the meshes of the living substance cell sap occurs. A
normal condition of such a cell is the plump, water-swollen,
elastic state known as turgor. If enough of the cell sap is lost
by evaporation through the delicate wall, the turgid condition
is no longer maintained and the cell becomes limp and flabby.
An organ composed of cells, — as for example, a leaf, — when the
cells have lost their turgidity through evaporation, becomes
wilted. In such a condition cell growth cannot go on, and
it may be stated categorically that for the growth of cells turgor
is a prerequisite.

Maintenance of turgor. In order to understand how turgidity
of a cell is established and maintained, the common physical
phenomenon of liquid dialyzing through a membrane must be
thoroughly understood. The living substance of a cell, having
an avidity for water, will readily absorb it if it can be obtained.
Since, however, having adopted the cell-habit, each particle of
living substance is surrounded by a continuous membrane or cell
wall, the liquid, to reach the interior, must filter through this
membrane. It is a fact of observation that certain liquids or
solutions pass through membranes much more readily than do
others. Thus, if a bladder be filled with brine and placed in a
tub of fresh water it will soon become swollen, because the
fresh water passes inward more rapidly than the salt water
passes outward. If, however, a bladder, distended with fresh
water should be placed in a tub of brine the reverse action

Minnesota Plant Life. 495

would take place and the bladder would become limp. If, fur-
ther, syrup were placed in the bladder and brine around it, the
first instance would be repeated and the bladder would become
swollen. Such observations indicate that syrup passes more
slowly through the membrane than does brine. In general it
may be said that solutions of relatively complex chemical sub-
stances move through membranes more slowly than do solu-
tions of relatively simple substances. The phenomenon of
dialysis through a membrane is termed osmose.

Living cells, since they are provided with cell sap and mem-
branes, are in a condition to maintain osmotic relations either
with neighboring cells or with any moisture-containing medium
that surrounds them. The presence or absence of osmotically
active compounds dissolved in the cell sap has much to do
with the regulation of turgor, as it has also with the conduc-
tion of food-solutions from one part of an organ to another.
Thus, not only are the various cells of a root-surface kept turgid
by the maintenance of an inward flow of liquid from the soil,
but compounds such as soluble salts of nitrogen or of metals
are transported — along special paths in the higher plants — until
they reach, perhaps, a starch-making and proteid-making organ
such as the leaf. Not only is this upward flow of crude food
solutions normal for the higher green plants, but simultane-
ously there is, of refined food-products, such as sugar and pep-
tones, a downward flow from the leaves to other parts of the
plant, even to the most distant rootlets.

A growing cell may then, upon the whole, be regarded as a
self-inflating bladder, which, through the activity of the living
substance, absorbs water from its surroundings. It does this
by the aid of osmotically active compounds produced by the
living substance and dissolved in the cell sap. In highly organ-
ized plants, such as the ordinary trees, other factors besides
osmose enter into the ascent of the sap, but need not here be dis-
cussed.

Growth of tissues and organs. Tissues, that is, structural
cell-aggregates, and organs, that is, physiological tissue-aggre-
gates, grow by the growth of their component cells. There
may be, however, cell-growth without, in a strict sense, growth
of the tissue or organ. For example, a nasturtium leaf-stalk

496 Minnesota Plant Life.

bends towards the light, and there may be enlargement of cells
on the convex side, or contraction of cells on the concave side,
or both ; yet such a curvature should scarcely be called growth
of the organ. Growth of a tissue or organ might perhaps be
defined as permanent enlargement arising through growth of
the component cells.

There are ordinarily distinguished three important stages in
the growth of an organ. These are: i, the stage of cell-
multiplication; 2, the stage of cell-enlargement; 3, the stage
of cell-differentiation. A mature organ commonly consists of
very many more cells than would be found in the same organ
when immature. But since all cells arise from preceding cells
and never, so far as known, in any other way, whatever, it is
evident that there must have been a general division of pre-
existent single cells into cell-groups. This leads to an inquiry
into the nature of organ-rudiments. It may be stated broadly
that the rudiment of any plant organ is either a single cell or a
group of cells. The stems and leaves of a moss or of a liver-
wort, the stems and roots of ferns, the spore-cases of "true"
ferns and, perhaps, even the stems of pine trees, are examples
of organs arising from single-celled rudiments. Of organs
arising from groups of cells there might be mentioned the roots,
stems and leaves of the higher seed plants, the spore-cases of
club-mosses, the spore-cases of seed-producing plants and, in
brief, organs generally in higher forms.

The tip of a growing organ is commonly occupied by a little
group of cells in process of division. Thus the tips of roots,
the tips of buds inside the covering of overlapping scales, and
the tips of very young leaves, will be found to consist of small,
thin-walled cells, packed full of living substance, and each
capable of dividing into two cells by the formation of partition
walls. In such rudimentary areas the cells are at first very
similar, but before long some cells of the mass begin to assume
shapes and structures that are distinctive. Close behind the
growing tip of a young root the skin-cells will have begun
to flatten and the cells of the central conduction-path will have
begun to elongate. These differences and many others be-
come progressively more marked and in older parts of the
root each tissue — the skin, the wood, the pith, the reservoir-

Minnesota Plant Life. 497

tissue, the bast, the cork, the milk tissue and the skeleton tissue
—will have become developed with its own structural pecul-
iarities.

In growing organs the cells live together somewhat after the
manner of individuals in a community. They influence each
other in a variety of ways — by mutual pressure, by contact, by
transfers of solutions, by propagation of impulses and even
by direct interchange of living substance. In growing tips
the partitions between the cells often have extremely minute
perforations through which the protoplasm is continuous from
cell to cell. By this continuity the tip remains an organic unit,
and every plant organ, from the earliest rudiment, must be
regarded, not as built up, cell upon cell, in the manner that
bricks are laid in some edifice of human construction, but
rather, as an elaboration of living substance growing under the
restraints of physical and chemical law, under the ever present
influences of the surroundings, and under the hereditary bonds
of the cell-habit.

Irritability. This term is applied to that quality of living sub-
stance manifested when, by contraction or chemical change, it
responds to stimulation; and when the response is apparently
altogether disproportionate to the stimulating cause. Starch-
making under the influence of sunlight is not classified as a
form of irritability, since it is a reaction not particularly differ-
ent, in degree, from the reaction that goes on when a photo-
graphic plate is exposed to the chemical rays of the sun. There
is here no apparent disproportion between cause and effect and
the reaction does not essentially differ from similar changes that
might be initiated in altogether lifeless substance. But when
a nasturtium vine places its leaves perpendicular to the rays
of the sun, accomplishing this by a very complicated series
of changes in the shapes of cells and in the living substance
itself of the leaf-stems, there is a reaction out of proportion to
the immediate ca.use and possible only since a mechanism exists,
and this mechanism has been put in motion by the sunlight.
Irritable responses, as made by the plants and animals of to-day,
indicate not only mechanism capable of responding, but con-
note also an inheritance through the ages in view of which
the mechanism is what it is. As in all other manifestations of

33

498 Minnesota Plant Life.

the living substance, irritable phenomena are related with past
time as well as with the present. Here, indeed, lies one of the
principal differences between a living thing and an insentient
mechanism composed of springs, wheels, pulleys, levers and
rods. One has a past ; the other is a creature of the present.

Irritable behavior of living substance. While all manifes-
tations of irritability must be attributed to responses by the
living substance, it is convenient to examine first those responses
made by living substance, as such; and later to consider the irri-
table responses of cells and organs. A further distinction may be
made, for purposes of analysis, between induced and automatic
responses. Really, all responses are induced by stimuli ; but
if these stimuli originate within the living substance — as a result
of subtle rearrangements of its component structure — the re-
sponses may then be termed automatic, in contradistinction to
responses which are plainly induced by external stimuli. Thus,
the extraordinary marshalling into groups of the component
parts of a mass of living substance, before division of a cell
takes place, would be termed automatic ; the lashing of a swim-
ming thread, such as that of a spermatozoid, is also automatic ;
but the contraction of a portion of protoplasm when exposed
to a slight electric shock would be regarded not as automatic
but as induced.

Examples of automatic irritable phenomena in living sub-
stance are very numerous. Here should be classified the stream-
ing movement, the lashing movement, the crawling movement,
and the spontaneous contractions of protoplasm. Here, too,
should be grouped those amazing evolutions by which the
nucleus of a cell divides itself into two, prior to cell division.
It is by no means a mere halving of the nucleus that then
takes place ; but a complex segregation of certain portions on
one side and certain portions on the other side of a neutral line,
the whole recalling military marchings and countermarchings,
or the working of some ingenious manufacturing contrivance,
such as the pressroom of a metropolitan newspaper. Automatic
movements are dependent upon suitable outward conditions,—
as are also induced movements. Thus, too high or too low a
temperature, too strong or too weak illumination, or some
other condition of the environment, may prevent their appear-

Minnesota Plant Life. 499

ance. They are not, however, the normal immediate responses
to the presence of certain temperature or light conditions and,
therefore, cannot be regarded as actually caused by light or heat,
as are certain induced movements.

Among induced responses of living substance might be men-
tioned the change in position undergone by particles of leaf-
green when the illumination becomes intense. In many higher
plants the particles of leaf-green, so abundantly distributed
through the cells of the leaves, are shaped like two watch-
crystals faced together. That is, they are lens-shaped and
biconvex. When exposed to weaker illumination they custom-
arily turn their broad faces towards the light; but if the illum-
ination becomes too intense they shift their positions until only
their edges are presented to the rays. Another example of an
induced irritable movement is afforded by some free-swim-
ming cells that normally swim either towards a source of light
or away from it. Certain organisms of microscopic size are
known to swim invariably towards the positive or towards the
negative pole of an electric field. Still others are directed by
chemical substances in solution. Thus, the minute Euglena
plants swim towards concentration of organic substances that
would be suitable for food, and spermatozoids, directed by
chemical emanations, swim towards the eggs of their species
So invariably are these directive movements induced that if a
very weak solution of sugar, malic acid, or whatever the specific
chemical may be, is placed in a capillary glass tube and then
immersed in a dish of distilled water containing stimulable
spermatozoids, they will swim into the tube by thousands.
From such experiments it is learned that the spermatozoid finds
the egg with which it is to fuse, because it is induced to swim
from a weaker to a stronger solution of some substance that the
egg is excreting.

Still another example of an induced movement is furnished
by the large jelly masses of living substance characteristic of
slime-moulds. These have a habit of climbing up upon the
bodies of herbs or other objects and spreading themselves out
on the leaves or elsewhere, as a preliminary to the production
of spores. The significance of such a habit is not hard to un-
derstand, for through it the spores when produced are likely

Minnesota Plant Life.
,

to obtain wider distribution. The movement is, no doubt, in-
duced by the force of gravity. Stimulated by this force the jelly
mass crawls upward. Such behavior is an excellent example of
an irritable response to an outward stimulus. Clearly such an
upward movement is distinctly different from the upward
movement of a balloon. The jelly mass is much heavier than
the air and it crawls away from the surface of the earth because
the force of gravity induces its mechanism to make this form
of response. There is a great difference between mechanism,
as such, and the material of which the mechanism is constructed.
If it were not alive it would respond to the force of gravity pre-
cisely as a stone does.

Irritable behavior of plant organs. While, as has been
stated, all phenomena of irritability must receive their ultimate
explanation in the structure and nature of the living substance,
yet it is expedient to separate, in an analysis, the irritable be-
havior of organs from that of living substance. As before, and
under the same conditions, the manifestations may be grouped
either as automatic or as induced.

Among examples of automatic irritable phenomena in a grow-
ing organ, there might be named the movements of growth,
as they are termed. 'It may be discovered by careful observa-
tion that a stem in process of elongation does not increase in
length regularly, but in such a way that the tip describes a spiral
in the air. This growth-movement is termed nutation. It
may best be detected by taking, at intervals of a few moments,
a continuous series of photographs of some growing shoot.
By comparison of the different pictures it will be learned that
the stem has not been thrust straight up, but that it has been
nodding, first to one side and then to the other, in a highly
erratic manner. In part, the movement is determined by ex-
ternal conditions of nutriment, illumination, temperature, among
others, but there is also an automatic quality in the movement
of nutation which permits it to be mentioned here.

Another remarkable automatic movement — in this instance,
in a mature organ — is that of the leaflets in an exotic member
of the pea family, known as the "telegraph plant." The leaf of
this plant is composed of a large central and two lateral and
smaller leaflets. The central leaflet is quiet, but the two small

Minnesota Plant Life. 501

blades keep up a flapping motion, which, although slow, is
plainly visible. Of what use this may be, no one clearly knows.
Possibly it serves to frighten away leaf-cutting ants, but this
seems doubtful. In any event such a movement is typically
automatic. It takes place only under suitable conditions of
temperature and nutrition, but these conditions cannot be
termed the cause of the movement. That, indeed, must be
very complex and should be sought in the intimate structure
of the plant.

Induced movements of organs are numerous — so numerous,
indeed, that it may be said of every organ that it is capable
of making a variety of irritable responses to the impulses reach-
ing it from the outer world. Among the various effective
stimuli are the forces of gravity, light, heat, magnetism and
electricity, also air, moisture, matter in solution, matter in
contact, and various mechanical tensions, pressures and strains.

While not the only methods of response, very characteristic
reactions of organs to an outward stimulus are by maintenance
of positions parallel with, or perpendicular to, the force-lines
of the stimulus, or by curvature in some definite direction.
Thus, under the constant action of the force of gravity, shoots
ordinarily maintain an erect position, growing against the force ;
while roots grow with the force. Both positions are manifesta-
tions of irritability. In the various plant-positions, there is
also to be distinguished an automatic type of irritability. Thus,
quite apart from the force of gravity, root and shoot grow in
opposite directions. They will do this if whirled on a hori-
zontal wheel, as in the experiment of Knight, who thus demon-
strated the similarity between the response to centrifugal force
and that to gravity, for in such an apparatus shoots grow
towards the center and roots towards the rim. There is, so to
speak, a polarity in plant organs. They have tips and bases, or
upper and under sides, or fixed and free ends. In the main-
tenance of polarity automatic influences are at work. For this
reason counteraction of the force of gravity, by revolution of
the plant upon a vertical wheel, does not permit the plant or-
gans to become shapeless and unrecognizable. On the con-
trary, they retain their polarity, though their direction may
be different.

502 Minnesota Plant Life.

Nevertheless the constant action of the force of gravity may
be said to induce the upright position of a normal shoot. It
is true this position may be modified in a variety of ways
by a variety of forces, or by the so-called correlations of growth.
A lateral ray of sunlight may force a shoot out of the perpen-
dicular, either towards the ray, as in the nasturtium, or away
from it, as in the ivy. And in an organ-complex, such as the
branching crown of a tree, the mutual interrelations of the twigs
cause positions to be taken which are quite the reverse of those
that they would take if growing by themselves. The young
sapling of the soft maple, for example, grows erect. When it
begins to branch the branches form angles with the primitive
stem, and, in a mature tree, twigs will be found growing directly
downward, perhaps — a thing that they would not do unless
correlated with the other branches of the tree. Sometimes the
erect position of one organ inhibits such a position in a sub-
ordinated organ. An illustration of this is often seen in
pine trees. As long as the terminal shoot is active it is the only
one to maintain the erect position ; but let it be destroyed and
a 1'ateral shoot will bend into the erect position. Evidently the
lateral shoot has the structure fitted to maintain the erect posi-
tion and was prevented from so doing simply because correlated,
as a lateral branch, with the original terminal axis.

When all necessary reservations have been made it becomes
apparent that most plant organs are strongly influenced by the
direction from which the forces of light and gravity may strike
them. Evidence of this may be seen whenever a grass stem
beaten down by hail lifts itself again, or in the leaning towards
the light, of plants in a window-garden.

Besides the manifestations of irritability that have been
alluded to, there are many others, to which but a cursory refer-
ence can be made. Roots bend from a less moist to a more
moist substratum. They commonly bend away from the light.
Greater oiMess warmth may exert a directive influence upon
growth. Chemical substances in solution influence aquatic or-
gans. A number of organs grow towards oxygen or towards
the air. Others grow away from it. Thus, if several pollen-
spores germinate in a drop of sugar solution all the pollen-
tubes will grow towards the center of the drop, and away from

Minnesota Plant Life. 503

the air in which it may be suspended. Some organs place
themselves against a stream of water, while others grow with
the current. Some organs bend towards the positive electric
pole, others towards the negative. Growth in a magnetic field
shows that magnetic force has its directive influence. Contact
induces curvatures. Root tips upon touching a hard body be-
come convex toward the body that touches their sensitive
area. Tendrils, on the other hand, and twining stems be-
come concave toward the body that touches their sensitive
surfaces, thus enabling themselves to seize hold of supports.
A wound often induces curvature. Thus, branding a root tip
with a hot wire induces it to curve to one side. In general, the
plant is a sensitive creature feeling easily slight changes in the
surroundings and accommodating itself to them, so far as pos-
sible, by irritable curvatures.

'Special organs of irritability are present in many plants. Of
these the piilvinns of the pea family and the tendril of gourds
or smilax, might be cited as illustrations. At the base of each
leaflet of a bean plant, for example, may be noticed a short sec-
tion of the leaf stem in which the color is deeper green than
elsewhere. A similar section exists at the base of the main
leaf-stem. Such an area is called a pulvinus and is the motile
organ of the leaf. When provided with pulvini, as are beans,
clovers, wood-sorrels and several other plants, the leaves easily
change their positions under slight stimuli. Clover leaves ex-
amined at night will be found to be in sleep-positions different
from those of the day, and doubtless induced by falling tem-
perature and less illumination. Leaves with pulvini commonly
make automatic movements, most noticeable in the telegraph
plant mentioned above. Some leaves with pulvini are highly
sensitive, and of this condition the well-known Mimosa is an
example. In this plant a slight shock or burn causes the
numerous leaflets to fold together and the whole leaf to drop
downward on its stem. The rapidity with which the action
takes place makes it very striking, but it is not particularly
different, except in amplitude and celerity, from many other
sensitive reactions. All plants are sensitive plants, if one
watches them closely enough. The curious Venus's fly-trap of
Carolina is another quickly-moving variety. Its leaf-blade may

504 Minnesota Plant Life.

snap together along the pulvinus-like midrib, quite after the
manner of a steel trap. The mere contact of an insect is
enough to set off the irritable mechanism.

A tendril is a singularly ingenious contrivance. At first it
is straight, or with the free end slightly bent. It sweeps about
slowly with the growth-movement known as nutation, and w7hen
its tip encounters a resistant body, the tendril becomes bent
around the object that it has found and fastens itself to it.
Then the whole cylindrical organ coils into a spring, drawing
the leaf or stem up against the support. Later the tissues of
the tendril become woody, giving strength, while the coiled
structure gives elasticity. Thus plants with these organs are
the most perfect of climbers and support themselves lightly but
firmly upon their trellises.

All the responses to stimulation that have just been reviewed
would be classified as curvatures. When a gall-forming insect
stings a plant, or when a witches'-broom fungus obtains a foot-
hold upon it, there is, rather, as a result of the stimulation, an
abnormal growth of tissue. Galls, in particular, are often very
extraordinary structures. The huge purple root-galls of the
wild rose, the spherical papery shells of the oak, the little hem-
ispherical nodules on basswoods leaves, the cone-like grey
bodies on willows and the great bushy tangles on black ashes
are all familiar objects in Minnesota. In such galls special
anatomical structures are called into existence by the virus in-
jected with the insect's sting. Special gall-types characterize
particular plants, and will not be found elsewhere. Between
the specific virus and the specific character of the living sub-
stance of the plant a relation exists ; and upon this depends the
anatomical and physiological character of the gall.

Another type of induced irritability of organs is seen in the
arrangement of skeleton-tissues, for the large leaf will have more
strengthening material in the stem than will the small leaf of
the same species. Such strengthening areas are found to lie
very exactly in the regions of pressure or of tension, and may
be regarded as having come into being by the response of cells
to such stimuli. The cross-section of the familiar rhubarb
leaf-stalk shows it to be half-cylindrical in form. The arched
side is towards the ground and the calling into existence of

Minnesota Plant Life. 505

the arched form of leaf-stalk depends upon the action of pres-
sure, owing to the weight of the leaf-blade. All the beautifully
accurate arrangements of strengthening beams and elastic tissues
in stems and leaves may be regarded as possible only through
irritability of the living cells, some of which, under pressure,
thickened their walls to withstand it ; while others, in a region
of flexions, adopted elasticity of structure.

Summary statement. What has been brought forward upon
the subjects of plant nutrition, growth and irritability, suf-
fices merely to direct attention to a few of the paths along
which investigation has proved profitable. No attempt has
been made in so limited a space to present a complete outline
of plant-physiology. In cursive manner, the existence of a
living substance has been affirmed and it has been intimated
that the physiological activity of the plant is in fact the physi-
ological activity of living substance. For this reason, ad-
vanced research must be with aid of the microscope and all
the other appliances of the modern laboratory. The secret of
the plant lies very deep and is not to be wrested from it by
superficial examination or analysis.

Self defense. Not only must the plant utilize the materials
and forces about it and adapt its structure and behavior to the
environment, but it is also often called upon to defend itself
against unfavorable conditions. Two of the common animal
types of defense are but sparingly employed by plants. These
are active opposition and night. Not being provided with
muscles, the plant can rarely run from threatening dangers, nor
can it often combat them by an active display of force. Among
the lower plants flight is of defensive value for diatoms and
other motile varieties. They swim away from undesirable local-
ities and seek those where they can best maintain their exist-
ence. Motile cells, such as spermatozoids and swimming
spores, may also protect themselves in this manner. Active
opposition is very rare, but is practiced, perhaps, by such a plant
as the Venus's fly-trap when it snaps at the insect that may
have approached it with some notion of feeding upon its
tissues.

Most plants maintain a passive defense against unfavorable
or harmful influences. A great variety of such defenses are

Minnesota Plant Life.

practiced. Some are structural, while others are physiological.
The principal dangers to which plants are exposed are these:
desiccation, inundation, fracture by wind or water, poisoning
by salts, over- or under-illumination, over-heating, cold, and
attack by other plants or by animals. The defensive adapta-
tions against the various inanimate harmful influences have
already been discussed in Chapter XL; but there remain a few
words to be said concerning defense against other plants and
animals. The most universal method is by producing distaste-
ful or poisonous substances in the tissues. Among such should
be. counted the acids, alkaloids, tannins and resins that are
characteristic of many plants. By means of these substances,
dissolved in their juices, they make themselves objectionable
to grazing animals, to insects and snails, and even to parasitic
fungi. Sometimes the poisonous materials are projected to a
distance, as is true of the poison-ivy and poison-dogwood. In
such instances the animals are dissuaded even from approaching
the plant.

Another common method of defense, especially against
animals, is the wearing of armor. This ordinarily takes the
form of prickles, spines, or thorns, though it may rarely appear
as hard scales or plates. Armor is not limited to the plants
of any particular region or of any adaptational group. The
aquatic water-fern, Salvinia, has its sharp-pointed hairs to deter
small insects from feeding upon its fruiting areas; the meso-
phytic hawthorns, roses, and brambles are bristling with prickles
and thorns, while the xerophytic cacti and spurges are unap-
proachable in the effectiveness of their defense. Armor is par-
ticularly useful to desert plants, for they are most exposed to
attack by hungry animals. Less ordinarily in mind, when
plant-armor is mentioned, is the skin on leaves and green twigs.
This, while not defensive against animals of large size, is suffi-
cient, perhaps, to puzzle some of the smaller insects, and often
suffices to prevent the infection-tube of a fungus from obtaining
an easy entrance to the soft inner tissues of the leaf or stem.

Mimicry is a peculiar method of defense adopted by some
plants. Thus, an innocuous plant by its resemblance to a
poisonous variety often escapes injury. In deserts some kinds
of plants are gray in color, irregular and massive in shape, and,

Minnesota Plant Life. 507

in sliort. so much like stones that they are likely to be passed
over as members of the mineral kingdom. Such an appear-
ance must help them just as its green color helps the tree-toad
by making it inconspicuous. Another kind of mimicry has
been thought to characterize certain tropical herbs with mottled
leaves. Some begonias and aroids suggest themselves as ex-
amples. It has been supposed that by their resemblance to
snakes they may avert danger to themselves, from grazing
animals. The sensitive plant, which at a slight shock drops
into an apparently shriveled and dry condition, may by this
behavior startle or deceive animals that would otherwise feed
upon its foliage.

Utilization of allies is a not uncommon method of defense.
Thus, plants growing in hedge-rows obtain protection because
the thorny or impenetrable vegetation about them is sufficient
to withstand the attack of animals. Some plants may obtain
defense by hiding themselves in out of the way places, but this
is scarcely a calculable matter. A peculiar alliance is that
which exists in the tropics between certain trees and ants. In
these regions leaf-cutting ants are abundant and some trees, by
the secretion of sweet liquid on the twigs, attract large num-
bers of warrior ants that feed upon the honey. The plants even
develop shelter for such ants and when leaf-cutting ants attempt
to ascend the tree the honey-eaters swarm out and offer battle.
An ant-defended tree, such as a Cccropia, is an extraordinary
object. A slight blow upon the trunk calls out thousands of
angry ants from every crevice. By keeping such a body-guard
of insects, the plant undoubtedly protects itself. Many other
such alliances might be mentioned but one further example
must suffice.

Seedlings of trees are particularly exposed to harm. As in
man, so in plants, the expectation of life is at first decidedly
low. Most seedlings perish before they are firmly established
and those that are fortunate enough to persist and finally to
mature into sapling-trees have generally been nursed along b\
surrounding plants which have happened to be of kinds not un-
favorable to the seedling itself. Thus the young red pine
plants make excellent nurses for the seedling of the white pine,
and if the former are abundant on the forest floor, the white
pines are more likely to obtain a foothold.

508 Minnesota Plant Life.

The maintenance of a plant, like that of an animal, depends,
in the words of Herbert Spencer, upon a continuous adjustment
between internal and external conditions. If this adjustment
ceases to be made, death is the result. Every fundamental
problem of life that confronts the animal, confronts also the
plant. The solution may be by different processes, but solu-
tion there must be in the one instance as in the other. Struc-
turally and physiologically the living substance of plants and of
animals shows many resemblances, and it is not at all
erroneous to say that plants and animals are but different man-
ifestations of the organizing power of living substance. In
plants the constructive processes preponderate, in animals the
energy-producing; but fundamentally the two kinds of creatures
are much more decidedly alike than different.

Chapter XLV.

Maintenance of the Plant Species*

The methods by which individual plants are maintained as
units in Nature may be regarded as methods, also, for main-
tenance of the species. A species consists of all the individ-
uals, living and extinct, that are judged to form a single and
definite line of inheritance and are of practically identical
structure. Thus, one speaks of the human species, meaning
not only the men and women of to-day, but also their an-
cestors. In the same manner one may take into the mind
the conception of a plant-species, such as the dandelion, or
the white pine. While the lives of individuals are compara-
tively brief, the life of a species may be of long duration,
varying, perhaps, from a few hundred to many millions of
years. Most species are more than ten thousand years old — at
least this is the belief that has been strengthened by researches
in geology and in the history of development.

In order to continue the chain of individuals that constitutes
a species, the living substance both among plants and animals
has the universal habit of separating portions, usually single
cells, from the mature body, and these, if properly situated,
will build up new bodies from the organic or inorganic world
by which they are surrounded. Such a process is termed re-
production. It is analogous to growth and may be regarded as
a function of living substance that has become specialized
owing to the establishment, for each kind of living thing, of a
life-period. The normal life-period may vary in different or-
ganisms from a few clays to many hundreds of years. Some
individuals are comparatively ephemeral, while others are able
to maintain themselves over periods almost as long as that of
human history. Whatever is the duration of the life-period, it
may always be considered as expressing a ratio between the
bodily vigor of the organism and the average sum total of

5 jo Minnesota Plant Life.

unfavorable chances against it, in the outer world. Thus, for
each kind of living thing an hereditary rhythm comes to be
established.

At first the number of individuals in a species may be few;
later, a climax may be reached in the maintenance of the spe-
cies, and following this the number of individuals may dwindle
until finally the species becomes altogether extinct. There is,
therefore, a "life of the species" distinct from the life of the
individual. For a species to maintain itself through the cen-
turies it must be strong — that is, composed of strong individ-
uals, each able to hold its own in the battle with other types of
life and with the forces of Nature. For this reason the "in-
stinct of self-preservation" characterizes every living thing. A
species composed of negligent, apathetic or suicidal individuals
could not continue in competition with others in which the
opposite qualities were developed. Nevertheless, although the
instinct to live is universal among living things, the necessity
of death is equally universal and here one faces an extraordi-
nary dilemma. For the interests of the species, each individual
is placed in a contradictory position. Yet the apparently
irreconcilable situation is understood when it is observed that
while the passion for life, in an animal, serves to keep the
species strong, the death, also, of the animal, at the end of a
definite life-period, serves precisely the same end ; since in this
manner the species may consist always of fresh, young and
vigorous organisms rather than in large part of those old,
decrepit or shattered. While in the sphere of the individual
there is no solution of the problem of life and death, it is
illuminated in the sphere of the species. Thus, death at the
end of an appointed life-period has been described by Weis-
mann as an "acquired physiological trait," developed for the
advantage of the species as a whole and no less useful than the
instinct to live which characterizes each individual.

With these conceptions in mind it may be understood how
a plant or animal species may be regarded as a continuous,
very long-lived organism in which, in a rhythmical succession,
individuals constantly form and disintegrate. Possibly the liv-
ing substance of the species as a whole might be conceived of
as a sea in which that of the individual oro-anisms was as the

Minnesota Plant Life. 511

waves rising1 and falling through the whole period in which the
sea existed. Even an ocean, however, as taught by geological
science, may disappear; and in the same manner many species,
after existing perhaps for thousands of years, have become
extinct. Schopenhauer beautifully illustrates this thought by
his figure of the waterfall, in which he compares the lions of the
desert to the drops of water that hurry to the brink of a
cataract, are poised there for a moment, and then plunge into
the abyss below. The lion species continues, like the fall, and
the lion quality persists — just as the rainbow crowns the spray
so long as water flows and rocks are strong.

Reproduction in its broad sense may, therefore, be defined
as that form of growth in which a species bridges the gap from
individual to individual. It is not a process by which new
organisms are created, but one by which the immortal and un-
derlying living substance may keep intact the chain of individ-
ual bodies that constitutes the species.

Propagation. It is customary to classify reproductive phe-
nomena as propagative and as reproductive in the narrower sense.
Propagation is a term applied to all processes by which new
individuals come into existence through divisions of the parent
body other than in the formation of special reproductive cells.
Thus the growth of new potato plants from the bud's or "eyes"
on the tubers, the multiplication of house-plants or trees by cut-
tings, buds or grafts, the development of blackberries from
bent-over canes, of strawberries from runners, of onions from
aerial bulbs, are all classified as forms of propagation. Such
processes are indicative of strong regenerative powrer in plants,
but it should be noticed that considerable difference exists
among different plants in their ability to propagate. Some,
like the willows, propagate very easily, others, like the castor-
oil plant, with difficulty. Propagative or regenerative power
may exist in most of the vegetative organs, and sometimes in
true reproductive areas like spore-cases, spermaries or egg-
organs, (ienerally speaking, however, propagation is a func-
tion of the vegetative tract and is most common in the least
specialized portions. Roots and stems, for example, much
more frequently give rise to new individuals than do leaves,
flower-stalks, petals or seed-coats. In some groups of plants,

§12 Minnesota Plant Life.

*

such as the mosses, propagation is abundant; in others, such
as the mustards, it is rare or unusual. Special propagative
bodies, like the gemmae of the umbrella-liverwort, the bulbils
of ferns or of tiger-lilies, and the brood-cells of many mosses and
fungi are not uncommon. When they are one-celled they are
difficult to distinguish from true spores.

Of important propagative organs among higher plants should
be mentioned the rootstocks, tubers, bulbs, corms and trailing
stems of many varieties of herbs. Here, too, should be in-
cluded certain buds, such as the separable buds of pondweeds
and bladderworts ; and the offsets, stolons, suckers, runners,
and other branches with propagative tendencies. The leaf of
the walking-fern, and the leaves of some begonias have strong
propagative power. In mosses almost any portion of the body,
if isolated, proceeds to develop a new individual.

Reproduction. Reproduction in the narrower sense, as it
takes place in organisms that have developed the cell habit,
begins by the formation upon the parent body of special re-
productive cells. These are either perfect or imperfect. Per-
fect reproductive cells are those that, after separation from the
parent body will, if conditions are favorable, develop into new
organisms. Such cells are called spores. Imperfect reproduc-
tive cells are those that will not normally at once develop into
new organisms, but will fuse together in pairs as a preliminary
to development. Such fusing cells are called gametes, and ordi-
narily a division of labor exists among gametes in view of which
some, in a species, are motile, or at least mobile, and active,
while the others are quiescent or passive. The motile gamete
is called a spermatosoid and the quiet gamete is called an egg.
In certain lower algae, such as the water silk, both gametes are
provided with swimming lashes and are consequently motile.
In higher types, however, one gamete retained the motile char-
acter while the other lost it and as a consequence of its quiet
life, grew larger. Thus arose the distinction between male
and female cells, a distinction that lies almost as deep as that
between plant and animal cells. In both kingdoms similar
conditions have arisen, and in both, the formation of eggs and
sperms is a normal and constant character in all species above
the very lowest in the scale. In both kingdoms the sperms

Minnesota Plant Life. 513

are generally provided with swimming lashes, or their vestiges,
though, sometimes, as in red algae, these are altogether lost
and the sperms depend upon water currents for their transfer
to the eggs.

After a sperm and egg have fused — by a complex process
entailing a profound rearrangement and combination of parts —
the resultant cell, known as the fecundated egg, becomes capable
of elaborating a new organism.

There are, then, in the plant world, four types of repro-
ductive cells: i, the originally perfect cell or spore; 2, the im-
perfect motile, male cell or sperm ; 3, the imperfect quiet, female
cell or egg, and 4, the secondarily perfect cell or fecundated egg.
The story of plant reproduction concerns the formation, struc-
ture and behavior of each of these four types of cell and the
interrelations that arise between them, their products and the
mature areas of the individual upon which they are produced.

Production of spores. Almost all spores are of microscopic
size. In quantity, they appear as a dust. The spores of a
puff-ball or the pollen of an Easter lily will illustrate this.
There are two principal methods of spore production. They
may be formed either from superficial cells of the body, by
abstriction, or from the contents of special cells known as spore-
mother-cells. The former method is illustrated by the blue
moulds, mushrooms, red algae and related plants, in which cer-
tain superficial cells pinch off their free ends as one or more
special spore-cells. The latter method is much more universal,
and characterizes mosses, ferns and all higher plants. Further-
more, it is the method common in many types of algae, such
as the brown seaweeds, and in many fungi, such as the black
moulds, fish-moulds, and sac-fungi. Spore-mother-cells may
produce, in different types, from one to many hundreds of
spores. Large numbers arise in the mother-cells of the giant
kelp, the fish-moulds and the black moulds. In many sac-
fungi the number is commonly two, four or eight, while in liver-
worts, mosses, ferns and the higher plants four spores are ordi-
narily produced from each mother-cell, except in the instance
of embryo-sacs.

Spore-producing areas are often aggregated as definite or-
gans. Examples of such are the gills of mushrooms, upon

34

Minnesota Plant Life.

which the spores form a superficial layer, and the various cap-
sules containing numerous mother-cells — such as those of
mosses and ferns, or the pollen-sacs of flowering plants. An-
other aggregate body is seen in the fruit of the cup-fungus,
where the lining consists of numerous sacs in each of which a
definite number of spores is formed.

In any case, spores arise by the division of preexisting cells
of the body and, after formation, they are either distributed
to a distance or retained upon the body and permitted to ger-
minate near the point where they arose. The first is the primi-
tive and ordinary treatment of spores, but certain special types,
such as the large-spores (embryo-sacs) of seed-producing plants,
are retained in the rudimentary seeds where they were formed
and go through their germination processes without distribu-
tion to a distance. While maturing, spores are protected,
moistened and nourished by various devices.

Distribution of spores. If spores are to be removed from
the body of the plant producing them, some method of sepa-
rating them from their point of origin must be devised, and
some agency must be found that will transport them to a spot
where they may be able to germinate. Of abstricted spores,
such as those of mushrooms, the separation is little different, in
most instances, from a mere falling off the support. Yet in
certain cluster-cup fungi special wedges of cell-wall-substance
are produced between the successive spores of a chain and by
means of these they are loosened from each other. And in the
fly-cholera fungus the terminal spore is projected from its stalk
by an explosive mechanism that not only separates the spore
from the body of its parent, but throws it some little distance
from its point of origin.

In order that spores formed internally, within spore-mother-
cells, may be distributed, the walls of the spore-mother-cells
must be broken or dissolved. Sometimes only the ends of the
sacs break down to release the spores, as in cup-fungi and disc-
fungi, and in such the release is sometimes of an explosive
character. Again the whole wall of the spore-motlier-cell may
dissolve. This is true of mosses and ferns, of club-mosses and
higher plants. In these instances the spores come to lie freely,
in the form of a dry powder, within the capsules where the
spore-mother-cells were developed.

Minnesota Plant Life. 515

Having been liberated either from the stalk to which they
were attached or from the chamber in which they were confined,
spores become units for which various distributional devices
have arisen. They are borne away by gusts of wind, by cur-
rents of water, or by insects or birds that have picked them
up either by accident or design. Sometimes special assistance
is given them by the parent plant — directly, as when a liver-
wort produces, in its capsule, writhing cells or clatcrs, by the
struggling movements of which the spores are scattered ; in-
directly, as when the flowering plant secretes honey near where
its pollen spores are formed, thus attracting insects that may
act as carriers. A great many structures in the plant world
have arisen to assist in the distribution of spores. Among
these may be mentioned the erect stems of moss capsules, serv-
ing to lift the spores into the wind, the teeth at the margin of a
moss capsule, serving to sift out the spores at favorable times,
the spring-back of the catapult-like spore-case of true ferns, and
the explosive pollen-sacs of some flowering plants; but no
adequate idea of the variety that exists can be given in a limited
space.

Sometimes spores attend to their own distribution by the
development of motile organs, such as swimming threads, as
in fish-moulds or green felts, or by the production of gas bags
by which they float more easily in the wind — a condition that
exists among the spores of the pines. Many pollen-spores have
viscid or spinous surfaces that facilitate their attachment to
the bodies of insects, and in general, the surface of the spore
is commonly adapted to aid in distribution.

Not infrequently spores are distributed en masse rather than
separately. Orchids and milkweeds furnish good illustrations
of this when several hundred of their spores cohere in little
club-shaped or saddlebag-shaped clusters and these are carried
away as units upon the bills or legs of insects. Similar aggre-
gates of spores are produced in many lower plants, as in the
water-ferns, Azolla and Salvinia; and a somewhat related con-
dition characterizes the green felts. In the latter each motile
perfect reproductive body is covered with swimming lashes,
indicating that it is equivalent to an undivided group of spores,
each one of which, if separate, would have had its own pair
of lashes.

516 Minnesota Plant Life.

It makes a difference, in the economy of the plant, whither
the spores are carried, in the distribution. The chances against
their finding spots favorable for germination are met either by
their production in enormous numbers, or by highly accurate
methods of distribution. Pines illustrate the former condition,
while orchids, in the management of their pollen spores, illus-
trate the latter. Much depends upon the needs of the sporeling
— the plantlet that arises from the spore, upon its germination—
and many structures and habits of spores are determined by the
special requirements of the new plant. Thus, it happens among
scouring-rushes that certain spores will produce little male
plants, while others will produce small females. It is important
that these plants should not arise isolated from each other, for
then it would be difficult for them to breed. Therefore, scour-
ing-rush spores are provided with curious grappling append-
ages by which they cling together in groups. Again, in some
ferns, many club-mosses and all flowering plants two kinds of
spores are formed, differing in size. The large ones, contain-
ing more food material, are better suited to give birth to female
plants of the species, while the small ones, not so well nourished,
can produce only males. Females need generally to be larger
than males, for they have to form and nourish the larger gamete-
cells, the eggs. Such a difference in size of spores occasions
difference in their distribution and since it is more economical
to transport the smaller bodies it happens that in higher plants
the large spores are not distributed at all, and the small ones
are brought near them so that upon germination of both, the
male and female plants will not be too far apart. Various de--
vices are employed in the different families. Very remarkable
is the' behavior of the little water-fern, Azolla, in which a cluster
of small spores, embedded in mucilage and furnished with
barbed grappling appendages upon the group, is ejected from
the spore-case and is carried by water currents to find an
anchorage among slender, thread-like appendages of the large
spore, provided for that purpose. Under such an adaptation
the two sexes arise in close proximity.

In flowers all the extraordinary arrangements for distribu-
tion of pollen are associated with the peculiar habits of the males
and females of the higher plants. The female originates, as a

Minnesota Plant Life. 517

microscopic body, from the undistributed large-spore within
the rudimentary seed. The male, therefore, has come to be
a degenerate, cobweb-like organism that lives parasitically on
tissues near the spot where the female is situated. Thus pollen
spores must be distributed not haphazard, as may be the spores
of liverworts, mosses and ferns, but to some particular spot —
either to the end of the rudimentary seed, as in lower seed
plants such as pines, or, as in higher seed plants, to a special
area known as the stigma. Since, further, all enlargements of
experience are generally valuable for a plant as for an animal
species, it happens that very often pollen spores are carried from
one flower to stigmas of another, perhaps on another plant.
This is called cross-pollination — a very different matter from
cross-fecundation with which it must not be confused. For
generations a false analogy has existed in the minds of almost
every one, botanists included, that there is some comparison be-
tween pollination and a breeding act. There is no comparison ;
the two processes are absolutely distinct. Pollination is merely
a special type of spore distribution of which the "puff of smoke"
from a puff-ball is a more general type. Fecundation, — the
blending of sperm and egg, — is an entirely different matter.
In flowering plant species, after pollination has occurred and
small spores have been placed in a position where they can
germinate, male plants come into existence and the breeding-
act takes place between microscopic organisms living parasit-
ically upon the tissues of the spore-producing individual of their
species. To speak of the "sexes" of flowers, or to call stamens
"male" structures, or to name one cottonwood tree a male
and the other a female, is in every instance an indication of
ignorance or sloth, or it is a concession to the ignorance assumed
to exist among one's hearers.

The colors, forms, structures, perfumes, secretions, positions,
divisions of labor, and succession of flowers are all intimately
connected with pollen-distributing devices. To discuss them
in detail would require not merely volumes but libraries. It
must suffice here to remark that every special type of flower
has its own particular mechanism for spore distribution. It
may utilize currents of air or water, or more commonly insects.
Thus, by their interrelations, the two groups of living things,

518 Minnesota Plant Life.

flowering plants and insects, have come to be highly developed
as a partnership, constituting, indeed, the most remarkable
association of all those existing between plants and animals.

Germination of spores. When a spore enters upon the course
of development through which a new plant comes into exist-
ence, it is said to germinate. Perhaps not quite all the cell
divisions that are undergone by spores should be classed as
germination-stages. In lichen-fungi, for instance, and in many
others, spore-cells before they are separated from the parent
plant divide once or more, even building considerable aggre-
gates; but this behavior seems rather a multiplication of the
spore-cells than true germination. Yet even among distrib-
uted spores germination sometimes begins before the spore
leaves the body of its parent. This is true of the cone-headed
liverwort, the spores of which become . divided into internal
compartments before they are scattered from their capsule.
Such division seems to constitute a true germination, for later
divisions, by which the liverwort first-stage plant is constructed,
follow in unbroken sequence, after the spore wall has been
fractured. Undistributed spores, such as embryo-sacs, ger-
minate at the spot where they were produced.

If the outer wall of the spore is hard and brittle, as is usually
the case, it must be broken by the expansion of its contents
unless the sporeling is destined to remain principally or en-
tirely within the confines of the spore. The latter condition
actually obtains among many large-spores and is notably char-
acteristic of the embryo-sacs of flowering plants. In them the
female matures and produces her eggs without ever leaving
the spore from which she arose. And in smaller club-mosses,
quillworts and four-leafed water-ferns the male matures within
the small-spore, the wall of which is finally broken open to
liberate the spermatozoids. In all such instances the sporeling
nourishes upon substances present in the spore and does no
independent vegetative work. If, however, the sporeling is
destined to gather nutriment from the outer world it very early
establishes itself as a filament, plate or mass of cells, breaking
or dissolving the original spore wall in the process. Thus, fern
spores, when ejected from their capsules upon a sufficiently
moist surface, soon crack open and a transparent-walled cell is

Minnesota Plant Life. 519

protruded which undergoes rapid divisions, growth and' differ-
entiation, finally becoming a little green, prostrate, heart-
shaped body with abundant root hairs and leaf-green granules.
So, too, a fungus spore customarily protrudes, through a cleft
in its wall, its first pale thread that nourishes upon whatever
may be its proper food, ultimately divides, branches, grows and
brings into existence a new fungus body. The pollen spores
of flowering plants are not infrequently furnished with special
thin places in their walls, through which the tubular sporeling
may easily emerge. The necessary general conditions of ger-
mination are sufficient warmth and moisture and, in some in-
stances, the chemical stimulus of a proper food supply outside
the spore wall.

Care of sporelings. In all plants more or less provision is
made for the protection and nourishment of the sporelings.
The spore commonly contains food material, or mechanism for
making it, and the supply of food is carefully adjusted to the
needs of the new plant. For this reason in smaller club-
mosses, quillworts and water-ferns the large spore is furnished
with a comparatively generous stock of provisions, in the form
of starch and aleurone grains, and consequently becomes as
large as a grain of sand. Unlike most spores, these are dis-
tinctly visible without magnification. In the plants mentioned,
the female, consisting of numerous cells, among which the egg
is of prime importance, does little or no independent vegetative
work, and must perforce have provisions enough reserved for
her use to enable her to reach maturity. Sporelings with spe-
cial necessities, such as pollen-tubes, have special food sub-
stances provided for them and are stimulated and directed in
their growth by structural adaptations of the tissues around
them and by chemical stimuli that guide them towards the eggs
of their species.

Production of spermatozoids. All plants except the lowest
algae and fungi produce gametes, or fusing cells. In a few
lower algae the cells that fuse are alike, and in many fungi the
fusing cells become blended into one body, in which it is diffi-
cult to distinguish the male and female portions. In most of
the algae, in liverworts, mosses and ferns and in all the higher
plants there are undoubted distinct and dissimilar sperms and
eggs formed in special cells or organs.

e20 Minnesota Plant Life.

Spermatozoids are typically small motile cells provided with
two or more swimming lashes, by means of which they can
progress in the water. The sperms of the water silk and some
of its relations are pear-shaped, with the lashes on the smaller
end. Those of the brown seaweeds are somewhat pointed, with
the lashes on one side. Those of mosses, ferns and higher
plants are commonly more or less corkscrew-shaped. In mosses
and club-mosses two swimming lashes are formed, but in ferns,
cycads and some other higher plants that have been studied the
number of lashes is greater. In two high types of plants the
lashes seem to have been lost, viz., in red algae and in most
flowering plants. The size of Spermatozoids is almost inva-
riably below the limit of unaided vision, but sperms of cycads are
plainly visible, without the assistance of a microscope, as tiny
specks. As produced in some of the algae, sperms contain
leaf-green and considerable living substance in addition to the
portion termed the nucleus; but in brown and red algae and
in flowering plants the substance is principally nuclear. Unlike
many spores, Spermatozoids are not formed as superficial cells,
but originate from the divisions internally of mother-cells.
Sometimes, as in the sphere-alga, enormous numbers arise from
a single mother-cell, but more commonly only one sperm de-
velops in each. The mother-cells may be superficial and aggre-
gated, possibly, in exposed clusters, as among brown and red
algae. On the other hand they may form the core of a solid
organ, the spermary, as in mosses, liverworts and ferns. In
the cone-headed liverwort, for example, thousands of sperm-
mother-cells arise in each microscopic melon-shaped spermary,
and, in the course of its life, a male cone-headed liverwort
produces millions of such cells. In higher plants the males
become greatly diminished in size and the number of Sper-
matozoids that one can produce during its life is reduced to a
score or less in water-ferns, to four in the quillwort, and to two
in most seed-producing plants.

Distribution of Spermatozoids. Each spermatozoid is care-
fully constructed within its mother-cell, and when the latter,
by solution of its wall, opens to release the tiny male cell, this,
in moss or fern types, swims rapidly away. It is carried in red
algae types by water currents, and is liberated directly beside

Minnesota Plant Life. 521

the egg in seed-plant types; for in them the pollen-tube con-
taining the sperms grows into the immediate vicinity of the
eggs produced by the female of the species. In its movements
the spermatozoid is guided by chemical stimuli. The duration
of its locomotion varies in different forms, but is rarely known
to exceed a few hours.

Production of eggs. Plant eggs occur in all species that
produce sperms, for the two kinds of cells are complementary.
In lower forms eggs may be motile and very much like sperms
in appearance. They are distinguished, however, by tiring
more quickly or by their slightly larger size. Typically, how-
ever, eggs have no swimming lashes and are quiet, passive cells,
containing leaf-green bodies or their rudiments, in such plants
as produce leaf-green ; and they are much larger than the sper-
matozoids of their species. Yet plant eggs never reach the
size of similar cells in animals, and the largest, among which
should be counted the eggs of pine trees, are little ovoid, whitish
bodies that may be dissected out of the rudimentary seed where
the female lives and produces them, and may be picked up on
a needle point for examination by the unaided eye. Most plant
eggs are microscopic.

Eggs, like sperms, may be produced in mother-cells, some-
times several from each, but more often only one. In the
sphere-alga a row of almost spherical eggs is produced in each
of certain tubular cells of the filamentous plant-body. But occa-
sionally eggs arise as the terminal cells of filaments, as in bass-
weeds, where they are protected by a sheathing layer. Since
the egg is a very important cell in the plant economy, it is
protected from harm, in all higher plants, by surrounding cells ;
and thus in the series of plants extending from the liverworts
to the pines, eggs arise in flask-shaped organs, one egg at the
bottom of each flask. Clusters of such microscopic flasks are
found at the end of the stem of a female moss plant, on the
under side of fern sexual plants, and embedded in the surface
of the enclosed female plant of rudimentary pine seeds. The
egg organ serves the double function, in such plants, of pro-
ducing the egg and protecting the young embryo during its
early stages.

In a few plants eggs are ejected from the body of the female,
as among many animals — for example, fish; but generally the

5 2 2 Minnesota Plant Life.

egg is not ejected and remains in the organ where it was
formed, awaiting fecundation. Certain brown seaweeds illus-
trate the first condition. The sperms and eggs are ejected into
the sea water, where they find each other and pair. The sec-
ond condition is that of the red seaweeds and of the whole
series from mosses to seed-plants. Moreover, it essentially
characterizes the fungi and many of the • bright-green algae.
In the management of their eggs plants remind one somewhat
of the mammals. Because of the small size, and concealment
of plant eggs they are not familiar objects like those of insects,
fishes and birds.

On account of their motile character, sperms are much more
likely to be lost than eggs, consequently plants produce them
in much greater numbers. Ordinarily many thousand sperms
are constructed for one egg that is fecundated. But in
seed-plants where the male grows as a parasite upon tissues
close to the location of the female, only a pair of spermatozoids
are needed, one for each egg produced by the female. In such
forms the cells that are peculiarly in danger are the pollen-
spores and these are commonly formed in extraordinary pro-
fusion.

Fecundation. The fusing of sperm and egg is known as
fecundation. After fusion the egg is said to be fecundated.
Exactly the meaning of the process is not clear. It is known
that by it the offspring derives the benefit of a double line of
inheritance, thus enabling it to make favorable variations, and
perhaps accommodating it more precisely to its surroundings.
But a single sperm fuses with each egg, and after this has taken
place the egg commonly secretes a membrane which before was
absent, and thus shuts out later sperms that might attempt
a- fusion. The cell mechanics of the fecundation process are
decidedly complex, for this is by no means a mere blending of
two masses of living substance, but is an orderly reorganization
of the two structures into one. Not every portion of the egg
is fitted to receive the sperm. There is generally a particular-
spot on the egg surface at which the fusion takes place. This
is known as the "receptive spot," and in some forms it differs
in color and texture from the rest of the egg. The swimming
lashes of the sperm seem always to blend with that portion of

Minnesota Plant Life. 523

the egg outside the nucleus, while the head of the sperm fuses
directly with the nucleus of the egg. In cycads the swimming
lashes of the sperm are separated from its body immediately
after entering the egg and may be seen lying isolated in the
living substance around the nucleus.

Behavior of the fecundated egg. After fecundation has
been completed the fused body is regarded as a single cell, so
perfectly have the two components merged their identity in
their common product. This single cell is the fourth and last,
as here classified, of the important types of reproductive cells
formed by plants. After a period of rest it normally segments
and grows, and by the continuation of this process a new
structure is brought into existence. This organism is known at
first vmder the general name of embryo, and matures into one or
another type of body, as may be determined in the species of
plant to which it belongs. Upon the whole, the behavior of
plant eggs is more various than that of animal eggs. Among
animals it is customary for the egg to mature into an organism
similar to one of those which, by the production of sperms or
unfecundated eggs, cooperated in the formation of the egg
itself. This is also true in certain groups of plants, as, for
example among the brown seaweeds, but is by no means the
general rule. In all higher plants, including the red seaweeds,
the higher fungi and the entire series from liverworts to seed-
plants, the egg does not grow into an individual capable of
producing sperms or eggs, but invariably into a spore-produc-
ing organism or its homologue. There are, therefore, in the
plant world two main types of egg segmentation, known re-
spectively as the direct and the indirect. When an egg seg-
ments directly it forms an embryo that gradually matures into
a sexual plant or its homologue. When an egg segments in-
directly it forms an embryo that matures into an asexual spore-
producing organism or its homologue. From the spores of
the asexual plant new sexual plants may arise, thus establishing
the phenomenon known as "alternation of generations."

The extraordinary significance of alternation has already
been discussed in Chapter XIV, and need not again be elu-
cidated. In the simpler alternating life histories it would seem
that the first few cells of the young embryo become separated

Minnesota Plant Life.

from each other, and each then builds up a new sexual plant.
Thus the phenomenon is equivalent to true twinning among
animals. It is extremely difficult to grasp this conception
without long familiarity with all the facts involved, but it is
regarded as very certain that the ordinary plants of forest and
field are really interpolations between the successive sexual
plants of their species. One might say, indeed, that the real
fundamental plants are, in such species, only those that form
sperms and eggs, while the great spore-producing organisms
are "structural afterthoughts." In such types as the seed-
plants or some ferns, the sexual plants are inconspicuous and
even microscopic. This adds to the difficulty of comprehend-
ing the true state of affairs, and it is still further obscured by
the false nomenclature and wrong significance that has been
applied to the parts of the flower. It must be remembered that
in a wilted Easter lily there are living numerous tiny organisms,
some male and others female. These are the real, primitive lily
plants. It is they that have the ancestral line reaching back
into the remotest past. The male plants are cobweb-like tubes
buried in the tissues of the rudimentary fruit. The female
plants are exceedingly minute organisms hidden one at the
center of each rudimentary seed. The great leaf-bearing,
flower-producing organism, rooted in the soil is an "after-
thought" in the species. When this conception is taken into
the mind, then and then only is it possible to institute proper
structural comparisons between plants and animals.

Very remarkable divisions of labor come to exist among
embryos in higher seed plants. In this group each female
produces two very minute eggs, with each of which a sperm
from the pollen-tube may fuse. One of the eggs forms an
embryo that can go on and develop into a plantlet, and, as such,
constitutes an essential portion of every seed. The other egg
forms a degenerate embryo, known as the albumen, that fulfills
its function in the species when it is consumed by its stronger
twin. This truly astonishing cannibalism goes on in the seeds
of all higher flowering plants, but not distinctively in the seeds
of cycads, pines and their allies. In them the so-called albu-
men is the body of the mother-plant, and while more than one
egg is formed in pines the embryos that arise are none of them

Minnesota Plant Life. 525

essentially subordinated. Each and any may grow into an
independent plant.

When embryos are young they often have special nursing
organs that do not characterize their maturer stages. Remark-
able structures of this sort are found in the embryos of nastur-
tiums, orchids, and madders, as well as in many others. They
may be compared physiologically with the embryonal organs
of birds and mammals.

Care of the young. The instinct of maternity so character-
istic of the higher animals is not wanting among the higher
plants. The brown sea-weed, like a fish, ejects its eggs into
the sea, leaving them to be fecundated and to develop and shift
for themselves; but higher plants have devised a multitude of
structures for the care, protection and suitable establishment of
their progeny. The industry and pugnacity of a hen with
chickens is well known. Her duckings, rufflings and scratch-
ings are to be interpreted as indications of her motherly instinct
to protect and nourish her young. Not otherwise in a plant
species, such as an apple, must the greenness of the fruit be
interpreted as a device for nourishing the young seeds by the
aid of sunlight, the sourness as a method of defending them
from attack, and the subsequent sweetness, flavor and aroma as
adaptations for securing their distribution through the agency
of animals. While ripening its seeds the lady's-slipper is
peculiarly poisonous to the touch. Many seeds contain deadly
poisons, making them secure from the attack of hungry animals
or birds. By thorns, secretions, warning colors, hard walls and
distributional contrivances such as burs, wings, bristles, and
pulp, seeds and fruits show the care lavished upon the young
of the plant species. The moss mother, with her green leaves
and root hairs collects and elaborates food for her progeny, the
capsule. The Russian thistle covered with fruits, breaks loose
from the soil and rolls over the prairie, scattering the seeds
along its path. Innumerable structural and physiological
adaptations have in view the one end of assisting the young,
and in their sphere of life plants, like animals, subordinate the
needs of the individual to the necessities of the species. Thus,
when germination has begun, female pine plants are altogether
consumed by the young plantlets in the seed. This protective

526 Minnesota Plant Life.

instinct extends back over more than one generation,. and not
only does the mother plant assist the young, but the spore-
producing plant, from the spores of which the mother-plants
arose, helps the young, forming for them seed-coats and hold-
ing the seeds upon the scales of its cones, thus protecting them
until ready for distribution to a distance.

In the care of the young, other plants and even animals are
utilized. Thus certain seedlings are nursed along by neighbor-
ing plants that protect them from winds, drought or too
brilliant sunshine. And animals carrying about upon their
feet or fur the burs and sticky seeds of various species serve also
as illustrations of the interdependence between different kinds
of living things.

Words in conclusion. My labor is now at an end, and if
I have succeeded in portraying the vegetation of Minnesota as
an assemblage of living creatures, as a world of infinite variety
yet with a fundamental unity of plan, as forms linked together
in structure, function, and adaptation, and as a field worthy of
study and enthusiasm, I shall feel content. Much has been left
unsaid. In the words of Newton, but a few pebbles have been
collected on the far-stretching strand of truth. The whole
story will never be told.

Inde

Absinthe, 411

Acacia, 280

flower, 348

Acacia, False, 301

Acanthus, 367

Acetic acid ferments, Bacteria

producing, 114

Acid, 506

Prussic, 292

Aconite, 264

Aconite (poison), 273

Adder's-tongue, 161

Adoxa, 388, 393

Age of lichens, 96

Agrimony, 290

Ailanthus, 305

Air chamber, Bladderwort, 443

Bulrush, 455

Duckweed, 443

Liverwort, 135

Quillwort, 163

Sedge, 455

Air plant, 472, 481, 489

pore, 435

Aitkin county, 309

Albumen, 524

Definition of. 183

Alcoholic fermentation, 73

Bacteria of, 102

Alder, 245, 249, 462

Bacterial nodules, 119

Witches'-broom on, 74

Alder, Black, 249, 312

Dwarf, 319

Green, 249

June-berry, 287

Tag, 246, 460

-leafed buckthorn, 319

Aleurone grains, 491

Alfalfa, 298

Bacterial nodules, 118

Algae, 29, 448, 472, 489, 512, 519

Deep water, 453

Economic importance of, 41

Algae. Fertilizing material, 41

General remarks, 41

Groups, 29

Iodine, 41

in leaves of floating-fern, 169

Limestone formation, 30

encrusted with lime (Half-
tone), 31
in tank, Lime-encrusting

(Half-tone), 35

Lichens, 93

Marine, 39, 40

Noxious, 41

Number in Minnesota, 27

Nutrition, 48

Oldest kinds of plants, 42

Originators of all other plants, 42
Origin of higher plants from, 196
Parasitic on Jack-in-the-Pulpit, 37
Pig-pen odor, 41

Poisonous, 41

Silica formation, 31, 41

Sinter formation, 31

Travertine formation, 31

Algae, Blue-green,

26, 29, 424, 443, 446, 453
Bright-green, 29, 446, 522

Brown, 29, 39, 513, 520

Deep water, 453

Flower-pot, 35

Hot spring, 31

Leaf-dwelling, 37

Lime-secreting, 41

Red, 29,39,40,446,513,520

Rolling, 34

Rock, 467

Rock-forming, 30

Silica-secreting, 41

Skin, 32

Sphere, 37, 520, 521

Warm water, 42

Algal fungi, 43

parasites, 45

plankton, 443

Alkali-grass, 226

528

Minnesota Plant Life.

Alkaloids, 5o6

Fungus,

veratrine, 226

Alliance between trees and ants, 507
Almond, 280, 292

Alternation of generations, 128, 523
Definition, 123

Alternate-leafed cornel, 342

Alum-root, 283

American (Engr. 282), 283

Rough, 283

Amaranth, 259, 260, 476

Amaryllis, 224

American alum-root, 283

elm, 252

linden, 321

mountain-ash, 289

redroot, 319

senna, 297

Ammania, 333. 334

Androsace, 35$

Anemone, 264, 268, 269, 426, 475, 479
Flower axis, 345

Resemblance to avens, 290

Resemblance to five-finger, 290
Rue, 269

Rue, false (Half-tone), 270

Animals, Diseases, 109

Fecundated egg of higher, 128
Habits, 18

Plants compared with, 25

and plants, difference be-
tween higher, 128
Anise, 375
Annuals, Desert plants, 464
rings of stems, 197
Anoka county, 327
Ants and trees, Alliance between, 507
Antidotes, Ivy and elder poison-
ing, 311
Antiseptic surgery, 114
Appendaged waterleaf, 370
Apple, 280, 286, 290, 422, 525
blossoms (Half-tone), 288
Carpels and stamens, 346
Flower, 347
Fruit, 423
Seed distribution, 19
Apple, Balsam, 396
May, 274
Wild crab, 286
Apricot, 280, 292
Aquatic nature of terrestrial
plants, I6

Aquatic plants,

417, 422, 434, 442, 450, 453, 489

vegetation (Half-tone), 12

Arbor-vitae (see white cedar), 186

moss, 152

Arbutus, Trailing, 350, 355

Architectural structure of

plants, 179, 418, 424, 505

Arctic vegetation, 424, 428

Arctic dwarfed raspberry, 291

Arethusa, 228

Armor, Plant, 506

Arnica, 412

Aroid, 507

Arrow-grass, 2oo

-leafed violet, 328

Arrowhead (Engr. 202. Half-
tone, 199, 201), 7,201,450,458
Floating, 448, 449
Arrowwood, 388, 390
Downy-leafed, 391
Maple-leafed, 391
Artichoke, 410
Arum, family, 217
Fruit, 217
Warming-up color, 218
Ash, 336, 360, 417, 470, 478
Family, 360
Flower, 361
Black, 361
Black, Galls, 504
Blue, 361
Green, 361
-leaved maple, 313
Mountain, 280, 286, 290
Poison, 310
Prickly, 305, 307
Red, 361
Three-leaved. 307
White, 360
Asparagus, 225, 226, 465
Asphodel, 225
Assimilation, 488
Aster (Half-tone, 408, 410), 6, 7,
24, 399, 401, 402, 407,
415, 427, 469, 470, 472, 478, 479
dodder, 368
Australian blue-gum tree, 434
Autumn flowers, 426, 479
foliage, 426
Autumn dandelion, 403
Avens, 289
Resemblance to anemone, 290
Azalia, 350

Minnesota Plant Life.

529

Azolla (see floating-fern),

168,443, 515, 516

Bachelor's-button, 413
Bacillus, 102
Bacteria, 29, 101, 424, 446, 459, 492
Causes of disease, 104
Classification, 101, 102
clover root, 117
Color producing, 102, 115
Consumption, 106, 108
Crop-rotation, 118
Dairy, in
Deep water, 453
Disease-producing, 102, 103, 105
diseases, 109, 453
Energy produced by, 104
Ferment-producing, 453
Fertilizers of the soil, 104
Cheese, in
Heat-producing, 115
Infection of eggs, 113
Interest to the human race, 104
Iron, 120
Light-producing, 115
Milk-curdling, 114
Milk-souring, 113
Mineral springs, 120
Nitrifying, 102, 117
Nitrogen, 117
Nodules of alders, 119
Nodules of alfalfa, 118
Nodules of beans, 118
Nodules of vetches, 118
Number of in Minnesota, 27
Nutrition, 103
Nutrition of purple, 116
Parasitic, 453
Producing acetic acid, 114
Producing alcohol, 102
Producing lactic acid, 113
Pitcher-plant, 279
Purple, 116
Putrefaction, 102, 109
Red, 115
Relations of to man, 120
Retting, in
Root-tubercle, 119
Smallpox, 106
Sources of ferments, 104
Substances formed by, 103
Substances and forces harm-
ful to, 104
Sulphur, 120, 453

Bacteria

Tanning, in
Tobacco-curing (see preface), in

Typhus, 106

Urine, 119

Vinegar, 114

Waste products of, 103

Water, 443

Bacterial phosphorescence, 104

Purple, 104

Bailey's dogwood, 341

Ball-tossing puff-ball, 70

Ejection of spores, 71

Balm of Gilead, 238, 239

Balsam (see Fir), 186, 192

Balsam thicket, 472

wood, 352

-apple, 396

-poplar, 238, 239

Witches'-broom, 54

Banana, 228

Fruit, 423

Baneberry, 268, 269

Bar plants (Half-tone, 449), 447,451

Barberry, 264, 274

Wheat rust, 50

Bark-moss, 149

Bark of trees, 234

Barley, 205

Barnyard grass, 205

Barrel-hoops, 244

Barrens, 469

Barrens, Jack-pine, 470

Oak, 470, 478

Basil, 375, 377
Bass-weed, 13, 38, 448, 451, 521
Bass-weeds, Lime-encrusting, 38

Propagative bulbils of, 38
Basswood, 252, 321, 423, 462, 478

Galls, 504

Basswood, European, 323

Half-tone, 324

Bast, 497

Bay, 275

Bayberry, 243

Beach, 469
Beach vegetation (Half-tone), 241

Beach heather, 327

peas, 304

Beaked hazelnut, 246

Bean, 280, 418, 503

Bacterial nodules on, 118

530

Minnesota Plant Life.

459
305
478

355

Bean

Buck, 363, 458
Castor,

Wild, 297, 304,

Bearberry, 350,

Beardtongue, 381

Beck's marigold, 411

Bedstraw (Engr. 389), 388

Beech, 246

Beech-fern, 166

Water, 246

Beechdrops, 385

Beer, Souring, 114

Beet, 425, 491

Beetle-fungi, 91, 99

Spores, 100
Beggars'-lice, Seed distribution, 19

Beggar-tick, 401, 410
Begonia, 326, 425, 507, 512
Behavior of the fecundated egg, 523

Bellflower, Marsh-, 396

Tall, 396

Wood-, 396

Bellwort, 225, 226

Beltrami county, 315

Benzoin gum tree, 360

Bergamot, 37-

Biennial, 428

Bignonia, 367

Big Stone lake, 262

Big trees, Fossil, 26

of California, 39
Bilateral symmetry of flowers, 228

Bilberry, 4(5o

Dwarf, 356

*^ > 1 C^S

Thin-leafed, 356

Bindweed, 258, 367, 478

Birch (Half-tone, 145, 195),

245, 246,

-bark, Indian uses of,
beer, Flavoring,

Birch, Black, 246- 24?>

Canoe (Half-tone, 247, 248;,

246,
Dwarf,

Glandular, 24£

Gray, '

246,

462
247
24Q

249
24g

247

Birch

Root-fungi,
Scrub,
Shelf-fungi,
Yellow,

Birds, Habits of,
Bird's-eye maple,
Bird's-foot violet,
Bird's-nest-fungus,
Bird's-nest-fungus, Fruit-body,
Bishop's cap,
Bittersweet, „

Climbing,
Black alder,

ash,

ash, Gall,

birch,

cherry,

-eyed Susan,

fungus,

fungus lichens,

haw,

knot, Cherry,

knot, Chokecherry,

knot, Plum,

maple,

mould,

mould, Eggs,

mould, Fruit-body,

mould, Reproduction,

mould, Spores,

nightshade,

89
246

57, 58
246, 247
18
316
328
69
/o
284

312,418,479

249, 312
' 36l

5O4

246, 247, 249
2Q4
32-

80, 83, 95
98

390, 462
85
85
85
3I3> ^

Paper (Half-tone, 247),

*ed'
Rlver»

246, 247
246,247

44
43
44
44
378
249,250,251

2gi
5I

338

T86, 192
243; 244

241

280,290,511
291
291
54

291

309,313
Bladderwort (Engr. 383),

233-367,384,418, 512
Air chamber, 443

Flower, . 384

Hibernaculae, 451

Nutriment, 384

Pollination, 384, 445

Resemblance to water-mil-
foil 384

oak,

raspberry,

rust,

snakeroot,

spruce,

walnut,

willow,

Blackberry,
High,
Low,
Rust,
Swamp,

Bladdernut,

Minnesota Plant Life.

Blazing-star (Engr. 407),

Bog,

453

401, 402, 406, 415, 470

blueberry,

357

Bleeding-heart,

277

huckleberry,

356

Blephilia,

375, 376

plant,

436

Blight,

80

rush,

225

Grass,

80

wintergreen,

35i

Hooked,

80

Boltonia,

401, 407

Lilac-,

80

Boneset (Engr. 407),

373, 401

Pear-,

103, 109

Borage,

367, 371

Toadstool-,

80

family,

371

Willow-,

80

Flower,

37i

Blinds, Manufactured from

Resemblance to verbena,

374

white pine,

186

Wheat rust on,

50

Elite,

259

Borneo ferns,

164

Western,

260

Bottle-gourd,

394

Blood-root (Engr. 276),

275

Box-elder, 309,

313, 317

Bloodwort,

224

Braced-plant,

179

Bloom on fruit,

435

Bracken fern (Half-tone, 419),

Blown cheese,

112

164,

165, 472

Blue ash,

361

Bracted plantain,

387

cohosh,

274

Brake,

161

Earth county,

332

Bramble, 280, 290, 439, 460,

470, 506

-eyed grass,

227, 457

Rootstock,

455

-eyed-Mary,

222

Branch, Drooping,

422

flag, 219, 224, 227,

457, 458

system,

422

flag, Flower,

348

Brazil-nut.

322

flax, Wild,

306

Bread, Diseases,

112

grass,

205, 206

-making, Yeast,

72

-green algae,

Souring,

114

26, 29, 424, 443,

446, 453

Brewing Yeast,

72

-green algae, Extraction

of

Bright-green algae, 29,

446, 522

iron oxide from water,

3°

-green algae, Lichens,

93

-green algae, Lichens,

93,94

Broad-leafed aster,

479

-green algae, Lime-encrust-

cat-tail,

198

ing,

30

goldenrod,

479

gum tree, Australia,

434

green milkweed,

367

lobelia, Large,

397

puccoon,

O*-V

171

lobelia, Pale,

397

Brookside vegetation (Half-tone,

mould, 44, 78, 86, 513

366).

honeysuckle,

392

Broom.

280

phlox,

369, 370

-rape,

367, 385

Blue-stoning,

50

-rape, Louisiana,

386

verbena, Wild,

374

Brown algae,

Bluebell (Engr. 395),

29, 513, 520,522,

523, 525

3/2, 394,

396, 462

Buck-bean, 363,

458, 459

Blueberry, 350,

356, 470

Buckeye,

317

Bog,

357

Buckthorn, 319.

459, 462

Canada,

356

Alder-leafed,

319

Dwarf,

356

Wheat rust on,

50

Low,

356, 357

Buckwheat,

257

Swamp,

457

False,

258

Tall,

356

Bud,

425

Bluejoint,

205

Separable of pondweed.

512

Bluet,
Blunt-leafed milkweed,

389
366

Buffalo-berry, 332,
Canada,

437, 465
333

532

Minnesota Plant Life.

Buffalo-berry

Silver, 333

-grass, 205, 206, 464

Bugle-weed, 375

Bug, Potato, 379

Bugseed, 259

Bulb, 512

Burrowing, 21$

Subterranean, 426

Bulblet-fern, 166

Bulrush (Half-tone, 201, 213, 421),

i j, 30, 38, 214, 451, 457, 459

Air chamber, 455

Rootstock, 458

Stem structure, 422

stem, Three-cornered, 215

Bunchberry, 340

Burdock, 399, 401, 413, 415

Involucre, 399

Seed distribution, 19

Large, 413

Small, 413

Bur-marigold, 401, 410

Submerged leaves, 417

Water, 449

Burning-bush, 312

Bur oak (Half-tone, 419), 249, 251, 478

Bur-reed, 198

Burrowing bulb, 218

Burweed, 4=58

Bush clover, 303

-honeysuckle, 393

Bushed willows, 241

Butter, Diseases, 112

"June flavor," m

-seed, 360

Buttercup, 256, 264, 268, 475, 476

flower, 348

Water, fruits, 272

Water-, 272, 448, 417

Water-, Stiff, 272

Water-, White (Engr. 271) 272

Butterfly-weed, 365

Butternut, 243, 244

Fungus, 86

Butterweed, 4I2

Swamp, 458

Butterwort, 384, 418

Nutrition, 385

Use in cheese-making, 385

Button-bush, 388, 389

-bush dodder, 369

Button-snakeroot, 338

Butyric acid-producing bacteria, 102

Cabbage, 277

Slime-mould on roots, 27

Yeast growing on cooked, 74

Cabinet-making, 193, 244, 247, 297

Cactus, 417, 436, 437, 465, 474, 506

Melon, 33o, 465

Prickly-pear, 22, 468

Prickly-pear, Western

(Engr.), 330

Purple, 329

Calamint, 375

Calla lily, 217, 219, 451, 458

Callirrhoe, 323, 324

Calopogon, 231

Calycanthus, 275

Calypso, 228

Calyx, 346

Cambium, 486

in trees, 234

Camphor plant, 326

Campion, 263

Canada balsam, 192

blueberry, 356

buffalo-berry, 333

plum, 293

toad-flax, 381

violet, 329

Canary-seed grass, 205

Cancerroot (Half-tone, 385), 385, 438

Parasitism, 439

Clustered, 386

One-flowered, 386

Canna, 228

Canning of fruits, etc., no

Canoe birch, 246, 247

Canterbury-bell, 372, 468

Caper, 275, 468

Capsicum, 367

Capsule, Cone-headed liverwort, 134

Horned liverwort, 139

Leafy liverworts, 141

Liverwort, 154

Moss, 154

Origin and development of,

moss and liverwort, 130

Caraway seed, 340

Care of the young, 525

Carex-sedge, 215

Cardinal-flower, 397

Carlton peak, 148

Carnation, 263

disease, 103, 109
Carnivorous plants,

278, 418, 438, 460, 481, 489

Indian cup, 408, 409

Minnesota Plant Life.

533

Carolina geranium, 305

Carpel, 197

Definition, 184

Carpet-moss, 152, 459

plant, 211

-weed (Engr. 261),

24, 259, 261, 470, 476

Carrion-fungus, 66, 67

Carrot, 34°, 49 1

Cass county, 186, 221

Cass lake, 357

Cassiope, 35°

Castor-bean, 305

-oil plant, 511

Casuarina tree, 236

Catalpa, 367, 383

Leaves, 423

Caterpillar fungus, 82, 438

Catchfly, 259, 263

Catnip, 375, 376
Cat-tail (Half-tone, 12, 18),

197, 198, 437, 457, 458, 459

Rootstock, 455

Broad-leafed, 198

Cauliflower, 277

Cecropia, 5°7

Cedar-apple, 54

Cedar lake (Half-tone), 10

swamp, 457

Cedar, Red (Half-tone, 193),

186, 192, 193, 472

Red, Flower, 346

White (Half-tone, 189), 186, 190

Cell, 497

division, 498

growth, 494

Origin, 493

-parasites, 45

Reproductive, 513

sap, 495

Century-plant, 465, 473, 474

Chaffweed, 350, 358, 359

Checkerberry, 350, 355

Cheese, Bacterial flora, in

Blown, 112

Diseases, 113

-making, Use of butterworts

in, 385

plant, 323

Ripening, 112

Cherry, 292, 293

Black, 294

Black knot, 85

Choke- 294
choke-, Flowers (Engr.), 293

Cherry, Dwarfed, 293

Dwarfed, 293

Ground-, 367, 378

Pin-, 293

Pocket-fungus, 74

Sand- (Half-tone), 292

Sand-, Western, 293

Wedge-leafed, 293

Witch's-broom, 74

Chestnut, 246

Horse, 309, 317

oak, 249, 251

Chickweed, 263

Chicory, 399, 402

Chisago county, 221

lake, 363

Choisy's dodder, 369

Choke-cherry, 294

Black knot, 85

Chokeberry, 286, 287, 290, 470

Chlorophyll, 488

Christmas-green plants, 156

trees (see spruce), 192

Chrysanthemum (Half-tone,

400), 401

Cigars, diseases, 112

Cigar-moss (Lichen), 97

Cinchona, 388

Cinnamon fern, 164, 173

Citron, 394

Clammy ground-cherry, 378

-weed (Engr. 276), 275

Classification of bacteria, 102

Classes, Higher seed plants, 197

Claytonia, 262, 437

Clearweed, 254, 255

Clematis, 264, 268, 271, 439, 479

Ground-, 271

Cliff-brake, 165, 468

Climate, 480

Climatic history of plants. 427

Climbing bittersweet, 312, 418, 479

nightshade, 379

Clintonia (Engr. 225), 225,479

Closed gentian, 362

Closets, Moth, 193

Clover, 280, 298, 427, 476, 503

roots, Bacteria, 117

root nodules, 117

Clover, Bush, 303

Prairie, 297, 301

Prostrate, 299

Red, 298

Sweet, 298

534

Minnesota Plant Life.

Clover, Sweet,bushes (Half-tone), 299

White (Half-tone, 300), 298

Yellow, 298

Club-fungus, 438

Club-Moss (Engr. 156), 156,

469, 490, 514, 5l6, 518, 519, 520

Cones, 157
Cones, Origin of the flower, 343

Life-history, 156

Minnesota, 159

Origin, 123
Relation to horned liverwort, 140

Rootstock, 455

Spore production, 159

Club-moss, Flat-branched (Engr.

158).

Smaller (Engr. 159).

Club-root, 27

Cluster-cup fungus, 52, 514

Clustered cancerroot, 386

Coal, Formation, 146

Cob, Corn, 207

Coca tree, 305

Cocaine, 305

Coccus, 102

Cockle, 21, 259
Cocklebur, (Engr. 404),

12, 399, 401, 405, 415

Involucre, 399

Seed distribution, 19

Cockscomb-grass, n

Cocoanut, Fruit, 423

Seed, 420

Coffee, 388

tree, Kentucky (Engr. 296),

296, 297

Cohosh, Blue, 274

Collomia, 369, 370

Color, Alpine flowers, 425

Origin of in flowers, 426

Polar flowers, 425

producing bacteria, 102, 115

Purple, 433, 449

Warming-up, 36

Warming-up," Peat-moss, 146

Colts' foot 411

Columbine, 264, 268

Comfrey, 371, 373

Common milkweed, 366

phlox, 370

plantain, 387

toad-flax, 380

yellow pond-lily, 266, 448

yellow violet, 329

Compass-plant, 401, 403, 434, 464, 471
Rosinweed (Engr. 411), 409,464
Wild lettuce (Engr. 403), 464
Composite (Half-tone, 408),

394, 399, 409, 471

family, 402, 414

family, Flower-cluster,, 414

Flower, 400, 415

Fruit distribution, 400

Number in Minnesota, 401

Winged distribution, 416

Cone, Club-moss, 157

Cone-flower (Half-tone, 412), 401, 409

Long-headed, 409

Prairie (Engr. 413), 413

Cone-headed Liverwort, 133, 518, 520

Liverwort Capsule, 134

Liverwort Spermary, 136

Confection, Marshmallow, 325

Mint, used in, 378

Consumption bacteria, 106, 108

Contagious diseases, 106

Cook county, 354

Coral-root, 228, 231, 438, 479, 490

Root-fungus, 89

Coriander seed, 340

Cork, 497

elm, 252

Corm, 512

Corn-cockle, 263

Smut, 48

flower (Engr. 414), 402, 413

Indian (Half-tone, 207), 205, 206

Indian, hybrids, 207

cob, 207

ear, 207

husk, 207

stalk, 431

tassel, 207

salad, 393, 394

Squirrel, 276

Cornel, 336

Alternate-leafed, 342

Dwarf (Engr. 341),

340, 342, 416, 428

Silky, 341

Corpse-plant (See Indian-pipe), 350
Coteau, Prairie scene (Half-tone), 9
Cotton-grass, 146, 213, 457, 460

Cottonwood (Engr. 238. Half-
tone, 235, 452, 474), 238, 239, 462
Life-history, 183

Seed distribution, 20

Minnesota Plant Life.

535

Counterpoise area, Duckweed, 444

Salvinia, 444

Water-hyacinth, 444

County, Aitkin, 309

Anoka, 327

Beltrami, 3^5

Blue Earth, 332

Cass, 186, 221

Chisago, 221

Cook, 354

Goodhue, 325

Pipestone, 33°, 359, 468

St. Louis, 146

Stearns, 341

Sherburne, 327

Winona, 356, 393

Wright, 327

Cowbane, 338, 340

Cowberry, 356, 357

Cowslip (Engr.), 268

Cow-parsnip, 338

Cow-wheat, 379, 383, 385

Nutriment, 383

Coxcomb, 259, 260

Crab-apple, 286

Wild, 286

Cranberry,

22, 146, 350, 356, 357, 424, 457, 460
Position of, 349
Resemblance to partridge-
berry, 389
Rootstock, 455
High bush (Engr. 390), 390, 41 5
Mountain, 356
Small (Engr), 357
Creeping-charley, 323
Creeping raspberry, 291
resemblance to violet, 291
Cress, Rock, 275, 278
Water (Engr. 277), 275, 278
Crocus, 264, 268
Crop-rotation and bacteria, 118
Cross-fecundation, 517
-pollination, 230, 517
Crowberry, 309, 437, 457, 459- 460
family, 309
Resemblance to yew, 309
Crowfoot, 268
family, 264
Musk, 393
Water, Submerged leaves, 417
Cubeb, 236
Cucumber, 394, 395
-rot, 103, 109

Cucumber, Star-, 394, 395

Wild, 394, 396, 439

Cudweed, 401

Cultivated field, 476

Cup-fungus, 72, 76, 95, 438, 514

Distinguishing characters, 77

Spores, 77

Tamarack, 78

Moss, 150

Cuplets, Umbrella-liverwort, 137

Curly-leaved dock, 258

maple, 315, 3*6

Currant, 283, 284

Seed distribution, 19

Flowering, 284

Indian, 392

Red, 284

Skunk, 284

Wild black, 284

Cut-leafed ground-cherry, 378

nightshade, 378

Cycad, 520, 522, 524

Fossil, 26

Cyperus-sedge, 213

Cypress knees, 455

Dairy, Bacteria, in

Daisy, 407, 4*5

Oxeye, 476

Dandelion,

399, 402, 415, 429, 433, 480, 509

family, 402

flowers (Half-tone), 401

fruits (Half-tone), 402, 441

parachute, 400

Position of 415

Relatives of, 402

Seed distribution, 21

Dandelion, Autumn, 403

Dwarf, 403

Dead-nettle, 375

Deadly nightshade, 378

Death of an organism, 484

Deerberry, 356

Definitions, 123, 181, 182, 183, 184

Albumen, 183

Alternation of generations, 123

Carpel, 184

Embryo-sac, 180, 184

Flower, 184

Ovule, 180, 184

Pollen-grain, 181, 184

Pollen-tube, 182

Seed, 180, 184

Seed-coat. 182

536

Minnesota Plant Life.

Definition, Stamen, 181, 184

Stigma, 181, 184

De-nitrifying bacteria, 102,117

Deposition of silica, Scouring-

rush, 175

Desert plant,

418, 428, 436, 442, 463, 481, 506

Leaves, 464

Odor, 437, 465

-succulent, 474

Desmanthus, 296, 297

Desmid, 34, 443

parasites, 45

Diatom, 39, 443, 453, 505

Deposition of silica, 40

parasites, 45

Disc-alga, Relation to liverwort, 129
fungus, 78, 95, 514

Disease, Immunity to, 106
-producing bacteria, 102, 103, 105

Diseases, Animal, 109

Bacteria, 109

Bread, 112

Butter, 112

Carnation, 103, 109

Cheese, 113

Cigar, 112

Contagious, 106

Egg, 112

Grain, 50

Grape vine, 46

Ice-cream, 13

Infectious, 106

Invasive, 106

Meat, H3

Milk, II2

Plant, iog

Potato, 46

Vegetable, ^3

Distribution, Carrion-fungi spore, 66

Morel spore, 75

Plant, 5

Seed, 344) 4l6

Spermatozoid, 520

Spore, 344) SI4

Winged composites, 4i6

Ditch-moss, 203

stone-crop, 282

Dock, 257, 258

Curly-leaved, 258

Golden, 258

Dock, Prairie,
Red-veined,
Swamp-,
Yellow,
Water,

409
258

258, 458
258
258

Dodder (Half-tone, 368), 233, 367, 368

Nutrition, 368, 369

Parasitism, 369, 439

Sucking organs, 369

Aster, 368

Button-bush, 369

Choisy's, 369

Field, 368

Goldenrod, 368

Gronovius, 369

Hazel, 369

Massive, 369

Smartweed, 369

Sunflower, 368

Dog's-tooth violet (Engr. 225),

225, 226

Dogbane, 360, 364
Resemblance to flowering

spurge, 308
Resemblance to milkweed, 364

Dogwood, 12, 332, 336,

340, 342, 428, 459, 460, 462, 472, 478

Position of, 349, 415

Dogwood, Bailey's, 341

Dwarf, 336

Flowering, 340, 416

Poison, 310, 506

Rough-leafed, 341

Round-leafed, 341

Silky, 428

Smooth-leafed, 428

Doors, Manufactured from white

pine, 186

Doorweeds, 258

Douglas county, 221

Downy-leafed arrowwood, 391

phlox, 369, 370

Dragon's-head, 375, 376, 377

-head, False, 376

Duckweed, 220^436,449

Air chamber, 443

Counterpoise area, 444

Pollen distribution, 282

Pollination, 445

Duckweed, Ivy-leaved, 220

Smaller, 220

Three-cornered, 220,444

Three-pronged, 133

Minnesota Plant Life.

537

Duluth,

259, 262, 266, 284, 332, 354, 355, 357
Rock-vegetation near (Half-
tone), 189
Dune, 469
-grass, 211
Dung-moss, 139
Dutchman's-breeches, 275, 276
Dutchman's-pipe, 256
Root-fungi, 89
Dwarf shrubs, 428
Dwarf alder, 319
bilberry, 356
birch, 459
blueberry, 356
cherry, 293
cornel, 340, 342, 416, 428
dandelion, 403
dogwood, 336
ginseng, 336, 337
horse-tail, 179
snowberry, 428
willow, 428
Ear, Corn, 207
-fungus, 90
Earth-star, 68
Spore distribution, 69
Easter lily, 224, 513, 524
Ebony tree, 360
Economic importance, Algae, 41
Ergot, 82
Lichens, 97
Liverworts, 143
Edible fungus, 63, 65, 76
lichens, 98
morels, 75
mushrooms, 61
pore-fungi, 58
reindeer moss (Lichen), 98
seaweed, 41
Western prickly-pear fruit, 330
Eel-grass, 197, 202, 263
282, 448, 449, 450, 451, 452
Holdfast, 447
Egg, 512, 513, 52i
Diseases, 112
Fecundated, 513
fecundated, Behavior of, 523
Fecundated, of higher ani-
mals, 128
Fecundated, of higher plants, 128
Infection with bacteria, 113
production, 521
Spermatozoid directed to-
ward, 499

Eggs, Bass-weed
Black mould,
Desmid,
Red algae,
Sphere-algae,

Elater, Liverwort,

Elder,
bush,

38
44
34
40

37

135, 140, 515

388, 390

390

Resemblance to wild elder, 337

Box-, 309, 313, 317
Poison, 310,311,312

Wild, 336
Wild, Resemblance to elder

bush, 337
Electricity, Adaptations of

plants to, 437

Ellisia, 37i
Elm (Half-tone, 10, 14, 429),

234, 243, 251, 252, 462, 478
Leaves, 430
Seed distribution, 20
woods, 6
American (Engr. 251. Half-
tone, 252), 252
Cork, 252
Red, 252
Rock, 252
Slippery, 252
Three-leaved, 307
White, 252
Embryo, 523
-sac, Definition, 180, 184
-sac, Germination, 518
Enchanter's nightshade, 335
Energy produced by bacteria, 104
Ensilage, Souring of, 114
Erect habit of plants, 130
Ergot, 81
Economic importance, 82
tubers, Poisonous, 82
Rye, 81
Wild rice, 81
Eucalyptus, 332
Australian, 39
Euglena, 499
Nutrition, 445
Plant or animal, 445
European basswood, 323
puccoon, 373
verbena, 374
Evening-primrose,

332, 334, 426, 429, 468, 470, 478

Shrubby prairie, 335

White, 335

538

Minnesota Plant Life.

Evergreen plants, 428

Everlastings, 401, 4°7

Extract, Mint, 378

Eyebright, Parasitism, 383

Fairy's spears, 210

False acacia, 301

beechdrops (see pine-sap), 350

buckwheat, 258

dragon's-head, 376

gromwell, 371, 373

heather, 326

indigo, 297

indigo, Herbaceous, 298

indigo, Large, 300

indigo, Low, 301

indigo, Shrubby, 300

indigo, White, 298

loosestrife, 334, 358

mallow, 323

mermaid, 309

nettle, 254

pennyroyal, 376

pimpernel, 379

rue-anemone, . 268

Solomon's seal, 225, 226

Family, 198

Farina grains, 491

Febrifuge, 242

Fecundated egg, 513

Behavior of, 523

Fecundation, 517, 522

Cross-, 517

Scouring-rush, 178

Fence poles, Manufactured from

tamarack, 191
Fencing lumber, Manufactured

from white cedar, 190

Fennel, Hog-, 338

Water-, 3O8

Ferment, 103

-producing bacteria, 102, 109, 453

Fermentation, 73

of wine, Yeast in, 72

Fern (Half-tone, 165, 455),

161, 468, 472, 476, 490, 496,
512, 513, 514, 5i6, 518, 519, 520

Distinctive features, 174

embryo (Engr.), -169

leaves, 161, 170

Number in Minnesota, 27

Nutrition, 48

Ordinary, jg^

Origin, I23, 174

Sexual plant (Engr.) 168

Fern, Spore-case (Engr.), 171

Adder's-tongue (Half-tone), 162
Beech, 166

Bracken, 164, 165, 472

Borneo, 164

Bulblet, 166

Cinnamon, 164, 173

Clayton's (Engr. 164. Half-
tone, 167), 167
Cliff-brake (Engr.), 166
Filmy, 164
Floating, 164, 168, 220
Floating, Alga in leaves, 169
Floating, Root-caps, 220
Flowering, 164
Forking, 164
Grape, 161
Interrupted (Engr. 164.

Half-tone, 167), 164

Lady (Half-tone, 173), 165

Maiden-hair (Engr. 170. Half-
tone, 173), 165
Ostrich, 166
Ostrich, Leaves, 173
Perching, 472
Polypody (Engr.), 170
Royal, 165
Sensitive (Half-tone, 165), 166
Shield- (Half-tone, 167), 166, 459
Sweet-, 242, 460
Tree, 164
True, 163, 496
Twining, 164
Virginia grape- (Engr.), 163
Walking (Half-tone, 172), 165
Water-,

161, 444, 506, 5i5,5i6, 519, 520
Water-, Four-leafed (Engr.

168), 164,166, 173,448,518

Fertilizer, Algae, 41

Fescue grass, 205

Fever plants, Hay, 405

Feverwort, 391

Fibre, Flax, 306

Field, Cultivated, 476

dodder, 368

horse-tail, 178

Fig, 251

Figwort, 367, 379, 381

Resemblance to lobelia, 397

Resemblance to mint, 379, 397

Filmy fern, 164

Fireweed, 334, 412

Minnesota Plant Life.

539

Fir, 186

Flower, 347

Seed distribution, 20

Firewood, Jack pine, oak, tam-
arack, white poplar,

190, 191, 238, 250

First-stage, Liverwort, 124, 128

Moss, 124, 128, 151

Fish-mould, 45, 513, 515

Life-history, 46

parasites, 45

Spermatozoids, 46

Fivefinger, 289

Resemblance to anemone, 290
Marsh, 289

Flag, Blue (Half-tone, 12, 225,

226,250), 219,224,227,437

Blue, Flower, 348

Sweet (Half-tone, 12), 219,437

Flax, 305, 306, 475

seed, 306

Flax, Grooved yellow, 306

Stiff yellow, 306

Toad-, 380, 438

Wild blue, 306

Fleabane, 401, 402, 407, 469

Flesh-eating fungus, 58

Fleur-de-lis (see blue flag), 227

Floating leaves, 449

arrowhead, 448, 449

fern, 164, 168, 220

fern, Alga in leaves, 169

fern, Root-caps, 220

-heart, 364

liverworts, 132

marsh-marigold, 268

Riccia, 443

Flooring, Manufactured from
sugar maple, 316

Flora, North America, 16

Florida milkweed, 367

Flower, 414

Alpine colors, 425

Autumn, 426, 479

axis, Development, 345

axis, Anemone, 345

axis, Mousetail, 345

axis, Rose, 345

axis, Strawberry, 345

Bilateral symmetry, 228

Closing of at night, 427

-cluster, Development, 414

-cluster, Composite family, 414
Definition, 184, 346

Flower, Development, 343

Irregularity, 348

High types, 343

Law of variation, 343

Low types, 343

Origin, 343, 440

Spring, 426, 479

Perfect, 321

Polar colors, 425

Prototype of, 343

Radial symmetry, 228

Sleep-position, 427

Typical, Definition of, 346

Typical Development of, 346
Why one of higher type than

another, 349

Passion, 326

-of-an-hour, 325

-pot alga, 35

Spider, 275

State, 231

Flowering plant, 490, 514, 516, 518, 520

Honey secretion, 515

Number in Minnesota, 27

Nutrition, 48

Origin, 174

Planktonic, 445

Flowering-currant, 284

dogwood, 340, 416

fern, 164

Spurge, 308

Flowering Spurge, Resemblance

to dogbane, 308

Fly-cholera fungus, 45, 438, 514

honeysuckle, 392

Fogfruit, 373, 374

Food-material, Reserve, 426
Partnerships for obtaining, 489

Plant, 488, 489

Storage, 490

Disposal, 4Qi

Forage plants, 21

Forces harmful to bacteria, 104

Forest (Half-tone), 7
Dominant plants, 7
and prairie, Difference be-
tween, 8, 14
Hardwood (Half-tone, 480),

252, 475, 478

horse-tail, 178

Minnesota, 6, 12

Pine, 472

Forget-me-not, 371, 372

540

Forking fern,
Formation of coal,

of peat-bog,
Fossil cycad,

diatoms,

plants,

seaweeds,
Four-leafed milkweed,

water-fern, 164, 166,

water-fern, Leaves of
Four-o'clock,
Fox-glove,
Fox-grape,

-tail grass,
Fragrant sumac,
Fringed gentian,

Houstonia,
Frost-grape,
Frostweed,
Fruit, Bloom on,

canning of, etc.,

Heavy,

Structure,

Fruit, Agrimony,

Apple,

Avens,

Banana,

Blackberry,

Cherry,

Cocoanut,

Fivefinger,

Gourd,

Hawthorn,

Liverwort,

Moss,

Mountain-ash,

peach,

Pear,

Plum,

Pumpkin,

Raspberry,

Rose,

Spiraea,

Squash,

Strawberry,
Fruit-body, Bird's-nest

Black mould,

Blight,

Carrion-fungus,

Caterpillar fungus,

Morel,

Mushroom,

Peat-moss,

164

146

146

26

39

26

26

366

173, 448, 518

166

259, 261

367
321
476
310
362
390
321
326
435
no
422
420
295

295, 423
295
423
295
295
423
295
423
295
123
123
295
295
295
295
423
295

292, 295

295

423

295

fungus, 70

43
80

67
82

75

63

147

Minnesota Plant Life.

Fruit-body, Reindeer moss, 97

Slime-mould, 28

Smut, 48

Fruit-cluster, 416

Fruit distribution, Snakeroot, 339

distribution, Sweet cicely, 339

Fuchsia, 334, 436

Fuel, Cottonwood, 239

Sugar-maple, 316

Fuller's-teazel, 388

Fumitory, 12, 275, 277

Golden, 277

Pale, 277

Yellow, 277

Fungus, 22, 488, 489, 506,

512, 513, 519, 522, 523
alkaloids, 82

Edible, 63, 65, 76

Growing in darkness, 429

Life of a, 87

Number of species in Minne-
sota, 27, 43
Nutrition, 48, 87
Origin, 88
Parasitic, 49, 74, 98, 438, 506
Poisonous in tamarack

swamps, 59

Reproduction, 87

Spores produced in sacs, 72

Spores produced on stalks, 72
Starch-manufacture, 48

Algal, 43

Algal, Parasitic, 45

Beetle-, 91, 99

Beetle, Spores, 100

Bird's-nest, 69

Bird's-nest, Fruit-body, 70

Black, 80, 83, 95

Butternut, 86

Carrion-, 66, 67

Caterpillar, 82, 438

Club- (Half-tone, 56), 55, 438
Cluster-cup, 5*4

Cup- (Half-tone, 76),

72, 76, 95, 438, 514

Cup, Tamarack,

Disc-,

Ear-,

Flesh-eating,

Fly-cholera,

Higher,

Leaf-spot-,

Lichen-,

78

78,95,514
90
58

45, 438, 5H
48

83,84
95, 5i8

Minnesota Plant Life.

Fungus, Pine-knot, 54

Pocket- (Half-tone), 74

Pore-, (Half-tone, 59, 60), 57

Pore-, Edible, 58

Pore-, Oak tree, 58

Pore-, Poisonous, 82

Pore-, Sulphur-colored, 58

Prickle, 56
Root, 80, 88

Root, Birch, 89

Root, Coral-root orchid, 89

Root, Dutchman's pipe, 89

Root, Oak, 89

Root, Orchid, 89

Root, Pyrola, 89

Root, Tamarack, 89

Sac-,

72, 74, 80, 95, 513

Shelf- (Half-tone, 57), 57

Shelf Toadstool-like, 59

Shelf, Birch, 58

Shelf, Poisonous, 59

Skin-, 55
Spot-disease (Half-tone),

82, 83, 84, 85, 86, 87

Staghorn, 86

Stalk-, 95

Tar-spot, Maple, 78

True, 43, 48

True Parasitic, 48

Trembling, 55

Twig- (Half-tone, 88), 85

Furniture, Manufactured from

basswood, 323
Manufactured from butternut, 244
Manufactured from red or

river birch, 247
Manufactured from soft

maple, 315
Manufactured from sugar

maple, 316

Gall, 361, 504

Gamete, 512

Gas bubbles, Water flower, 29

bubbles, Algal plankton, 443

Gaura, 335

Scarlet, 335

Gemma propagation, Origin, 138

Moss, 150

Umbrella-liverwort, 137

Gentian, 6, 360, 362, 426, 459, 462, 475

Closed, 362

Fringed, 362
Horse-, 388, 391

Gentian, Oblong-leafed, 362

Narrow-leafed, 363

Red-stemmed, 363

Soapwort, 363

Spurred, 363

Stiff, 362

Yellow (Engr. 362), 363

Geranium, 305, 432

Carolina, 305

Spotted-leafed, 305

Gerardia, 379, 382

Germination, Spore, 518

Spore, Scouring-rush, 177

Gesnera, 367

Giant kelp, 513

lily of the Amazon, 433

puff-ball, 69

Gilia, 369, 370

Ginseng (Engr. 337), 336

root, 337

Dwarf, 336, 337

True, 337

Glade-mallow, 323, 325

Gland, 465

Glandular birch, 246, 247

Glasswort (Engr. 259),

259, 436, 437, 473, 474

Glenwood lake, 38

Gloxinia, 367

Golden dock, 258

fumitory, 277
Goldenrod (Half-tone, 309, 408,
410), 6, 9, 399, 401, 402, 406,

426, 427, 430, 469, 478, 479

dodder, 368

Early (Engr.) 409

Golden root, 268

saxifrage, 283

Goldthread, 264, 268

Goodhue county, 325, 393

Gooseberry, 280, 283, 284

Seed distribution, 19

Prickly, 284

rust, 54

Goosefoot, 259

Salt-loving, 473

Gosling, 268, 271

Gourd, 395, 427, 503

family, 394

family fruit, 423

Flower, 394

Seed distribution, 19

Grain, 421

disease, 50

542

Minnesota Plant Life.

Grain Grass, 204

Grand Marais, 3.29

Grand Rapids (Half-tone), 145, 212
Granite lake rapids, 281

Granite moss, 148

Granitic region vegetation, 463

Grape (Half-tone, 320), 319, 427, 439
disease, 46

Mildew, 46

Grape, Fox-, 321

Frost-, 321

Riverside, 321

Summer, 321

Wild, 320, 418, 479

Wild, Resemblance to moon-
seed, 320
-fern, 161
Grass (Half-tone, 10, 12, 18,471), 7,
12, 198, 204, 430, 459, 460, 464, 465,
468, 470, 471, 475, 476, 478, 480, 502
Dominant prairie plants, 7
Grain of, 204
Grain distribution, 210
Position of, 349
Resemblance to sedge, 212
Spikelets, 204
Varieties, 2C,6
Alkali-, 226
.Barn yard (Engr.), 205
Beard (Engr.), 205
Beckman (Engr.), 206
blight, 80
Blue, 205, 206
Blue-eyed, 227, 4.57
Buffalo, 205, 206, 464
Canary-seed, 205
Cockscomb-, n
Cotton- (Half-tone, 212),

146, 213, 457, 460

Dune-, 211

Eel- (Engr. 202),

263, 282, 448, 449, 450, 451, 452
Eel-, Holdfast, 447

Fescue, 2O5

Fox-tail, 476

Kalm's brome- (Engr.), 209
Knot-, 11,258

Mat-, 2II

Millet, Smut, 4g

Muhlenberg (Engr.), 206

Panic, 205

PePPer, 275, 278

-pink, 23I

Grass, Prairie (Half-tone, 471), 437
Reed- (Half-tone, 213),

13, 205, 206, 451, 457, 458, 459

Rib, 387

Salt-loving, 473

Sand-binding, 205, 211

Sand-loving, J2

Spear, 210

Star-, 227

Star-, Water, 217, 222

Tumbling, 205,206,211

Tumbling, Seed distribution, 21

Whitlow-, 275, 278

Yellow-eyed, 221, 457

Gravity, Influence on plants, 418

Gray birch, 246

willow, 241

Great lakes region, 238

Greek valerian, 369

Green plants, 488

Green alder, 249

ash, 361

felt, 37,493,515

-flowered wintergreen, 351

milkweed, 367

mould, 44, 78

slime, 426

Grindelia, 406

Gromwell, False, 371

Gronovius' dodder, 369

Grooved yellow flax, 306

Ground-cherry, 367, 378

Clammy, 378

Cut-leafed, 378

Long-leafed, 378

Low, 378

Philadelphia, 378

Virginia, 378

-clematis, 271

-hemlock, 185, 194, 468

-pea, 280

-plum, 298, 302

tomato, 378

Groundnut, 304, 336

Groundsel, 412

Marsh, 412

Growth, 43o, 488, 491

Cell, 494

Living substance, 492

Organs, 495

Tissues, 495

Movements, 500

Gul1 lake> 353, 354

Minnesota Plant Life.

543

Gum-plant,

406

Hemlock, Ground-, 194, 468

tree, Benzoin,

360

Poison-, 338, 339

Gutta-percha,

360

Water- (Engr. 340), 338

Habit of plants, Erect,

130

Hemp, 251, 253

Hackberry, 251, 252,

253

-nettle, 376

Leaves,

430

Water-, 259, 261

Hairy-capped moss, 151,459,
honeysuckle,
milkweed,
Halberd-leafed rose-mallow,

472
392
366

Hen-and-chickens, 282, 474
Hepatica, 268, 269
Herbs and trees, Comparison, 234
Hickory (Half-tone, 244),

243, 244, 245

323,

325

Seed distribution, 20

violet,

329

Pignut, 243, 244

Halophyte,

473

Shell-bark, 243, 244

Hard maple,

313

Swamp, 243, 244

-skinned puff-ball,

70

White, 243

Hardening of cider, Yeast,

72

High blackberry, 291

Hardwood forest, 252, 475,

478

bush cranberry, 388, 390, 415

Hare's-ear,

338

Higher plants, 513, 514, 520, 523, 525

Harebell,

396

plants, Comparison with

Haw, Black, 390,

462

lichens, 98

Hawk's-beard,

403

plants, Division of labor, 490

Hawk weed, 402,

403

plants, Nutrition, 103, 118, 119

Hawthorn (Engr. 287),

plants, Origin, 129, 196

286, 287, 290, 478,

506

plants, Origin of root, 157

Hay-fever plant,

405

plants, Origin of seed, 160

Hazel, 245,

246

seed plants, 197, 517

scrub,

477

seed plants, Characters, 197

dodder,

369

Hoary puccoon, 372-

Witch- 274, 280,

284

verbena, 374

Hazelnut, Beaked,

246

willow, 241, 242

Heal-all,

3/6

Hog-fennel, 338

Heart-leafed plantain,

387

Holly, 309, 312, 462, 465

willow, 241,

242

Mountain, 312

wintergreen,
Heat-producing bacteria, 102,

351
H5

Hollyhock, 321, 323.
Honewort, 338

Heath, 6, 146,

Honey, Secretion in flowering

437, 457, 459, 460, 465,

472

plants, 515.

Resemblance to partridge-

-locust, 280

berry,

389

Honeysuckle, 392, 428

Rootstock,

455

family, 388, 390-

bush,

469

Blue, 392

Lichen,

469

Bush-, 393,

Moss,

468

Fly-, 392

Heather, Shrubby,

469

TT •

Hairy, 392

Beach (Engr. 327),

327

Involucred, 393

False,

326

Mountain-, 392

Hedge, - 190,

241

Smooth, 392-

-hyssop,

38i

Sullivant's, 392

-mustard,

278

Swamp, 392, 393

-nettle, 375,

376

Yellow, 392-

Hellebore, 225,

226

Hooked blight, 80

Hemlock, 186,

190

Hop, 251,253,439,479

bark,

191

Medicinal value, 253.

544

Minnesota Plant Life.

Hop tree, 3O7
-hornbeam (Half-tone, 245),

245, 246

Hornbeam, 246
Horned liverwort, 139
liverwort, Relation to club-
moss, 14°
Hornwort, 264, 267
Horse-chestnut, 309, 3*7
family, 3*7
gentian, 388, 391
-tail (Engr. 176), 175
-tail, Minnesota, 178
-tail, underbrush habits, 179
Horse-tail, Dwarf, 179
Field, 1/8
Forest, 178
Water, 178
Horsemint, 375, 376, 377
Hot spring, 424
spring algae, 31
spring vegetation, 453
Hound's-tongue, 37i
Houstonia, 388, 389
Fringed, 39°
Long-leaved, 390
Huckleberry, 350, 357
Bog, 356
Squaw, 356
Hudsonia, 327
Humus, 438, 459
plants, 479, 489
Husk, Corn, 207
Hybrids, Indian corn, 207
Hydrangea, 280
Hydrophyte, 442
Modified, 453
Hydrophytic vegetation, 462
Hyssop, 367, 375, 377
Ice-cream, Diseases, 113
Ice-plant, 259
Immunity to disease, 106
India-rubber tree, 251
Indian corn, 205, 206
corn hybrids, 207
corn, Smut, 48
cup, 408, 409
currant, 392
lotus, 264, 267, 452
pink, 379, 382
-pipe, 350, 352, 438, 479
-pipe, Resemblance to pine-
sap, 353
plantain, 412

Indian reservations, 379

rice (see wild rice), 205

tobacco, 407

tobacco lobelia, 398

turnip, 217, 300

uses, Birch-bark, 247

Indigo-plant, 280

False, 297

Infectious diseases, 106

Inoculation, 107

Insect pollination of orchids, 229

pollination of pipe-vine, 257

Insects, 20

Instinct of self-preservation, 510

International boundary,

281, 309, 322, 356, 357, 362
Interrupted fern, 164

Introduced plants, u

Invasive diseases, 106

Involucre, 399

Burdock, 399

Cocklebur, 399

Involucred honeysuckle, 393

Iodine, Manufactured from algae, 41
Iris (See blue flag), 220, 224

Iron, 102

bacteria, 102

bacteria and iron ores, 120

oxide, Extraction by algae, 30
Ironweed, 401, 405

Ironwood (Half-tone, 245), 245, 246
Irritable behavior, Living sub-
stance, 498
behavior, Plant organs, 500
Irritability, 488, 497
Islands in Lake of the Woods
(Half-tone), 7, 468
in Mississippi river (Half-
tone), 14
Isle Royale, 329
Ivy, 432, 502
Poison (Engr. 311),

309, 310, 3H, 506
-leaved duckweed (See three-
cornered duckweed), 220
Jack-in-the-pulpit (Half-tone,
431), . 197, 217, 218, 219, 450., 479
Leaves, 43°
Parasitic alga, 37
Tack-pine, 186, 470
Jack-pine-barren, 470
Economic importance, 190
Jasmine, 360

Minnesota Plant Life.

545

Jelly, Made from silver buffalo-
berry, 333
Jimson-weed, 379
Joe-pye weed (Half-tone), 406
Joint-rush (See scouring-rush), 175
Jointweed, 258, 335
Judas-tree, 296
June-berry, 280, 286, 287, 290
Alder, 287
Round-leafed, 287
"June flavor" of butter, in
Juniper (Half-tone, 189),

1 86, 192, 194, 462, 468, 469, 470, 472

Flower, 346

Seed distribution, 19

Juniper cedar-apple, 54

Kalnrs lobelia, 39$

Kalmia (Half-tone, 354), 354, 457, 460

Resemblance to rosemary, 354

Kelp, Giant, 39, 5^3

Kentucky coffee-tree, 296, 297

Ketmia, 323, 325

Kettle river, 355, 357

Kidney-leafed violet, 329

Kinnikinic, 341

Use of by Indians, 342

Knot-grass, 11,258

Knotweed, 258

Koch's lymph, 108

Labrador tea, 350, 353, 456, 460

tea, Narrow-leafed, 353

violet, 329

Laburnum, 280

La Crosse, 267

Lactic acid-producing bacteria,

102, 113

Lady-fern, 165

Lady's-slipper, 228, 232, 342, 525

Yellow (Half-tone), 229

Lake vegetation (Half-tone),

18, 199, 201, 213, 380

Lake Alexandria, 267

Benton, 370

Big Stone, 262

Calhoun (Half-tone, 245, 324,

40i), 267

Cass, 357

Cedar (Hall-tone), 10

Chisago, 363

Glenwood, 38

Granite lake rapids, 281

Great lakes region, 238

Gull, 353, 354

Lake of the Isles (Half-tone), 18
Michigan, Limestone pebbles, 41
Mille Lac, 259

Minnetonka (Half-tone, 252),

29, 267

Osakis, 267

Pepin, 267, 281, 355

Red, 304

Rainy, 190, 194, 327, 469

Saganaga, 96, 469

Superior, 259, 283, 284, 303, 309
321, 322, 332, 356, 358, 363, 384
White Bear, 267

of the Woods (Half-tone, 7,
241,248), 7, 29, 194, 242, 253,
266, 304, 322, 327, 332, 356, 363,

461, 469

Lamb-lettuce, 388, 393

Lance-leafed violet, 329

Land plants, Parasites, 46

plants, Zonal distribution, 10

Large blue lobelia, 397

burdock, 413

cranberry, 356, 357

false indigo, 300

-toothed poplar, 238

Larkspur, 264, 268, 269

Flower, 348

-leafed violet, 328

Lasts, Manufactured from birch

wood, 247

Lath, Manufactured from white

pine, 186

Laurel, 264, 275, 350

Lead pencils, Manufactured

from red cedar, 193

Lead-plant, 298, 301

Leaf, Fern, 161

-green, 1 17, 429, 438, 488, 499

Floating-fern, Alga in, 169

-spot-fungus, 83

-spot-fungus, Number in

Minnesota, 84

-succulent, 282, 473

Leafless habit of plants, 214

Leaflessness, Swamp plants, 457

Leafy liverwort, Allies, 141

liverworts, Capsule, 141

Leatherleaf, 350, 356, 460

Leather-leafed wintergreen, 437

Leatherwood, 332

family, 332

Poisonous bark, 332

546

Minnesota Plant Life.

Leaves, 423, 435

Adaptation for spreading to

sun, 429

Coatings, 465

Desert plants, 464

Floating, 449

Habit of shedding, 425

Position on plant body, 429

Propagation, 512

Rain tips, 435

Rolled margins, 457

Shapes, 430

Sizes, 430

Sleep-position, 427

Submerged, 417, 449

Water plants, 450

Fern, What they really are, 170

Ledum oil, 354

Legume, 280

Definition, 295

Lemon, 305

Lesser wintergreen, 351

Lettuce, 399

Compass-plant, 464

Lamb-, 393

Prickly, 403

Wild (Engr. 403), 402,403,476

Lichen (Half-tone, 95), 22, 91, 424,

438, 439, 459, 467, 470, 472, 489
Age, 96

and algae, 93

Comparison with higher

plants, 98

Economic importance, 97

Edible, gg

heath, 469

Life of, QI

Minnesota, 95

Number in Minnesota, 27, 95
parasites, 98

partnerships, 98

Propagative bodies, 94

Starch-making, 99

Structure, 93

Black-fungus, 98

-fungus, 95, 5I8

Limestone, gi

"Old man's beard" (Half-
tone), 93
Reindeer moss (Half-tone,

97), 96, 462, 469

Rock (Half-tone, 92), 93, 96, 467
Sandstone, 9I

Tamarack, QI

Licorice, Wild, 298, 302

Lid-moss, 149

Life-history, Cottonwood, 183

Club-moss, 156

Fish-mould, 46

Liverwort, 124

Mildew, 46

Moss, 123, 124

Stinking smut of wheat, 49

Life-period, 509

Light, Effect on plants, 428

Influence on growth of

stems, 432

-producing bacteria, 102, 115

Lilac, 360

Lilac-blight, 80

Lily, 224, 460, 471

Allies, 225

Flower, 346, 347, 348

Calla, 217

Easter, 224, 513, 524

of the Amazon, Giant, 433

Pond- (Half-tone, 12, 204),

13, 266, 451

Pond-, Common yellow, 448

Sweet-scented, 266

Tuber-bearing, 266

Water- (Half-tone, 265), 13,

266, 273, 351, 448, 449
Water-, Leaves, 435

Water-, Small while, 266

Lime.. 305

encrusting bass-weed, 38

encrusting blue-green algae, 30
encrusting slime-mould, 28

encrustation, Algae (Half-
tone), 31,35
oxalate crystals, 217
-secreting algae, 41
Limestone formed by algae, 30
lichens, 91
pebbles in Lake Micnigan, 41
region vegetation, 463
Linden, 323
Flower, 348
American, 321
Linen, 306
Linseed-oil, 306
Lippia, 373
Live-forever, 465, 474
-oak, 428, 438
Liverwort, 42, 122. 439, 460, 472,

496, 513, 515, 519, 520, 521, 523
Air chambers, 135

Minnesota Plant Life.

547

Liverwort, Breeding habits, 123
capsule, 154
capsule, Origin and de-
velopment, 130
distinguished from moss,

123, 126, 144

Economic importance, 143
elaters, 135, 140
First-stage, 124, 128
Fruit, 123
Life-history, 123, 124
.Minnesota, I32
Number in Minnesota, 27
Origin, 122
Relation to disc-alga, 129
Reproduction, 127
Scientific interest, 143
Second-stage, 125, 126, 128
Spores, 135
Spore distribution, 440
Water-pocket, 142
Cone-headed, 133, 518, 520
Cone-headed, Capsule, 134
Cone-headed, Spermary, 136
Floating, 132
Horned, 139
Horned, Capsule, 139
Horned, Relation to club-
moss, 140
Leafy, 141
Leafy, Capsule, 141
Mud-flat (Engr. 132), 132
Purple-edged, 137
Swimming, 133
Umbrella- (Engr. 136, 138), 137
Umbrella-, Propagative

branches, 137
Living substance, 484, 508
Chemical composition, 487
Growth, 492
Irritability, 498
Location, 485
Physical structure, . 486
Physiological character, 488
Requisitions made on en-
vironment, 488
Lizard' s-tail, 236, 237
-tail, Resemblance to plan-
tain, 237
Lobelia, 388, 394, 397
Flower, 394
Resemblance to figwort, 397
Resemblance to mint, 397

Lobelia, Blue (Engr.), 396

Blue, Large, 397

Blue, Pale, 397

Indian-tobacco, 398

Kalm's, 398

Red, 397

Water, 396, 448, 449, 450

Water, Leaves, 417

Loco-vetch, 302

-weed, 302

Locust, 280, 298, 301, 417, 427

Honey-, 280

Lombardy poplar, 238, 240

Long-headed coneflower, 409

-leafed ground-cherry,. 378

-leafed Houstonia, 390

-leafed willow, 241, 242

-spurred violet, 329

Loosestrife, 333, 358

family, 332

False, 334, 35«

Purple, 334

Swamp, 333, 334

True, 333

Tufted, 358

Lopseed, 367, 386

Low birch, 246, 247

blackberry, 291

blueberry, 356, 357

false indigo, 301

ground-cherry, 378

serrated wintergreen, 351

snowberry, 392

Lotus, 13, 300

Indian, 264, 267, 452

of the Nile, 267

Louisiana broom-rape, 386

Lousewort (Engr. 382), 379, 385, 438

Parasitism, 383

Lucerne, 298

Lumpy-jaw, 107

Lungwort, 371, 372

Tall, 372

Virginia, 372

Lupine, 280, 298

Wild (Engr.), 298

Lycopodium powder, 156

Lygodesmia, 404

Lymph, Koch's, 108

Lythrum, 334

Seed, 334

Machinery, Manufactured from

elm, 253

548

Machinery, Manufactured

from sugar maple, 3J6

Manufactured from white ash, 360

Madder, 388, 525

family, 388

Magnetism, Effect on plants, 437

Magnolia, 264, 268
Fossil,

Maiden-hair fern, 165

Maize, 2°5

Mallow, 32i, 323

False, 323

Glade-, 323, 325

Poppy-, 323, 325
Poppy-, Triangular-leafed, 324

Prairie, 325

Rose-, 323, 325

Rose-, Halberd-leafed, 323, 325

Round-leafed, 323

Man, 21
An agent in plant distribution, 21

Mandrake (Engr.), 275

Wild, 274

Mangrove, 332

swamp, 442, 473

Mankato, 297, 325

Manomin, 207

Many-flowered prairie-clover, 300

Maple (Half-tone, 309),

22, 252, 305, 309, 462, 475, 478

Seed distribution, 20

Flower, 426

trees, 313

underbrush, 477

woods, 6

Maple,, Ash-leaved, 313

Bird's-eye, 316

Black, 313, 316

Curly, 315, 316

Hard, 313
leaf tar-spots,
-leafed arrowwood,
Moosewood (Engr. 316), 313,

Mountain- 313,

Red, 313,
Silver-leafed,

Soft, 313, 314,
Sugar (Engr. 314. Half-
tone, 315), 313,

Marcgravia,

Mare's-tail, 335,

Marigold, Beck's,

78
39i
3i6
317
3i5
238
502

315
326
450
411

Minnesota Plant Life.

Marigold, Bur-, 410

Bur-, Submerged leaves. 417

Bur-, Water (Engr. 414), 449

Marsh- (Eng. 268), 459

Wrater-, 411

Marine algae, 39, 40

Marsh (Half-tone, 452), 453

in oak wood (Hall-tone), 250

plants, 418

Reed, 457

Salt, 259
vegetation (Half-tone, 406), 451

-bellflower, 396
-elder, 402, 405

fleawort, 412

groundsel, 412
marigold, 264, 268, 459

-marigold, Floating, 268

St. John's-wort, 326

-violet, 328

Massive dodder, 369

Masts, Ship, Manufactured from

white pine, 186

Mats, Indian, Manufactured

from white cedar, 190

Mat-grass, 211
plant, 24, 211, 418,

429, 434, 470, 480

spurge, 308

Matches, Manufactured from

white pine, 186

Matting, Manufactured from
sedges,
Manufactured from hemp,

May-apple (Engr. 275),

Meadow (Half-tone, 475),
Moss,

Wet,

-parsnip,

rose,

-rue,

salsify,

-sweet,

violet,

Meat, Diseases,
Mechanical forces,

tissue,
Melon,

-cactus,
Melostoma,
Mendota,
Menziesia,
Mermaid-weed,

216

253
274
12, 475
459
459
338
291

264, 268, 273
403

286, 459
328

H3
420
450
394

330, 465
332
267

350, 354
336

Minnesota Plant Life.

549

Mesophyte,
Mesophytic shrub,

vegetation,
Microbe,
Mignonette,

442, 473
477
475
101

275

Migrating plants, Struggles, 24

Mildew, 46

Life-history, 46

Nutrition, 46

Mildew, Grape, 46

Mustard, 46

Potato, 46

Shepherd's-purse, 46

Milfoil, 13
True, 336
True, Resemblance to pond-
weed, 336
Water, 448

Milk-curdling bacteria, 114

Diseases, 112

-fermenting yeast, 74

Fermented, 114

-souring bacteria, 113

"Turnip odor," 113

Milkweed (Half-tone, 12, 366),

7, 360, 364, 515
Strengthening device for

leaves, 423

Flower, 365

Insect pollination, 364
Resemblance to dogbane, 364

Seed distribution, 20

Milkweed, Blunt-leafed, 366

Common, 366

Florida, 367

Four-leafed, 366

Green, 367

Green, Broad-leafed, 367

Green, Woolly, 367

Hairy, 366

Oval-leafed, 366

Poke, 366

Purple, 365

Showy, 366

Sulliv ant's, 366

Swamp (Engr. 365), 365

Tall, 366

True, 367

Whorled, 366

Milkwort, 307

Mille Lac, 259

Millet, 205, 206

grass, Smut, 48

Mimicry, 506

Mimosa, 503

Mineral springs, Bacteria, 120

Minneapolis (Twin Cities), 221

243, 267, 323, 325

Minnehaha falls, 281

Minnesota climate, 2

geography, i

physical history, 3

Minnesota river (Half-tone), 235

river valley,

7, 23, 262, 327, 330, 359, 387, 468
Mint, 367, 375

extracts, 378

family, 375

Flower, 377

Pollination, 377

Resemblance to figwort, 379

Resemblance to lobelia, 397

Horse- (Half-tone, 376.

Engr.), 377

Mountain-, 377

Water-, 377

Wild (Engr.), 375

Mississippi, river (Half-tone, 14,

410), 323, 327, 341, 362, 389

Mistletoe, 233

Parasitism, 439

Miterwort, 283, 284

Moccasin flower, 228, 231

flower, Poisonous, 231

flower, Yellow, 231

Moisture, Adaptation (Half-tone), 434

Monkeyflower (Engr. 381), 379, 381

Moonseed, 264, 274

Resemblance to wild grape, 320

Moonwort, 161

Moor, 453

Moosewood maple, 313

Morel (Half-tone, 75), 72, 74

Edible, 75

Morning-glory, 367, 439, 478

family, 367

Moschatel, 388, 393

Moss (Half-tone, 12. Engr. 125,

127, 153), 12, 22, 42, 122, 424, 439,

464, 467, 469, 470, 472, 476, 496,
512, 513, 514, 519, 520, 521, 522, 525

Breeding habit, 123

-capsule, 154

-capsule, Origin and develop-
ment, 130
Caterpillar fungus, 82

550

Minnesota Plant Life.

Moss, distinguished from

liverwort, 123, 126, 144

Deep water, 453

First-stage, 124, 128, 151

Fruit, 123

Gemma, 150

heath, 468

Life-history, 123, 124

Minnesota species, 144

Number in Minnesota, 27

Nutrition, 48

Origin, 122

Parasitic, 150

Reproduction, 126, 127

Second-stage, 125, 128, 151

spermary (Engr.), 126

Spermatozoids, 126

Spore distribution, 153, 440

stem, 152

Terminal type, 155

Wet meadow, 459

Xerophytic, 472

Moss, Arbor-vitae, 152

Bark, 149

Carpet-, 152, 459

Cigar (Lichen), 97

Cup-, 150

Ditch, 203

Dung-, 149

Granite-, 148

Hairy-capped, 151, 459, 472

Higher, 148

Lid-, 149
Peat- (Engr. 147. Half-tone,

212), 34, 145, 425, 459, 460, 462

Peat-, Fruit-body, 147

Peat-, Parasites, 45

Peat-, Spores, 49
Peat-, Warming-up color. 146

Pool-, 152
River-, 145, 151, 446, 448

Rock, 467

Rose-, I5o

"Spanish," 91

Tree-like, IS2

True, I49

Turf, I50

Water, 44g

White, I49
Moss-plant (Engr. 355, Cassiope), 354

Mould parasite, 44

Mould, Black, SI3

Blue, 78, 86, 513

Mould, Fish-, 513, 515

Fish-, Life-history, 46

Fish-, Parasites, 45

Green, 78

Pill-throwing, 44

Mountain-ash, 280, 286, 288, 290

American, 289

Western, 289

Mountain cranberry, 356

holly, 312

-honeysuckle, 392

-maple, 313, 317

-mint, 377

Mousetail, 268, 272

Flower axis, 345

Movement, Growth, 500

Protoplasmic, 498

Mud-flat liverwort, 132

Mudwort, 371

Mulberry, 251, 253

Red, 253

Mullein (Half-tone, 380),

367, 379, 430, 465, 476

Mushroom (Half-tone, 61, 62, 63,

64)> 61. 438, 513, 514

Fruit-body, 63

Gills, 513

Prussic acid odor, 65

Rules for eating, 61

Spores, Color, 65

Mushroom, Deliquescent, 63

Edible, 61

Milk, 64

Miniature, 63

Poisonous, 61, 82

Mushroom, True, Characters, 62

Classification, 65

Musk crowfoot, 388, 393

Muskeg spruce. 186, 192

Mustard, 22. 275, 277, 512

Mildew, 46

Hedge-, 278
Tumbling, Seed distribution, 21

Myrrh, 340

Myrtle, 332

-leafed willow, 240, 241, 460

Naiad, 200. 450, 452

Narrow-leafed gentian, 363

Labrador tea, 353

verbena, 374

Nasturtium,

305, 306, 432, 495, 497, 502, 525

Neighbors, Plant, 480

Minnesota Plant Life.

Nettle (Half-tone, 254),

234, 243, 251, 254

Nettle, Dead-, 375

False, 254

Hedge-, 375, 376

Hemp-, 376

-leafed verbena, 374

Slender, 254

Stinging, 254

Wood, 254, 255

New Jersey tea, 319

New Ulm, 23, 262, 330, 332

Nicollet county, 297

Nightshade, 367, 378

family, 378

Nightshade, Black, 378

Climbing, 379

Cut-leafed, 378

Deadly, 378

Enchanter's, 335

Prickly, 378

Ninebark, 286

Nitragin, 118

Nitrogen bacteria, 117

salts, 103

Nitrifying bacteria, 102, 117

Norway pine (See red pine), 188

Nothocalais, 404

Noxious algae, 41

Northwest angle, Inlet, 461

Nucleus, 494

Nutation, 500, 504

Nutrition, 431, 439, 488, 489

Bacteria, 102

Bacteria, Purple, . 116

Bladderwort, 384

Butter wort, 385

Cow-wheat, 383

Dodder, 368, 369

Euglena, 445

Fern, 48

Flowering plant, 48

Fungi, 48, 87

Higher plants, 103, 118, 119

Mildew, 46

Moss, 48

Pine-sap, 353

Pitcher-plant, 278, 418

Pond-scum, 33

Purple bacteria, 116

Sundew, 280, 418

Nuttall's violet, 329

Oak (Half-tone, 245, 250. Engr.

249), 243, 249, 252, 428, 470, 475, 478

Oak-barren,

Gall,

scrub,

Seed distribution,
Oak, Black,

Bur,

Chestnut,

Chestnut, Scrub,

Live-,

Poison-,

Pore-fungus,

Red,

Root-fungus,

Scarlet,

White,
Oats,

Smut,
Oblong-leafed gentian,

470, 478
504
477

20

249,250,251

249, 251

249, 251

249,251

428

309, 310

58

249, 250

89

249, 250, 251
249, 251
205
48
362

Odor, Algae with pig-pen, 41

Desert plants, 465

Mushroom with prussic acid, 65

Offset, 512

Oil, 49l

Ledum, 354

Old man's beard (Lichen), 91, 98

Oleander, 435

Olive, 360

One-flowered cancerroot, 386

Wintergreen, 350

Onion, 450, 471, 491, 511

Wild, 225

Orange, 305

Osage, 251

Orchid

(Half-tone, n), 5, 146, 224, 228,

438, 459, 46o, 463, 474, 515, 516, 525

family, 474

Flower, 347, 348

Insect pollination, 229

Microscopic female, 483

Poisonous, 232

Position of, 349, 415

Rein, 228, 231

Root-fungus, 89

Round-leafed, 229

Tree-top, 428, 472, 481

Tress, 228, 231

Orchis, Wild (Engr.), 230

Orders, 198

Organs, Irritability, 500

Polarity in, 501

Organism, Death of, 484

Origin, Cell, 493

Color in flowers, 426

Minnesota Plant Life.

Origin, Club-moss, 123

Fern, 123, 174

Flowering plant, 174

Fungus, 88

Gemma-propagation, 138

Higher plants, 129, 196

Higher plants, Root, 157

Higher plants, Seed, 160

Life, 42

Liverwort, 122

Liverwort Capsule, 130

Moss, 122

Moss Capsule, 130

Parasitism in plants, 439

Pine, 123

Orpine, 280

family, 282

Ortonville, 331

Osage orange, 251

Osier, Red, 341, 342

Osmose, 495

Ostrich-fern, 166

Leaves, 173

Oval-leafed milkweed, 366

Ovary, 197

Higher seed plant, Diagram

(Engr.), 181

Ovule, Definition, 180, 184

Oxeye, 409

daisy, 407, 476

Ox-yokes, Manufactured from

elm, 253
Paddles, Indian, Made from white

cedar, I90
Painted-cup, 382
Pale blue lobelia, 397
dock, 258
fumitory, 277
Palm of Java, Rotang, 39
Sago, I95
Fossil, 26
Panic-grass, 205
Pansy, 42;
Paper, Manufactured from bass-
wood, ^2-\
Manufactured from white

Poplar, 238

birch, 246

Pappus, 40Q

Parachute, Dandelion, 400

Parasite, 4g9

Definition, 44

Parasite, Cell-,

Parasite, Alga, On jack-in-the-

pulpit, 37

Algal fungus, 45

Bacteria, 453

Desmid, 45

Diatom, 45

Dodder, 368, 439

Fish-mould, 45

Fungus, 49, 74, 98, 438, 506

Land plant, 46

Lichen, 98

Moss, 150

Mould, 44

Peat-moss, 45

Pollen grain, 45

Pollen grain, Pine, 45

Pond-scum, 45

Root, 383

Slime-mould, 27

True fungus, 48

Parasitism, Origin of in plants, 439

Dodder, 360)

Eyebright, 383

Lousewort, 383

Yellow-rattle, 383

Parnassia, 284, 363, 459

Marsh (Engr.) 283

Parsley, 336, 459

family, 338, 458

family, Poisonous roots, 339

family, Umbels, 338

Wild (Half-tone, 339), 476

Parsnip, 340

Cow-, 338

Meadow-, 338

Water-, 338

Wild, 338, 340

Partnerships, Plant, 89,93,94,117

Plant, Obtaining food, 489

Plant, Intra-specific, 490

Lichen, 98

Partridgeberry (Engr. 389),

355, 388, 389, 424, 457

Resemblance to cranberry, 389

Resemblance to heath, 389

Resemblance to twinflower, 391

Pasque flower, 268, 271, 426

Passion-flower, 326

Pasture rose, 291

Pawpaw, 264, 268

Pea, 28o, 286, 417

family, 295, 464, 500, 503

Flower, 348

Position of, 349

Minnesota Plant Life.

553

Pea, Beach, 304

Ground, 280

Sensitive, 297

Sweet, 295

Peach, 280, 292

Seed distribution, 19

Peach-leafed willow, 241

Peanut, 273, 280

Wild, 297, 478

Pear, 286, 290

-blight, 103, 109

Pearlwort, 263

Peat-bog (Half-tone, 11, 145), 12,

34, 201, 213, 231, 279, 283, 354,

355, 357, 381, 398, 442, 457, 459, 460

-bog, Formation, 146

-bog, Plants, 146

-bog, Raised, 146

deposits, 26

-moss, 22, 34, 145, 425, 459, 460, 462

-moss, Fruiting habits, 147

-moss, Parasites, 45

-moss, Spores, 49

-moss, Warming-up color, 146

-moss, Water-reservoir cells, 145

-tundra, 459, 461

Pellitory, 254, 255

Pembina, 259

Pennyroyal, 375, 377

False, 376

Pennywort, 338

Peony, 264

Pepper, 236

-grass, 275, 278

Peppermint, 375, 377

Peptone, 491

Perching fern, 472

plant, 418, 439

Perennials, 454, 462

Peat-bog, 460

Perfect flower, 321

Perfumery, Mint, 378

Perianth, 197, 346

Persimmon tree, 360

Petunia, 367

Phacelia, 371

Philadelphia ground-cherry, 378

Phlox, 367, 369

Blue, 369, 370

Common, 370

Downy, 369, 370

Smooth, 369, 370

Phosphorescence, Bacterial, 104

Pickerel-weed, 222

Pieplant, Wild, 413

Pigeon river, 353

Pignut hickory, 243, 244

Pigweed, 259, 476

Winged, 259

Pilewort, 381

Pill-throwing mould, 44

Pimpernel, False, 379

Scarlet, 359

Pin-cherry, 293

Pine, 7, 9, 22, 24, 185, 186, 196, 465,

496, 502, 515, 516, 517, 52i, 524, 525

Comparison with yew, 194

cone, Arrangement of scales, 346

cone, Prototype of the

flower, 343

Flower, Pistillate, 186

Flower, Staminate, 186

forest, 6, 342, 472

Origin, 123

pollen grain parasites, 45

seed, 182

seed distribution, 20

Jack (Engr. 188), 186

Jack, Economic importance, 190
Norway, 188

Pitch, 187

Red, 186, 188, 472, 507

Red, Economic importance, 188
White (Half-tone, 7, 187,

189, 195), 186, 472, 507, 509

White, Economic importance, 186
White, Resin, 187

-drops, 350, 352, 438

-knot fungus" 54

-sap, 350, 353, 438, 490

-sap, Nutrition, 353

-sap, Resemblance to In-
dian-pipe, . 353
Pineapple, 223
Pink, 12, 259, 263, 468
-flowered wintergreen, 351
Grass, 231
Indian, 379
Pinweed, 326, 327
Pipe-vine, 256, 257, 418
-vine, Insect pollination, 257
Pipestone county, 330, 359, 468
Pipe wort, 221, 420, 448
Pipsissewa, 350, 352
Pitch pine, 187
Pitcher-plant (Engr. 278. Half-
tone, 461), 146, 278, 280, 459, 460

554

Minnesota Plant Life.

Pitcher-plant, Bacteria, 279
-plant, Nutrition, 278, 418
Plankton, 443
Planktonic flowering plants, 445
Plant, Adaptations against cold, 425
Adaptations, Defensive, 506
Adaptations against evapora-
tion, 437
Adaptations against illumi-
nation, 433
Adaptations, Influences af-
fecting, 480
Adaptations, Intra-specifk, 440
Adaptations against loss of

heat, 427

Adaptations to moisture, 434
Adaptations for reducing

transpiration, 455
Adaptations, Seed distribu-
tion, 440
Adaptations to surroundings, 417
Adaptational groups, 417, 442
Animal types of defense, 505
Architectural structure,

179, 418, 424, 505

armor, 506
Branch system, 422, 423

Climatic history, 427

Comparison with animals, 25

Dangers, exposed to,

diseases,

distribution,

Erect habit,

Food (See nutrition),

Effect of light on,

Growth, Hours of,

506

IOQ

5, 18, 21
130

488, 489
428
43i

Growth, Temperature limit, 424

individual, Maintenance

Lower seed,

Number in Minnesota,

Origin of flowering,

migrating, Struggles,

organs, Elasticity,

organs, Irritability,

organs, Polanty,

products,

Introduced,

Leaf-shedding habit,

Leafless habit,

in Minnesota, Number,

in the world, Number,

Parasites on land,

partnerships,

Peat-bog,

483

194, 517
27
174
24
42 r
500
501
491
ii
425

214, 457
26
26
46

89,93, H7
146

Plant populations in a state of
tension, IQ

Relation to other living

things, 438

Root system, 434, 435

Seed-producing, 184

Self defense, 505

species, Maintenance, 509

Stem, 8, 418

Starch-making of green, 429

Terrestrial, Aquatic, nature of, 196
Transpiration of water, 436

Two-leaved seedlings, 233

zones, 10

Air-, 472, 489

Aquatic, 417, 418, 422, 434, 442,

447, 450, 489

Aquatic, Reproduction, 451

Aquatic, Retraction of fruit, 452
Bar, 447

Bar, Distribution, 451

Bog, 436

Braced-, 179

Camphor, 326

Carnivorous,

278, 418, 438, 460, 481, 489
Carpet, 211

Cheese, 323

Climbing, 439

Indigo-, 280

Desert, 418, 428,

436, 442, 463, 481, 506
Desert, Leaves, 464

Desert, Odor, 437, 465

Evergreen, 428

Flowering, 490, 514, 518

Green, 488

Higher, 196, 490, 513, 523, 525

Higher, Comparison of

lichens with, 98

Higher, Difference between

higher animals and, 128

Higher, Fecundated egg, 128
Higher, Nutrition, 103, 118, 119
Higher, Origin, 129, 196

Higher, Origin of root, 157

Higher, Prostrate stems, 131

Humus, 479, 489

Lead-, 298, 301

Marsh, 418, 436

Mat, 211,418,429,434,470,480
Perching, 418

Rain-water, 446

Roadside, 10

Minnesota Plant Life.

555

Plant. Rock, 418, 446, 467, 468, 469
Rosette, 429, 433, 47O

Salt, ' 436,473

Sand, 469. 470

Sensitive, 280

Sensitive, Wild, 297

Shade, 219, 418

Shore, 447

Shore, Distribution, 451

Sun, 418

Surf, 214, 420

Swimming, 445

Switch, 214

Tea, 326

Twining, 439

Wand, 418, 472

Yeast, 73

Plantain, 375, 386, 468, 470, 473, 480
family, 4T5

Flower, 387

Resemblance to lizard's-tail, 237
Bracted, 387

Common, 387

Heart-leafed, 387

Indian, 412

Rattlesnake, 231

Rib, 387

Rugel's (Engr. 386), 387

Salt marsh, 387

Water-, 197, 201

Woolly, 387

Plates, 506

Plow-handles, Manufactured
from hickory, 244

Plum, 280, 292, 478

Black knot, 85

Canada, 293

Ground-. 298

-pocket, 74

Pocket-fungus, 74

Wild, 293

Pocket-fungus on cherry, 74

-fungus on plum, 74

-;ungus on poplar, 74

Pogonia (Half-tone, n), 228

Poison-ash, 310

-dogwood, 310, 506

-elder, 310,311,312

-hemlock, 338, 339

-ivy, 309,310,311,506

-ivy. Resemblance to wood-
bine, 31.1
-oak, 309, 310
-sumac, 310, 462

Poisoning, Antidotes for ivy or

elder, 311

Poisonous algae, 41

ergot-tuber, 82

fungi, Tamarack swamp, 59

leatherwood bark, 332

moccasin flower, 231

mushroom, 61, 82

orchid, 232

parsley roots, 339

pore-fungus, 82

shelf-fungus, 59

Poke milkweed, 366

Pokeweed (Engr. 260), 259, 261

Polemonium, 370

Polishing powder, Diatom, 39

Pollarded willow, 241

Pollen grain, Definition, 181, 184

grain, Parasites, 45

spores, 517

spores, Germination in sugar, 502

-tube, Definition, 182

Pollination, 345, 517

Cross-, 230,517

Insect, 348

Bladderwort, 384

Milkweed, 364

Mint, 377

Orchid, 229

Pipe-vine, 257

Polygala, 305, 307

family, 307

Polypody, 165, 468

Pomegranate, 332

Pomme de terre, 298, 300

Pond-lily, 13, 30, 266, 451

-lily, Common yellow, 266, 448

-lily, Small yellow, 266

-scum (Engr. 34. Half-tone,

35), 33, 4i, 443

-scum, Nutrition, 33

-scum,, Parasites, 45

-scum, Reproduction, 33

-scum, Starch-construction, 33

Pondweed (Half-tone, 199), 13, 38,
199, 273, 448, 450, 45i, 452, 453, 512
Resemblance to true milfoil, 336
Clasping-leaved (Engr.), 200

Pool-moss, 152

Poor man's weather-glass, 358, 359

Poplar (Half-tone, 195),

233, 237, 238, 425- 427, 470, 478
scrub, 477

Seed distribution, 20

556

Minnesota Plant Life.

Poplar vegetation (Half-tone), 237

Balsam-, 238, 239

large-toothed, 238

Lombardy, 238, 240

pocket-fungus, 74

Silver-leafed, 238

White, 238

Poppy, 275

-mallow, 323, 325

-mallow, Triangular-leafed, 324

Pore-fungus, 57

Edible, 58

Oak, 58

Poisonous, 82

Sulphur-colored, 58

Willow, 58

Portulaca, 259, 465

Posts, Manufactured from jack

pine, 190
Potato, 367, 431, 491, 511
-bug, 379
-bug plant, 379
disease, 46
Mildew, 46
-scab, 103, 109
Sweet, 227, 367
Prairie (Half-tone, 9), 471
Dominant plants, 7
and forest, Difference be-
tween, 8, 14
Minnesota, 6
Prairie-clover, 297, 301
Many-flowered, 300
Purple, 301
Silky, 301
Silver-leafed, 300
White, • 301
-dock, 409
evening primrose, Shrubby, 335
grass (Half-tone, 471), 437
mallow, 325
rose, 291
-turnip, 300
violet, 328
Preserves, Silver buffalo-berry, 333
Prickle, 506
Prickle-fungus, 56
Prickly ash, 305,307
gooseberry, 284
lettuce, 403
nightshade, 378
-pear, 319, 329, 465
-pear cactus, 23, 468

Prickly-pear cactus, Western, 330

Edible fruit, 330

Primrose, 357, 358, 426, 475

Evening-,

332, 334, 426, 429, 468, 470, 478

Evening-, Rootstock, 455

Evening-, Shrubby prairie, 335

Evening-, White, 335

Production of seed, 180

of eggs, 521

of spermatozoids, 519

of spores, 513

Propagation, 511

Origin of gemma-, 138

Propagative bodies of lichens, 94
branches of Umbrella-liver-
wort, 137
bulbils of bass-weed, 38

Prostrate stems, 131

Clover, 299

Proteids, 491

Protoplasm(Seelivingsubstance), 484

Movement, 498

Prussic acid, 292

Ptomaines, 107

Puccoon, 371, 372

Broad-leafed, 373

European, 373

Hoary, 372

Yellow, 373

Yellow, Closed flowers, 373

Puff-ball, 66, 67, 513
Ball-tossing, 70, 71

Giant, 69

Hard-skinned, 70

Slitted, 69

Stalked, 68

Truffle, 67

Tufted (Half-tone), 69

Warty (Half-tone), 68

Pulp, Manufactured from box-
elder, 317
Manufactured from cotton-
wood, 239

Pulse (Half-tone, 10), 471
family, 280, 295

Pulvinus, 503

Pumpkin, 394, 395

Fruit, 423

Purple, Bacteria, 116

bacteria, Nutrition, 116

bacterial, 116

cactus, 329

Minnesota Plant Life.

557

Purple-edged liverworts, 137

loosestrife, 334

milkweed, 365

prairie-clover, 301

Purslane,

24, 259, 262, 437, 465, 468, 474, 476

Rock, 474

Salt-loving, 473

Water-, 333

"Pussy" willow, 241

Putrifaction bacteria, 102, 109

Putty-root, 228, 232

Pyrola, Root-fungus, 89

Quarantine, 107

Quartz (See silica), 32

Quince, 280, 286, 290

Quillwort (Engr. 164),

163, 448, 449, 450, 518, 519, 520

Air chambers, 163

Leaves, 417

Quinine, 388

Radial symmetry of flowers, 228

Radish. 277

Rafflesia, 256

Ragweed (Engr. 405),

11, 399, 401, 405, 468

family, 402

Tall, 405

Ragwort, 401, 412

Railway construction, Red pine

used in, 188

Rain-water plants, 446

Rainy lake, 190, 194, 327, 469

river, 362

Raised peat-bog, 146

Raspberry, 280, 290

Seed distribution, 19

Arctic dwarfed, 291

Black, 291

Creeping, 291

Creeping, Resemblance to

violet, 291

Red, 291

Sour. 291

Rat Portage, Ontario, Poplar veg-
etation near (Half-tone), 237
Rattlebox, 267, 298
Rattlesnake plantain, 231
root (Engr. 404), 402, 404
Ravine vegetation (Half-tone), 447
Red algae, 29, 446, 513, 520
algae, Reproduction, 40
ash, 361

Red bacteria, 115

birch, 246, 247

cedar, 186, 192, 193, 472

cedar, Flower, 346

clover, 298

currant, 284

elm, 252

lake, 304

-leafed wintergreen, 351

lobelia, 397

maple, 313, 315

mulberry, 253

oak, 249, 250

osier, 341, 342

pine, 186, 188, 472, 507
pine, Economic importance, 188

raspberry, 291

river, 3
river valley, 7, 259, 260, 263.,

332, 333, 359, 376, 387, 473, 476

rust, 51

seaweed, 522, 523

snow, 36, 424

-stemmed gentian, 363

-veined dock, 258

-wood, Fossil, 26

Redbud, 280, 296

Redroot, 259, 319

American, 319

pigweed, 261

Red Wing, 267

Redwood Falls, 193, 33°

river, Derivation of name, 342

Reed (Half-tone), 18, 199

-grass, 13, 205, 206,

451, 457- 458, 459

-grass, Rootstock, 455

Marsh, 457

Reed, Bur- (Engr.), 198

Rein orchid, 228, 231

Reindeer-moss (Lichen),

96, 98, 141, 462, 469

-moss, Edible, 98
Relations of bacteria to man, 120

Reproduction, 488, 509, 512

Definition, 511

Black mould, 44

Fungus, 87

Liverwort, 127

Moss, 126, 127

Pond-scum, 33

Red algae, 40

Water-net, 36

Minnesota Plant Life.

Reproductive cell,

Resin,

White pine,

Retting bacteria,

Rhododendron,

Rhubarb,

Ribs, Canoe, Indian, Made from
white cedar, 190

-grass, 387

plantain, 387

Riccia, Floating, 443

Swimming, 443, 449

Rice, Wild (Half-tone, 204, 208.
Engr. 209), 205, 206, 207, 457

River birch, 246, 247

K«ttle, 355, 357

Minnesota (Half-tone, 235),
7, 23, 262, 327, 330, 359, 387, 468
Mississippi, 14, 323, 327,

341, 362, 389

Pigeon, 353

Rainy, 362

Red, 3, 7, 259, 260,
263, 332, 333, 359, 376, 387, 473, 476
Redwood, 342

St. Croix (Half-tone, 195), 56,

179, 327, 330, 334, 355, 356, 389
-moss, 145, 151, 448

-moss, Slime covering, 447

Riverside grape, 321

Riverweed (Engr. 281), 280, 281, 446
Pollination, 281

Slime covering, 447

Roadside plants, 10

vegetation (Half-tone, 10,

254, 477),
Rock algae,

cress,,

-succulent,

elm,

-lichen,

moss,

plant,

plant, Air chamber,

plant, Holdfast,

purslane,

-rose,

-vegetation (Half-tone,

189,466),
Rolling alga,
Root, Fleshy,

Higher plants, Origin,

Poisonous,

system,

513 Root-hernia, 27

187, 506 -parasites, 383

187 nodules, Clover, 117

1 1 1 Ginseng, 337

350 -cap, Floating-fern, 220

257, 504 -fungus, 80, 88, 481, 490

-fungus, Birch, 89

-fungus, Coral-root orchid, 89
-fungus, Dutchman's pipe, 89
-fungus, Oak, 89

-fungus, Orchid, 89

-fungus, Pyrola, 89

-fungus, Tamarack, 89

-tubercle, Bacteria, 119

Rootstock, 455, 458, 512

Rope, Manufactured from hemp. 253
Rose (Half-tone, 291),

280, 286, 291, 470, 478. 506
Flower axis, 345

Fruit, 292, 294

-mallow, 323, 325

-mallow, Halberd-leafed, 323, 325
Meadow, 291

-moss, 150

Pasture, 291

Prairie, 291

Rock-, 326, 468

Swamp, 291

Wild, Gall, 504

Rosemary, 350, 355, 457, 460

Resemblance to Kalmia, 354

Rosette plant, 429, 433, 470, 474

Rosinweed, 401, 408

Compass-plant (Engr.

411), 409,464

476 Rotala, 333, 334

467 Rough alum-root, 283

275, 278 -leafed dogwood, 341

468, 474 Round-leafed dogwood, 341

252 -leafed June-berry, 287

93, 96, 467 -leafed mallow, 323

467 -leafed orchid, 229

418, 467, 468, 469 -leafed violet, 328

446 -leafed wintergreen, 350

446 Royal fern, 165

262, 468, 474 Rue, 305

326, 468 family, 307

-anemone, 268, 269

189 -anemone, False, 268

443 Meadow-, 268

426 Meadow-, Early (Engr.), 272

157 Rugel's plantain, 387

339 Rules for eating mushrooms, 61

434, 435 Runner, 512

Minnesota Plant Life.

559

Rush (Half-tone, 199, 224),

224, 457, 458, 459, 460, 465, 470

Bog, 225

Wood, 225

Russian thistle, 260, 473, 474, 525

thistle, Seed distribution, 21

Rust, 48, 50

Apple, 50

Aster, 50

Bean, 50

Bellwort, 50

Black (Engr. 51), 51

Blackberry, 54

Flax, 50

Goldenrod, 50

Gooseberry, 54

Horsemint, 50

Juniper, 50

Labrador tea, 50

Pear, . 50

Pine, 50

Poplar, 50

Red (Engr. 51), 51

Spruce, 50

Sunflower, 50

Tamarack, 50

Thistle, 50

Violet, 50
Wheat (Engr. 51, 52, 53), 50

Willow, 50

Rye, 205, 422

Ergot, 81

Wild, 470

Sable island (Half-tone, 470), 253, 327

Sac-fungus, 72, 74, 80, 95, 513

Sage, 376
-brush (Half-tone, 408),

402, 437, 464, 465

Sago-palm, 195

Salt-succulent, 474, 481

marsh, 259

marsh plant, 436

marsh plantain, 387

Nitrogen, 103

plant, 473

vegetation, 473

Salvinia, 506, 515

Counterpoise area, 444, 445

Sand-dune (Half-tone, 470),

211, 327,437

plant, 469

rock (See silica), 32

vegetation, 469

Sand-bar willow, 241

-binding grass, 205, 211

Sand-bar-binding plant, 470

-bur, 205, 210, 480

-bur, Smut, 48

-cherry (See dwarfed cherry), 293

Sandalwood, 256

Sandstone lichen, 91

Sandwort, 263

"Sang," 336

Sanitation, 107

Sarsaparilla, Wild, 336, 337

Sash, Manufactured from white

pine, 186

Sassafras, 275

Savin (See juniper), 186

Saxifrage, 280, 283, 468

Golden, 283

Swamp, 283, 455, 459

Scale, 506

Pine cone, 346

-moss (Liverwort, 142), 125, 126

Scarlet gaura, 335

oak, 249, 250, 251

pimpernel, 359

Scheuchzeria, 457

Scientific interest of liverworts, 143

Scouring-rush, 175, 439, 457, 476, 516

-rush, Deposit of silica, 175

-rush, Male and female

plants, 178

-rush, Rootstock, 455

-rush, Minnesota species, 178

-rush spores, Germination, 177

-rush, Spores (Engr.) 177

-rush, Stems, 176

Screw-pine, 198

Scrub birch, 246

chestnut oak, 249, 251

Sea-blite, 436, 473

-milkwort, 358, 359

Seaweed, 442, 453

Edible, 41

Fossil, 26

Gigantic, 39

Slime covering, 447

Brown, 520, 522, 523, 525

Red, 522, 523

Second-stage, Liverwort, 125, 126, 128

-stage, Moss, 125, 128, 151

Sedge (Half-tone, 12, 18, 191, 224,

458), 12, 13, 204, 212, 456,

457, 458, 459, 460, 464, 465- 470
Air-chamber, 455

Characters, 216

Economic importance, 216

56°

Minnesota Plant Life.

Sedge, Flower (Engr.), 210

Manufacture of matting, 216

Position of, 349

Resemblance to grass, 212

Rootstock, 455

umbel, 213

Bulrush- (Engr.) 214

Carex- (Engr. 215), 215

Cyperus- (Engr. 211), 213

Smut, 48

Seed, Definition, 180, 184

distinguished trom spore, 183
Distribution, 18, 344, 416

habit, 344

Origin, 160, 440

How produced, 180

Structure, 420

-coat, Definition, 182

-plant, 184, 520, 522

-plant, Ancestors, 440

-plant, Breeding habits, 181

-plant, Higher, 197, 517

-plant, Lower, 194, 197, 517

-plant and primitive seedless

plants, Relation between, 195
Cocoanut, 420

Pine, 182

Water-lily, 182

wheat, Smut spores, 50

Yew, 185

Seedless plants, Relation be-
tween lower seed-plants and
primitive, 195

Seedlings, 233, 235

Tree, 507

Self defense of plants, 505

-preservation, Instinct of, 510

Seneca snakeroot, 307

snakeroot, Medicinal value, 307

Senecio, 412

Senna, 280, 296, 297

American, 297

Sensitive fern (Half-tone, 432), 166
pea, 297

plant, 280, 427, 507

plant, Wild, 297

Sequoia, 483

Serrate-leafed wintergreen, 351

Serum therapy, 108

Shad-bush, 287

Shade plant (Half-tone, 430,
431, 432, 441), 219, 418

Sheepberry, 390

viburnum, 391

Shelf-fungus, 57, 59

Shelf-fungus, Birch, 57, 58

fungus, Poisonous, 59

fungus, Toadstool-like, 59

Shell-bark hickory, 243, 244

Shepherd's-purse, 275, 278

purse, Mildew, 46

Sherburne county, 327

Shield-fern, 166

Water-, 459

Shingles, Manufactured from

white cedar, 190

Manufactured from white

pine, 186

Shinleaf, 351

Shoe-pegs, Manufactured from

birch, 247

Shooting-star, 358, 359

Shore plant, 447

plant, Distribution, 451

Shoreweed, 387

Showy milkweed, 366

Shrub, 428

Dwarf, 428

Mesophytic, 477

Shrubby heather, 469

prairie evening-primrose, 335

Silica, Deposited by algae, 32, 41

Deposited by diatoms, 40

Deposited by scouring-rush, 175

Silk, Corn, 207

Silky cornel, 34*

dogwood, 428

prairie-clover, 301

Silver buffalo-berry, 333

-leafed maple, 238

-leafed poplar, 238

-leafed prairie-clover, 300

Silverberry, 332, 333, 465

Sinter formed by algae, 31

Skin-fungus, 55

Skull-cap, 375, 376

Skunk-cabbage (Half-tone, 218),

197, 217, 218, 219

-cabbage, Warming-up color, 218

currant, 284

Slender nettle, 254

Slime-mould, 26, 27, 438, 485, 493, 499

-mould, foam patches, 28

-mould, Lime-encrusting, 28

-mould, Number in Minnesota, 27

-mould parasites, 27

• -mould, Plants or animals, 27

-mould, Roots of cabbage, 27

-mould, Roots of turnip, 27

Minnesota Plant Life.

Slime-mould spores, 28

Slippery elm, 252

Slitted puff-ball, 69

Small burdock, 413

cranberry, 356, 357

yellow pond-lily, 266

Smaller duckweed, 220

Smallpox bacteria, 106

Smartweed (Half-tone, 12),

257, 258, 456

dodder, 369

Water-, 258, 448

Smilax, 197, 226, 439, 503

Smooth honeysuckle, 392

-leafed dogwood, 428

phlox, 369, 3/0

yellow violet, 329

Smut, 48, 49

Sandbur, 48

Corn cockle, 48

Indian corn, 48

Millet grass, 48

Oat, 48

Peat-moss, 49

Sedge, 48

Wheat, 48

Wheat, Seed, 50

Snakeroot, 307

Distribution of fruit, 339

Black, 338

Button, 338

Seneca, 307

Seneca, Medicinal value, 307

Snapdragon, 367, 379, 381

Sneezeweed, 401

Snow-on-the-mountain, 308

plant, 442

vegetation, 453

Snowberry (Engr. 392),

350, 357, 388, 391, 39^, 460

Dwarf, 428

Low, 392

Soapwort, 263

gentian, 363

Soft maple (Half-tone, 452),

313, 314, 502

Soil, Relation of to plants, 437

Sorrel, 258, 475

True, 257

Wood-, 305

Wood-, Violet, 306

Wood-, White, 306

Wood-, Yellow, 306

Sour raspberry, 291

37

561

399, 402, 403

91, 223, 438, 472

217

210
509

379, 382, 475
5U, 520
520

Sow-thistle,

"Spanish moss,"

Spathe,

Spear-grass,

Species, definition of,

Speedwell,

Sperm,

Spermary,

Cone-headed liverwort, 136

Spermatozoids, 505, 512, 520

Directed toward eggs, 499

Distribution, 520

Production, 519

Bass-weed, 38

Fish-mould, 46

Moss, 126

Red algae, 40

Sphere-alga, 37

Sphere-alga, 37, 443, 520, 521

Spice, 236

-bush, 275

Spider-flower, 275

Spiderwort, 222

Spikelet, Grass, 204

Spikenard, 336, 337

Spindle tree, 312

Spine, 506

Spiraea, 280, 286, 459

Willow-leafed, 286

Spleenwort, 165

"Spontaneous combustion," 115

Spools, Manufactured from

birch, 247
Spore, 512, 513

distinguished from seed, 183
distribution, 344, 514
distribution, Carrion-fungus, 66

distribution, Earth-star, 69

distribution, Morel, 75

distribution, Moss, 153
Germination, 177, 518

-mother-cell, 513

Pollen, 517

production, 513

Beetle-fungus, 100

Black mould, 44

Club-moss. 159

Cup-fungus, 77

Fly-cholera fungus, 45

Liverwort, 135

Mushroom, Color, 65

Peat-moss, 49

Puff-ball, 68

Puff-ball, Ball-tossing. 71

Scouring-rush, 177

562

Minnesota Plant Life.

Spore, Slime-mould, 28

Smut, 49

Sphere-alga, 37

Yeast-plant, 73

Spore-producing leaves, Four-
leaved water-fern, 166
Sporeling, Care of, 519
Spotted-leafed geranium, 305
wintergreen (See Pipsisse-

wa, 350, 352

Spring-beauty (Engr. 262), 262, 465

flowers, 426, 479

Spruce (Half-tone, 7, n, 145), 7,

12, 24, 54, 192, 424, 436, 442, 457, 460

Branch, 422

Seed distribution, 20

swamp, 353, 472

woods, 352

Black, 186, 192

Muskeg, 186, 192

White, 186, 192

Spurge, 305, 307

family, 305, 418, 470,480, 506

Seed distribution, 20

Flowering, Resemblance

to dogbane, 308

Mat, 308

Spurred gentian, 363

Squash, 394

Fruit, 423

Squaw huckleberry, 356

-weed, 412

Squawroot, 385

Squirrel corn, 276

St. Croix river (Half-tone, 195), 327

St. Croix river valley,

56, 179, 330, 334, 355, 356, 389

St. John's-wort, 326

Marsh, 326

St. Louis county, 146

St. Paul, 221, 267, 323, 325

St. Vincent, 259

Staghorn-fungus, 86

Stalk-fungus, 95

Stalked puff-ball, 68

Stamens, 197

Definition, 181, 184

Staminate flower, Pine, 186

Star-cucumber, 394, 395

-grass, 227

Starch, 490

-making, Fungus, 48

-making, Green plants, 429

-making, Lichens, 99

Starch-making, Pond-scum, 33
Starflower, 358
Starwort, 448
Water-, 305, 308
State flower, 231
Stearns county, 341
Stem, 426
Annual rings, 197
Growth of, 432
-succulent, 474
Methods of developing, 8
Trailing, 512
Bulrush, 422
Higher seed plant, 234
Moss, 152
Water plant, 450
Xerophyte, 465
Stickseed, 371, 372
Stiff gentian, 362
water-buttercup, 272
yellow flax, 306
Stigma, 517
Definition, 181, 184
Stinging nettle, 254
Stinking smut of wheat, 48, 49
Stitchwort, 263
Stolon, 512
Stone-crop, 282
-crop, Ditch, 282
Stonewort, 38
Storage of food, 490
Strawberry, 280, 289, 419, 511
Flower axis, 345
Stream-side vegetation (Half-
tone), 227,448
Struggles of migrating plants, 24
Strychnine plant, 360
Submerged leaves, 449
Substances formed by bacteria, 103
harmful to bacteria, 104
Substratum, 480
Relation of plant to, 437
Succulent, 473
Origin, 474
Sucker, 512
Sucking organ, Dodder, 369
Sugar, 316
Manufactured from sugar-
maple, 314
-cane, 205
-maple, 313, 315
Sullivant's honeysuckle, 392
milkweed, 366
Sullivantia, 283

Minnesota Plant Life.

563

Sulphur, 102

bacteria, 102, 120, 453

-colored pore-fungus, 58

Sumac (Half-tone, 309), 309, 310, 475

underbrush, 477

Fragrant, 310

Poison- (Engr. 310), 310,462

Summer grape, 321

Sun plant (Half-tone, 429), 418

Sundew (Engr. 280), 279, 460

Nutrition, 280, 418

Sunflower (Half-tone, 9, 408),

9, 399, 401, 402, 416, 470, 471, 490

family, 394, 402

Flower, 394, 409

Head, 416

herbs, 409

Position, 413, 415

Relatives, 405

Seed distribution, 21

Sunflower dodder, 368

Surf plant, 214, 420

Surgery, Antiseptic, 114

Swamp plant. Air chamber, 455

plant, Leaflessness, 457

plant, Tissues, 455

underbrush, 462

vegetation, 453, 455

blackberry, 291

blueberry, 457

butterweed. 458

cypress. Knees, 438

-dock, 258, 458

hickory, 243, 244

-honeysuckle. 392, 393

loosestrife, 333, 334

Mangrove, 442, 473

milkweed. 365

rose, 291
-saxifrage (Half-tone, 456),

283, 455, 459

Spruce, 353, 472
Tamarack, 34. 145, 200,

213, 221, 222, 231, 279, 283,

318, 342, 357, 472

valerian, 393, 394

Sweet cicely, 338

cicely, Fruit distribution. 339
clover, 298

fern. 243, 460

-flag, 217, 219, 437. 457, 458

-flag, Rootstock, 455

pea, 295

-scented lily. 266

Sweet potato,

violet,

william, Wild,
Swimming plants,

liverwort,

Riccia,
Switch-plant,
Sycamore,
Tag-alder,
Tall bellflower,

bilberry,

blueberry,

lungwort,

milkweed,

ragweed,

227, 367
328

369, 370
445
133

443, 449
214

280, 285

246, 460
396
356
356
372
366
405

Tamarack (Half-tone, n, 145,
455), 12, 186

191, 3io, 352, 436, 442, 457, 460
swamp (Half-tone, 191), 34,

145, 20O, 213, 221, 222, 231,

279, 283, 318, 342, 357, 472

swamp, Poisonous fungi of, 59

cup-fungus, 78

lichens, 81

root-fungus, 89

Tamarind, 280

Tamarisk, 326

Tan-bark, 250

Tannin, 191, 506

Tanning, 191

bacteria, in

Tansy, 401, 411

Tassel, Corn, 207

Tapioca, 305

Tar spot, Maple leaf, 78

Taylor's Falls (Half-tone, 187,

195), 262, 330, 353

Tea, Labrador, 456, 460

plant, 326

Tear-thumb, 258, 439

Teazel family, 388

Fuller's-, 388

Telegraph plant, 500, 503

poles, Manufactured from

tamarack, 191
poles, Manutactured from

white pine, 186
Temperature limit of plant

growth, 424

Tendril, 503, 504

Tension, Continental, 14

Minor (Half-tone, 14), 14

Plant populations in a

state of, 10

564

Minnesota Plant Life.

Terrestrial plants, Aquatic

nature, 196

Thin-leafed bilberry, 356

Thistle, 11, 399, 401, 402, 413, 475, 476

Position of, 413, 415

Russian, 260, 473, 474, 525

Russian, Seed distribution, 21

Sow-, 402, 403

Thorn, 506

Thoroughwort (Half-tone, 406.

Engr. 407;, 401, 402,

406, 415, 462, 476

Three-cornered duckweed, 220, 444

-leaved ash, 307

-leaved elm, 307

-pronged duckweed, 133

Thunder Bay, Lake Superior, 322

Tick-trefoil (Engr. 303), 298, 302

-trefoil, Seed distribution, 19

Tickseed, 401, 410

Ties, Railway, Manufactured from

tamarack, 191

Railway, Manufactured from

white cedar, 190

Tiger-lily, 225, 226, 512

Timber, 250

Timothy, 205, 206

Tissues, 455, 496

Bast, 497

Cork, 497

Mechanical, 450

Milk, 497

Pith, 496

Reservoir, 496

Skeleton, 497, 504

Skin, 496

Strengthening, 504

Wood, 496

Toad-flax, 256, 379, 380, 438

-flax, Canada, 381

-flax, Common, 380

Toadstool, 61

Edible, 61

-blight, 80

-like shelf-fungus, 59

Tobacco, 367

-curing, Bacteria, in

family, 378

-root> 393, 394

Indian, 407

Wild, 379

Tomato, 367

hairs, 485

Ground-, 378

Tool handles. Manufactured

from elm, 253

handles, Manufactured from

sugar-maple, 316

handles, Manufactured from

white ash, 360

Touch-me-not (Engr. 317. Half-
tone, 447), 305, 309, 318, 462, 479
Seed distribution, 19

Town, Duluth, 189, 259,

262, 266, 284, 332, 354, 355, 357
Fergus Falls, 284

Grand Marais, 329

Grand Portage, 354

Grand Rapids, 145, 212

La Crosse, 267

Lucerne, 298

Mankato, 297, 325

Minneapolis, 221,243,267,323,325
New Ulm, 23, 262, 330, 332

Ortonville, 331

Pembina, 259

Rat Portage (Half-tone), 237
Red Wing, 267

Redwood Falls, 193, 330

St. Paul, 221, 267, 323, 325

St. Vincent, 259

Taylor's Falls (Half-tone,

187, 195), 262, 330, 353

Trailing arbutus, 350, 355

Travertine formed by algae, 31

Tree fern, 164

-like moss, 152

-top orchid, 428, 472, 481

-top-succulent, 474

Trees, 428

Alliance between ants and, 507

Bark, 234

Cambium, 234

and herbs, Comparison of, 234

Dominant forest plants, 7

Wood, 234

Christmas (See spruce), 192

Tress orchid, 228, 231

Trestles, Manufactured from

red pine, 188

Triangular-leafed poppy-mallow, 324

Trillium, 225, 479

Flower. 348

Leaves, 430

Tropical vegetation, 424, 428

True fern, 163

fungi, 43, 48

ginseng, 337

Minnesota Plant Life.

565

True loosestrife,

333

Valsa,

86

milfoil,

336

Vegetable, Diseases,

113

milfoil, Resemblance 10

Vegetation, Abyssal,

453

pondweed,

336

Aquatic,

450, 453

milkweed.

367

Arctic,

424, 428

moss,

149

Climatic formation,

481

mushroom,

62

Granitic region,

463

primrose,

35B

Halophytic,

473

Solomon's seal,

225, 226

Hot spring,

453

sorrel,

257

Hydrophytic,

462

Truffle,

72,78

Limestone region,

463

puff-ball,

67

Marsh,

451

Trumpet-creeper,

418

Mesophytic,

475

Tuber,

426, 512

Neighborhood,

481

-bearing lily,

266

Roadside,

476

Ergot,

82

Rosette,

474

Tufted loosestrife,

358

Salt,

473

Tulip, Flower,

348

Sand,

469

tree,

268

Snow,

453

tree, Fossil,

26

Substratum formation,

481

Tumbleweed, 259.

260, 471

Swamp,

453, 455

Tumbling grass, 205,

2O6, 211

Tropical,

424, 428

grass, Seed distribution,

21

Xerophytic,

442, 463

mustard, Seed distribution, 21

Velvetleaf,

323, 325

Tundra,

453

Venus' fly-trap, 278,

503, 505

Peat-,

459, 461

looking-glass,

396, 397

Turf-moss,

150

Veratrine, Alkaloid,

226

Turgor,

494

Verbena, 360, 367, 373, 468,

475, 480

Turnip,

2/7

family,

373

odor of milk,

113

Resemblance to borage,

374

Prairie,

300

Blue (Engr.;,

373

Slime-mould,

27

Blue, Wild,

374

Turpentine,

187

European,

374

Turtle-head,

379, 38i

Hoary,

374

Twig-fungus,

85

Narrow-leafed,

374

Twin-Cities,

323

Nettle-leafed,

374

Twinflower,

388, 391

Vetch, 7,

297, 304

Resemblance to partridge-

Bacterial nodules,

118

berry,

391

Loco-,

302

Twining fern,

164

Viburnum,

390

Typhus bacteria,

1 06

Sheepberry,

391

Umbel,

337

Vine (Half-tone, 254),

319

Parsley family,

338

Vinegar bacteria,

114

Sedge,

213

fermentation, Bacteria,

102

Umbrella-liverwort,

137, 512

Violet, 328,

426, 462

Umbrellawort,

261

Flower,

348

Underbrush (Half-tone),

478

Position,

349

Swamp,

462

Resemblance to creeping

rasp-

Urine, Bacteria,

119

berry,

291

Vaccination,

107

Arrow-leafed,

328

Valerian,

388, 393

Bird's-foot,

328

(drug),

393

Canada,

329

family,

388

Dog's-tooth,

225, 226

Greek,

369

Halberd-leafed.

329

Swamp,

393, 394

Kidney-leafed,

329

566

Minnesota Plant Life.

Violet, Labrador, 329

Lance-leafed, 329

Larkspur-leafed, 328

Long-spurred, 329

Marsh-, 328

Meadow, 328

Nuttall's, 329

Prairie, 328

Round-leafed, 328

Sweet, 328

Sweet white (Engr.), 328

wood-sorrel, 306

Yellow, Common, 329

Yellow, Smooth, 329

Virginia creeper (Half-tone,
322, 433), 319, 321, 336

ground-cherry, 378

lungwort, 372

waterleaf, 370

Volvox, 35

Wagon-tongues, Manufactured

from hickory, 244

Wahoo, 309, 312

Wakerobin, 225

Walking- fern,, 165, 512

Walnut, 243

Seed distribution, 20

Black, 243, 244

Wand plants,

303, 397, 404, 406, 418, 470, 472, 478
Warm water algae, 42

Warming-up color, 265, 425, 426, 432
color, Arum, 218

color, Peat-moss, 146

color, Skunk-cabbage, 218

Waste products., Bacteria, 103

Water current, 21

plants, Ripening of seeds, 272
plants, Zonal distribution, 12

-reservoir cells, Peat-moss, 145
Transpiration, 436

-beech, 246

bur-marigold, 449

-buttercup, 272, 448

-buttercup, Fruit, 272

-buttercup, Submerged leaves, 417
cress, 275, 278

crowfoot, Submerged leaves, 417
-dock, 258

eel-grass,, 449, 450

eel-grass, Holdfast, 447

-fennel, 308

-fern, 161, 444, 506,

515, 5i6, 519, 520

Water-fern, Four-leaved,

164, 1 66, 173, 448, 518
-fern, Four-leaved, Spore-pro-
ducing leaves, 166
-flower, 29, 30, 41, 443
-flower, Formation of gas

bubbles, 29

-hemlock, 338

-hemp, 259, 261

-hoarhound, 377

-horse-tail, 178

-hyacinth (See pickerel-weed), 222
-hyacinth, Counterpoise area, 444
-lily, 13, 264, 266, 273, 448, 449, 451
-lily family, 264

-lily, Leaves, 435

-lily, Seed, 267

-lily, Small white, 266

-lobelia, 396, 448, 449, 450

-lobelia. Leaves, 417

-marigold, 411

-milfoil, 332, 335, 448, 450, 452
-milfoil, Resemblance to blad-

derwort, 384

-mint, 377

-moss, 448

-net, 36

plant, 418, 447

plant, Annual, 450

plant, Attached, 446

plant, Leaves, 450

plant, Perennial, 450

plant, Propagation, 451

plant, Retraction of fruit. 452

plant, Stems, 450

-pocket, Liverwort, 142

-parsnip (Engr. 338), 338

-pimpernel, 358

-plantain, 197, 201

-purslane, 333

-shield (Engr. 264),

13, 264, 433, 449

-silk, 512, 520

-smartweed, 258,, 448

star-grass, 217, 222

-starwort, 305, 308, 450, 451

Waterleaf, 367, 370

Appendaged, 370

Virginia (Engr. 370), 370

Watermelon, 395

Waterweed, 203, 450, 451, 453

Wedge-leafed cherry, 293

Weeds (Half-tone, 479), n, 476

Loco-, 302

Minnesota Plant Life.

567

Weed, Pickerel-, 222
Western blite, 260 '
mountain-ash, 289
prickly-pear, Edible fruit, 330
sand-cherry, 293
Wet meadow, 459
Wheat, 22, 205, 209
Cow-, 379, 383
-rust, 50, 53
rust on barberry, 50
rust on borage, 50
rust on buckthorn, 50
Smut of, 48, 50
Smut, Stinking, 48
White ash, 360
cedar, 186, 190
clover, 298
Earth Reservation, 362
elm, 252
evening-primrose, 335
false indigo, 298
hickory, 243
moss, 149
oak, 249, 25 1
pine, 8, 186, 472, 507, 509
pine timber, Economic im-
portance, 186
poplar, 238
prairie-clover, 301
spruce, 186, 192
water-buttercup, 272
water-lily, Small, 266
wood-sorrel, 306
White Bear lake, 267
Whitewood, 268, 321
Whitlow-grass, 275, 278
"Whorled milkweed, 366
Wickerware, Manufactured from

willow, 241

Wild bean, 297, 304, 478

black currant, 284

blue flax, 306

blue verbena, 374

crab-apple, 286

cucumber, 394, 396, 439

elder, 336

elder, Resemblance to elder

bush, 337

ginger, 256, 257

grape, 320, 418, 479
grape. Resemblance to

moonseed, 320

lettuce, 402, 403, 476

licorice, 298, 302

Wild mandrake,
morning-glory,
onion,
parsley,
parsnip,
peanut,
pieplant,
plum,

274
467

225, 226
476

338,340

297, 304, 478

413

293

rice, 13, 205, 206, 207, 457

rice, Ergot, 8/

rice, Seed distribution, 19

rose, Gall, 504

sarsaparilla, 336, 337

sensitive-plant, 297

sweet william, 369, 370

tobacco, 379

rye, 470

water-fern, 444

Willow (Engr. 240. Half-tone,
14, 201, 421), 12, 22, 233, 237, 240,

425, 427, 428, 459, 462, 472, 511
Position of, 349

Gall, 504

bark, 242

Black (Half-tone, 241), 241

-blight, 80

Bog- (Half-tone), n

Bushed, 241

Dwarf, 428

Gray, 241

Heart-leafed, 241, 242

-herb, 7, 334, 459, 478

-herb, Flower, 347

-herb, Seed distribution, 20

Hoary, 241, 242

-leafed spiraea, 286

Long-leafed (Half-tone,

241), 241,242

Myrtle-leafed, 240, 241

Peach-leafed (Half-tone, 239), 241
Pollarded, 241

Pore-fungus, 58

Pussy, 241

Sand-bar, 241

Shining-leafed, 242

Wind currents, 20

Wine, Souring of, 114

Winged distribution, Com-
posites, 416
pigweed, 259
Winona county, 356, 393
Wintergreen (Engr. 351),

22, 342, 350, 355, 472, 479
bog, 351

568

Wintergreen, Green-flowered, 351

Leather-leafed, 437

Lesser, 351

Low serrated, 35 1

One-flowered, 35°

Pink-flowered, 35 1

Red-leafed, 351

Round-leafed, 35°

Serrate-leafed, 35 i

Spotted, 352

Witch-hazel, 274, 280, 284

-hazel extract, 285

Witch's-broom, 54. 361, 504

-broom, Alder, 74

-broom, Cherry, 74

Withe-rod, 321

Wright county, 327

Wolfberry, 3Q2

Wood of trees, 234

Wood-pulp, Manufactured from

basswood. 323
-pulp, Manufactured from

poplar, 238

-bellflower, 396

Wood-lily (Half-tone), 430

-nettle, 254, 255

-rush, 225

-sage, 375

-sorrel, 305, 503

-sorrel, Violet, 306

-sorrel, White, 306

-sorrel, Yellow, 306

Woodbine, 321, 432

Resemblance to poison-ivy, 311

Woodenware, Manufactured from

basswood, 323
Manufactured from box-
elder, 317
Manufactured from buck-
eye, 318
Manufactured from soft

maple, 315

Manufactured from white

pine, 1 86

Woodsia, 166

Minnesota Plant Life.

Woolly green milkweed, 367

plantain, 387

Worms, 20
Wormwood (Half-tone, 408;,

402,411,437,464,465

Xerophyte, 442, 463

Xerophytic moss, 472

plant, Stem, 465

Yam, 224, 227

Yarrow, 401,411

Yeast, 72, 73

Bread-making, 72

Brewing, 72

Cooked cabbage, 74

Fermentation of wine, 72

Milk-fermenting, 74

Hardening of cider, 72

Manufactured from hops, 253

Yellow birch, 246, 247

clover, 298

dock, . 258

-eyed grass, 221, 457

flax, Grooved, 306

flax, Stiff, 306

fumitory, 277

gentian, 363

honeysuckle, 392

moccasin, 231

pond-lily, Common, 448

puccoon, 377

-rattle, 379

-rattle, Parasitism, 383

violet, Common, 329

violet, Smooth, 329

wood-sorrel, 306

Yew (See ground-hemlock) 196

Compared with pine, 194

Resemblance to crowberry, 309

Seed, 185

Young, Care of the, 525

Zizia, 338

Zonal distribution of land plants, 10

distribution of water plants, 12

Zones, Plant, 10, 13

UNIVERSITY OF CALIFORNIA
BRANCH OF THE COLLEGE OF AGRICULTURE

THIS BOOK IS DUE ON THE LAST DATE
STAMPED BELOW

5m-8,'26

9136

QKL68

..iiirttyi 11 a.nf

G

M35

Minnesota

pltvnt life*

.

1

^^

xx

LIBRARY, BRAN

" AfiRirillTIIRF

9(36

CH OF THE COLLEGE Of