as 5 < m u 1 S 13 « u v» S -p -■d Q) C CO 03 0} 5:5 •H ■a PJ 03 O wU 03 (D >> ^ 0 ^ +2 O •H rH C o -P rH ^ •H eg fi c (73 ^-l » •H •H r-\ 15 0) C 1^ e •H 0} 0 cC 0 «H +3 ?H O C , • « >> O • >s r-j >^ ,~i ^ 0 o o P5 Q) ^H >S r-*^ o C l>s •rl ^ >H CO c ^ n:^ ■ f v1fe. W-^^ ^K- :l ;!|j ^ *•!;-■;■ .,. ■■' ' '■'' . '#«-*' Minnesota Trees and Shrubs An Illustrated Manual of the Native and Cultivated Woody Plants of the State FREDERIC E. CLEMENTS HEAD OF THE DEPARTMENT OF BOTANY AND STATE BOTANIST C. OTTO ROSENDAHL PROFESSOR OF BOTANY FREDERIC K. BUTTERS ASSISTANT PROFESSOR OF BOTANY Report of the Botanical Survey IX THE UNIVERSITY OF MINNESOTA MINNEAPOLIS, MINNESOTA 1912 PUBLISHED BY AUTHORITY OF THE REGENTS OF THE UNIVERSITY FOR THE PEOPLE OF MINNESOTA AUGUST 15. 1912 EDITION 3000 THE INDEX PRESS Preface The present book is the third of a series intended to render more familiar and usable the plants of the important or interesting groups found in the State. It is less technical than "Minnesota Algae", though more technical than "Minnesota Mushrooms", but it is hoped that the abundant illustrations will made the book as useful to the layman as to teachers and students of botany, to foresters and others. All of the native woody species known with certainty to occur within the State have been included, while a few hitherto reported have been 'Omitted owing to the lack of specimens or other authentic evidence 'of their occurrence. In the desire to make the book as helpful as possible, a few herbaceous species which resemble shrubs closely have also been included. It has naturally been impossible to take into :account all of the rare exotic trees and shrubs grown in the State. Some effort has been made to discover which of these occur in at least three places, and all such cultivated species have been described. The descriptions have been drawn largely, and in some groups wholly, from Minnesota material contained in the Herbarium of the University. In addition, fresh material has also been used in certain groups, particularly for the drawings. The latter have likewise been made chiefly from Minnesota specimens, though a few have neces- sarily been borrowed from Sargent's "Silva", Britton and Brown's "Illustrated Flora" and Bailey's "Cyclopaedia of Horticulture". The drawings have been made to scale and, except where indicated, they are natural size. A number of drawings were made by Professors Rosendahl and Butters, and a few by Miss Misz and Miss Jensen of the departmental staff. The majority of the drawings were made by advanced students in botany under the supervision of the respective authors. The half tones have been made from photographs taken by various members of the Botanical Survey from time to time. The Minnesota ranges of the species have been taken from the compre- hensive unpublished catalogue of the flora of the State, prepared several years ago by the botanical staff from many sources, Upham's ■"Catalogue", MacMillan's "Metaspermae", etc. The continental iv MINNESOTA TREES AND SHRUBS ranges have been, drawn chiefly from Sargent's "Silva" and "Alanual" for the trees, and from Britton and Brown's "Illustrated Flora" and Gray's "JMamial" for the shrubs. The information in regard to the properties and uses of the wood of the various species has been ob- tained almost wholly from Sargent's "Silva". The illustrations of leaf forms have been drawn from Gray's "Lessons in Botany," and the authors are under obligation to the publishers, the American Book Company, and to the holders of the copyright of the bopk for kind permission to use them. Questions of nomenclature, of synonyms and of English names have been largely determined by each writer for his own portion, though it is hoped that the results are fairly consistent. In a some- what popular manual, it has seemed chiefly important that the reader should be able to refer readily and certainly to the standard manuals and to Sargent's "Silva". The sequence of families followed in the text is that of the "Besseyan System", the Monocotyledons being placed after the other phyla, partly because of. their supposedly hter origin, as well as to avoid separating the Ranales from the other Dicotyledons. Of the descriptive text, Professor Rosendahl has writ- ten about half, comprising Ranales, Rosales, Celastrales, Sapindales, Umbellales, Rubiales and Asterales, with the exception of a few genera. Professor Butters litis written somewhat more than a fourth, comprising the Gymnosperms, the Heaths, and the genera, Rosa, Quercus, Lonicera and Diervilla. In addition, he has written the part of the introduction dealing with the distribution of the woody vegeta- tion, and has prepared the map showing the forest regions. The text deals with loo genera, represented by 274 species and about 25 varieties. All the genera are illustrated, with the e.xception of one not certainly known to occur in jMinnesota. Of the 274 species, 15 are not represented by figures. The total number of illustrations is 118, of which 103 are line drawings, and 15 half-tones. The botanical publications of the Geological and Natural History Survey constitute, with the present book, nine volumes, under the general heading, "Botanical Series''. Four of these volumes belong to the subseries, "^Minnesota Botanical Studies", the fourth volume of which is current. Botanical publication in the Survev was sus- pended from 1904 to 1908, and on resuming publication, it seemed wise to make the first number of the "Botanical Studies" part one of volume four. A'olume three thus contains but three parts, the title page and index to which are found in part two of volume four. In addition, a popular series, entitled "Minnesota Plant Studies" was PREFACE begun in 1908. A complete list of the publications of the Botanical Survey follows : I. REPORTS OF THE SURVEY. Minnesota jMetaspermae 1892 : Conway IMac^Iillan. INIinnesota Botanical Studies, volume i, parts 1-12, 1894-98. Minnesota Plant Life 1899: Conway MacAIillan. Minnesota Botanical Studies, volume 2, parts 1-6, 1898- 1902. Minnesota Plant Diseases 1905 : Edward M. Freeman. Minnesota Botanical Studies, volume 3, parts 1-3, 1903-04. Minnesota Botanical Studies, volume 4, parts i, 2, 1909- jMinnesota Algae 1910: Josephine Tilden. Minnesota Trees and Shrubs 1912: II. MINNESOTA PLANT STUDIES. 1. Guide to the Spring Flowers; F. E. Clements, C. O. Rosen- dahl, F. K. Butters. First edition, ^larch 1908; second edition, April, 1910. 2. Guide to the Trees and Shrubs : F. E. Clements, C. O. Rosendahl, F. K. Butters. First edition, October, 1908 ; second edition, September, 1910. 3. Guide to the Ferns and Fern Allies, July, 1909 : C. O. Rosendahl. F. K. Butters. 4. Minnesota Mushrooms, September, 1910: F. E. Clements. The Guide to Autumn Flowers has been printed in key form and used with classes for the past two years, but it has not been published for distribution. The above publications of the Survey are sent upon request to residents of Minnesota, and to the schools and colleges of the State. Thev are also sent free to working botanists and botanical de- partments and institutions upon the exchange list of the Survey. To all others, the publications are for sale at the following prices : Minnesota Plant Diseases (edition nearly exhausted), $2; Minne- sota Algae, $1 ; Minnesota Trees and Shrubs, $1 ; Guides to Spring Flowers, Trees and Shrubs, and Ferns, loc. each; Minnesota Mush- rooms, paper 50c., cloth $1. Minnesota ^letaspermae and the first three volumes of Minnesota Botanical Studies are sent for the cost of transportation to those who can use these technical works. The edition of Minnesota Plant Life is entirely out of print, but copies can still be obtained from the New York dealers in second hand books. Frederic E. Clements, Minnehaha-on-Ruxton, Head of the Department of Manitou, Colorado, Botany and State Botanist. July 31, 191 2. Contents Introduction — How to Use the Keys - - - - - - - ix The Names of Plants ------- xiv Pronunciation - ____--- xv A'erification and Determination of Specimens - - - xv Explanation of the Chart ------- xv Chart of Evolution and Relationship - - - _ xvii \'egetation Regions ------- xviii \'egetation Map -------- xx Key to the Genera - - - - - - - -ii Flower Key to the Families ------ i6 GyMNOSPERMS --------- ip Pine Order --------- ig Ginkgo Order --------- ^^ Angiosperms --------- 44 Buttercup Order --------44 Pink Order --------- 51 ]\Iallow Order --------- yo Geranium Order -------- go Heath Order --------- 84 Phlox Order --------- 106 Gentian Order --------- 107 Snapdragon Order - - - - - - - -116 Rose Order - - - - - - - - -118 Bittersweet Order -------- 194 ]\Iaple Order - - - - - - - - -215 Carrot Order --------- 270 ]\Iadder Order --------- 275 Aster Order --------- 297 Lily Order ---------- 298 Glossary ---------- ^03 Index ----------- ^509 Introduction HOW TO USE THE KEYS. Since all the genera, e. g., elm, oak, willow, pine, etc., and nearly all the species, e. g., red elm, cork elm, red oak, white oak, bur oak, etc., are illustrated, it will often be possible to find the name of a tiee or shrub by turning directly to the illustration. This is especially true when the plant is known to belong or thought to belong to a ]:articular family or genus. For the be'gmner, however, this method would usually prove long and tedious, as well as uncertain in its re- sults. Much the better method is to make use of the two keys found {jn pages ii and i6. The first key is based chiefly upon the leaves and twigs, and is for use from the time the leaves unfold until' they drop in the fall. The second key is based primarily upon the structure of the flower, and hence can be used only with flowering specimens. It is especially helpful in the spring for the large number of deciduous trees in which the flowers appear before the leaves, as well as for many woody plants in which the leaf characters are similar. While it is possible to determine the names of trees and shrubs in their winter condition, it is so difficult for anyone who does not already possess considerable knowledge of them, that such a key has been omitted. The best plan for the beginner to follow is to become acquainted with individual trees and shrubs during the summer, and then learn the habits and appearance of these same individuals during the winter. Both keys are made after the same plan, namely, of- making a choice for the most part between two alternatives. For example, if one wishes to find the name of the common upland oak by means of a leaf twig, he would turn to the "Key to the Genera" on page ii. Here the first choice must be made between "I. Leaves needle-like or scale-like", and "II. Leaves not needle-like or scale-like." The former are the leaves of pines, spruces and tamaracks, the latter of the broad- leaved woody plants, such as elms, oaks, willows, lilacs, etc. LInder "II", the oak clearly belongs in "i. Trees", and not in "2. Shrubs or vines" (page 13). Again, under "i", choice must be made between X INTRODUCTION "a. Leaves simple" (figs. I and II) and "b. Leaves compound" (fig. VI). After the former, the lobed leaf of the oak brings one to "(2). Leaves lobed" (page 15), and under this the choice goes to I. Outlines of Simple Leaves. 12 3 6 7 8 4 5 1. Rounded. 2. Cordate (heart-shaped). 3, 4. Reniform (kidney-shaped). 5. Peltate (shield- shaped). 6. Sagittate (arrow-shaped). 7. Auriculate (eared). 8. Hastate (halberd-shaped). "(b) Leaves alternate or fascicled". Lender the latter, the oak agrees with "y. Leaves neither fan-shaped nor fascicled", and then with "(y) Leaves more than two-ranked". After the latter, the choice falls upon "n. Leaves less lobed; bark not white", and then upon "(n) Leaf-margin entire". This brings one to the oak genus, O u e r c u s, which is described on page 257. Here the first step is to read care- II. Outlines and Bases of Simple Leaves. 123 4 5 6 789 10 1. Linear. 2. Lanceolate (lance-.=haped). 3. Oblong. 4. Elliptic. 5. Oval. 6. Ovate (egg-shaped). 7. Oblanceolate. 8. Spatulate (spatula-like). 9. Obovate (reversed ovate). 10. Cuneate (wedge-shaped). fully the description of the genus to make sure that one has reached the right place. The second step is to turn to the key to the species on page 258, and to find the species by making choice between "i" and "2", "a" and "b", etc. The bur oak with the deep rounded blunt lobes of the leaf falls under "2", and then under "a". Here the leaves, but especially the acorn cup, guide one to "(2) Quercus macro- HOW TO USE KEYS xi carp a". This determination is then checked by turning to pages 264 and 265, where the description and iUustration of the species are found. If the pine is taken for determination, the choice first falls upon "i. Leaves needle-like or scale-like". The pine with its needles in III. Leaf Edges. 12 3 4 5 6 1. Serrate (saw-toothed). 2. Dentate (tooth- ed). 3. Crenate (scalloped). 4. Undulate (wavy). 5. Sinuate (bayed). 6. Incised (jagged). groups of 2-5 then goes in "i. Leaves alternate or fascicled", and beneath this, not in "a", but in "b. Leaves or some of them fascicled". Under this, the few evergreen leaves in a fascicle lead one to "(2) Leaves persistent, 2-5 in each fascicle" . . . Pinus : pine". On page 30 is found the description of the pine genus, and below this the key to the various pines. The five needles of the white pine at once determine this to be Pinus S t r o b u s, while the pines with two needles in a fascicle may be sought in the general key on page 32, or in the key based upon leaf-sections, page 31. IV. Leaf Tips. 12 3 4 5 6 1. Acuminate. 2. Acute. 3. Obtuse, tuse. 6. Emarginate. 7. Obcordate. cronate. 4. Truncate. 5. Re- 8. Cuspidate. 9. Mu- Tn the case of flowering twigs, the method of finding the name is essentially similar. The lilac, for example, in the "Flower Key to the Families", falls under 'T. Petals present", the alternative choice, INTRODUCTION "II. Petals absent", being impossible. The next choice is "i. Flowers single or in clusters", not "2. Flowers in heads", as in the dandelion or the clover. The united petals lead one past ''a. Petals separate" to "b. Petals united", and then one goes successively to *'(i) Ovary superior", "(a) Flowers regular", and "x. Stamens 2". The family is consequently the olive family, O 1 e a c e a e, to be found on page V. LoBED Simple Leaves. Pinnately: 1. Lobed. 3. Cleft. 5. Parted. 7. Divided Palmately: 2. Lobed. 4. Cleft. 6. Parted. 8. Divided. 107. Here the family description should first be checked over, and then the genus of the lilac is sought in the "Key to the Genera". The choice between "i" and "2" falls readily upon the latter and beneath "2", first upon "a", and then upon "(i) Flowers purple . Syringa". After checking over the description of the latter upon page III, the common lilac is found to be Syringa vulgaris by means of the "Key to the Species". It is described on page 112 and figured on page 114. In the case of the cottonwood, the small flowers of the hanging catkins, which are of two kinds, reddish brown on one tree and green- ish on the cotton-bearing tree, are seen to lack both petals and sepals. Hence, under "11. Petals absent", the choice is "2. Sepals absent, or occasionally very minute". The next choice is "b. Leaves not scale-like or needle-like, deciduous", and after this, "(i) Leaves simple". Under this, the ovate leaves lead to "(b)" and the cottonv seeds to "(x) . . . Salicaceae", or willow^ family, page 53. Here HOW TO USE THE KEYS xiii the genus is found to be P o p u 1 u s. and the species, by means of the key on page 54. to be d e 1 1 o i d e s. The many differences of leaves and flowers make it impossible to describe plants or construct keys without the aid of scientific terms 1. Odd-pinnate. 2. Tendril-pinnate. 3. Even-pinnate. 4. Palmate or digitate VI. Compound Leaves. 5. Twice-pinnate xiv INTRODUCTION to give definiteness and accuracy. The beginner's greatest difficulty is to decide just how much of a quality, such as lobing, hairiness, etc., corresponds to a particular term. It is evident that practice alone can give readiness and certainty in finding the names of plants, but the constant use of the cuts, figures I-VI, and of the glossary, page 302, will greatly reduce the practice necessary. The first plants determined will inevitably take much time and patience, but the student who makes sure of his facts before deciding upon each step of the key will be rewarded by rapidly increasing facility in using the keys. The tend- ency to guess at points of structure or at the meaning of terms must be avoided at all times, if satisfactory results are to be secured. As a further precaution, both of the alternative choices at each step in the key must be considered, since one often throws light upon the other. Finally, much time, patience and eye-sight will be saved by the use of a good hand lens, magnifying 10-15 diameters and costing from one to three dollars. Such lenses can be obtained from the H. W. Wil- son Company, or the Minnesota Co-operative Store in Minneapolis, from the Spencer Lens Company, Bufifalo, or the Bausch & Lomb Company, Rochester, N. Y. THE NAMES OF PLANTS. The name of a plant consists as a rule of two parts or words, for example, Piniis Strohus, Ulmiis americana, Acer saccharum, etc. The first word indicates the genus, and is always capitalized. The second word indicates the species, or kind, and is rarely capitalized. The meaning of the terms genus (plural, genera) and species (plural, species) may be clearly illustrated by the pines and maples. The white pine, jack pine and Norway pine are different kinds, or species, of the genus of pines, Pin us, each one designated by a species name, Strobus, divaricata and resinosa, respectively. The hard maple, soft maple, red maple and the boxelder are different species of the maple genus, Acer; they are designated by the respective species names, saccharum, saccharinuni, rubrum and negundo. Genera which are relat- ed to each other are placed in the same family, for example, the pines, spruces, firs and larches in the pine family, Pinaceae, the roses, apples, plums, cherries, hawthorns, etc. in the rose family, Rosaceae. The end- mg, -aceae, which is always used to denote a family, is the feminine plural of the Latin suffix, -aceus, meaning like or related to. The family name, Rosaceae, is really an adjective agreeing with plantae, plants, and mcanmg "plants related to the rose." Related families are them- selves grouped into orders, which also bear a distinctive ending, e. g., PRONUNCIATION xv Pinalcs, Rosalcs. This ending is likewise in the feminine phiral, and the meaning of the name is "plant families related to the pine family," et'c. Orders are further arranged into larger groups, such as Mono- cotyledons, flowering plants with a single seed leaf, scattered bundles in the stem, parallel-veined leaves, and a flower plan of 3, and Di- cotyledons, with two seed leaves, ringed bundles, netted-veined leaves and a flower plan of 5 or 4. These two groups form the Angiospernis, with closed pistils and usually with sepals and petals, which are con- trasted with the Gyninospernis, with open pistils and no sepals or petals. PRONUNCIATION. The simplest and most usable pronunciation of the names of plants is probably that in which the consonants are pronounced as in English, and the vowels and diphthongs as in Latin. This makes possible a uniform and phonetic pronunciation of botanical names, such as is greatly to be desired. The sounds of the vowels may be in- dicated as follows : o as ah ; ^ as ay ; i as ee; 0 as oh ; u as 00 ; Greek 3; much like the German ii. The diphthongs are as follows : ae as aye; au as ow in how; oe as oy ; ei as ay; en as eoo; ni as ooee. VERIFICATION AND DETERMINATION OF SPECIMENS. The beginner will necessarily find occasional plants which he is luiable to name. Even the student of more experience will now and then find very puzzling forms. In such cases, it is necessary to refer the question to a good herbarium if one is accessible, or to the botanist. The department of botany will be glad to have fresh or dried plants sent to it for verification or determination at any time. This applies to mushrooms and other lower forms as well as to flowering plants. Fresh specimens can be sent readily through the mails by wrapping them in moist paper and placing them in a pasteboard box. The de- partment will also be glad to verify the dried specimens in the herbaria of high schools or of individual students. EXPLANATION OF THE CHART. The chart on page xvii is designed to show the general lines of descent of flowering plants from the ancestral ferns, and to indicate the relationships of the various orders. It is based primarily upon the development of the flower as a special organ for pollination and seed- production. In consequence, the trees and shrubs appear in it at various places, since the woody habit may develop in almost any order, quite irrespective of its flower structure. Some families consist wholly ^,■1 INTRODUCTION of woody plants, as in the beech, birch, ehii, pahn and willow families. Others, such as the rose and pea families, contain a large number of trees and shrubs, while many, such as grasses, orchids, mustards, pinks, primroses, etc., contain only an occasional woody genus or are entirely herbaceous. Families with the simplest flowers, that is, those with the flowers least changed from the fruiting organs of the ferns, are placed at the bottom of the chart. Such families are found in the gymnosperms and in the buttercup order. The flowers of the former are wind- pollinated, and lack both calyx and corolla. The flowers of most buttercups, on the other hand, are pollinated by insects, and possess both calyx and corolla, or a showy calyx. These are regarded as the primitive or earliest type of flower of the angiosperms. From the specialization of these, in response to insect and wind pollination, have been derived the orders and families of the three lines of evolution shown in the chart. In detail, the primitive flower shows a large number of separate stamens and separate pistils, the petals are alike and separate, and there is no union between any of the four parts, sepals, petals, stamens and pistils. In the increasing adaptation of a flower to its work of pollination and seed production, this primitive form has given rise to the higher or more specialized forms char- acteristic of the various orders of the chart. The chief steps by which this has been brought about are only four, namely, reduction in num- ber of parts, union, change in shape, and change in position of the corolla, or elevation, but these changes have not appeared in the same sequence in all three lines. Reduction in number to a flower plan of 3, 4 or 5 has been almost universal in the groups just above the butter- cups, though flowers occasionally occur witli number plans of 6, 7, 8 and even 9. In flower structure, the arrowheads are essentially buttercups with parts in threes, while the lilies are arrowheads with the stamens and pistils reduced in number, and the latter united to form a compound pistil. In the irises, the colored perianth of sepals and petals is upon or above the ovary, and in the orchids, the corolla is strikingly irregular, one petal usually taking the form of a lip or sack. In the roses, the buttercup type is modified by the gradual grow- ing together of the calyx and receptacle, and finally of the ovary also, with the result that the corolla and stamens are above the calyx and ovary. In the lower roses, the number of stamens and usually of pistils also, is large, and the pistils are separate. In the higher fam- ilies, the pistils are united into a compound pistil. In the madders and Carvopl vIl les /'■Pin ■^^,^^^ /Tanur ' Popla «ilk st Gutliferalfs •Teas' \ Salibu he \ Malvales •■MalloMs' Lindens ElriK Mulberries Cymnoiptmu CHART OP EVOLUTION AND RELATIONSHIP xviii INTRODUCTION honeysuckles, the petals have become united, and finally, in most of the asters, some or all of the flowers of the characteristic heads be- come irregular as to their petals. In the mustards, pinks and gerani- ums, the flower parts are regularly reduced to the number plan of 4 or 5, and the pistils are united. In the primroses, the petals become united, and in the snapdragons and mints, the corolla as a rule is highly irregular. Many trees and shrubs have the flowers typical of the family to which they belong. The locust and redbud are readily seen to be- long to the pea family, the apple, cherry and plum to the rose family, the bamboo to the grass family and the matrimony vine to the potato family. On the other hand, the flowers of the lilac and the ash seem wholly unlike, though they are placed in the same family. The maple and the boxelder appear to be very different, though they are usually put in the same genus, while the flowers of willows and cottonwoods seem to have nothing in common with the pinks and tamarisks from which they have descended. In a sense however, these striking differ- ences are superficial, and are due to the excessive reduction or com- plete loss of calyx and corolla in consequence of lack of use in wind pollination. The absence of a corolla renders many of our tree flowers inconspicuous, especially those that bloom before the leaves appear, and has led to the popular impression that many trees do not have flowers. Trees, like all flowering plants, produce flowers every year as a rule, and it is possible to determine their real relationships even when the flowers are reduced to stamens or pistils alone. The simple appearance of the flowers of many trees and shrubs has fre- quently led to their being regarded as the lowest of flowering plants. A comparison of the flowers of maples, elms, oaks, ashes, etc., with those of the pine, spruce and fir will readily prove that this is not the case, and that the majority of our tree flowers belong fairly high in the scale of evolution. VEGETATION REGIONS. From the standpoint of vegetation, Minnesota may be divided into three great regions, occupied originally by the evergreen forest, the deciduous forest, and the prairies, respectively. Each of these regions has its characteristic plants, while comparatively few of the tiees and shrubs of the state are equally at home in all three of them. The general outline of these regions is indicated in the map on page XX. The evergreen forest originally covered the northeastern one-third of the state, extending south to a line about half wav between Duluth VEGETATION REGIONS xix and Alinneapolis, and west nearly to the Red River valley. These evergreen forests are continuous with those of Ontario on the north- east, and with those of northern Wisconsin and upper Michigan on the east. The characteristic trees of this region .are the three native pines, white spruce and balsam fir in mature upland forests, black spruce, tamarack and white cedar in the swamps. Throughout this region deciduous trees are either minor or temporary factors in the vegetation. Thus although the hard maple, basswood, red oak and white elm occur throughout the regions they do not occupy such great areas as they hold farther south, and the abundant growth of aspen, balsam, poplars and birches which usually follows the destruction of the conifers by cutting or burning, is itself followed by evergreens, if not further disturbed. The shrubs as well as the trees of the evergreen forests are, many of them, characteristic. Here are found the white-flowered thimble- berry, the mountain maple, dwarf birches, alders, sweet-fern, several kinds of bush honeysuckle, high-bush cranberry, and, most character- istic of all, numerous heaths, such as trailing arbutus, wintergreen, dwarf Kalmia, the numerous blueberries and huckleberries. The deciduous forest occupied a strip extending across the state from southeast to northwest and forming an almost complete barrier between the evergreen forests and the prairies. Throughout this region the number of species of trees diminishes steadily from south- east to northwest. The most characteristic trees on heavy rich subsoil are hard maple, basswood, elm and red oak. The finest strip of hard- v.'ood timber in the state, known to the early settlers as the "Big Woods," consists very largely of these trees. Lying about fifteen miles west of Minneapolis, it originally extended about fifty miles east and west and nearly a hundred north and south. In the south- eastern corner of the state, the dominant trees are black oak, black walnut, and shellbark hickory in addition to those species which occur farther north. Throughout the southern half of the state, somewhat sour clay subsoils are apt to be covered with a nearly pure growth of white oak. On drier and less fertile subsoils are usually open for- ests of bur oak, scarlet oak and northern pin oak, which pass into mere thickets where the soil is very light and porous. Throughout this region of deciduous forest, there are almost none of the conifers which are so abundant in the northeastern part of the state. The tamarack alone occurs to any extent. It occupies many bogs and swamps as far south as the Minnesota river. These tamarack swamps are, as it were, little pieces of the northern forest MAI' OF AllXXKSOTA, SHOWING THE NATURAL DISTRI- BUTION OF FOREST AND PRAIRIE. ADAPTED FROM UPHAM'S FLORA OF MINNESOTA. VEGETATION REGIONS xxi existing in the midst of the entirely different flora of tlie deciduous forest. The most abundant shrubs of the deciduous forest are the dog- woods, especially Cornus paniculata, sumacs, thorn apples, black haw, Rosa blanda and in somewhat sterile soil, the common hazel. The prairies occupy the southwestern quarter of the state, ex- tending thence eastward almost to the Mississippi, and northward through the Red River valley into Manitoba. It is notable that the line between the prairies and the hardwood forests is much sharper north of the Minnesota river than south of that stream, a fact prob- ably due to the grouping of the numerous lakes in the former region and their scarcity in the latter. Throughout the prairie region of the state, trees occurred naturally only along river valleys and in groves about lakes. The commonest trees are the cottonwood, box-elder and white elm, though numerous others occur, especially in the south. The bur oak is the only oak which extends far into the prairie parts of the state, and there it is often scarcely more than a bush. The most characteristic shrubs of the prairie district are the Amorphas, roses, especially Rosa arkansana, hazel, and in the extreme western part of the state, the buffalo berry, Shepherdia argentea. Key to the Genera I. Leaves needle-like or scale-like 1. Leaves alternate or fascicled a. Leaves all alternate and scattered (1) Trees with fragrant leaves (a) Leaves square, inserted on prominent bases Plcca : spruce 25 (b) Leaves flat X. Leaves bright green, bract scales trifid, projecting Pseudotsuga; Douglas spruce 23 y. Leaves dark and glossy above, whitish be- low, bract scales rounded, included (x) Cones large (5-10 cm.)> erect, scales deciduous Abies: fir 20 (y) Cones small (1.2-3cm.), pendent, scales persistent Tsuga : hemlock 24 (2) Shrubs, leaves not fragrant (a) Leaves minute and scale-like, less than 2 mm. long Tamarix : tamarisk 52 (b) Leaves more than 2 mm. long, not scale-like X. Leaves turned in at the edge, blunt Empetrum : crowberry 105 y. Leaves flat, sharp-pointed 7'axtis : yew 41 b. Leaves or some of them fascicled (1) Leaves deciduous, many in each fascicle Larix: larch ' 28 (2) Leaves persistent, 2-5 in each fascicle Pinus: pine 30 2. Leaves opposite or in whorls of three a. Leaves in whorls of three, needle-like, jointed at base Juniperus : juniper 40 b. Leaves opposite, scale-like, appressed on mature branches (1) Twigs flattened; pairs of leaves of two kinds alternating Thuja: arbor vi/ae 35 (2) Twigs not flattened; leaves all alike on the same twigs Sabina: red cedar 38 IL Leaves not needle-like or scale-like \. Trees a. Leaves simple (1) Leaves not lobed (a) Leaves ovate or round, broad X. Leaves entire, mostly very large (x) Leaves opposite, mostly cordate at base Calalpa: caialpa 116 (y) Leaves alternate, rounded or narrowed at base Magnolia : magnolia 45 y. Leaves serrate to dentate (x) Twigs very tough ; fruit round, per- sistent, stalk winged Tilia : basszuood 70 (y) Twigs ibrittle; fruit disappearing in spring Populus : cottonwood 53 MINNESOTA TREES AND SHRUBS (b) Leaves somewhat oblong, much longer than broad X. Leaves opposite ]'ibunium : black Jiazv 280 y. Leaves both opposite and alternate, per- sistent in autumn Khaminis: buckthorn 197 z. Leaves alternate (x) Leaves two-ranked, or apparently so m. Sap milky; small trees Moms: mulberry _ 79 n. Sap not milky (m) Leaves with one distinct mid vein r. Bark smooth, except when very old, splotched Carpinus : hornbeam 243 s. Bark rough (r) Leaves very oblique at base; bark coarsely furrowed Ulmiis: elm 73 (s) Leaf base not oblique; bark finely furrowed Ostrya : ironwood 245 (n) Leaves with three large veins at base ; bark ridged Cellis : hackberry 77 (y) Leaves not two-ranked m. Bark with long conspicuous lenticels Bclula : birch 246 n. Bark without conspicuous lenticels (m) Leaves doubly serrate or toothed r. Stems and twigs more or less thorny Crataegus: haivthorn 154 s. Stems and twigs without thorns Malus: apple 159 (n) Leaf margin with a single row of teeth r. Buds small, scales overlapping, many; fruit fleshy Prunus: plum, cherry 163 s. Buds larger, covered by a single scale ; fruit dry Salix : willow 59 (2) Leaves lobed (a) Leaves opposite Acer: maple 219 (b) Leaves alternate or fascicled X. Leaves fan-shaped, many of them fascicled Ginkgo : maiden-hair tree 43 y. Leaves neither fan-shaped nor fascicled (x) Leaves two-ranked Morus: mulberry 79 (y) Leaves more than two-ranked m. Leaves deeply cut-lobed ; bark white (m) Leaves small, bark separating into papery layers Bclula : birch 246 (n) Leaves silvery beneath, bark not papery Popuhis : poplar 53 n. Leaves less lobed ; bark not white (m) Leaf margin toothed r. Stems and twigs thorny Crataegus: hawthorn 154 s. Stems and twigs not thorny Malus: apple 159 (n) Leaf margin entire Quercus: oak 257 Leaves compound (1) Leaves palmate (a) Leaflets 3 Ptelea: hoptree 82 (b) Leaflets many Aesculus: horse chestnut 216 (2) Leaves pinnate (a) Leaves even-pinnate x. Leaves twice-compound (x) Leaves 3-9 dm. long; leaflets ovate Gymnocladus: coffee tree 172 (y) Leaves 1-2^ dm. long; leaflets oblong Gleditsia: honey locust 173 y. Leaves once-compound Caragana: pea-tree 179 (b) Leaves odd-pinnate X. Leaves opposite (x) Leaflets entire or finely serrate Fraxinus: ash 107 KEY TO THE GENERA 13 (y) Leaflets lobed or doubly serrate Acer: boxelJer 219 y. Leaves alternate (x) Leaflets entire m. Leaflets elliptic, small; thorny Kobinia : locust 175 n. Leaflets ovate, large; thornless Ailaiitlms: trce-of-heaven 83 (y) Leaflets at least finely serrate m. Large tree; fruit a nut ' (m) Pith in plates; leaflets 11-23 Juglans: 7c>ahint, butternut 232 (n) Pith solid; leaflets 5-11 Cary<2 : hickory 238 n. Small trees ; fruit fleshy, bright red (m) Sap milky Rhus: sutnac 111 (n) Sap not milky Sorbus: mountuiii ash 147 2. Shrubs or vines a. Leaves evergreen and leathery (1) Creeping or prostrate shrubs (a) Leaves narrowly linear, thick, edges folded back Einpctrum : crowberry 105 (b) Leaves lanceolate to rounded, rarely linear X. Leaves less than 12 mm. long (x) Leaves much longer than wide Vacciiiitim: cranberry 97 (y) Leaves broadly ovate Chiogenes: suozvberry 95 y. Leaves regularly more than 12 mm. long (x) Leaves serrate, fragrant Gaulthcria : u-intergreen 93 (y) Leaves entire, not fragrant m. Leaves narrowed at base (m) Leaves scarcely 12 mm. long, pale and resinous below J^acciiiiu/n : niouiiiaiii cranberry 102 (n) Leaves 12-25 mm. long, green and veined below Arctosiaphylos: bearberry 94 n. Leaf base not narrowed; leaf broadly elliptic Eplgaca : trailing arbutus 90 (2) Erect shrubs (a) Leaves entire, with revolute margins X. Leaves woolly below Ledum : Labrador tea 87 y. Leaves smooth and white below (x) Leaves opposite or in threes Kalmia : swamp laurel 89 (y) Leaves alternate Andromeda: moorivort 92 (b) Leaves toothed X. Plant distinctly woody, leaves finely toothed Chamacdaphne : leatherleaf 91 y. Plant semiherbaceous, leaves coarsely toothed Chimaphila : pipsissewa 86 b. Leaves deciduous (1) Leaves simple (a) Leaves not lobed on mature twigs X. Leaves opposite or in whorls (x) Leaves entire m. Leaves silvery-scurfy Shephcrdia: buffalo berry 211 n. Leaves green (m) Stipules present, leaves often in threes Cephalanthus : button-bush 276 (n) Stipules absent, leaves in pairs r. Leaf-scars running together to form a ring (r) Stems hollow h. Low shrub, 0.3-1 m. high Symphoricarpus: ivolf-berry 284 i. Tall shrubs or vines, over 1 m. high Lonicera : honeysuckle 286 (s) Stems solid h. Flowers and fruit axillary, in pairs, leaves very short peti- oled Lonicera: honeysucJde 286 i. Flowers and fruit in terminal ,4 MINNESOTA TREES AND SHRUBS clusters, leaves mostly long- petioled Cornus: dogwood 270 s. Leaf-scars distinct (r) Leaf-scars very small and flat, petioles short Ligustrum: privet 115 (s) Leaf-scars round h. Leaves smooth, flower- and fruit-clusters terminal Syringa: lilac 111 i. Leaves hairy or pimply beneath, flower- and fruit-clusters lat- eral Chionanthtis: fringe-tree 115 (y) Leaves toothed m. Leaves mostly in whorls of three Hydrangea : hydrangea 183 n. Leaves in twos, strictly opposite (m) Buds hidden by the petiole Philadelphus : syringa 181 (n) Buds not hidden r. Leaves coarsely toothed Viburnum : viburnum 280 s. Leaves finely serrate (r) Bark ridged, roots white Euonymus: burning bush 195 (s) Shrubs .7-1.3 m. high; bark not ridged h. Leaf-scars running together to form a ring Diervilla : bush-honeysuckle 294 i. Leaf-scars round, distinct Forsythia 113 (t) Shrubs 2-5 m. high, petioles wide and glandular Viburnum : black haw 280 y. Leaves alternate or fascicled (x) Thorny shrubs with fascicled leaves Berberis: barberry 48 (y) Shrubs or vines with alternate leaves m. Leaves entire (m) Leaves silvery Elaeagnus: silverberry 209 (n) Leaves not silvery r. Thorny vines (r) Leaves oblong, pinnate veined Lycium : matrimony vine 106 (s) Leaves cordate, more or less parallel veined Smilax: smilax 300 s. Smooth shrubs (r) Tall shrub; leaves crowded at tips of twigs Cornus: dogivood 270 (s) Low shrubs h. Bark very tough Dirca: lealherwood 208 i. Bark not especially tough (h) Leaves resinous below Gaylussacia : huckleberry 95 (i) Leaves not resinous Vaccinium : huckleberry 97 n. Leaves toothed or serrate (m) Twining vine Celastrns: bittersweet 195 (n) Shrubs r. Leaves with three distinct veins Ceanothns: redroot 199 s. Leaves pinnately veined (r) Leaves unequal at base Hamamclis: witch hazel 193 (s) Leaf bases equal h. Shrubs with spines or thorns (h) Spiny shrubs, about 1 m., leaves smooth and glossy t\\ Ti,!!'°''^ 1, u . „ , Cydonia: Japanese qtiince 146 (i) Thorny shrubs, taller, leaves 154 (h) Leaves blunt to rounded at tip p. Leaves fragrant Myrica: sweet gale 268 cu ^"°^E^os^y Crataegus: hawthorn bhrubs without thorns KEY TO THE GENERA 15 q. Leaves not fragrant (p) Leaves crowded at the tips of twigs Mcnzicsia 89 (q) Leaves not crowded at the tips of twigs e. Cultivated shrubs Spiraea: spiraea 128 f. Native shrubs (e) Tall shrub, leaves over 5 cm. long Ahius: alder 254 (f) Low shrub, leaves less than S cm. v. Swamp shrub Betula: birch 246 w. Shrubs of dry ground Amelanchier : juneberry 150 (i) Leaves acute to long-point- ed at tip p. Leaves long-pointed (p) Leaves broadly ovate Corylus: hazel-nut 241 (q) Leaves lanceolate to linear Salix : willow 59 q. Leaves acute but not long- pointed (p) Fruit fleshy e. Fruit with a single stone -f''"'"'-f : /"'«<'«, cherry 163 f. Fruit several-seeded (e) Fruits solitary or 1-3 in a cluster v. Fruit red Ilex: ivinierberry 213 w. Fruit black, some leaves often op- posite Rhanunus : buckthorn 197 &• (f) Fruits several 6r many in a loose cluster V. Fruit ripening in mid-summer Amelanchier: jtmeberry 150 w. Fruit ripening in the fall Aronia: chokeberry 153 Fruit many-seeded Vacciniiim: huckleberry 97 (q) Fruit dry e. Fruits in catkins ; seeds cottony Salix : ivillotu 59 f. Fruits in branched clusters Spiraea: spiraea 128 (b) Leaves lobed X. Leaves opposite (x) Petioles usually with stipules and glands Viburnum : viburnum 280 (y) Petioles without stipules or glands m. Leaves sharply and deeply lobed Acer: maple 219 n. Leaves crenately lobed Symphoricarpus: snowberry 284 y. Leaves alternate (x) Leaf margin entire m. Vines with broad palmately veined leaves Menispermum : moonseed 50 n. Low aromatic shrub with linear leaves Comptonia : sweet fern 269 o. Low densely silky shrubs ; leaves with 3-9 linear lobes Artemisia : wormwood 297 (y) Leaf margin toothed m. High-climbing vines (m) Tendrils coiling, without disks Vitis: grape 202 (n) Tendrils attached by disks Parthenocissus: Boston try 203 ,6 MINNESOTA TREES AND SHRUBS n. "Shrubs (m) Bark many-layered, splitting into shreds Physocarpus : niuebark 127 (n) Bark firm r. Tall shrub with thorns Crataegus: lia'wihorn 154 s. Bushes, sometimes prickly (r) Leaves 1-2^ dm. broad Rubits: raspberry 121 .(s) Leaves 1-10 cm. broad h. Leaves broad, deeply lobed Ribes: currant, gooseberry 185 i. Leaves longer than broad, slightly lobed Spiraea : spiraea 128 (2) Leaves compound (a) Leaves pinnate X. Leaves opposite (x) Vines Clematis: clematis 46 (y) Shrubs Sambucus: elderberry 278 y. Leaves alternate (x) Leaf margin entire m. Leaves odd-i)innate (m) Tall spiny shrub with aromatic leaves Xaiithoxylum : prickly ash SO (n) Low bristly shrub; leaves not aro- niatic Robinia: rose acacia 175 (o) Neither spiny nor aroriiatic r. Leaflets over 5 cm. long Rhus: poison sumac 227 s Leaflets 5 cm. or less (r) Leaflets 5-7 Potentilla: potentilla 119 (s) Leaflets 11-49 Amorpha: amorpha 177 n. Leaves even-pinnate Caragana: pea tree 179 (y) Leaf margin toothed m. Leaflets 3-5 (m) Low small shrub or tall vine ; leaf- lets obscurely toothed or some- times lobed Rhus: poison ivy 227 (n) Spiny bushes; leaflets coarsely toothed Rubus: raspberry, blackberry 121 (o) Smooth shrubs; leaves finely serrate Staphvlea: bladder nut ' ^15 n. I^eaflets 5-many (m) Bushes or vines, usually prickly Rosa: rose 134 (n) Shrubs r. Sap milky j.j,^^^. ^,^,^,^^ s. Sap clear (r) Tall native shrub Sorbus: mountain ash 147 (s) Low cultivated shrub s^,.-/,,,.;, • ^./. / j j.- \\-, (b) Leaves palmate ^So,t>a,,a. ash-leaved sp.raea 132 X. Vines with tendrils p,,.,; r)„^.„„ J