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Full text of "The weed flora of Iowa"

iDtatt College of Agriculture 

3t Cornell Wlnibnsitp 

stbata, ja. B- 



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SB 612.l3PlTl913''""'"-'''™'^ 
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3 1924 002 892 002 




The original of tiiis book is in 
tine Cornell University Library. 

There are no known copyright restrictions in 
the United States on the use of the text. 



http://www.archive.org/details/cu31924002892002 



IOWA 



GEOLOGICAL SURVEY 



Bulletin No. 4 



THE WEED FLORA 

OF IOWA 



GEORGE F. KAY, State Geologist 
JAMES H. LEES, ASSISTANT State Geologist 




DBS MOINES: 

Published for Iowa Geological Survey 

1913 



DES MOINES 

ROBERT HENDERSON, STATE PRINTER 
JOHN M. JAMIESON, STATE BINDER 



GEOLOGICAL BOARD. 



His Excellency, George W. Clarke Governor of Iowa 

Hon. John L. Bleakly Auditor of State 

John G. Bowman President State University of Iowa 

Raymond A. Pearson President Iowa State College 

C. N. Kinney President Iowa Academy of Science 



ADMINISTRATIVE OFFICERS. 



George F. Kay State Geologist 

James H.- Lees Assistant State Geologist 

Nellie E. Newman Secretary 



LETTER OF TRANSMITTAL 

Iowa Geological Survey. 



To Governor George W. Clarke and Members of the Geological 
Board: 

Gentlemen : I submit, herewith, a bulletin on The Weed Flora 
of Iowa and recommend that it be published for distribution among: 
the people of the state. 

The thanks of the whole state are due Dr. L. H. Pammel of the 
lowia State College of Agriculture and Mechanic Arts for the 
preparation of a comprehensive and thorough report, represent- 
ing many years of careful and painstaking scientific work, on a 
subject that is most intimately related to agriculture, the industry 
that far exceeds in importance all other industries of our great 
state. 

The Survey wishes to express its thanks to Dean Curtis, Director 
of the Iowa Agricultural Experiment Station, for his co-operation, 
and for his kindness in permitting the Survey to include in the 
bulletin on weeds results of investigations which were carried for- 
ward by Doctor Pammel while connected with the Experiment 
Station. 

The Iowa Geological Survey had the honor, about ten years 
ago, to publish a complete monograph by Doctor Pammel on the 
Grasses of Iowa. This publication proved to be of great value, 
and it is with the fullest confidence that the bulletin on The Weed 
Flora of Iowa will be of equal if not of greater service to the 
agricultural and related interests of the state that it is now pre- 
sented for publication as Bulletin 4 of the Iowa Geological Survey. 

I have the honor to be, 

Yours very sincerely, 

George P. Kay, 
State Geologist. 



THE WEED FLORA OF IOWA 

By L. H. PAMMEL 

WITH THE COLLABORATION OF 

CHARLOTTE M. KING J. N. MARTIN J. C. CUNNINGHAM 

ADA HAYDEN and HARRIETTE S. KELLOGG 



TABLE OF CONTENTS 



CHAPTER I. 

Page 

Descriptive Manual 1 

CHAPTER II. 
The General Characters of Seeds 405 

CHAPTER III. 
The Microscopic Structure of Some Weed Seeds 503 

CHAPTER IV. 
Morphology of Flowers and Leaves 589 

CHAPTER V. 
Scattering of Weeds 627 

CHAPTER VI. 
Roots and Root-stocks of Weeds 641 

CHAPTER VII. ; 

Numher and Kinds of Weeds in Different Soils •. .655 

CHAPTER VIII. 
Injuriousness of Weeds 669 

CHAPTER IX. 
Weed Migration 685 

CHAPTER X. 
Medicinal Weeds 771 

CHAPTER XI. 
Phenology of Weeds 783 

CHAPTER XII. 
Weed and Seed Laws 791 

CHAPTER XIII. 

History and Bibliography 817 

Glossary 862 



PREFACE 



Weeds do an enormous damage to 'the crops of Iowa. A con- 
servative estimate places the injury at $25,000,000 annually. This 
loss could be largely avoided if we had more concise information 
on the subject, land if we could conserve the matchless resources 
of our soil by keeping the weeds down, the farmers would be greatly 
benefited in a financial way.' It would seem appropriate, therefore, 
to publish a volume of the Weed Flora of the state at this time. 

The need of a volume dealing with Iowa weeds as a feature of 
the flora of the state has long been felt by the public schools. 
Many papers have been published by the Iowa Agricultural Ex- 
periment Station, but these papers are mostly out of print. This 
work is much more comprehensive than anything heretofore pub- 
lished in this state. The title indicates that it is not a weed book, 
but rather a weed flora. Much stress has been laid on the geograph- 
ical distribution of weeds. It is a contribution to the local flora 
of the United States. 

The chapter on the geographical distribution of weeds will be 
found of special interest to the phytogeographer. I desire to ex- 
press my thanks to Dr. M. L. Fernald, Messrs. R. I. Cratty, F. W. 
Paige, 0. M. Olson, J. P. Anderson and Prof. B. Shimek for assist- 
ance in giving the geographical distribution of Iowa weeds. The 
chapter on the microscopic structure of weed seeds brings together 
in English much on the subject which has hitherto been inacces- 
sible to the student not familiar with German or French litera- 
ture. The chapter on morphology will greatly help the student to 
understand the changes occurring in the development of the flower 
and the formation of the &eed. The chapter on the use of weeds 
in medicine will be of interest to those who occasionally make use 
of wild plants for medicinal porposes. The chapter on seeds de- 
scribes la large number of weed seeds ; this will be found of value 
to thos'e engaged in a study of seeds. 

The chapter on various weed laws gives a summary of laws 
in various states in the Mississippi Valley. In compiling these 



xii PREFACE 

laws I have been aided by Mr. Small of the Iowa State Library, 
Mr. Moore of Wisconsin, Mr. Michel of South Dakota, Dr. Howard 
of Missouri and H. L. Bolley of North Dakota. 

In the preparation of this Weed Flora, I have been greatly 
assisted by Professor J. N. Martin, who has written the chapter 
on morphology of the plant ; Miss Ada Hayden, who has written 
the chapter on dissemination ; Professor J. C. Cunningham, who 
has written the chapter on. roots and underground organs; Miss 
Charlotte M. King, who is the joint author of the chapters on gross 
characters and microscopic structure of seeds. Miss King is also 
responsible for many of the excellent drawings. The chapter on 
medicinal weeds was prepared by Miss Kellogg. I am greatly in- 
debted to her for painstaking editorial- work and for preparing the 
bibliography and the index. In the matter of bibliography, it has 
seemed best to divide the subject into various sections so that the 
student may easily find the desired literature. The bibliography 
is not complete but enough papers are given to enable the student 
to find the important literature. I am indebted to Dr. Clark, of 
the Canadian Seed L/aboratory, for the privilege of using some 
of the admirable illustrations of the Canadian work on weeds, 
also to Dr. Ernest Bessey for illustrations from Beal's Weeds 
of Michigan, and the classical Hillman seed figures in the -Michi- 
gan bulletin, and to the Nevada Station for the use of the Hill- 
man cuts. Some of the Hillman and a few other figures have 
been taken from the government publications. I am also indebted 
to various publishers for figures which have been taken from sev- 
eral textbooks of botany, as the Bergen & Davis book published by 
Ginn & Co.; several botanical works like Thome's published in 
German, and to the Connecticut Experiment Station. A few fig- 
ures have been taken from the Botanioal Gsizette. Credit is given 
under each figure. The photographs were made by P. E. Colbum, 
photographer at the Iowa Agricultural Experiment Station, G. T. 
Hart and C. R. Quiade. The clerical work of the volume was per- 
formed by iliss Bertha Herr and my daughter, Miss Harriet. 
Mr. Burlingmair assisted in a study of weeds in different fields. 
To Mr. James H. Lees for his assistance in proof reading and edi- 
torial work I am also indebted. To all I wish to express my sincere 
thanks. 

The reader will find it advisable to have several of the recent 
treatises on weeds. Mention may be made of my work "Weeds of 
the Farm and Garden," a general treatise of three hundred pages 



PREFACE xiii 

with numerous illustrations; the work of Fletcher and Clark of 
Canada; Bolley's "North Dakota Weeds;" Blatehley's "Indiana 
Weed Book;" W. J. Beal's "The Weeds of Michigan." A list of 
these publications and where they may be obtained will be found 
in the bibliography. 

Ames, Iowa, December 18, 1912. 

L. H. PAMMEL. 



Page 754 Eosenberg, 1882 should be 1782. 

Page 837 Patrick, P. E., should be Patrick, G. E. 

Page 838 BlankensMp should be Blankinship. 

Page 842 L. T. Henderson should be L. F. Henderson. 



Page 858 Panton, J. H. Weeds of Ontario should be listed on 
page 845. 



Page 861 T. L. Williams should be T. A. Williams. 



CHAPTER I. 

DESCRIPTIVE MANUAL 

L. H. PAMMEL 



CHAPTER I. 



KEY FOR FAMILIES. 

I. Plants without true flowers; not producing seeds. . .PteridopJiyta. 
Stems jointed, rushlike Eguisetaceae. 

I. Plants with true flowers, stamens, and pistils and producing seeds. 

SpermatopJiyta. 

II. Ovules not borne in a closed ovary (Pine, Spruce) 

Oymnospermae. 

II. Ovules borne in a closed ovary (Rose, Willow, Corn, etc.) 

Angiospermae. 

III. Stems endogenous without central pith; no annual rings; 
parts of the flower usually In threes ; single cotyledon. . . 

Monoeotyledoneae. 
1. Grasslike plants 2. 

2. Flowers enclosed by chaff-like scales. 

Stems hollow; sheaths of leaves split.. .Qramineae. 

Stems solid; sheaths of leaves not split. Cyperaceae. 

2. Flowers not inclosed by chaff-like scales. .Juncaceae. 

1. Plants not grasslike; flowers with a perianth of 6 

pieces ; stamens 6 Liliaceae. 

III. Stem formed of bark, wood, and pith, exogenous; leaves 

netted- veined; embryo with a pair of cotyledons 

Dicotyledoneae. 
1. Corolla absent 

2. Plants fleshy or scurfy Chenopodiaceae. 

2. Plants not fleshy or scurfy 3. 
3. Ovary free 4. 

4. Flowers unisexual. 

Ovary 1-celled Urticaceae. 

Ovary 3-celled Euphor'biaceae. 

4. Flowers perfect. 

Calyx and bracts greenish and scarious 

Amarantliaceae. 
Calyx generally coroUa-llke. 

1. Fruit a 1-seeded achene Polygonaceae. 

1. Fruit a 5-12 seeded berry. . .Phytolaccaceae. 

3. Ovary inferior Nyctaginaceae. 

1. Calyx and corolla present. 
2. Corolla of separate petals 3. 

3. Plants fleshy, flowers yellow Portulacaceae. 



WEED FLORA OP IOWA 

3. Plants not fleshy 4. 
4. Pistil single 5. 
5. Flowers regular. 

Stamens numerous, tree.. .Ranunculaeeae. 
Stamens numerous; sepals and petals pres- 
ent, inserted on calyx Rosaceae. 

Stamens 10; fruit a legume. . .Leguniinosae. 
4. Pistil compound 6. 
6. Ovary free. 

Ovary 1-celled Caryophyllaceae. 

Ovary more than 1-celIed 7. 
7. Ovaries united into a ling. . .Malvaceae. 
7. Ovaries not united into a ring 8. 
8. Leaves simple. 

With punctate dots; stamens numer- 
ous Hypericaceae. 

Leaves not with punctate dots; sta- 
mens 6 Criuoiferae. 

Leaves compound, pinnately 3-foliate. 
Anacwrdiaoeae. 

Leaflets 3, obcordate Oxalidaceae. 

Leaflets 5-7 pairs Zygophyllaceae. 

Leaflets 3, viscid or fetid herbs 

Capparidaceae. 

6. Ovary adherent; flowers in umbels 

Vmbelliferae. 

6. Flowers not in umbels Onagraceae. 

1. Calyx and corolla present, petals more or less united. 
2. Flowers regular 3. 

3. Plants with milky juice. 

Stamens united Asclepiadaceae. 

Stamens distinct Apocynaceae. 

3. Plants without milky juice. 

4. Plants twining Convolvulaceae. 

4. Plants not twining 5. 
5. Stamens 5 or more 6. 

6. Style 2-cleft; flowers not in heads; fruit 

2-4 seedlike nutlets Boraginaceae. 

Fruit many seeded pod. . .Hydrophyllaceae. 
Flowers in heads; anthers in ring or 

tube about the style Compositae. 

6. Style 1; fruit many seeded Solanaceae. 

5. Stamens fewer than corolla lobes 

Caulescent, flowers blue Verienaceae 

Acaulescent, flowers greenish. Plantaginaceae 
2 Flowers irregular. 

Stems 4-angled; ovary deeply 4-lobed Lahiatae. 

Stems not 4-angled; ovary 2-celleCi. .Scrophulariaceae. 



DESCRIPTIVE MANUAL 



PTERIDOPHYTA, FERNS AND THEIR ALLIES. 

This group of plants, sometimes called vascular cryptogams, is 
represented in our flora by the maidenhair fern, brake, spleenwort, 
shield fern, etc. The Boston fern is frequently cultivated. 




Fig. 1. Common Horsetail (Equisetum arvense). Roadsides, fields, common 

everywhere in Iowa. 
(Photographed by Colbum.) 




Fig. 1-A. Distribution of Common Horsetail. 



G WEED FLORA OF IOWA 

EQUISETACEAE, HORSETAIL FAMILY. 
This small family of rushlike plants contains a few species only 
and but one that is weedy. 

Common Horsetail {Equisetum arvense L.). 

Description. — ^A rushlike perennial with running rootstocks and 
annual stems; branches in whorls; fertile and sterile plants, the 
fertile appearing early in spring with a terminal cone, yellowish 
in color, bearing the spore cases (sporangia) underneath a scale; 
spores provided with hygroscopic bands; sterile frond with 
whorled branches. 

Distribution. — Widely distributed in North America, common in 
sandy moist fields, on railroad embankments; common in Story, 
Boone, Carroll, Crawford, Harrison, Woodbury, Clinton, Dubuque, 
Lee, Page, Polk, Cerro Gordo, Emmet, Webster, Marshall, Johnson, 
Winneshiek and Allamakee counties 

Extermination. — This is a most persistent perennial ; only by giv- 
ing frequent shallow cultivation after small grain is removed 
during the summer can the weed be kept in check. 

SPERMATOPHYTA, FLOWERING PLANTS. 

The seed plants have stamens and pistils and reproduce by seeds. 
Kepresented by the pine, spruce, hemlock, wheat, rye, corn, rose, 
maple, ash, aster, goldenrod, squash, etc. 

GYMJVOSPEBMAE, GYMNOSPERMS. 

The seeds are not inclosed in an ovary. Trees or shrubs gener- 
ally with needlelike or scalelike leaves; represented in Iowa by 
the red cedar, white pine, etc. None are weedy. 

ANGIOSPERMAB, ANGIOSPERMS. 

Ovules borne in a closed ovary. Eepresented by a large number 
of our native and cultivated plants, like wheat, corn, lily, rose, 
clover, tomato, etc. 

MONOCOTYLEDONEAE, MONOCOTS. 

Plants with endogenous stem, the woody fibers in bundles dis- 
tributed through the pith. Annual ring absent. Flowers gen- 
erally on the plan of 3; embryo with a single cotyledon. Corn, 
lily, onion, asparagus, blue grass, switch grass are representatives. 



DESCRIPTIVE MANUAL 



GRAMINEAE, GRASS FAMILY. 
This large family is of great economic importance, since it con- 
tains many of our food plants, including the well known cereals, 




Fig. 2. Johnson Grass (Sorghum halepense) ; a, sessile splkelets. A most trou- 

blesoume weed. 
(Lamson-Scribner, U. S. Dept. Agr.) 




Fig. 2-A. Distribution of Johnson Grass. Reported recently from southwestern 

Iowa. 



8 WEED FLORA OF IOWA 

rye, wheat, oats, barley, corn, baffir com and millet, besides such 
forage grasses as blue grass, timothy, brome grass, foxtail, and a 
few ornamental plants, like pampas grass, ribbon grass, etc. 

Johnson Grass (Sorghum halepense (L.) Pers.). 

Description. — ^A stout perennial, with smooth, erect, simple 
culms, 3-5 feet high, and strong, creeping root-stocks; leaves 
elongated, i/4-%in. wide, acute; ligule ciliate, and on the back 
where leaf -blade joins the sheath there is more or less pubescence ; 
panicle open, 6-12 in. long, the whorled branches naked below, the 
3-5-flowered racemes clustered towards their extremities; pedicels 
of the staminate (rarely neutral) spikelets pilose with stout hairs; 
sessile spikelet broadly lanceolate, acute, 2-3 lines long, pale green 
or violet, becoming dark or nearly black at maturity ; callus small, 
obtuse, shortly and sparsely barbate; first glume coriaceous, spar- 
ingly pubescent on the flattened back, 5-7-nerved; second glume 
similar and equaling the first, convex below, subcarinate above, 
acute, the hyaline inflexed margins ciliate; third glume a little 
shorter than the outer ones, membranous, faintly 2-nerved, the in- 
folded margins ciliate ; fourth -glume broadly oval, obtuse, nearly 
% shorter than the second, 2-lobed or bidentate at the apex, ciliate 
awned; awn 5-8 lines long; palea a little shorter than the glumes, 
nerveless, ciliate. Introduced and cultivated in many southern 
states for hay; in many places it has become a dangerous weed, 
difficult to exterminate. 

Distribution. — The weed is common in the south, often a most 
troublesome weed. It has been reported as persisting in the 
vicinity of Hamburg, Fremont county. 

Extermination. — ^Use the same methods as for quack grass. This 
may become a most troublesome weed. 

Finger Grass (Digitaria sanguinalis (L.) Scop.). 

Description.— A much branched, leafy annual, 1-3 ft. high, 
spreading on the ground, with erect, smooth, spreading culms, fre- 
quently rooting at the lower joints, joints sometimes smooth, though 
more frequently bearded with deflexed hairs ; sheaths loose, gener- 
ally pilose, hairy, ciliate on the margins, with a membranaceous 
ligule; leaves 2-4 in. long with rough margins, occasionally pilose 
at the base; flowers produced in digitate spikes, hence the common 
name finger grass ; spikelets less than i/g in. long in pairs, 1 nearly 
sessile, the other with a stalk, each flower consisting of 2 sterile 



DESCRIPTIVE MANUAL 




Fig. 3. Common Crab Grass CDigitaria sanguinalis) . Common in fields, gar- 
dens, meadows. Rooting at the joints. 
(Photographed by Colburn.) 




Fig. 3-A. Distribution of Common Crab Grass. 



glumes and the flower proper; the first glume very small, the sec- 
ong about %-% as long as the spikelet, usually hairy on the mar- 
gin, the third glume somewhat longer than the fourth, which is 5- 



10 



WEED FLORA OP IOWA 



nerved and usuaUy silky-viUous along the marginal nerves, fourth 
glume smooth and acute; fruit minute, pitted and cross-striated, 
light straw color except where the sterile glumes remain attached, 
which are gray in color and minutely hairy. 

Distribution.— This European grass is cosmopolitan; abundant in 
the eastern and southern states and in California; common in all 
parts of Iowa, more particularly in gardens, com fields, and streets. 

Extermination.— This grass is much more difficult to remove than 
the foxtails because it roots so readily at the joints. Thorough 
cultivation will remove the weed. Do not allow it to go to seed. 

Chemical Composition.— Common crab grass XDigitaria sanguin- 
alis) has been used as a forage plant in many parts of the United 
States and many chemical analyses have been made. Analyses are 
reported from Mississippi, Tennessee and Iowa. The Iowa analysis 
reported by Weems is as follows : 







NATURAL 


CONDITION 






Sample 


Water 


Fat 


Protein 


AlbB- 
minoids 


Crude 
Fiber 


Ash 


Nitrogen 
Iree 

extract 


1 


66.95 


1.11 


2.52 


(1.86) 


8.62 


4.10 


16.70 







WATER FREE SUBSTANCE 



S.Si 



7.61 



(5.981 



26.11 



12.11 



50.53 



Smooth Crab Grass {Digitaria humifusa Pers.). 

Description. — An annual 6 in.-2 ft. high, closely resembling D. 
sanguvnalis in habit, but smooth throughout, excepting for a few 
hairs at the throat of the sheaths; spikelets 2-7, smaller than in 
D. sanguinalis, about 1 line in length; first glume very minute or 
obsolete; second and third glumes nearly equal in length, or the 
second a little shorter than the fourth, pubescent at the back. 

Distrilution.— Smooth crab grass is native to Europe but is 
now cosmopolitan; in eastern North America from New England 
to Texas and Mexico, Eocky mountains and Pacific coast ; less com- 
mon in Iowa than common crab grass; rapidly spreading in the 
state, more particularly in gardens; common in lawns and pas- 
tures. 




Figure 4 



Figure 4A. 



. Fig. 4. Crab Grass (.Digitaria aanguinalis). Common in cultivated fields. 
Fig. 4-A. Smooth. Crab Grass (.Digitaria humifusa) ; a, leaf with sheath ; 6j 
spikelet ; c, d, scales, stamens and pistils. Common in gardens and lawns. 
(Drawn by C. M. King.) 



12 



WEED FLORA OF IOWA 




Fig. 4-B. Distribution of Smooth Crab Grass. 

Extermination. — This weed is somewhat more difficult to exter- 
minate than the foxtail, especially in lawns where it is common. 
Here it produces seed so close to the ground that the lawn mower 
will not oatch this part of the plant. It may, however, be easily 
destroyed in fields which are cultivated. Stir the soil with a cul- 
tivator or hoe, exposing the roots to the sun. 



Old Witch Grass {Panicum capillar e L.). 

Description: — An annual with usually coarse, branching stems, 
1-3 feet long, with very hairy leaf-sheaths and capillary, widely 
spreading panicles, terminal on the culm or its branches; culm 
geniculate and branching near the base, rarely simple, generally 
pilose or pubescent below the bearded nodes;- sheaths pilose to 
densely hirsute, with spreading hairs; ligule very short, densely 
ciliate; leaf -blade flat, lanceolate or linear, acute, usually thinly 
hairy on both sides, margins scabrous and ciliate near the base; 
hairs throughout spring from small papillae, those on the leaf -blade 
being confined chiefly to the principal nerves ; panicle diffuse, 3-12 
in. long, the branches solitary in pairs, or rarely whorled, the ulti- 
mate branches and pedicels strongly hispid; spikelets 1 line long, 
ovate, acute, or abruptly acuminate-pointed, smooth; first glume 
clasping the base of the spikelet, obtuse or acute, 1-3-nerved, about 
% the length of the 5-7-nerved and nearly equal second and third 
glumes, the acute tips of which are sometimes minutely pubescent ; 
flowering glume smooth and shining, elliptical, obtuse, or subacute, 
a little shorter than the larger outer glumes. Variable. July to 
October. 



DESCRIPTIVE MANUAL 



13 




Fig. 5. Tickle Grass (.Panicum capUlare). Common in fields and gardens, etc. 
(Photographed by Hart.) 




Fig. 5-A. Distribution of Tickle Grass. 



14 WEED FLORA OP IOWA 

Distribution. — Old witch grass is common throughout the state, 
frequently as a weed. It is variable, the form occurring in cul- 
tivated fields being stout and hispid; but when occurring in moist 
meadows and old lake beds it has slender and somewhat capillary 
branches. In Iowa it is quite common in Plymouth, Woodbury, 
Muscatine, Story, Emmet, Franklin, Clinton, Carroll, Crawford, 
Pottawattamie, Scott and other counties. 

Extermination. — This annual grass is easily exterminated by cul- 
tivation. It seldom gives trouble in well cultivated com fields. It 
might be well also, when the weed is abundant, to rotate with some 
leguminous crop. 



Sprouting Crab Grass {Panicum dichotomiflorum Mx.). 

Description. — ^A' smooth, usually much-branched annual with 
stems 2-4 or 6 ft. tall, rather coarsely spreading or ascending 
(rarely erect) ; long, flat leaves and diffuse terminal and lateral 
panicles; sheaths smooth, lax, somewhat flattened; ligule ciliate; 
leaf-blade 6-12 or 24 in. long, 2-10 lines wide, acute, scabrous on 
the margins and sometimes also on the prominent nerves, rarely 
pilose on the upper surface; panicles pyramidal, 4 or 5-12 or 15 
in. long, the primary and secondary branches spreading, scabrous; 
spikelets rather crowded upon short, oppressed and scabrous pedi- 
cels, lanceolate-ovate; acute 1-1% lines long, smooth, green or 
purplish ; lowest glume embracing the base of the spikelet, usually 
obtuse and nerveless, rarely 1-3-nerved, %-% as long as the 
nearly acute 5-7-nerved second and third glumes, the latter having 
sometimes a hyaline palea in its axil; floral glume elliptical, sub- 
acute, smooth and shining, a little shorter than the larger outer 
glumes ; anthers saffron yellow. 

Distribution. — Widely distributed in eastern North America, 
common in m^any parts of Iowa, as Ames, Des Moines, Sioux City, 
Council Bluffs, Davenport, Eddyville. 

Extermination. — Prevent the formation of seed and give thor- 
ough cultivation. 



DESCRIPTIVE MANUAL 



15 




Fig. 6. Sprouting Grab Grass (.Panicum dichotomiflorum) ; a, b, c, spikeletsi 
&, e, flowering glume. Widely distributed in the state. 




Fig. 6-A. Distribution of Sprouting Crab Grass. 



16 



WEED FLORA OF IOWA 



Barnyard Grass {Echinochloa crusgalU (L.) Beauv.)- 
Description. — A coarse, ascending, leafy annual 1-5 ft. high, 
with wide leaves ; spike 1-3 in. long, crowded in a dense panicle ; 



1 

'A 


1 ■' 


ir 


J 


mSmu 


^> 


K-'U 


WlmtUrJS» 


1 


^m 


i 


^'< 




^ 


N^C^ 


:f:. ■'1 


^ 


w 


9 


1 






li/ 


X 


« " 




V 


r 






V. 


: 


^ 



Fig. 7. Barnyard Grass (.Bchinoohloa crusgalU). Fields, barnyards and road- 
sides. 
(Photographed by Hart.) 




Fig. 7-A. Distribution of Barnyard Grass. 



DESCRIPTIVE MANUAL 



17 



culms frequently branched near the base ; sheaths loose, smooth or 
sometimes hispid; leaves broad and flat, 6 in.-l ft. or more long; 
smooth or roughened, margin roughened; spikelets densely and ir- 
regularly crowded in several rows along one side of the spikelike 
branches of the panicle, 1% lines long, outer glume or bract from 
■!4:--V^ the length' of the spikelets, second and third glumes smooth, 
pubescent or hispid along the nerves, fourth glume smooth, awn- 
less or short awn-pointed. 

Distribution. — Barnyard grass is native to Iowa, also to other 
parts of North America, and is quite generally distributed, par- 
ticularly in barnyards, on shores of lakes, streams and in gardens, 
but is most abundant in low places. 

Extermination — By thorough cultivation and preventing the 
formation of seeds. 

\ Chemical Com,position. — Chemical analyses of this grass have 
been reported from Iowa, North Carolina, South Dakota and 
Mexico. Weems reports the following composition from Iowa ma- 
terial. 

NATURAL CONDITION 



Sample 


bate 


Height 


Water 


Fat 


Protein 


Albu- 
minoids 


CJrude 
Fiber 


Ash 


Nitrogen 

Iree 
extract 


1 







76.34 


.73 


1.43 


(1.36) 


9.44 


2.47 


9.59 


WATER TREE SUBSTANCE 


1 








3.09 


6.07 


(6.73) 


39.90 


10.46 


40.48 













Pigeon Grass, Foxtail (Setaria glauca (L.) Beauv.). 

Description — An erect annual 1-2% ft, high; with flat leaves; 
bristly cylindrical spike, from 1-3 in. long; heads slender; bristles 
tawny yellow; small seeds conspicuously cross-striated and easily 
distinguished from the next species because of their larger size 
and by the eross-striation. 

Distribution. — This weed is quite generally distributed in the 
United States, particularly in eastern states. It occurs every- 
where in the state of Iowa, particularly in corn fields, where it 
ex)mes up abundantly, after the corn is "laid by;" also in gardens 
and in pastures, especially in the fall. 
2 



18 WEED FLORA OF IOWA 

Extermination. — It is not generally recognized, but it is prob- 
ably true, that more money is spent in the extermination of fox- 
tails than of any other class of weeds we have in the state of Iowa, 
yet they are all easily destroyed. One of the best and most effective 
methods of destroying the foxtail is by plowing the small grain 
field as soon as the grain is removed. If this is not done a large 
amount of seed is produced. After this plowing in the fall the 
field should be disked and harrowed in the spring and then planted 
to corn. The com should be cultivated as frequently as possible, 
at least four or five times. This method should prove effective for 
the destruction of foxtail and pigeon grass. 




riG 8. Pigeon Grass (Setaria glauca) ■ a, spikelet showing the second glume, 

h! wv' r7>,"°S "* *^' flowering glume and bristles; b, spikelet showing 
the back of the first and third glumes. 

(U. S. Dept. Agr.) 



DESCRIPTIVE MANUAL 



19 



Chemical Composition. — Various analyses have been reported 
from "Washington, D. C, Mississippi, South Dakota and Iowa. The 
following analyses are given by Dr. "Weems : 




Fig. 8-B. Pigeon Grass (.Setaria glauca) ; a,, portion of leaf showing ligule ; 6, 
spilcelet with bristles ; o, spikelet; d, spikelet with first, second, and third 
glumes ; e, spikelet showing flowering glume and sterile glume ; f, flower 
opened showing stamens and pistil. 




Fig. 8-A. Distribution of Pigeon Grass. 



20 



WEED FLORA OF IOWA 

NAT0BAL CONDITION 



WATEB FEEB SUBSTANCE 



2.65 10.53 (9.86) 35.30 14.49 37.13 



PRESH OB AIB DBT SUBSTANCE 



Date 


1 




■1 

s 


o 

11 

<! 


IS 


<3 




9-U-1887 


80. 5S 


.60 


2.05 


(1.91) 


6.86 


2.92 


7.14 







< 


ea 


IS 


o 


a 1u 
III 


O 

1 = 


S. D. (7) 

Tenn. (2): 


8.17 

3.20 

74.20 

68.40 


13.40 
7.7S 
2.80 
2.29 


1.88 

3.80 

.60 

.84 


31. 2S 

si.r? 

6.69 
8.14 


10.63 
5.00 
4.39 
2.86 


34.77 
47.48 
12.42 
17.47 


8.94 


Washington, D. O. (S): 
Cut July 1, very young 
Out July 24, early 










WATER EREE SUBSTANCE 



S. D. (1): 
Aug. 8, 1898 

Tenn. (2) 

Washington, D, C. (3): 
Cut July 1, very young 
Cut • July 24, early 

bloom 

Mississippi 



14.59 
9.04 



10.80 



7.30 
16.74 



2.30 



2.70 
2.71 



34.03 
32.82 



21.70 



26.80 
86.04 



11.47 
5.16 



17.00 



9.00 
9.20 



37.86 
49.06 



48.10 



65.30 
34.31 



Green Foxtail {Setaria viridis (L.) Beauv.). 

Description. — An erect annual from 1-3 ft. high ; leaves 4-12 in. 
long, with rough margins; greenish, more or less compound cyl- 
indrical spikes from 1-5, or even in some cases 6 in. long; bristles 
few, much longer than the spikelets ; spikelets 1/2 in. long, the chaff 
of second and third glumes as long as the minute chaff of the 
fourth glume, the latter being dotted and striate. A single head 
produces an enormous number of seeds. 

Distribution.— This European grass is common in North Amer- 
ica, especially eastward. It is found everywhere in the state, more 
particularly in corn fields, gardens, and in vacant places. 

Extermination.— The same method of extermination should be 
used for this weed as for pigeon grass. 



DESCRIPTIVE MANUAL 



21 



Chemical Composition. — Green foxtail grown in Pennsylvania 
and cut Aug. 11, .1880, analyzed as follows, according to the U. S. 
Dept. Agr. (Chem. Comp. Am. Grasses, 1884, p. 125) :* 




Pig. 9. Green Foxtail (.Setaria viridis). Common in com fields, waste places. 
(After Clark and Fletcher.) 

♦Jenkins and Winton: Bull. Off. Exp. Sta. 11: 71. 



22 



WEED FLORA OF IOWA 




Pig. 9-A. Distribution of Green Foxtail. 
FRESH AIB DET MATEKIAL 



Water 


Ash 


Protein 


Fiber 


Nitrogen free 
extract 


Fat 


14.30 


6.80 


7.80 


18.80 


60.18 


2.62 


WATEH FREE SUBSTANCE 




7.9 


8.6 


21.9 


B8.5 


3.1 



Bristly Foxtail {Setaria verticillata (L.) Beauv.). 

Description. — An annual from 1-2% ft. high with leaves from 
2-7 in. long, somewhat narrower than in the preceding, from %-% 
in. wide; sheaths smooth, rough on the margins and veins; spike 
cylindrical, from 1-4% or 5 in. long, composed of short cylindrical 
clusters; bristles short, a little longer than the spike, single or in 
pairs, barbed downward; seeds small, greenish, % line long, 
minutely cross-striated and wrinkled. 

Distribution. — This European grass is more common eastward 
and southeastward. It is of ccimparatively recent introduction into 
Iowa, being most abundant in the southeastern part, though also 
occurring at such points as Marshalltown, Ames, Sioux City and 
Council Bluffs. It is found in gardens and in the streets. 

Extermination.— The foxtails are annuals and hence it ought to 
be an easy matter to destroy them. They produce an enormous 
amount of seed. Mr. G. M. Lummis estimated that a good sized 
plant of Setaria viridis had 2,500 to 5,000 seeds, and Setaria glauca 
1,000 to 5,000; this being the progeny of a single seed. 



DESCRIPTIVE MANUAL 



23 




Fra. 10. Bristly Foxtail (Setaria verticillata) ; o, spikelet showing bristle and 

glume ; 6j spikelet. 
(U. S. Dept Agr.) 




Fig. 10-.4.. Distribution of Bristly Foxtail. 



24 



WEED FLORA OF IOWA 



Where these grasses are so abundant the ground becomes thickly 
covered. Dr. Beal of the Michigan Agricultural College has found 
that the seed retains its vitality for a considerable length of time. 
After six years twenty-one seeds out of fifty germinated. The 
seeds of all three species are much more tenacious when young than 
when older. The ground is covered so thickly that only a few of 
the plants are destroyed. Covering up with soil or exposing the 
roots to the sun is effective. 




Fig. 11. A weedy cornfield : Foxtail, Sraartweed, etc. Such a weedy field ma- 
terially decreases the yield of corn. Notice how the weeds have crowded 
out the corn. 

(Photographed by Pammel.) 



Clark and Fletcher recommend as follows: "The only way to 
eradicate this weed is to mow it or hoe it out before it goes to 
seed. Anything which prevents it from going to seed for a number 
of years will eradicate it in time. Most ground, however, is so full 
of the seed that it takes a number of years of conscientious work to 
exterminate it. 



DESCRIPTIVE MANUAL 



25 



■ ' ' 


iflH 


---*" 


Jj^lf^H^^H 


^*'- M ^-'- ' 


^^rlKk^K * ^TffSSS^^^^^^^M 


m. , , ^%i^ 


i^iififlS^yMHI 


uyiL^^^^^H 


^f p-ii<R *" ^'^jkHhs 




HH^BbHB 


BlBB^BI^^^^^^^^^^ 


H 



Fig. 12. Foxtail and other weeds in back dooryard. Too many sucli places 

in Iowa. 
(Photographed by Charlotte M. King.) 



Sandbur (Cenchrus tribuloides L.). 

Description. — Annual, with spreading or ascending, much- 
branched culms, rarely 1 ft. high, somewhat compressed ; leaves flat 
or simply folded, about 6 in. long, acute, finely serrulate along the 
margins; sheaths generally much exceeding the intemodes, hairy 
along the margins and at the throat; burs containing the spike- 
lets, 6-20, nearly globose, covered with strong and more or less 
pubescent, barbed spines, which become very hard at maturity and 
readily fall off. 

Distribution. — Common in eastern North America, sandy 
shores of lakes, streams, and sandy soil. In Iowa, common on 
Muscatine Island, railroad embankments, gravel knolls, and in 
Polk, Clinton, Muscatine, Scott, Woodbury, Linn, Jackson, John- 
son, Dubuque, Webster and Black Hawk counties. 

ExtermiTMtion. — This weed is easily exterminated by cultivation. 
The roots are fibrous and exposure to the sun for a short time will 
destroy the weed. 



26 



WEED FLORA OP IOWA 




Fig. 13. Sandbur iCenchrua tribuloides) . Common on sandy soils, gravel 

knolls, etc. 
(Photographed by Hart.) 




Fig. 13- a. Distribution of Sandbur. 



DESCRIPTIVE MANUAL 



27 



Vanilla or Holy Grass {Eierochloe iorealis Roem. and Sehultes). 
Description. — A perennial grass with creeping, fragrant root- 
stocks, 1/2 ft. high; panicle somewhat one-sided, 2-5 inches long; 




Fig. 14. Holy Grass, Vanilla Grass (Hierochloe iorealis). Common in north- 
western and northern Iowa in low grounds. Creeping "roots" something like 
Quack Grass, but with the odor of vanilla. 

(Photographed by Colbum. ) 




Fig. 14-A. Distribution of Holy Grass. 



28 



WEED FLORA OF IOWA 



spikelets chestnut colored, 3-flowered; the 2 lower flowers stamin- 
ate with 3 stamens; the upper flower perfect, short pedicelled, 
awnless, with 2 stamens. 

Distribution.- — Common in the north. Frequently a trouble- 
some weed in Minnesota and northwest territory. Common only as 
a weed in a few of the northwestern counties of Iowa. 

Extermination. — This weed can be exterminated by giving a 
shallow plowing after the crop has been removed and stirring the 
soil thus exposing the root-stocks to the action of the sun. 

Poverty Grass (Aristida dichotom,a Michx.). 
Description.- — A slender, tufted, branched annual from 12-24 
inches tall; spikelets in narrow, striate, simple or compound spikes; 




^'^'a^n^lrT^ °!^^\ ^'^'-^'*'^" M^^^otoma). Common in dry. sterile soil, 
one Toned °' ^ splkelet; b, ^ floret showing awns, middle 



DESCRIPTIVE MANUAL 



29 




Fig. 15-A. Distribution of Poverty Grass. 

empty glumes nearly equal, longer than the flowering glume, 
equaling the small lateral awns; the awns unequal, the long mid- 
dle awn horizontal, but soon becoming reflexed. 

Distribution. — Poverty grass is common in dry, sterile, or clay 
soil in southeastern Iowa. 

Extermination. — The fibrous roots of the plant are easily killed 
by. cultivation. 



Long-awned Poverty Grass {Aristida tuberculosa Nutt.). 

Description. — A rigid, much-branched perennial, 12-18 in. tall; 
panicles simple, 4-7 in. long; erect, rather distant branches, the 
lower in pairs of which one is short and few-flowered, the other 
elongated and many-flowered; empty glumes, nearly equal, awn- 
pointed, flowering glume, twisted above to division of awns; awns 
nearly equal, articulated with glume. 

Distribution. — Common gravelly knolls and sandy soil, northern 
and eastern Iowa. 



Extermination. — Succumbs readily to cultivation. 



WEED FLORA OF IOWA 




Fig. 15-B. Poverty Grass (.Aristida tuherculosa) . Common in gravelly and 

sandy fields. 
(Photographed by Colburn.) 



Nimble Will {MiMenbergia schreleri J. F. Gmel.). 

Description. — A low, ascending perennial with slender, much- 
branched, wiry culms, 1-2 ft. long; sheaths smooth, pilose at the 
throat; ligule very short; leaf -blade 1-2 lines wide, 1-4 in. long, 
scabrous on both sides; panicles 3-7 in. long, slender, branches 
erect, rather densely flowered; spikelets 1 line long, equaling or 
exceeding the pedicels; empty glumes minute, unequal, the lower 
sometimes obsolete; flowering glume narrowly lanceolate, pilose 
near the base, scabrous on the nerves, above, terminating in a 
slender straight awn, 1-2 lines long; palea equaling the glume. 
Shaded thickets. 




Fia. 16. Nimble Will (Muhlenierffia sehreieri) ; a, sheath and base of leaf; h, d, 

glumes ; c, lower part of rachilla ; e, flower. In southern Iowa. 

(Drawn by C. M. King.) 



B2 WEED FLORA OF IOWA 

Distribution.— Nimble Will was originally confined to southeast- 
ern Iowa. It has spread northward along the Mississippi, where it 
is now abundant as far north as Dubuque. It occurs also in central 
Iowa in Story, Boone and Webster counties and is spreading. The 
grass is of little economic importance. 

Extermination.— This weed is much more difficult to destroy than 
the other nimble weeds illustrated. The root-stocks spread more or 
less horizontally and are large and fibrous. Give a thorough culti- 
vation, exposing the roots to the sun, and then follow with some 
leguminous crop. This weed is apt to be abundant in pastures. 
Here there is no other method of treatment than to get blue grass 
and white clover into the pasture. 

Mexican Drop-seed Grass {Muhlenbergia mexicana (L.) Trin.). 

Description. — ^An upright or ascending, usually much-branched 
perennial 1-3 ft. high, with a scaly, creeping root-stock; numerous 
flat leaves and contracted, densely-flowered panicles ; sheaths longer 
or shorter than the internodes, smooth; ligule % line or less long; 
leaf -blades 1-3 lines wide, 2-7 inches long; spikelets about 1 line 
long on very short pedicels ; empty glumes nearly equal, acuminate- 
pointed about the length of the floral glume (a little shorter or 
sometimes a little longer), scabrous on the keel; flowering glume 
lanceolate, acute or mueronate-pointed, 3-nerved, pilose near the 
base and on the callus; palea a little shorter than its glume, very 
acute. 

Distribution. — Widely distributed in eastern North America, 
from Canada to Minnesota, South Dakota, Iowa, Nebraska and 
Missouri. Common everywhere in waste ground in Iowa, espec- 
ially in Polk, Story, Pottawattamie, Webster, Crawford, Black 
Hawk, Calhoun, Clinton, Linn, Jasper, Lee and Dubuque counties. 

Extermination. — The character of the "roots" is so different 
from that of the roots of quack grass and the other perennial weeds 
that it is not difficult to exterminate. The ' ' roots ' ' of this weed and 
the allied species are more or less clustered. In an experiment con- 
ducted to exterminate it we found that by giving a shallow plow- 
ing of four or five inches and harrowing to expose the "roots" to the 
sun, they were killed, no growth making its appearance during the 
rest of the season. Of course this is not effective during rainy 
weather. 



DESCRIPTIVE MANUAL 



33 




Fig. 17. Mexican Drop-seed Grass or Nimble Will (.Muhlenberffia mexicana). 

Common in orchards, gardens and fields ; sometimes called Orchard Grass, 

but incorrectly also called Turkey Grass because of the thickened clustered 

"roots." I !!■ 'il iJ' 1j 

(Photographed by Hart.) 




Fig. 17-A. Distribution of Mexican Drop-seed Grass. 



34 



WEED FLORA OF IOWA 



Chemical Composition. — ^Mexican drop-seed grass has been 
chemically investigated by the Dakota, Tennessee and Iowa sta- 
tions. The Iowa analyses were made at 7 different times between 
April 29 and July 20 with the following results. The water con- 
tent varies greatly as does the protein content. 

NATURAL CONDITION 



Sample 


Date 


deight 


Water 


Fat 


Protein 


Albumin- 
oids 


Crude 
Fiber 


Ash 


Nitrogen 

free 
extract 


1 - - 


4-29-1886 
5-14-1886 
5-28-1896 
8- 8-1886 
6-18-1896 
6-29-1896 
6-20-1896 


4-12 
20-23 
26-2S 
36-38 
38-39 
39-40 
48-49 


84.82 
73.28 
82.96 
77.46 
73.37 
58.77 
81.98 


.88 
1.21 
.54 
.79 
.81 
1.49 
.63 


3.61 
5.12 
2.88 
2.41 
2.13 
3.22 
1.48 


( 2.73) 
( 3.78) 
{ 1.96) 
( 2.14) 
( 2.10) 
C 2.60) 
( 1.09) 


3.70 
7.72 
6.i3 
8.10 
9.01' 
18.32 
5. 82 


2.04 
2.77 
1.96 
2.08 
2.57 
2.64 
1.10 


5.05 


2 


9.90 


3 


6.27 


4 


9.16 


6 


12.U 


6 


20.66 




9.09 








Fig. is. Mexican Drop-seed Grass (.Muhlenbergia mexicana) ; a, b. spikelets. 



DESCRIPTIVE MANUAL 



85 









WATER 


TREE 


SUBSTANCE 








Sample 


Date 


Height 


Water 


Fat 


ProteiD 


Albumin- 
oids 


Crude 
Fiber 


Aeb 


Nitrogen 

free 
extract 


1 








5. SI 
4.52 
S.ll 
3.49 
S 03 
3.(12 
2.95 


23.16 
19.17 
16.77 
10.70 
8.00 
7.81 
S.28 


(17,03) 
(14,17) 
(11.46) 
( 9.52) 
( 7.88) 
( 6.30) 
( 6.11) 


24.38 
28.90 
37.75 
E5.94 
33.83 
32.31 
32.48 


13.41 
10.38 
11.43 
9,27 
9.67 
6.40 
6.16 


33,26 


2 








37.03 


3 








30.94 


4 

5 










40,60 
46.47 


6 






49,86 


7 








50,18 



Marsh Muhlenberg {Muhlenbergia racemosa (Mx.) B, S, P.). 

Description. — A rather stout, upright perennial, with very tough 
and densely scaly root-stocks, nearly simple culms, 2-3 ft. high, and 
densely flowered panicles, 2-4 in, long ; spikelets 2-3 lines long, the 
long, acuminate-pointed outer glumes nearly equal and exceeding 
the very acute flowering glume, which is densely bearded at the 




Fig, 19. Marsh Muhlenberg, Drop-seed Grass, Wild Timothy, and frequently 
called Orchard Grass IMuMenbergia. racemosa). Common in gardens, or- 
chards, and especially in grain fields in low grounds. 
(Photographed by Hart,) 



afi 



WEED FLORA OP IOWA 




Fig. 19-A. Distribution of Marsh Muhlenberg. 




Fig. 19-B. Marsh Muhlenberg (Muhlenbergia racemosa) ; a, spikelet with long 
acuminate-pointed outer glumes ; b, flowering glume, bearded. 



DESCRIPTIVE MANUAL 



37 



Distribution. — Widely distributed in eastern North America, es- 
pecially in meadows from Canada and New England, to New Jer- 
sey, west to the Rocky mountains, Iowa to Missouri. 

Extermination. — The clustered root-stocks are easily destroyed 
by exposing to the sun. Use the same methods as those given for 
the Mexican drop-seed grass. 

Sheathed Rush Grass {Sporobolus vaginiflorics (Torr.) Wood.). 

Description. — A slender, eaespitose annual, 1-3 ft. high, 'with 
narrow, short leaves, and simple, few-flowered, terminal and axil- 
lary, spikelike panicles which are about 1 in. long, and mostly en- 
closed in the somewhat inflated leaf-shea;ths ; spikelets 1-2 lines long. 




Fig. 20. Drop-seed or Rush Grass (Sporobolus vaginiflorus) . 
fields, lawns and gravelly soil. 
(Photographed by Hart.) 



Common in sandy 



38 



WEED FLORA OF IOWA 




Pig. 20-A. Distribution of Sheathed Rush Grass. 

Distribution.— Common in sterile fields and waste places from 
New England to Wisconsin, South Dakota, and Iowa, and south- 
ward. Especially common in pasitures, lawns, and along roadsides 
in Iowa. Story, Polk, Boone, Clinton, Crawford, Carroll, Web- 
ster and Emmet counties. 

Extermination. — This annual is easily exterminated by culti- 
vation. The small fibrous roots succumb readily when exposed to 
the sun. Do not permit the plant to form seed. 



Small Rush Gra,ss {Sporobolus neglectus Nash). 

Descriptinn. — Culms 6-12 in. high, erect, from a usually decum- 
bent base, slender, often much-branched, smooth and glabrous; 
sheaths about half as long as the internodes, inflated; ligule very 
short ; leaves 1 line wide or less at the base, smooth and glabrous be- 
neath, scabrous and hairy near the base above, attenuate into a 
slender point, the lower elongated, the upper 1-3 in. long, setaceous ; 
terminal panicle 1-2% in. in length, usually more or less included in 
the upper sheath, striate; lateral panicles enclosed in the sheaths; 
spikelets about 11/2 lines long, the outer scales acute, the lower one 
slightly shorter, third scale acute, glabrous, a little longer than the 
second, and about equaling the acute palet. 

Distribution. — Occurs from New Brunswick to Virginia, Wiscon- 
sin, Iowa, South Dakota and Texas. In similar situations with the 
preceding species. Along beaten paths, pastures and roadsides. 



DESCRIPTIVE MANUAL 



39 




Fig. 21. Drop-seed or Rush Grass iSporoiolus negleotus) . Pastures, sandy 

fields. 
(Photographed by Hart.) 




Fig. 21-A. Distribution of Small Rush Grass. 



Extermination. — This weed should be treated in the same man- 
ner as the preceding species. 



40 



WEED FLORA OF IOWA 



Wild Oats {Avena fatua It.). 
Desoription.-An erect, glabrous annual, 3-5 ft. high, with flat 
leaves and spreading panicles of large, oatlike, nodding spikelets; 




WILD OATS 



Fig. 22. Wild Oats (Avena fatua). In oat and grain fields, northeastern Iowa. 
(Alter Clark and Fletcher.) 



DESCRIPTIVE MANUAL 



41 




Fig. 22-A. Distribution of Wild Oats. J 

spikelets 2-4-flowered, with empty glames % to 1 in. long, and 
pubescent, flowering glumes 6-9 lines long, awns nearly twice as 
long as the spikelets. 

Distribution. — Common in Canada, rare in eastern North Amer- 
ica, abundant in the northwest, Wisconsin, Minnesota, Dakotas, 
Rocky mountains 'and Pacific coast. In a few counties in northern 
and northeastern Iowa. 

Extermination. — ^Largely spread with oats seed. Use only clean 
oats seed. It succumbs readily to cultivation. Practice rotation of 
crops. Corn or some other cultivated crop should follow oa,ts. The 
oats field should be brought into meadow. Clover and timothy are 
good rotations. 



Crowfoot Grass, Wire Grass {Eleusine indica Gaertn.). 

Description. — A coarse, tufted annual, with erect or spreading 
stems, 6-24 in. high, and digitate spikes; sheaths compressed and 
sparingly ciliate; leaf -blade long and narrow, both surfaces glab- 
rous, or the upper scabrous and thinly hairy; spikes 5-7, 2-4 in. 
long, digitate at the apex of the culm, often with 1 or 2 lower down, 
widely spreading ; spikelets closely imbricated, ll^-2 lines long, 3-6- 
flowered ; glumes Obtuse, the first small and l^nerved ; seeds rugose, 
enclosed within a thin, loose pericarp. 

Distribution. — Naturalized^ from the, Old World. In waste 
ground, streets, yards, from New England To 'Iowa, and common 
southward. In Iowa,' in Marshall,, Scott,, Pottawattamie, and Clin-, 
ton counties. 



42 



WEED FLORA OF IOWA 




FiQ. 23. Crowfoot Grass (.EXeusine indica). Streets, roadsides, southern and 

southeastern Iowa. 
(Photographed by Hart.) 




Fig. 23-A. Distribution of Crowfoot Grass. 



DESCRIPTIVE MANUAL 



43 



Extermination. — Cultivation readily destroys the weed. "When 
it appears in the lawn it must be pulled up or the grass cut closer 
to the ground. 

Chemical Composition:- — The chemical composition of Yard 
grass, Crowfoot, Crab grass. Wire grass {Eleusine indica) -. (Cut 
Aug. 11, 1880; grown in Pennsylvania) according to U. S". Dept. 
Agr., Chem. Comp. Am. Gnasses, 1884, p. 125, is as follows:* 



PBESH OE AIB DRY MATERIAL 



.Water 


Ash 


Protein 


Fiber 


Nitrogen free 
extract 


Fat 


14.30 


19.81 


10.14 


19.63 


4S.33' 


2.79 


WATER FREE SUBSTANCE 




11.5 


11.8 


22.9 


60.5 


3.3 



Candy Grass {Eragrostis major Host). 

Description. — ^A rather showy, much-branched annual, with erect 
or ascending stems, 6 inches-2 or 3 feet high ; sheaths striate, smooth, 
hairy at the throat; ligule a fringe of short hairs; leaf -blade flat, 
3-10 in. long, 1-3 lines wide, somewhat scabrous on the upper sur- 
face; panicle elliptical or oblong, the branches usually spreadiug, 
flowered, 2-8 lines long, l%-2 lines broad, spikelets ovate to linear, 
7-40 empty glumes nearly equal, ovate, obtuse, prominently nerved, 
and scabrous on the keel ; palea ciliate on the keels. 

Distribution. — Eragrostis major is a weedy grass in all parts of 
the state; introduced by the earliest settlers. 

Extermination. — This weed is easily exterminated by cultivation. 
The best way to kill it is to cultivate corn in the soil and follow 
with small grain. 

*BuIl Off. Exp. Sta. 11; compiled by Jenkins and Wlnton. 



44 



WEED FLORA OP IOWA 




Fig. 24. Candy Grass, Stink Grass (Eragrostis major). Common in gardens, 

fields and roadsides. 
(Photographed by Colburn. ) 




Pig. 24-A. Distribution of Candy Grass. 



DESCRIPTIVE MANUAL 



45 



Southern Spear Grass {Eragrostis pilosa (L.) Beauv.)- 
Descripticm. — An annual, 5-18 in. high, with erect or ascending 
steins diffusely branching near the base ; sheaths pilose at the throat, 
otherwise smooth, leaf-blade 1-7 lines long, 1/2-11/2 lines wide, con- 
duplicate when dry; panicle oblong-lanceolate to pyramidal, 3-8 
or 12 in. long, the widely spreading primary branches solitary, or 
2-3 together, the axils not pilose ; spikelets narrow-lanceolate, 2-4i/^ 
lines long, 3-15-flowered, appressed to the branches, nearly equal- 
ing or exceeding their capillary pedicels ; empty glumes ovate, acute, 
sciabrous on the keel, the longer one about % line in length ; flower- 
ing glume broadly ovate, obtuse, distinctly 3-nerved, scabrous on the 
keel, about % line long ; palea scabrous on the keels ; grain oblong. 




Fig. 25. Spear Grass (.Eragrostis pilosa). Roadsides, streets, fields, etc. 
(Photographed by Quade.) 



46 



WEED FLORA OF IOWA 




Fig. 25-A. Distribution of Spear Grass. 

Distribution. — This grass is widely distribu'ted in eastern North 
America in waste places, roadsides, and sometimes in fields, espe- 
cially in sandy soil. New England to Wisconsin, Minnesota and 
southward. 

Extermination. — Succumbs readily to cultivation. 

Soft Chess {Bromus hordeaceus L.). 

Description. — An erect, usually slender, pubescent annual, 1-3 
ft. high, with flat leaves, and contracted panicles, 1-3 in. long ; spike- 
lets 3-8-flowered, %-l in. long, with pubescent glumes, the flower- 
ing ones 3%-4i/^ lines long, obtuse and awned ; awns 3-4 lines long. 

Distribution. — Frequent in waste places, roadsides, and fields, 
from Canada to Virginia and Rocky mountains. Most abundant 
of the brome grasses in Iowa, Story, Boone and Polk counties. 

Extermination. — Succumbs readily to cultivation. Fields are 
largely sown from plants growing in waste places. Therefore, cut 
down the weed along roadsides and in waste places. 



Chemical Composition. — Chemical analysis made at the experi- 
ment station at Ames by Dr. Weems shows the following results : 



TDESCRlt>TIVE MANUAL 



47 




Fig. 26. Soft Chess, Annual Brome Grass (Bromus hordeaoeus). Common In 

fields and waste places. 

(Photographed by Colburn.) 




Fig. 26-A. Distribution of Soft Chess. 



48 



WEED FLORA OF IOWA 



NATUEAL CONDITION 



Sample 


' Date 


Height 


Water 


Fat 


Protein 


Albumin- 
oids 


Crude 
Fiber 


Ash 


Nitrogen 

free 
extract 


1 _ 


;4-24-1896 
6- 4-1896 

s-iMsae 

S-20-1896 
6- 1-1896 

i' 


6.10 
18-18 
18-24 


8S.07 
87.28 
79. S7 
80.63 
71.41 


1.41 
.94 
.85 
.78 
..86 


4.19 

■2.14 

! 2.62 

2.96 

3.52 


(3.23) 
( 1.38) 
(2.60) 
■ (;2.10) 
(S.08) 


3;18 
S.38 
5.47 
6.42 
10.01 


1.92 
1.83 
2.19 
2.05 

2.64 


4.23 


2 


4.46 


3 


9.60 


4 


7.16 


p 


11.67 




, ' WATEB 


FREE SUBSTANCE 









7.43 
4.10 
4.08 
2.95 



28.05 

le.'es 

12.71 
15.30 
12.30 



(26.61) 
(14.80) 
(12.12) 
(10.88) 
(10.76) 



21.31 
26.61 
26.ft4 
3J.18 
3S.01 



12.89 
It. 38 
10.64 
10.61 
8.91 



S4.7S 
46.01 



40.83 



This grass is very nutritious in its young condition. The protein 
varies from 2.14 per cent to 4.19 per cent, but there is a seeming 
variation with different plants found under different conditions. 

Chess, Cheat {Bromus secalinus L.). 

Description. — An erect annual, 2-3 ft. high; eulms smooth or 
pubescent at the nodes; sheaths striate smooth, scabrous or some- 
times pilose; ligule short, blunt; leaf -blade 6-12 in. long, rather 
broadly linear, smooth beneath, more or less rough and pilose on 
the upper surface ; panicle 4-8 in. long, erect, the more or less com- 
pound branches, spreading, even in fruits ; spikelets 6-10 lines long, 
oblong ovate, turgid, 6-12-flowered, pendulous in fruit, empty 
glumes oblong lanceolate, acute, the first 3-5, the second 7-nerved; 
flowering glumes ovate-oblong, obscurely 7-nerved, smooth or mi- 
nutely downy along the margins and toward the apex, becoming 
nearly cylindrical in fruit; palea obtuse, strongly nerved; nerves 
toothed or fringed with distant bristles. 

Distrihution.—Oommon wherever wheat is cultivated and some- 
times in waste places, from the Atlantic to the Pacific. At one time 
common in many parts of Iowa, but now occurring sparingly ex- 
cept where wheat is cultivated. 

Extermination.—JJse cha.n seed and sow in clean soil. The weed 
succumbs readily to cultivation. 

Chemical Compasition.—The common Bromus secalimis analyzed 
at the Iowa station by Weems shows the following analysis. 



DESCRIPTIVE MANUAL 



4fl 




Fig. 27. Cheat or Chess (Bromus secalinus). In grain fleWs. 
(After Clark and Fletcher.) 



50 



WEED FLORA OF IOWA 




Fig. 27-A. Distribution of Cheat or Chess. 



NATURAL CONDITION. 



1. 
2. 



Sample 


S 

sS 
Q 


.•a 






at 
1 






■s 

< 


a «3 

CD O 

got 

.s2!h 


1 


6-20-1 S«i 
6-15-1896 


25-30 
28-29 


79.22 
66.56 


1.99 
1.19 


2.74 
3.23 


(1.96) 
(2.49) 


9.16 
12.38 


2.21 
2.6t 


4.59 


2 


14 01 








WATEB FREE 

f 


SUBSTANCE. 











13.17 



(9.42) 
(V.44) 



44.04 
37.08 



10.63 
7.91 



22.57 
41.83 



There is considerable nourishment in the nutritive substance 
when the plant is young, but when old it can not be considered 
very nutritious. 



Downy Brome Grass (Bromus teciorum L.). 

Description.— k slender, erect, leafy annual, 7-25 in, high, with 
narrow, softly pubescent leaves, and open, nodding panicles, 3-7V2 
in. long; spikelets 5-8-flowered, with unequal, acuminate-pointed, 
hirsute, empty glumes, and rough or hirsute flowerijpg glumes, 4-6 
lines long ; awns 6-8 lines long. 

Tyistribv,tion.— Common in waste places. Rocky mountains and 
the Pacific coast, Atlantic states, Maine to Iowa. Not abundant in 
Iowa. 



DESCRIPTIVE MANUAL 



51 




Fig. 28. Downy or Awned Brome Grass (.Bromus tectorum). An annual grass 

in streets of our larger cities. 

(Photographed by Quade.) 




Fig. 2 8- a. Distribution of Downy Brome Grass. 



52 WEED FLORA OP IOWA 

Extermination. — Care should be used in destroying packing ma- 
terial. In the few localities in which this weed occurs in Iowa, it 
has come from packing maiterial. It succumbs readily to cultivation. 

Poison Darnel (Lolium temulentum It.). 

Description. — An annual, with smooth, stout culm, 2-3 ft. high ; 
sheaths scabrous; ligule short, spike 6-12 in. long; spikelets 5-7- 
flowered ; empty glumes sharp pointed, as long as the spikelet, flow- 
ering glumes turgid, awned or awnless, shorter and broader than 
in L. perenne. 

Distribution. — Introduced from Europe; naturalized in eastern 
North America and quite abundant on the Pacific coast; found in 
many counties in Iowa. 




Fig. 29. Poison Darnel (Lolium temulentum). Common In oat and wheat 
flelfls in northern Iowa. 
(Photographed by Hart.) 



DESCRIPTIVE MANUAL 



53 




Fig. 29-A. Distribution of Poison Darnel. 

Extermination. — Sow clean oats or wheat. The weed succumbs 
readily io cultivation. 



Quack Grass {Agropyron repens Beauv.). 

Description. — ^A perennial with a many-jointed, creeping rhi- 
zome (root-stock) ; culm from 18 in-4 ft. high, bearing numerous 
leaves from 5-12 in. long, and from %-% in. wide ; margins rough, 
very smooth beneath, slightly hirsute above; spikes 6-12 in. long, 
erect ; spikelets on opposite sides of a jointed and channeled raehis, 
pubescent on the margin, erect, 4-8-flowered ; lower or sterile glumes 
acute or short-awned, prominently 5-7-nerved, flowering glumes 
smooth ; palet acute or somewhat rounded, sm'ooth or slightly pube- 
scent. 

The Western Wheat Grass {Agropyron smithii Rydb.) is closely 
related to quack grass. The plant is glaucous; leaves are rigid, 
bluish green in color, scabrous on the margin, edges rolling in; 
spikelets 7-13 flowered, in a thicker spike ("head") than quack 
grass; running root-stocks ("roots"). Common along railways 
and in northwestern Iowa. This plant is not considered a weed. 
It may be used to plant railway embankments. 

The Slender Wheat Grass {Agropyron tenerum Vasey) produces 
a slender long head, greenish in color, running roots absent. 

Distribution. — This grass is common and widely distributed from 
MJamitoba, Minnesota, and western Iowa to Arkansas and Texas.. 
In Iowa it has been found and reported in the following localities : 
Afton Junction, Ames, Armstrong, Iowa and Minnesota line nea' 
Ceylon (Minnesota), Elmore, Hampton, Harcourt, Keokuk, Des 



S4 



WEED FLORA OF IOWA 



Moines, Mason City, Nora Springs, Ontario, Pilot Mound and in 
Hamilton county. It is especially common in the loess soil from 




COOCH QUACK OB SCUTCH GRASS 



Fig. 30 Quack Grass, Quick Grass, Scutch Grass (.Agropyron repens). Fields, 
waste places, around elevators, meadows, roadsides and pastures, especially 
northern Iowa. • f ■: 

(After Clark and Fletcher.) 



DESCRIPTIVE MANUAL 



55 




Fig. 30-A. Distribution of Quack Grass. 

Carroll to Lyon county land eastward and northward and -is found 
extensively along railroads. It is found in northern Iowa from 
Mississippi to Missouri rivers, probably in every county. 



Extermination. — ^With reference to the extermination of quack 
grass, experiments made at Ames indicate that quack grass can be 
exterminated. When it covers considerable areas it may be neces- 
sary to summer fallow. The land should be plowed in August when 
the small grain crop has been removed. The first plowing should 
be shallow, not more than two or three inches deep. Then harrow 
with a common drag. This will expose a large number of the 
"roots". If the grass appears again, run over the field with a disc 
and drag. This should be continued for the remainder of the sea- 
son. In the spring plow the soil six or seven inches ; drag and ex- 
pose the "roots". The field should be kept free from weeds of all 
descriptions during the entire growing season. It may be neces- 
sary to go over the field at least once a week to get all of the quack 
grass. Where land brings as much per acre as in Iowa, no farmer 
can afford to leave his land fallow. The field should he given the 
same treatment in the fall and early spring as outlined above. Sow 
thickly with one of the following crops: Sorghum, Millet, Buck- 
wheat, or Bye. These crops will not entirely hill the quack grass but 
will reduce its vitality to such an extent that what remams may be 
easily treated by plowing six or seven inches deep in the fall, follow- 
ing with a harrow. With sorghum very little quack grass will re- 
main. Experience has shown that quack grass is shallow-rooted and 
that the roots will not grow readily through the soil beyond a depth 
of six inches. 



VVIOED FLORA OF IOWA 




Fig 30-B. Western "Wheat Grass (.Agropyron smithii). Common along rail- 
roads and in northwestern Iowa. The distribution of A. smithii Is shown in 
flg. C and o£ Slender "WTieat Grass (A. tenerum) in flg. D. a, empty glumes; 
b. 'flowering glumes with flowers. 




FiQ. 30-C. Distribution of Western Wheat Grass. 



DESCRIPTIVE MANUAL 



57 



The following suggestions for exterminating the weed are made 
by Fletcher and Clark: "Let the plant exhaust its substance in 
the production of a hay crop, which should be cut and removed as 
soon as the head is formed and before' it is in bloom. Plow shallow 
and cultivate until the root-stocks have been brought to the surface 
by implements that can be forced, after repeated applications, to the 
full depth of the furrow. A disc is not satisfactory because the cut- 
tings from the root-stocks are difficult to gather and they perpetuate 




Fig. 30-D. Distribution of Slender Wlieat Grass. 

the growth, wherever transplanted. When brought to the surface the 
root-stocks should be gathered and burnt or removed. This should 
be done at once before the plant has had an opportunity to renew 
its growth. For Manitoba, S. A. Bedford recommends plowing up 
the couchgrass late in the spring and seeding at once to barley, three 
bushels to the acre. ' ' 

Chemical Composition. — Various chemical analyses have been 
made of quack grass. The following were reported by Weems from 
material grown in Iowa. 

NATURAL CONDITION 



Sample 


0} 

Q 


S 

'3 

W 


'S 




o 

hi 


s 
Is 

fl o 


o 


< 




1. 


4-18-1896 

B- 6-1896 

5-20-1896 

. 6- 1-1896 

6-l&-l£96 


4-8 
16.24 
20-30 
26.28 
26-28 


7S.96 
79.06 
79.66 
76.84 
80.66 


1.15 
..81 
1.51 
1.47. 
1.28 


■ 5.13 
4.41 
4.64 
4.23 
1.35 


(4.9?) 
(2.47) 
(2.11) 
(2.04) 
(1.32) 


6.13 
6..«6 
4.96 
6.6S 
5.05 


3.14 
3.11 
2.09 
2.66 
2.12 


10.49 


2. 


6.95 


3. — .. 


t.'ii 


i. 


9.64 


5. :.... 


9.64 






WATEB TREE 


SUBS] 


^ANOE. 










1 








4.41 
3.86 
7.37 
6.08 
6.59 


19.70 
21.06 
22.71 
17.52 
8.96 


(17 .B7) 
(11.80) 
(10.34) 
( 8.44) 
( 6.80) 


23.56 
27.12 
24.28 
27.66 
25.Sfr 


12.08 
14.84 
10.24 
11.00 
10.93 


40.26 


2. - . - 




.. 




33.12 


3 








•35.40 


4. _ - 








37.84 











49.66 



58 WEED FLORA OF IOWA 

It is no't as valuable for pasturage as blue grass but it compares 
very favorably with timothy in regard to the amount of protein and 
nitrogen free extract it contains. 

Squirrel-tail Grass {Hordeum jubatum L.) ■ 

Description. — An annual cr winter annual from 6 in -2 ft. high, 
producing fibrous roots which form solid, compact bunches, leaves 
not unlike those of blue grass, but paler in color, from 2-4 in. long, 
margins scabrous ; flowers in a dense spike from 2-4 in. long, pale 
green or purplish in color ; spike consisting of a number of 1-flow- 
ered spikelets, 3 occurring at each joint, 1 being perfect, the other 
spikelets awl-shaped, rudimentary, and borne on short stalks, 1 
sterile spikelet occurring on each side of the perfect flower, which 
bears a long awn ; at each joint will be found 6 empty long-awned 
glumes spreading at maturity giving to the plant its bristly appear- 
ance ; when mature, the spike breaks up into joints consisting of the 
rudimentary spikelets and a perfect flower, so that each joint has 
one "seed," the number of "seeds" in a spike varying from 35-60. 
A single cluster of plants may therefore produce from three hun- 
dred to two thousand mature "seeds". The plant has a wonderful 
capacity for "stooling". From a single plant as many as forty 
spikes may be produced, and the number no doubt often exceeds this. 

Distribution. — Squirrel-tail grass, originally, was abundant in the 
vicinity of alkali lakes and along the borders of streams west of 
Missouri river. It also occurred sparingly on the North Atlantic 
coast ; now, however, it is common across the continent. In Iowa it 
is abundant in all parts of the state not only in pastures but in mea- 
dows, fields and gardens. 

Extermination. — Squirrel-tail or wild barley is a most pernicious 
weed along the roadsides and in pastures and meadows; pernicious 
because it not only prevents the growth of the better grasses but is 
injurious to live stock. As this weed is most common in the pas- 
ture, the best way to treat it is to mow the pasture before the grass 
has matured its seed. Since this weed is an annual, or winter an- 
nual, this would effectively dispose of the plant were it not for the 
fact that the seed is blown in from neighboring fields and roadsides. 
Cultivation will readily destroy the weed and where it is abundant 
in fields shallow cultivation followed by the disk and harrow should 
be effective. 



DESCRIPTIVE MANUAL 



59 



Clark and Fletcher, in regard to exterminating this grass, which 
in Canada is known as Skunk- tail Grass, say : ' ' There is no diffi- 
culty in eradicating this grass from any land which can be plowed, 




Fio. 31. Squirrel-tail Grass or Wild Barley {Hordeum jubatmm,). Meadows, 

pastures and roadsides. 

(After Clark and Fletcher.) 



GO 



WEED FLORA OF IOWA 




F^Q. 31-A. Distribution of Squirrel-tail Grass. 

as the usual method of breaking in June will destroy it. It gives 
most trouble in waste places where it ripens its seed, which is spread 
abroad in every direction by wind and water. It grows freely about 
the edges of hay sloughs on the prairie and is generally ripe before 
the hay is cut. The remedy in this case would be cutting before the 
seed is formed. ' ' 




Fig. 32. Squirrel-tall Grass or Wild Barley (.Hordeum jubatum). 
trlbuted in Iowa pastures, roadsides, etc. 
(Photographed by Charlotte M. King.) 



Widely dls- 



Chemical Composition. — Analyses have been reported from Iowa 
and South Dakota. The following report is by Weems from Iowa. 



DESCRIPTIVE MANUAL 
NATURAL CONDITION. 



61 



Sample 


s 

Q 


1 

n 






a 
*S 

e 


.5. 

So 


<U a; 


J3 
DQ 
< 




1. ._ 


5-20-1896 
5-26-1896 
6- 5-1896 
6-17-1896 


10.15 
2S.24 
23.24 
21.25 


80.51 
72.80 

e7.« 

54.39 


.97 
1.69 

.94 
1.68 


4.33 
S.£8 
3.74 
6. SO 


(3.C0) 

(a.j6) 

12.75) 
{ 3.76) 


7.13 
10.10 
li.47 
17.85 


2.19 
2.SD 
2.70 
4.00 


4.87 


2. 


9.96 




12.18 


4. 


16.28 






WATEE PHEE SUBSTANCE. 


1. _ ___ _._ 








4.97 

S.fi4 
3.89 


22.21 
12.36 
11.78 
12. n 


(15.48) 
(8.62) 
( 8.67) 
( 8.24) 


3S.69 
36.90 
38.82 
39.14 


11.24 
8.46 
8.43 
8.78 


24.99 


2. - 








36.46 


3. 








37.93 


4. 








35.66 













Little Barley {Hordeum pusillum Nutt.). 

Description. — An annual, 4-10 in. high ; culms more or less genicu- 
laite at the lower nodes; sheaths smooth, the uppermost often in- 
flated and enclosing the base of the spike ; leaf -blade 1-3 in. long, 
usually a little pubescent on the lower srurf ace ; spikes narrow, 1-3 
in. long ; empty glumes rigid, the 4 internal ones of each group di- 
lated above the base, those of the central spikelet sublanceolate, all 
awn-pointed; outer glumes of the imperfect, lateral spikelets seta- 
ceous ; flowering glume of the central spikelet awned ; awn equaling 
those of the empty glumes ; florets of the lateral spikelets awnless, 
or nearly so. 

Distribution. — Common in Missouri and Illinois and becoming 
plentiful in southeastern Iowa ; also in Marshall and Pottawattamie 
counties. Common on the plains. 

Extermination. — This annual weed is easily destroyed by cultiva- 
tion. Comes up abundantly in streets and along roadsides. The 
production of seed in such places makes it possible for farm land to 
be sown. The plants should be cut to prevent seeding of farms. 

Chemical Composition.— Accovding to the Wyoming Experiment 
Station the composition is as follows :* 

*Bul. Wyo. Agr. Exp. Sta. 87 : compiled by Henry G. Knight, Prank B. Hep- 
ner, Chemists ; and Aven Nelson, Botanist. 



62 



WEED FLORA OP IOWA 




Fig. 33. Little Barley (Hordeum pusillum).. Roadsides, fields. Common in 

southern Iowa. 
(Photographed by Colburn.) 




Fig. 33-A. Distribution of Little Barley. 



DESCRIPTIVE MANUAL 63 



09 fa 

Spa 
goo 






Water 

Ash 

Ether extract 

Crude fiber 

Crude protein 

Nitrogen free extract . 



5.79 
9.25 
1.77 

il.BS 
6.49 

46.12 



9.82 
1.88 

33.62 
6.89 

47.89 



CYPERACEAE, SEDGE FAMILY. 

This family contains few eccnomic plants. The chufas is used as 
food for hogs. The papyrus of the ancients, and the so-called 
rushes of our ponds belong to this family. Many of the plants grow 
in low grounds. 

Northern Nut Grass {Cyperus esculentus L.). 

Description. — A grasslike plant growing from 1-21/2 ft. high; with 
triangular stems, leafy at the base when young, later leaves termin- 
ating the stems ; spikes of numerous spikelets with from 12-30 light 
chestnut or straw-colored flowers ; scales of the spikelets rough-mar- 
gined ; achene longer than broad. 

This perennial weed spreads extensively by its underground nut- 
like tubers. It is closely related to the Southern Nut Grass {Cy- 
perus rotu')idus L.) and in the north entirely replaces it. 

Distribution. — It is quite generally distributed in the state and 
occurs frequently in North America from New Brunswick to Texas ; 
common especially in low spots. Being somewhat yellowish in ap- 
pearance it is easily recognized. 

Extermination. — This weed can be exterminated only by thorough 
cultivation. Running the harrow over the field when corn is young 
will not extermiiiate the weed. The little offshoots merely sprout 
again giving rise to many more plants. Running the cultivator 
through the field is more effective, but not sufficient. In badly in- 
fested fields it will be necessary to use the hoe. 

JUNCACEAB, RUSH FAMILY. 

These grasslike plants are related to the lilies. They generally 
grow in low grounds and are of little economic importance. 



64 



WEED FLORA OF IOWA' 




Fig. 34. Northern Nut Grass iCyperus esculentus) . Corn fields, especially 
low grounds. Young plants have a yellowish color. Weed spreads by the 
"roots." 




Fig. 34-A. Distribution of Northern Nut Grass. 



DESCRIPTIVE MANUAL 



65 



Slender Rush {Juiicus tenuis Willd.). 

Description. — A leafy perennial, wiry stem, 9-18 in. high; leaves 
flat or channeled ; flowers in panicles, the panicles shorter than the 
involueral leaves; flowers green, sepals lanceolate-acute, spreading 
in fruit ; capsule green ; seeds small, ribbed. 

Distribution. — ^A cosmopolitan weed widely distributed in North 
America; common along beaten paths and fields, especially in pas- 
tures, in every part of Iowa. 





Figure 25 Figure 35A 

Pig. 35. Wire Grass or Slender Rush (Juncus tenuis). Common in pastures 

along roaflsides. 

(Photographed by Colburn.) 

Fig. 35-A. Distribution of Slender Rush. 

Extermination. — This weed is not difficult to exterminate by cul- 
tivation. "Where it occurs in pastures that cannot be cultivated, an 
effort should be made to start a leguminous plant like white clover 
which will kill out the rush to some extent. 
5 



fi6 



WEED FLORA OP IOWA 



LILIACBAE, LILY FAMILY. 
This family contains a number of economic plants like onion, gar- 
lie, leek, chives, such cultivated ornamental plants as the lily, lily 
of the valley, and hyacinth and some poisonous plants as the eolchi- 
cum and bunch flower. 

Common Bunch Flower {Melanthium virginicum I*.). 

Description. — Tall, leafy-stemmed plants 3-5 ft. high; leaves lin- 
ear, the lower sheathing, the upper similar and sessile ; flowers in an 
ample panicle, fragrant ; perianth of flat segments greenish yellow ; 
styles persistent, capsule 3-celled; 8-10 seeds in each cavity. 

Distriiution.-^lv. low meadows and prairies from New England 
to Iowa river basin, Minnesota, Texas 'and Florida. Common only 
in eastern central Iowa to the Missouri line. 




Fig. 36. Bunch Flower IMelanthium virginicum) In meadows, eastern and 

southern Iowa. Poisonous. 

(Photo Gardner.) 



DESCRIPTIVE MANUAL 



67 




Fig. 36-A. Distribution of Bunch Flower. 

Extermination. — This weed is common only in native meadows 
It is killed when these meadows are broken up and cultivated. 



Wild Onion {Allium canadense L.). 

Description. — ^A perennial herb, with small scapose bulb; bulb 
coat somewhat fibrous; flowers umbellate, umbels densely bulbifer- 
ous; perianth of 6 divisions which are narrowly lanceolate, as long 
as the 6 stamens or longer ; capsule 3-celled, not crested ; seeds black. 

Distribution. — Common in moist meadows in many parts of Iowa : 
Boone, Story, Marshall and Polk counties ; from New Brunswick to 
Wisconsin, Texas and Florida. 

Extermination. — This weed is common in native meadows, seldom 
persists like the wild garlic {Allium vineale) of Europe in cultivated 
fields; thorough cultivation of the field with a plow and disk and 
cultivator will destroy the weed. 



DICOTTLEDONEAE, DICOTS. 

Stem formed of pith wood and bark ; between the bark and wood, 
the cambium layer an annual ring of wood formed each year ; leaves 
netted veined ; flowers generally on tie plan of five ; embryo with a 
pair of cotyledons. Rose, pigweed, potato, bean, clover, Russian 
thistle, horse nettle, Canadian thistle belong to this division. 



(58 



WEED FLORA OP IOWA 




Fig. 37. Wild Onion (.Allium canadense). 
(Photographed by Charlotte M. King.) 




FiQ. 37-A. Distribution of Wild Onion. 



DESCRIPTIVE MANUAL 
URTICACEAE, NETTLE FAMILY. 



69 



This family in the large sense contains such economic plants as 
the fig, india rubber tree, hemp, hop, and such trees as the hiackberry 
and elm. 

Nettle {Urtica gracilis Ait.) . 

Description. — A perennial, stinging herb from 2-6 ft. high; spar- 
ingly bristly; leaves ovate-lanceolate, sharply serrate, with long 
petioles, 3-5-nerved sparingly pubescent, petioles usually bristly; 
flowers inconspicuous, paniculate, dioecious or of staminate and pis- 
tilate flowers; aehene compressed, inclosed by the persistent calyx. 
Hairs multicellular at base, urtieating. 




Fio. 38. stinging Nettle (.Urtica gracilis). Common along fences and in waSte 

places, a, stinging hairs of plant. 

(Photographed by Colburn. a drawn by Charlotte M. King.) 



70 



WEED FLORA OF IOWA 




Fig. 3 8- a. Distribution of Nettle. 

Distribution. — Eastern Canada to Wisconsin, Minnesota, central 
Canada and Louisiana; found along roadsides, borders of thickets 
and woods ; occasionally in gardens and waste places especially in 
eastern and southern Iowa. 

Extermination. — The perennial root stocks make this weed quite 
persistent and difficult to destroy, because the weed often occurs in 
inaccessible places along fence-rows ; howevei-, persistent cultivation 
will exterminate the weed. 

Chemical Composition.* 



I'RESH OB AIB DR^ tATEEIAL. 



Water 


Ash 


Protein 


Pibe 


Nitrogen free 
extract 


Fat 


82.44 


2.30 


5.50 


1.96 


7.1S 


0.67 


WATER FREE SUBSTANCE. 




13.1 


31.4 


11.2 


40.5 






Hemp (Cannabis sativa L.). 

Description. — A rough, stout, dioecious annual, 3-10 ft. tall; 
inner bark of tough fibers ; leave's digitate, of 5-7 linear-lanceolate, 
coarsely toothed leaflets, the upper alternate; flowers green; stam- 
inate, in compound racemes; pistillate, in erect spikes, each con- 
sisting of a calyx of a single sepal folded around the ovary and 2 
filiform stigmas ; fruit an achene ; endosperm fleshy ; embryo 
curved. 



♦Compiled by Jenkins and Winton: Bull. Off. Exp. Sta. 11. 



DESCRIPTIVE MANUAL 



71 




Fig. 38-B. Hemp (.Cannabis sativa). 




Fig. 38-C. Distribution of Hemp. 



72 



WEED FLORA OF IOWA 



Distribution. — ^Waste places, New Brunswick south to North 
Carolina and west to Minnesota, Kansas, and Kocky mountains. 
"Widely distributed through cultivation but often becoming a 
troublesome weed. In many parts of Iowa; reported from Story, 
Dubuque, Clinton, Polk, Boone, Allamakee, Winneshiek, Marshall, 
Grundy, Plymouth, Pottawattamie and other counties. 

Extermination. — Easily killed by cultivation. Practice rotation 
of crops. 

Pellitory {Pwrietwria pennsylvcmica Muhl.). 

Description. — ^A low, annual, simple, or sparingly branched mi- 
nutely downy plant ; oblong-lanceolate, thin leaves with opaque dots ; 
flowers monoeciously polygamous shorter than involucre ; glomerate 
except in the lower axils ; stigma sessile. 




Fro. 39. Pellitory {Parietaria 'pennsylvanica) . Common in shady places near 

buildings. 
(Fhotographed by Hart.) 



DESCRIPTIVE MANUAL 



73 




FiQ. 39-A. Distribution of Pellitory. 

Distrib'wtion. — ^Massachusetts to Minnesota and southward. Com- 
mon in Iowa in shady places, lawns and woods. 




Fig. 39-B. Pellitory (.Pariefaria pennsylvanica.') 



74 



WEED FLORA OP IOWA 



Extermination.— This weed is usually exterminated by eultivar 
tion and may be destroyed by the application of iron sulphate at 
the rate of 100 pounds to a barrel of water. 

POLYGONACEAE, SMARTWEED FAMILY. 

This family contains the pie plant, eanaigre, prince's feather, 
and buckwheat. 

Curled Dock, Yellow Dock {Bumex crispus h.). 

Description. — ^A smooth perennial from 3-4 ft. high ; leaves with 
strongly wavy and curled margins, lanceolate and acute, lower leaves 
with bases somewhat truncate or inclined to be heart-shaped ; flow- 
ers collected in dense whorls, extended or prolonged into racemes, 
entirely leafless above, but below with small leaves ; 6 sepals, the 3 
outer, herbaceous, leaflike, the 3 inner, larger and somewhat curled, 




Fig, 40. Sour Dock, Curled Dock or Yellow Dock (Rumex criapus). 
in low grounds, clover meadows, fields, etc. 
(Photographed by Colburn.) 



Common 



DESCRIPTIVE MANUAL 



75 




Fig. 40-A. Distribution of Curled Dock.' 

and after flowering forming the valves of the fruit, which surround 
the 3-angled fruit, each valve bearing a grain. The B. aitissimus 
Wood, occurs in low ground, and is from 2-6 ft. high, with leaVes 
oblong, lanceolate, acute, pale, thickish, but without curled margins 
as in B. crispus L., and longer; racemes long, spikelike, panicled, 
nearly leafless ; has a conspicuous grain. 

Distribution.— It is native to Europe where it has long been known 
as a troublesome weed ; common throughout eastern North America, 
Pacific coast, and Rocky mountains; abundant in Iowa in clover 
meadows, along roadsides and in pastures. 

Chemical Composition. — The following analysis has been re- 
ported.* 



Water 


Protein 


Fat 


Nitrogen free 
extract 


Crude 
Fiber 


Ash 


81.6 


21.7 


3.9 


39.4 


11.4 


9.3 



Extermination. — One of the most efficient means of destroying 
this weed is to root it out by the hand and this is done very readily 
in the spring when the soil is wet by taking hold of the plant just at 
the surface of the ground, giving the root a slight twist and at the 
same time an upward pull, when it will readily come from the soil. 
Where it is common, however, it is sometimes plowed or a spud is 
used. This method is not, however, so effective as the pulling 
method. 



*Storer and Anderson. 



76 



WEED FLOEA OP IOWA 




Fig. 41. Curled Dock (Bumex orispus). Roadsides, meadows, clover fields, etc. 
(Photographed by Charlotte M. King.) 

Clark and Fletcher suggest the following treatment : ' ' Sow clean 
seed. The prevalence of dock in meadows is due to sowing con- 
taminated grass and clover seeds. Land worked under a short rota^ 
tion of crops is never badly infested with docks. When the soil is 
soft lafter continued raia, they can be pulled from meadows and 
pastures. Pull or cut and destroy all seed-bearing plants before 
harvesting a clover seed crop. A handful of salt placed on the 
crown of docks, after cutting in dry hot weather, will extract the 
moisture and destroy the root; this is a remedy sometimes used in 
lawns and pastures when the soil is too hard and dry to permit 
pulling them. " 



Smooth Dock {Bumex altissimus Wood.). 

Description. — ^A tall, smooth, perennial; leaves pale, ovate, or 
oblong-lanceolate, thiekish ; flowers in paniculate spikelike racemes, 
in crowded whorls, nodding pedicels, shorter than the fruiting calyx; 
valves broadly ovate or obscurely heart-shaped, one with a conspicu- 
ous pale grain ; aehene triangular, pale. 

Distribution.— Common in the northern states and abundant in 
low grounds and highways, also in pastures throughout Iowa. 



DESCRIPTIVE MANUAL 



77 





Fig. 42. Smooth or Peach-leaved Dock (.Bumeo) altissimu^). Low meadows, 

roadsides and pastures. 

(Photographed by Colburn.) 




Fig. 42-A. Distribution of Smooth Dock. 



WEED FLORA OF IOWA 




Fig. 43. Smooth or Peach-leaved Dock (.Rumex altissimus). Dandelion ^Taraxa- 
cum officinale), and other weeds. This is where the seed comes from to 
spread weeds. 

(Photographed by Charlotte M. King.) 

Extermination. — This weed has running roots and cannot be de- 
stroyed in the same way as sour dock. The roots are, however, shal- 
low, and can be destroyed by giving cultivation exposing the roots 
to the sun. 



Bitter Dock {Bumex oMusif alius L.). 

Description.— A perennial herb, with roughish stem; leaves some- 
what wavy, the lowest ovate heart-shaped, obtuse, the upper oblong- 
lanceolate, acute; flowers inconspicuous, greenish on jointed pedi- 
cels ; valves of the fruit conspicuous, toothed at the base. 

Distribution.— Naturalized from Europe; eastern Canada to Wis- 
consin, Minnesota and south to Texas and Florida. It is found in 
waste places, sparingly introduced into lowia with clover seed. 

Extermination.— The yellow spindle-shaped root is easily pulled 
by giving the plant a slight twist, especially when the ground is 
moist. Clover seed containing this weed should not be sown. 



DESCRIPTIVE MANUAL 



79 




Fig. 44. Bitter Dock, Red Veined Dock (Rumex obtusif alius) . Common in some 

clover meadows in southern Iowa. 

(Photographed by Colburn. ) 




Fig. 44-A. Distribution of Bitter Dock. 



80 WEED FLORA OF IOWA 

Sheep Sorrel (Bumex acetosella L.). 

Description. — A low smooth annual or perennial, usually the lat- 
ter, growing from 6-12 in. high, producing an erect stem, with hori- 
zontal, creeping, woody root-stocks or rhizome; petioled, narrowly- 
hastate, narrow, lanceolate leaves, the upper linear; flowers on 
jointed pedicels, dioecious, small, in a terminal naked panicle ; small 
green calyx ; exserted stamens ; the valves not enlarging in fruit. 

Distribution. — Sheep sorrel has long been known as a troublesome 
weed in Europe, and in the northern states ; perhaps indigenous to 
the United States ; at least now common across the continent in the 
north. It is common everywhere in Iowa, more particularly in sandy 
or gravelly soils. 

Extermination. — The plant succumbs quite readily to cultivation, 
and where the iields are thoroughly cultivated with hoed crops, it 
is seldom troublesome more than one season. In fact the vast ma- 
jority of plants may be killed by cultivating the soil once or twice. 
The roots though produced abundantly seem to be unable to stand 
drying. The soil on which it occurs should receive a heavy coat of 
manure. This seems to be approved by Dr. Halsted who says: 
' ' This pest can be subdued by keeping the infested land under the 
plow for a short time. ' ' - 

Clark and Fletcher say in regard to this weed: "Sheep sorrel 
is said to be an index of soil characters. It seems to thrive best on 
sandy or gravelly soils deficient of lime. An application of lime to 
slightly acid soils produces a more vigorous growth of cultivated 
crops and curtails the opportunities of the sorrel to grow and spread. 
Old meadows and pastures that are overrun with it and that can- 
not well be brought under cultivation may be pastured with sheep 
for two or three years to prevent it from seeding freely. 

A three-year rotation of crops with good cultivation, including 
shallow plowing directly after hay crop and frequent cultivation 
until autumn to prepare for hoed crops, will keep sheep sorrel well 
under control even on lands that seem to be specially suited to its 
growth. ' ' 

Wallace 's Farmer suggests the following : "To control this weed 
in the meadows we would suggest applying manure and thickening 
up the grass stand. Putting the land into a cultivated crop destroy! 
this weed. ' ' 



DESCRIPTIVE MANUAL 



81 




Fig. 45. Sheep Sorrel or Horse Sorrel (Bumex acetosella). Common in sandy 

and gravelly soil. 
(After Clark and Fletcher.) 



82 



WEED FLORA OF IOWA 




Fig. 45-A. Distribution of Sheep Sorrel. 

Chemical Composition. — The ash of this weed is reported by Wein- 
hold as follows : 



Phosphoric acid 


Potash 


Sodium 


liime 


Magnesia 


9.7 


19.7 


1.3 


14.0 


8.4 



Erect Knotweed {Polygonum erectumh.). 

Description. — An annual, glabrous, stout, erect, or ascending yel- 
lowish green herb, 1-2 ft. high, with elliptical leaves ; flowers yellow- 
ish and inconspicuous, 1-2 in an axil; stamens 5-6; achene dull, 
included. 

Distribution. — Widely distributed from the northeast to Mani- 
toba, Wisconsin, Minnesota to Arkansas, and eastward. , Common 
in Iowa especially eastward, and in Story, Boone, Marshall, Polk, 
Allamakee, Clinton and Dubuque counties; 



Extermination. — Easily exterminated by cultivation. 



DESCRIPTIVE MANUAL 



83 




Pig. 46. Erect Knotweed (.Polygonum erectum). Common in many parts of the 

state. 
(Photographed by Hart.) 




Fig. 46-A. Distribution of Erect Knotweed. 



84 



WEED FLORA OF IOWA 



Dooryard Knotweed {Polygonum aviculare L.) . 

Descriptioh. — ^A scattered or somewhat ascending, bluish grey an- 
nual; leaves acute or acutish; flowers greenish with pinkish mar- 
gins ; achenes triangular, dull and minutely granular-striate. 




Fio. 47. Dooryard Knotweed {Polygonum aviculare). Common In dooryards. 
(Photographed by Hart.) 




Fig. 47-A. Distribution of Dooryard Knotweed. 



DESCRIPTIVE MANUAL 



85 



Distribution. — Native in the northern hemisphere, Asia and North 
America, common everywhere in Iowa in gardens and waste places. 
Usually affected by a white mildew. 

Extermination. — This annuial weed can be destroyed only by giv- 
ing the soil on which it occurs cultivation. It frequents dry and 
more or less beaten soil. Where it is abundant in lawns the soil 
should be stirred and sown to white clover. 

Bushy Knotweed {Polygonum ramosissimum Mx.). 

Description. — ^An erect or ascending, green or yellowish green 
smooth herb 2-4 ft. high ; leaves linear or lanceolate, tapering into a 
petiole; flowers inconspicuous, greenish; stamens 3-6; style short; 
aohene Snangled. 




Fig. 48. Bushy or Erect Knotweed {Polygonum ramosissimum). Common In 

flelfls. 
(Photographed by Hart.) 



86 



WEED FLORA OF IOWA 




Fig. 4 8- a. Distribution of Bushy Knotweed. 

Distribution. — From Manitoba to Texas, also in Pennsylvania; 
frequent in fields in many parts of Iowa, in Story, Boone, Worth, 
and Cerro Gordo counties. 

Extermination. — Easily exterminated by cultivation. 



Pink Smartweed {Polygonum lapathi folium L.).' 

Description. — Pink Ejmartweed is la native, glabrous, erect annual, 
with stem swollen at the nodes; lanceolate, acuminate leiaves with 
short ciliate petioles; racemes panicled, nodding, with many flow- 
ers; calyx white or pink, small 5-parted; 6 stamens, style included; 
aehene lenticular. 

Distribution. — This weed occurs from New England to Nebraska 
and Louisiana. Native to Europe, and common in eastern North 
America ; everywhere in Iowa, particularly in moist situations. • 

Extermination. — Easily exterminated, after drainage of slough, 
by cultivation. 



DESCRIPTIVE MANUAL 



87 




Fig. 49. Pink or Nodding Smartweed {Polygonum, lapathifolium) . Common 

in com fields. 
(Photographed by Colburn.) 




Fig. 49-A. Distribution of Pinlc Smartweed. 



88 



WEED FLORA OP IOWA 



Marsh Smartweed (Polygonum muhlenbergn (Meisn.) Wats.)- 

Description. — ^A somewhat pubescent or scabrous perennial with 
large black roots, decumbent or erect; leaves lanceolate to ovate, 
narrowly acuminate; flowera in rather long hispid spikes; sepals 5, 




Fig. 50. Tanweed, Marsh or Muhlenberg's Smartweed, Devil's Shoe-strine or 
Shoe-string (.Polygonum muhlenbergn) ; a, plant hairs. Low meadows and 
nelds. 

(Photographed by Colburn. Brawing by Charlotte M King ) 




FiQ. 50-A. Distribution of Marsh Smartweed 



DESCRIPTIVE MANUAL 89 

bright rose color; stamcBs 5, styles 2-cleft, exerted. Frequently 
only sterile plants, or flowering rather late in the season j trichomes 
multicellular, at base with thick outer epidermal walls. 

Distribution. — Common from Canada to Florida and west, found 
in all parts of Iowa ; an exceedingly variable plant ; sometimes found 
in very moist situations, and in stagnant water, or in somewhat 
higher but poorly drained situations. The black, thickish roots are 
quite characteristic of the plant. 

Extermination. — ^Marsh smartweed or tanweed, as it is sometimes 
called, is a persistent perennial and since the weed grows in wet 
places it is particularly difficult to destroy. The best method of 




Fig. 51. Tanweed, Marsh Smartweed (Polygonum muhlenbergU). 
(Photographed by W. Newell.) 



90 WEED FLORA OP IOWA 

treating it is by thorough cultivation, exposing all the root-stocks 
to the sun, then removing the young plants as rapidly as they mak« 
their appearance. 

Wallace's Farmer suggests the following treatment: "It grows 
less vigorously on well drained land, hence the first step in eradica- 
tion is to drain the field thoroughly. The summer fallow is perhaps 
the best course of treatment. Plow the infested patch early and 
keep the disk and plow working on it regularly all summer long. 
All the roots that can be located should be pulled up and burned 
after drying out. A heavy pitchfork and plenty of muscle will soon 
fin a wagon box with the long, tough, yellow roots. A heavy seed- 
ing of sorghum helps to weaken the stand, but we have seen patches 
as vigorous as ever -a year after two succeeding crops of-sorghum 
had been grown in an effort to smother out the pest. ' ' ' 



Smartweed (Polygonum pennsylvanicum h.). 

Description. — ^An annual 1-2 ft. high, with lanceolate leaves; 
branches below the flowers beset with numerous stalked glands; 
flowers whitish or rose-colored ; stamens 6-8, style 2-cleft ; fruit an 
achene, 1% lines long, flattened, brown, shining, part of the calyx 
remaining attached to the base. 

Distribution. — Pennsylvania smartweed is common from New 
England southwestward and westward and in every part of Iowa, 
coming up abundantly in corn fields, sometimes forming a mass of 
rose-colored flowers; also growing up abundantly in grain fields 
after harvest. 

E.rterm,ination. — This smartweed is easily exterminated by cul- 
tivction. 



DESCRIPTIVE MANUAL 



91 




Fig. 51-A. Pennsylvania Smartweed (Polygonum pennsylvanicum) . Common in 

com fields. 
(Pliotograplied by Colburn. ) 




Fig. 51-B. Distribution of Pennsylvania Smartweed. 



92 



WEED FLORA OP I<3WA 




Fig. 51-C. Smartweed (.Polygonum pennsylvanicum) . 
(Photographed by W. Newell.) 

Water Pepper {Polygonum hydropiper L.). 

Description. — ^Mueh like P. persicaria but more slender and often 
decumbent ; flowers greenish on slender nodding spikes ; achenes dull 
in color and the whole plant more or less acrid. 

Distribution. — Water pepper is widely distributed in eastern 
North America ; naturalized from Europe or may be indigenous in 
the northwest. Widely distributed in Iowa. 

Extermination. — This, weed is usually found in moist places and 
is not very troublesome in cultivated fields except in low places. 
Fields that are badly infested with it should be plowed and drained 
and if possible some legumiuous plants like alsike clover sown. 



DESCRIPTIVE MANUAL 



93 




Fig. 52. 



Common Smartweed or Water Pepper (.Polygonum hydropiper) . 
(Photographed by Colburn.) 



Lady's Thumb {Polygonum persicaria L.). 

Description. — A nodding, smooth, glabrous annual; sheaths 
bristly ciliate; leaves lanceolate, marked with a conspicuous dark 
of lunar spot ; spikes short cylindrie ; peduncles smooth ; achene flat- 
tened, smooth and shining. 

Distribution. — Lady's thumb is native to Europe, common in east- 
ern North America, Rocky mountains and on the Pacific coast. 
Common everywhere in Iowa, particularly in waste places and gar- 
dens, and growing up abundantly after grain has been harvested. 

Extermination. — This weed is easily destroyed by cultivation. 
The main point, however, is that seed production must be prevented ; 
hence it would be well to cut off the plants after they have started 
to produce flowers ; this will effectually prevent seed production. 



94 



WEED FLORA OF IOWA 




Plat? I 
PALE pep. SI C ARl A 



Fig: 53. Lady's Thumb {Polygonum perstcaria). Common in garflens, fields 

and along roadsides.) 
(After Clark and Fletcher.) 



DESCRIPTIVE MANUAL 



95 




Fig. 53-A. Distribution of Lady's Thumb. 

Water Pepper or Smartweed (P. hydropiperoides Mx.). 
Descnption. — A perennial not acrid; leaves narrowly lanceolate 
or oblong ; small flesh-colored flowers in erect slender spikes ; smooth 
achenes sharply triangular. 




Fig 54. 'Water Pepper (.Polygonum hydropiperoides). Common in low places, 

fields, etc. 
(Photographed by Colburn.) 



96 



WEED FLORA OF IOWA 




Fig. 54-A. Distribution of Water Pepper. 

Distribution. — Water pepper is distributed in swamps from east- 
em Canada southwest to Mexico; it is also distributed across the 
northern states to California ; common in low wet places in many 
parts of Iowa. 




Fig. 54-B. Water Smartweed (.Polygonum acre). 



DESCRIPTIVE MANUAL 



97 




Fig. 54-C. Distribution of "Water Smartweed. 

Extermination. — Since this perennial weed is most abundant in 
sloughs, drainage must be resorted to before an effective means of 
extermination can be used. After this it will give little trouble in 
cultivation. 

The Water Smartweed {Polygonum acre H B K) is a nearly 
smooth perennial with stems rooting at the decumbent base; erect, 
dense spikes of whitish or flesh-colored flowers. It is common in 
low grounds. 

Black Bindweed or Wild Buckwheat {Polygonum convolvulvs L.). 

Description. — An annual, twining, with smooth joints; leaves 
halberd or heart-shaped ; flowers in corymbose racemes ; achene dull 
black, triangular and minutely roughened. 

Distribution. — This weed is widely scattered with grain seed, 
especially with wheat and oats. It is often most troublesome in 
small grain fields. In Iowa, however, it occurs in gardens and along 
roadsides. 

Extermination. — It is not difficult to destroy the weed by giving 
clean cultivation, since it succumbs easily to such treatmen-t. Sow 
only clean seed. 

Clark and Fletcher recommend as follows: "Sow clean seed 
grain. The seeds retain their vitality for a relatively short period, 
probably not longer than three years, except in the drier soils of the 
western plains. The suppression of this pest is therefore largely 
dependent on the prevention of a continued supply of fresh seeds to 
the soil. This weed gives little trouble on land under a short rota- 
tion of crops, including hay, for two years. 
7 



98 



WEED FLORA OP IOWA 




Fig. 55. Bindweed or Wild Buckwheat (.Polygonum convolvulus). Common in 
grain fields and waste places. 
(After Clark and Fletcher.) 



DESCRIPTIVE MANUAL 



99 




Pig. 55-A. Distribution of Blaclc Bindweed. 

The seeds of wild buckwheat do not germinate in the spring until 
the soil is quite warm. Most of the early plan'ts can be destroyed 
in the grain crops by an application of the harrow when the grain 
is about three inches high. The young plants soon root firmly and 
the harrowing, to be effective, must be done jus't as they emerge 
from the ground. ' ' 

CHENOPODIACEAE, GOOSBFOOT FAMILY. 
Thia family contains the spinach, sugar beet, beet and salt bushes. 



"Winged Pigweed {Cycloloma atriplicifolium (Spreng.) Coult.). 

Description. — -An annual with alternate sinuate-toothed petioled 
leaves ; small inconspicuous flowers in open panicles ; winged seeds ; 
herb diffusely spreading or often spherical in form similar to the 
Russian thistle or Iowa tumbleweed. 

Distribution. — Native from Manitoba, Minnesota, to Illinois, Ark- 
ansas and the Rocky mountains. In Iowa it is found along Missis- 
sippi river in Dubuque and Muscatine counties, in Linn county, 
and along Missouri river. 

Extermination. — This weed is easily exterminated by cultivation. 
In Iowa has probably been spread with western grass seed and in 
stock ears. 



100 



WEED FLORA OF IOWA 













■ a; 



\.^4- 



Fig. 56. Western Tumbleweed or Winged Pigweed (Cyololoma atripjici/olium) 

Sandy soil, Muscatine Island, etc. 

(Photographed by Colburn.) 




Fio. 56-A. Distribution of Winged Pigweed. 



DESCRIPTIVE MANUAL 



101 




Fig. 57. Winged Pigweed (Cycloloma atripUcifoUum') . Seed and cross section of 

ovary. 
(After W. J. Beal, Mich. Agr. Exp. Sta.) 



Mexican Fireweed {Eochia scoparia Schrad.). 

Description. — ^An annual, erect, puberulent or glabrate herb; 
leaves lanceolate to linear, ciliate acuminate ; flowers sessile in the 
axils of the upper leaves, forming short dense-bracted spikes ; fruit- 
ing calyx segments each with a short triangular horizontal wing. 



102 



WEED FLOEA OF IOWA 
/ ^ 




Fig. 58. Mexican Pireweed. {Kochia scoparia). A frequent escate from cul- 
tivation. 
(Drawn by F. C. Collins.) 



DESCRIPTIVE MANUAL 



1.03 




Fig. 58-A. Distribution of Mexican Fireweed. 

Distribution. — In waste places commonly cultivated and now a 
frequent escape in Iowa. Common in many of the northern states, 
Rocky mountains and the Pacific coast. From eastern Europe and 
western Asia. 

Extermination. — This weed is easily exterminated by cultivation. 



Mexican Tea {Chenopodium amhrosioides L.). 

Description. — A smoothish annual, or slightly pubescent ; strong 
scented; leaves oblong or lanceolate, entire or cut-pinnatifld, nearly 
sessile ; spikes densely flowered, leafy ; flowers in small, dense, axil- 
lary spikes; calyx 3-parted enclosing the fruit. The wormseed 
( C anthelminticum) is an annual or sometimes a perennial ; leaves 
more strongly toothed; the flowers usually in bractless panieled 
spikes. 

Distribution.- — Mexican tea is found southward, occurring, how; 
ever, from Maine to California. The wormseed has nearly the same 
distribution occuring northward to Minnesota and Wisconsin. 
Neither of these weeds is common in Iowa. 

Extermination. — In Iowa both of these weeds are easily extermin- 
ated by cultivation. Do not permit any of their seeds to mature. 



104 



WEED FLORA OF IOWA 




Fig. 59. Mexican Tea (.Chenopodium ambroaioides') . In southern Iowa; streeti 

and fields. 
(Photographed by Colburn.) 




Fia. 59-A. Distribution of Mexican Tea. 



DESCRIPTIVE MANUAL 



105 





Fig. 59-B. Plant hair or triohome of (.Chenopodium botrys). 
bj glandular trichomes from calyx. 
(Drawn by Charlotte M. King.) 



a. from stem : 



Maple-leaved Goosefoot {Chenopodmm hylri&um L.). 

Description. — ^A bright green annual from 2-4 ft. high; widely 
branching, with an unpleasant odor like stramonitun ; leaves thin, 
triangular, heart-shaped sinuate-toothed; flowers inconspicuous, in 
loose, racemose panicles; calyx covering the fruit; seed firmly at- 
tached to the pericarp. 

Distribution. — Frequently found in woods and waste places ; ex- 
tending from Kansas to Manitoba, Wisconsin and Minnesota and 
southward ; common in Story, Boone, Marshall, Clinton, Polk, "Wood- 
bury, Pottawattamie, Dubuque, Allamakee and Cerro Gordo coun- 
ties. 



Extermination. — This annual weed can be killed by giving clean 
cultivation. Sometimes distributed with clover seed, but less fre- 
quently than the other species. Sow clean clover seed. 



106 



WEED FLORA OF IOWA 




Fig. 60. Maple-leaved Goosefoot (CTienop odium hyhridum). Frequent In woods 

and waste places. 
(After Mich. Agr. Exp. Sta.) 



DESCRIPTIVE MANUAL 



107 




Fig. 60-A. Distribution of Maple-leaved Goosetoot. 



Lamb's Quarters, Pigweed. {Chenopodium album L.). 

Description. — ^An erect annual from 1-4 ft. high; young plants 
generally mealy, older plants smooth ; leaves rhombic-ovate to lance- 
olate or the upper sometimes linear, acute, lower commonly toothed ; 
flowers produced in clustered, dense-spiked panicles ; calyx 5-parted, 
nearly covering the seed ; seeds surrounded by a loose perioarp form- 
ing an utricle. 

Distribution. — Native to Europe; widely naturalized in eastern 
North America and the Rocky mountains ; occurs in Utah and on 
the Pacific coast ; found everywhere in Iowa in cultivated fields and 
in gardens as well as along highways. 

Extermination. — Plants of this species produce an enormous 
number of seeds. The young plants are easily destroyed by cutting 
off below the ground. Covering the young plants is not effective 
unless the entire plant is covered. Older plants may be destroyed 
by pulling them up. The weed on account of the shade it produces 
destroys other vegetation underneath it. 



Chemical Composition. — According to a report of the Bussey In- 
stitution, the chemical composition is as follows:* 

*Bull. Bussey Inst, 1877: Jenkins and Winton ; Office Exp. Sta., Bull. 11. 



108 



WEED FLORA OF IOWA 




LAMBS QUARTERS OR PIGWEED 
( Chenopodnjm alburn / ) 



Fig. 61. Lamb's Quarters (.Chenopodium album). Common In gardens and fields. 
(After Clark and Fletcher.) 



DESCRIPTIVE MANUAL 



109 




FiQ. 61-A. Distribution of Lamb's Quarters. 



FRESH OH DET AIB MATEBIAl. 



Water 


Ash 


Protein 


Fiber 


Nitrogen free 
extract 


Fat 


80.80 


3.02 


3.91 


2.55 


8.93 


0.78 


WATER FREE tJUBSTANOE. 




15.Y 


20.5 


13.3 


46.5 


4.0 



Orach (Atriplex patula L. var. hastata (L.) Gray.) . 

Description. — ^A pale green or purplish, slightly scurfy, annual, 
2-3 ft. high ; leaves slender-petioled narrowly lanceolate-hastate, en- 
tire or somewhat sinuarte-dentate ; flowers inconspicuous, interrupted, 
slender-panicled spikes. 

Distribution. — ^Pound from eastern Canada northeast to Wiscon- 
sin and Iowa. In Iowa somewhat widely scattered. 



Extermination. — Easily exterminated by cultivation. Sheep are 
fond of it and may be utilized to destroy the weed. 



110 



WEED FLORA OF IOWA 




Fig. 62. Orach (Atriplex patula var. hastata). Streets, gardens, roadsides. 
(Photographed by Colburn.) 




Fio. 62-A. Distribution of Orach. 



DESCRIPTIVE MANUAL 111 

Russian Thistle {Salsala Kali L. var. tenuifoUa G. F. W. Mey). 

Description. — An herbaceous, smooth or slightly pubescent an- 
nual, diffusely branched from the base, from ly^-S ft. high, spherical 
in the mature form ; leaves fleshy, alternate, succulent, linear, sub- 
terete, 1-2 in. long, pointed in the older specimens, upper leaves in 
the mature plant persistent, each subtending 2 leaf -like bracts and 
a flower; stem and branches red; apetalous flowers solitary and ses- 
sile; calyx consisting of 5 persistent lobes, enclosing the dry fruit 
which is usually rose-colored, about 1-12 in. long; 5 stamens nearly 
as long as the calyx ; pistils with 2 slender styles producing a single 
obconical depressed seed, dull gray or green, without albumen ; em- 
bryo spirally coiled ; on germination cotyledons are subterete. The 
plant flowers in July or August, the seeds maturing in August. 

Distribution. — Russian thistle is native of Russia and western 
Asia. Since its introduction into the Dakotas it has been widely 
scattered in the northern states and is common from Minnesota to 
the Pacific northwest and in the Rocky mountains from Montana to 
New Mexico. It is widely scattered in Iowa but abundant only dur- 
ing dry years, along the right of way of railways, and in the vicinity 
of stockyards. 

Extermination. — The Russian thistle as said before, is an annual, 
hence it would seem an easy matter to destroy it ; and as a matter of 
fact, when taken in time, it is not a difficult weed to remove. Its nox- 
iousness comes largely from the fact that the plant is so productive. 
If a Russian thistle is once cut off at the surface of the ground it 
never grows again ; hence in cultivated fields it is not likely to prove 
a great pest. The question is, however, a very different one in pas- 
tures, meadows and roadsides; here the weeds oannot be removed 
by cultivation and many of the plants mature their seeds unobserved. 
The removal of the weeds along the roadsides is important, because 
it is largely from this source that our fields become infested. The 
removal of such weeds can be best accomplished by running over the 
patch with a mower. 

Fletcher and Clark recommend as follows : ' ' Hand-pull wherever 
practicable. Harrowing growing crops is an effective remedy ; it is 
easily killed by this method when young. The harrow should be ap- 
plied just before the grain emerges from the ground and again when 
the crop is three inches high. ' ' 



112 



WEED FLORA OF IOWA 




Fig. 63. Russian Thistle (.Salsola kali var. tenuifolia). Common in western 

Iowa. Fleshy herb becoming spiny. 

(Photographed by Gardner.) 




Fia. 63-A. Distribution of Russian Thistle. 



DESCRIPTIVE MANUAL 



113 



Wallace's Farmer suggests the following treatment: "Russian 
thistle is easily controlled by cutting it off just below the surface of 
the ground before it seeds in August. It has not proved a dangerous 
weed east of Mississippi river." 



CHEMICAL COMPOSITION. 





Original 
Sample 


Dry 
Matter 


Water — — - 


(2.22) 


84.52 
15.48 

84.52 
3.41 
.34 
6.10 
2.78 
2.86 


(14.35) 








100 parts contain: 




Crude ash . _- 

Ether etxtract (crude fat) __ '__ 


22.01 
2.50 


Nitrogen free extract (soluble carbohydrates) 


39.38 
17.94 




18.46 


True albuminoids (albuminoid N x G.2S) — — - 








100.00 




100.00 



AMARANTHACBAE, PIGWEED FAMILY. 

This family contains few economic plants. Some, like the cock's- 
comb, are grown for ornamental purposes. 



Pigweed, Redroot (Amaranthus retro flexus L.). 

Description. — ^A roughish, more or less pubescent annual ; 3-5 ft. 
tall ; leaves ovate or rhombic-ovate, undulate ; long-margined petiole, 
entire ; flowers in thick spikes crowded in a stiff or bunchy, spiky 
panicle; bracts subulate, longer than the mueronate or obtusely- 
tipped sepals. 

Distribution. — ^A weed throughout North America, especially east- 
ward ; abundant in every county in the state. 

Extermination. — ^Frequently distributed with clover seed; sow 
clean clover seed in a clean field. Easily exterminated by cultiva- 
tion. 

Fletcher and Clark recommend as follows: "When embedded in 
the soil, the seeds retain their vitality for several years, though prob- 
ably not more than five in a moist soil, and produce seedling plants 
only when brought by cultivation within about two inches of the 

surface." 
8 



114 



WEED FLORA OF IOWA 




Pig. 64. Pigweed, Redroot (.Amaranthus retroflexus) . Common in gardens, 

roadsides and fields. 
(After Clark and Fletcher.) 



8 



DESCRIPTIVE MANUAL 



115 





Fig. 64A Figure MB 

Fig. 64-A. Trichomes or plant hairs from stem of pigweed. 
(Drawing by Cliarlotte M. King.) 

Fig. 64-B. Distribution of Figweefl. 

Chemical composition. — According to the University of Minnesota 
the composition is as follows:* 



Dry Matter 


Crude Protein 


Ether Extract 


Nitrogen Iree 

extract and 

fiber 


Ash 


97.00 


26.54 


1.3S 


.62.86 


9.24 



Tumbleweed {Amaranthus graecizans L.). 

Description. — A smooth, pale green much-branched annual; at 
maturity a spherical mass, which separates easily from the root; 
leaves oblong-spatulate or ovate ; small flowers greenish, inconspicu- 
ous, polygamous, several together in small axillary clusters, small 
and pointed. 

Distribution. — Common in North America especially from Ohio 
westward. In waste grounds. The detached leafless plants may 
be seen rolling over fields. 

Extermination. — Easily exterminated by cultivation. 



♦Bull. Minn. Agr. Exp. Sta. 11, by Harry Snyder. 



116 



WEED FLORA OF IOWA 





jJifM 


1^^^^ 




i 


f^^^J^ 


^ 


"Sl^^ 1» 


r^ 


. 


/^\ 


^^A^ 


\, 


/"* K 


r^ 


^ 


^^s 


k 



FiQ. 65. lawa Tumbleweed or Tumbling Pigweed (.AmaramXlvaa ffroecteon*). 
Common in com fields. Plant grows in circular form, separates from th» 
root in the autumn and rolls over and over, scattering the seeds. 
(Photographed by Hart.) 




Fia. 66-A. Distribution of Tumbleweed. 



DESCRIPTIVE MANUAL 



117 



Prostrate Pigweed {Amaranthus Uitoides Wats.). 
Description. — ^A diffusely branched, prostrate herb, spreading on 
the ground, often in mats 4 or 5 ft. long ; leaves obovate or spatu- 
late; flowers inconspicuous, greenish, in short axillary clusters. 




Fic. 66. Prostrate Pigweed (.Amaranthus Uitoides). Common along roadsides, 

streets, fields, and in waste places. 

(Photographed by Hart.) 




Fig. 66-A. Distribution of Prostrate Pigweed. 



118 



WEED FLORA OP IOWA 



Distribution.— Common in every county in the state of Iowa and 
east to northeast ; indigenous to the Rocky mountains. 

Extermination. — Easily exterminated by cultivation. 

"Water Hemp {Acnida tuherculata Moq.). 

Description. — A tall, erect annual; leaves lanceolate to rhombic- 
ovate, acute, or acutish; flowers dioecious; pistillate flowers small, 
green, clustered in naked or leafy , terminal and axillary spikes ; 
staminate flowers pale; dehiscent pericarp thin. 

The Acnida ta/mwriscina (Nutt.) Wood, of similar habit. Has 
circumscissille fruit, otherwise like 'the A. titberculata. 

Distribution. — Common along water courses, prairies and marshes 
from northeast to Minnesota and Dakota. Found in Iowa in Story, 
Boone, Polk, Pottawattamie, Woodbury, Emmet, Cerro Gordo, Clin- 
ton, Linn, Marshall and Allamakee counties. 




Fig. 67. Water Hemp (.Acnida tmberculata) . Common plant with yellowish 

aspect. In old lake beds and prairies. 

(Photographed by Colburn.) 



DESCRIPTIVE MANUAL 



119 




Fig. 6 7- a. Distribution of Water Hemp. 

Extermination. — Easily exterminated by cultivation; not infre- 
quent in clover seed, and not long present in well cultivated fields 
especially when they are well drained. 

NYCTAGINACEAE, FOUR-O'CLOCK FAMILY.' 
This family contains the well known cultivated four-o'clock. 



Four-o'clock, Umbrella Plant (Oxybaphus nyctagineus (Mx.) 

Sweet.) 

Description. — A nearly smooth, deep-rooted perennial 2-4 ft. high ; 
forking leaves, broadly ovate, cordate, or lanceolate, opposite, round- 
ed or truncate at base ; petioled involucre ; flowers persistent ; fruit 
obovoid, pubescent ; calyx bell-shaped, rose or purple ; stamens gen- 
erally 3. 

Distribution. — From Manitoba to Louisiana, introduced eastward ; 
common in cultivated fields, on railway embankments and in waste 
places. 

Extermination. — This weed propagates both by its seed and root ; 
however, it is not difficult to destroy when the roots are cut off 
during dry weather. 

Wallace's Farmer suggests the following treatment: "The 
wild four-o'clock, although not yet very common in the corn 
belt, has possibilities of becoming a bad weed. It is a perennial, 
with a big, fleshy root and spreads freely from the seed. It spreads 
very little from the root. This weed may be exterminated in time 
by cutting it off close to the ground every year just before it seeds. ' ' 



120 



WEED FLORA OP IOWA 




Fig. 68. Wild Four-o'clock (.Oasybaphus nyctagineus) . Common in fields, along 

roadsides and on railway embankments. Plants have a long, stout root. 

(Pliotographed by Colburn.) 




FlQ. 68-A. Distribution of Wild Four-o'clock. 



CARYOPHYLLACEAB, PINK FAMILY. 
This family contains the well known carnation, spurrey and gar- 
den pink. 



DESCRIPTIVE MANUAL 



121 



Ghickweed {Stellaria media (L.) Cyrill.). 
Description. — An annual, or winter annual, whose spreading 
stems are mairked with one or more pubescent lines; leaves ovate 




(After Clark and Fletcher.) 
FiQ. 69. Chlokweed (.Stellaria media). Gardens, lawns, dooryards. 



122 



WEED FLORA OF IOWA 




F:g. 69-A. Distribution of Chickweea. 

f 

or oblong, from 1/2 to 2^ in. long, lower leaves on hairy petioles, 
sepals 4 or 5, greenish ; petals 4 or 5 ; shorter than the calyx and 
2-parted; stamens 3-10; styles 3. Pod ovoid. 

Distribution.' — Chickweed is widely distributed in the northern 
states to the Pacific coast; naturalized from Europe; common m 
many places in lawns and in shady places, not especially trouble- 
some except on the lawn, where often it runs out blue grass. 

Extermination. — This weed is easily exterminated by cultivation. 
Since the lawn, however, cannot be cultivated the best and most ef- 
fective means of exterminating the weed is to spray with iron sul- 
phate at the rate of 100 pounds to a barrel of water. Spray as soon 
as the plants make their appearance and repeat 2 to 5 times during 
the s;eason. 



Nodding Chickweed (Cerastium nutans Raf.). 

Description. — A clammy, pubescent, much-branched annual with 
slender, erect stems 6-20 in. high; leaves oblong, lanceolate, acute, 
the lowest spatulate ; flowers numerous in open loose .cymes ; pods 
nodding on the stalks, curved upward, larger than the calyx. The 
larger mouse-ear chickweed {Cerastium viscosum) is a perennial 
with obovate, clammy, hairy stem; leaves varying from oblong to 
lanceolate ; flowers clustered at first ; sepals rather obtuse, small. 

The common mouse-ear or chickweed {C. vvZgatum) is a peren- 
nial with clammy pubescence. 

Distribution. — From New England to Minnesota, especially south- 
ward in southern Iowa and Missouri. 



DESCRIPTIVE MANUAL 



123 




Fig. 70. Nodding Chlokweed (.Oerastium nutans). Common in fields, waste 

places and streets, southern Iowa. 

(Photographed by Colburn. ) 



Extermination. — This annual is easily exterminated by cultiva- 
tion. When it occurs in places that cannot be cultivated, like pas- 
tures and lawns, iron sulphate at the rate of 100 pounds to a barrel 
of wMer may be used. 



124 



WEED FLORA OF IOWA 




Fio. 70-A. Mouse-ear or Chlckweed (Cerastium vulffatum). Common In pas- 
tures. 
(Photographed by Colburn.) 




Pig. 70-B. Distribution of Larger Mouse-ear or Chlckweed (.Oeraatiitm via- 

eosum). 



DESCRIPTIVE MANUAL 



125 



Corn Cockle (Agrostemma githago L.). 

Description.— A hairy, annual weed, clothed with long, soft hairs ; 
leaves linear-lanceolate, acute or long-acuminate; flowers purple and 




Fig. 71. Com Cookie (.Agrostemma githago). In grain fields. 
(After Clark and Fletcher.) 



126 



WEED FLORA OF IOWA 




Fig. 71-A. Distribution of Corn Cockle. 

long peduncled; calyx lobes long, linear, surpassing the purplish 
red petals ; seeds large, roughened and black. 

Distribution. — A weed long known as troublesome in European 
grain fields, and widely scattered throughout the grain growing sec- 
tion of North America. It is most abundant in Iowa in the wheat- 
growing section but occasionally is found in other places around 
grain elevators. 

ExtermiTiation.- — This weed is an annual and in order that it may 
be checked in its spread, use only clean seed. The seed should be 
put in clean soil. 

Fletcher and Clark recommend as follows : "In the prairie pro- 
vinces, harrowing the grain crop just before it emerges from the 
gound and again when it is about three inches high keeps down this 
weed. Where the land is infested with purple cockle, a thorough 
summer fallow is the best method of getting rid of it. ' ' 



White Campion {Lychnis alba Mill.). 

Description. — A freely branching biennial, with a slightly plea- 
sant odor; leaves ovate-oblong or ovate-lanceolate; flowers loosely 
paniculate, white or pink, fragrant; capsule ovoid-conical, swelling 
with the ripening of the pod ; petals 2-clef t, crowned. 

Distribution. — Introduced with clover seed from Europe, not, 
however, as common in the east as Lychnis dioica. 



DESCRIPTIVE MANUAL 



127 




Fig. 72. White Cockle (Lychnis alba). In clover meadows. 
(After Clark and Fletcher.) 



128 



WEED FLORA OF IOWA 




Fig. 72-A. Distribution of Wliite Cockle. 

Exiermination. — This weed can be exterminated by cutting oflf 
the plants when in bloom or by cutting them off a few inches below 
the surface of the ground. Since this weed is being spread with 
European clover seed, care should be used to sow only clean clover 
seed. 

Catchfly {Silene dichotoma Ehrh.). 

Description. — A tall, more or less hirsute, annual, somewhat viscid, 
pubescent; leaves lanceolate or oblanceolate ; flowers in branched 
racemes, short-pediceled in the forks, or solitary at the nodes ; calyx 
5-ribbed, hirsute ; petals white or pink, bifid. 

Distribution. — Introduced from Europe, spreading occasionally 
in clover fields from the northeast to Iowa and Texas, also to the 
Pacific coast. 



Extermination. — A remedy in this case is to sow only clean seed, 
clean clover or alfalfa seed in clean soil in localities where the weed 
occurs. Give thorough cultivation. Do not allow any of the plants 
to go to seed. 



DESCRIPTIVE MANUAL 



129 




Fig. 73. Catchfly (Silene Mchotoma Ehrh.). In waste places. 
(W. J. Beal, Mich. Agr. Exp. Sta.) 



i?o- 



WEED FLORA OF IOWA 




Fig. 73-A. Distribution of Catchfly. 



Night-flowering Catehfly {Silene noctiflora L.)- 

Description. — ^A viscid, pubescent annual from 2-3 ft. high ; lower 
leaves spatulate, upper lanceolate and pointed; flowers few, large, 
peduncled, white, fragrant; calyx prominent veined; pod enlarged 
in ripening of the fruit. 

Distribution. — In waste places in Europe, Canada to Manitoba 
and southward, found in many counties in Iowa. 

Exterrmnation. — This weed is easily exterminated by cultivation. 
It has been widely spread in recent years with clover seed, particu- 
larly clover seed coming from the east and from Europe. Sow only 
clean clover seed on clean soil. 

Fletcher and Clark m.ake the following suggestions for extermin- 
ating the weed : "Farmers who sow clover and grass seed free from 
the seeds of catchfly will not long have trouble with it on lands 
worked under a short rotation of crops. A rotation of crops ex- 
clusive of alsike seed should be adopted for six or eight years. Grass 



DESCRIPTIVE MANUAL 



131 




^'"^ 



STICKY COCKLE 



Fig. 74. Night-flowering Catohfly {Silene nocUflora) . In clover meadows, gar- 
dens, etc. 
(After Clark and Fletcher.) 



132 



WEED FLORA OF IOWA 




FiQ. 74-A. Distribution of Night-flowering Catchfly. 

or clover seed containing catchfly should be thoroughly cleaned in 
milla equipped with screens specially designed to remove this im- 
purity, and should not be used on land that may later be required 
for the production of alsiko seed." 



Cow-herb {Saponaria vaccaria L.). 

Description. — ^A glabrous annual, from 1-2 ft. high with opposite 
ovate-lanceolate leaves ; flowers in oorymbed cymes ; calyx 5-angled, 
enlarged and angled in fruit; petals pale red. 

Distribution. — This weed has long been known as troublesome in 
grain fields of Europe, and is common in North America. It is com- 
mon in Iowa only where wheat is grown. 

Extermination. — Clean seed sown in clean soil is the only method 
of exterminating the weed. 

Clark and Fletcher suggest the following treatment : ' ' Sow clean 
seed. Prevention is the best and least expensive method of fighting 
it. It is a large showy plant and when not present in excessive num- 
bers can easily be hand-pulled. The seed will not retain its vitality 
long ; when land is seeded to timothy or western grass and left for a 
few years, the supply of vital seeds in the soil will be greatly re- 
duced, if not eutirely exhausted." 



DESCRIPTIVE MANUAL 



133 




Fig. 75. Cow-herb (.Saponaria vaccaria}. In grain fields. 
(Clarlc and Fletcher.) 



134 



WEED FLORA OP IOWA 




Fig. 75-A. Distribution of Cow-herb. 



Bouncing Bet {Saponaria officmalis L.). 

Description. — ^Perennial herbs with, large flowers in cymose clus- 
ters; calyx narrowly ovoid or oblong, 5-toothed; petals clawed or 
unappendaged, stamens 10, styles 2, pod 1-celled or incompletely 
2 or 4-eelled and 4-toothed at the apex. 

Distribution. — ^About 40 species in Europe, Asia, and Northern 
Africa. Saponaria officinalis is frequently cultivated in old gar- 
dens. The mucilaginous juice forms a lather with water and is 
valuable for taking grease spots out of woollen cloth. Commonly 
escaped from gardens to roadsides and railway embankments in 
many parts of Iowa but especially in northeastern and eastern 
Iowa. 

Extermmation. — Though this weed is a perennial it is not diffi- 
cult to destroy in cultivated fields and gardens. In lawns and 
places where the soil is not cultivated it is best to dig up the 
patches, remove the dirt from the roots and let the sun dry them ; 
covering with tarred paper will kill the weed, if it is kept covered 
long enough, say from 6 to 8 weeks. 



PORTULACACBAE, PURSLANE FAMILY. 
This family contains the well known moss rose, spring beauty, etc. 



DESCRIPTIVE MANUAL 



135 




Fig. 76. Bouncing Bet, Soapwort (Saponaria officinalis'). 



136 



WEED FLORA OP IOWA 




Fig. 76-A. Distribution of Bouncing Bet. 




Fig. 77. Bouncing Bet (Saponaria officinalis') . Near a building. Seeds mature 

and spread from such places. 

(Photographed by Charlotte M. King.) 



Pusley, Purslane (Portulaca oleracea L.). 



Description. — A fleshy, prostrate, smooth annual with scattered 
obovate or wedge-shaped leaves ; small sessile flowers with a 2-clef t 
calyx; 5 small, yellow petals, inserted on the calyx; stamens 7-12, 
style deeply 5-6-parted ; seeds small, finely rugose. 



DESCRIPTIVE MANUAL 



137 




Fio. 78. 



Purslane or Fusley (Portulaca oleracea). Gardens and oom-fields. 
(After Clark and Fletcher.) 



138 



WEED FLORA OF IOWA 




Fig. 78-A. Distribution of Purslane. 

Distribution'. — Purslane is native to Europe and is common from 
the Atlantic to the Pacific especially in cultivated soil. Common 
everywhere in the state in gardens and in com fields. 

Extermination. — Purslane is not difficult to exterminate if the 
green weeds are placed in piles or removed from the garden. They 
may be fed to hogs. It should be said that the leaves and stems 
show considerable vitality, since the whole plant is fleshy. Fletcher 
and Clark say: "A three-year rotation, including summer-fallow 
directly after the removal of a crop of early clover, followed by a 
hoed crop and again by cereal grain for the third year, will keep 
it in cheek. If given access to corn and potato fields, sheep will feed 
on late plants, and if their pasture is short, will prevent many of 
them from seeding." 

Chemical Composition. — ^According to a report of the Bussey In- 
stitution* the chemical composition is as follows : 

FRESH OR AIR DRY MATERIAL,. 



Water 


Ash 


Protein 


Fiber 


Nitrogen free 
extract 


Fat 


92.61 


1.6S 


2.24 


1.03 


2.16 


0.40 


WATEB FREE SUBSTANCE. 




21.1 


S0.2 


19.9 


29.4 


5.1 



•Bull. 1877: Jenkins and Winton, Bull. Off. Exp. Sta. 11. 



DESCRIPTIVE MANUAL 
RANUNCULACEAE, BUTTERCUP FAMILY. 



136 



The plants of this family are acrid. There are few economic 
plants among them ; some like the peony, columbine, buttercup, lark- 
spur, and aconite are cultivated for ornamental purposes. 

Small-flowered Crowfoot {Eanunculus dbortivus L.). 

Description. — A small, slightly pubescent, succulent biennial; 
from 6 in.-2 ft. high with multiple roots; root leaves roundish or 
kidney-shaped, crenate ; stem leaves often 3-5-lobed or parted, mostly 
toothed ; petals small, pale yellow ; shorter than the reflexed calyx ; 
carpels minute. 




Fig. 79. Crowfoot (Banuncuhis abortivus) . Common in woodland pastures, 

pastures. 
(Photographed by Hart.) 



140 



WEED FLORA OF IOWA 




Fig. 79-A. Distribution of Crowfoot. 

Distribuiion. — Common everywhere in Iowa in waste places 
along roadsides and in fields, occasionally eastward to Newfound- 
land, south to Florida and north to Manitoba, also in the Rocky 
mountains. 

Extermination. — This weed is easily exterminated by cultivation. 



Swamp Buttercup {Ranunculus septentrionalis Poir.). 

Description. — A branching, prostrate, smooth or sometimes pubes- 
cent perennial with multiple fibrous roots, frequently rooting at 
the nodes and often forming long runners; leaves large, petioled, 
3-divided, divisions mostly cuneate, petals obovate, larger than the 
spreading calyx ; achenes flat, strongly margined, pointed by a stout 
straight beak. 

Distribution. — Common in fields, especially low grounds from 
eastern Canada to Manitoba ; south to Kansas and Kentucky. Com- 
mon everywhere in Iowa in low places in Story, Boone, Marshall, 
Polk, Linn, Clinton, Buchanan, Emmet, Worth, Woodbury, Potta- 
wattamie, Plymouth, Kossuth, Dallas and Allamakee counties. 

Extermination. — Drainage of the soil and thorough cultivation 
will soon exterminate this weed. 



DESCRIPTIVE MANUAL 



141 




Fig. 80. Creeping Buttercup (.Ranunculus septentrionaKs) . Common in low 
grounds. Flowers yellow. 
(Photographed by Hart.) 




Fio. 80-A. Distribution of Creeping Buttercup. 



142 WEED FLORA OP IOWA 

Prairie Larkspur {Delphinium .pena/rdi Huth.). 

Description. — A perennial, pubescent or hairy herb, more or less 
glandular above, with simple, erect stem, 3-5 ft. high; leaves 3-5 
parted, divisions 2-3 cleft; the numerous flowers white, or bluish- 
white, in elongated raceme, spur ascending or erect ; follicle many- 
seeded. 

Distribution. — From Illinois and Wisconsin, westward and north- 
ward. Common on gravelly knolls along railroads throughout the 
state of Iowa. 

Extermination. — This perennial is easily exterminated by culti- 
vation. The roots of the plant readily succumb when exposed to 
the sun. 




Pig. 80-B. Prairie JJarkspur (DelpMnlum penordi). Common on gravelly knolls. 
(Drawing by Ada Hayden.) 



CRUCIFERAB, MUSTARD FAMILY. 

This family contains the well known sweet alyssum, cabbage, cauli- 
flower, rape, radish, turnip, white and black mustard, water cress, 
etc. They are all pungent herbs. 



DESCRIPTIVE MANUAL 



143 



Pennyeress {Thlaspi arvense L.)- 

Description. — ^An annual or winter annual with simple, smooth, 
erect or branching stem ; leaves of stem clasping, with arrow-shaped 




-t 'iN f'CRESi 



Fib. 81. Stinkweed or Field Pennyeress CThlaspi arvense). Grain and clover 

fields. - ■ 

(J^fter Clark and Fletcher.) 



144 



WEED FLORA OP IOWA 




Fig. 81-A. Distribution of Pennycress. 

base ; root leaves petioled ; flowers white ; petals nearly equal ; seeds 
purplish brown, longer than broad; cotyledons accumbent. 

Distribution. — CJommon in waste places, particularly in clover 
fields; Story, Woodbury, Winneshiek, Allamakee and some other 
counties in the state. Common in Manitoba, Minnesota, Dakota, and 
eastern Canada, particularly in the prairie provinces. The weed 
is abundantly distributed by spring floods and also to some extent 
by clover seed. 



Large Peppergrass {Lepidium virgiiucum L.). 

Description. — ^An erect annual, at first quite simple, later much 
branched, 8 in.-2 ft. high ; leaves divided, entire or vrith irregular, 
pointed teeth ; flowers small, white ; pod circular or oval with a lit- 
tle notch at the upper end; seeds light brown, elongated, with a 
prominent ridge on one side, on addition of water becoming muci- 
laginous; cotyledons accumbent. 

Distribution. — ^Large peppergrass is native to the Mississippi val- 
ley, east to New England; more common in Missouri, Illinois and 
Ohio. It is widely scattered in Iowa, being particularly common 
in timothy meadows in some years. 

Extermination. — This peppergrass sometimes comes up abund- 
antly in the fall. The fields should, therefore, be plowed in the fall 
and when sowing small grain given a thorough dragging. In com 
fields the ordinary methods of cultivation will destroy the weed. 
Do not permit any of the plants to seed. Frequent in timothy seed. 
Sow only clean timothy seed. 



DESCRIPTIVE MANUAL 



145 



t^ 







Fig. 82. Large or Virginia Peppergrass {Jje'pidAum virginicum) . Common In 

fields, gardens, etc. ; along roadsides. 

(Photographed by Colburn.) 




Fig. 82-A. Distribution of Large Peppergrass. 



10 



146 



WEED FLORA OF IOWA 



Small Peppergrass {Lepidium apetalum 'Willd.) . 
DescnpUon. — ^Much like the foregoing, an annual 8 in-2 ft. high, 
but leaves and pods smaller; flowers small, greenish; seeds light 




WILD PePPtRGRASS 



Fig. 83. Small Peppergrass (Lepidium apetalum). Commqn in timothy 

meadows, fields, etc. 
(After Clark and Fletcher.) 



DESCRIPTIVE MANUAL 



■147 




FiQ. 83-A. Distribution of Small Peppergrass. 

brown, elongated, with prominent ridge on one side, becoming muci- 
laginous when moistened with water ; cotyledons incumbent. 

Distribution. — Small peppergrass is common in the northern 
states from New England across the continent; apparently native 
in the west ; in the east introduced from Europe. It is abundant in 
fields and waste places. In some years it is particularly common in 
timothy and clover meadows. 

Extermination. — The peppergrasses are not difficult to extermin- 
ate in cultivated fields since they are annuals. In growing timothy 
seed it is important above all to have a field as clean from weeds 
as possible. Timothy should therefore be sown in a field that has 
been under thorough and clean cultivation for several years and 
clean seed only should be used. In this way the peppergrass can 
largely be prevented from growing. 

Fletcher and Clark make the following suggestions: "Only 
autumn plants which live through the winter give trouble in grain. 
Thorough surface cultivation in the spring, with the plow, disc or 
broad-shared cultivator, is efficacious. linmature seeds may ripen 
in the pods when plowed down." 



Hoary Alyssum (Berteroainccma (L.) DC). 

Description. — A tall, green, erect annual or biennial with entire, 
pubescent, pale green, lanceolate leaves; flowers white, 2-parted; 
pods caneseent. 



148 



WEED FLORA OP IOWA 




ir,„ R4 Hoary Alyssum (.Berteroa incona) ; a, flowering stem; 6. flower; o. 




Fig. 84-A. Distribution of Hoary Alyssum. 



DESCRIPTIVE MANUAL 149 

Distribution. — Said to be common in northeastern United States 
and becoming frequent in other Atlantic states ; found in Mississippi 
and adjacent states; found not infrequently in Iowa; reported from 
Ida county in 1912, and said to have been introduced with clover 
seed. 



Extermination. — Sow clean clover and alfalfa seed. Succumbs 
readily to cultivation. 

False Flax {Camelina sativa Crantz.). 

Description. — ^An erect annual with single or sparingly branched 
stem, 1% ft. long, smooth or slightly pubescent stellate hairs ; leaves 
erect, lanceolate or arrow-shaped, entire or nearly so ; flowers small, 
yellow, pedicels in fruit spreading ; pod obovoid 4-6 in. long, smooth, 
reticulated, margined from beak down along placental side with 
smaller ribs between them ; seeds light brown, 1 line long, minutely 
pitted, caulicle prominent, running lengthwise with a prominent 
groove between it and the cotyledons which are incumbent ; on the 
addition of water seeds become mucilaginous. 

Distribution. — This weed is particularly common in the grain 
growing sections of the north, as Dakota, Manitoba and Saskatche- 
wan. In recent years it has become more common in Iowa, par- 
ticularly in the northern counties. 

Extermination. — Clark and Fletcher recommend the following 
treatment: "When a crop of winter wheat is infested with false 
flax, harrowing in the spring kills the young plants without injur- 
ing the wheaA. A thorough summer-fallow, with cultivation the pre- 
vious fall and continuous cultivation throughout the summer, is 
recommended for fields badly infested with this weed. ' ' 



150 



WEED FLORA OF IOWA 




Fig. 85. False Flax (CameUna sativa). In grain and flax fields, waste places. 
(After Clark and Fletcher.) 



DESCRIPTIVE MANUAL 



151 




Fig. 85-A. Distribution of False Flax. 

Shepherd's Purse {Capsella iursa-pastoris Moeneh.) 

Description. — ^An annual or winter annual 1-1^2 ft. high; root 
leaves clustered, nearly divided or merely toothed ; stem leaves ses- 
sile ; flowers small, white, in fruit spreading ; pods much wider above 
than below, many-seeded ; seeds light brown, elongated, with a promi- 
nent ridge, mucilaginous when moistened with water; cotyledons 
incumbent; trichomes stellate, roughened. 

Distribution. — Shepherd's purse is native to Europe and one of 
the most common early spring flowers from the Atlantic to the Pa- 
cific. Common everywhere in gardens and fields in the state. 



Extermination. — Clark and Fletcher state : "It has an enormous 
I)ower of propagation ; a single plant will ripen 50,000 seeds. Waste 
places should be cleared as far as practicable and seeded to grass. 
It does not give serious trouble on lands worked under a short rota- 
tion, with clean cultivation of hoed crops. Sow clean grass and 
clover seeds." 



152 



WEED FLORA OF IOWA 




Fig. 86. Shepherd's Purse (Capsella bvrsa-paatoria) . Common In gardens, 

fields and waste places. 

(After Clark and Fletcher.) 



DESCRIPTIVE MANUAL 



153 





Figure 86A Figure 86B 

Fig. 86-A. Plant hair or trichome of Shepherd's Purse. 
(Drawing Charlotte M. King.) 

Fig. 86-B. Distribution of Shepherd's Purse. 




li'ia. 86-C, Shepherd's Purse (Capsella bursa-pastoris) . Weed in city streets. 
(Photographed by Charlotte M. King.) 



Jointed Charlock {Baphanus raphanistrumli.) . 

Description. — Biennial or annual, having a slender root, rough 
leaves, lyrate, pinnatifid, with a large terminal lobe; flowers yel- 
lowish fading to white, or purplish veined ; pods linear or oblong, 
jointed, 2-8-seeded. 



154 



WEED FLORA OF IOWA 




WILD RADISH i-B JOiNTbD CHARLOCK 



Fig. 87. Wild Radish or Jointed Charlock (Baphanus raphanistrum) . In oat 

fields in northern Iowa. 

(After Clark and Fletcher.) 



DESCRIPTIVE MANUAL 



155 




Fig. 87-A. Distribution of Jointed Charlock. 

Distribution. — Common; spreading eastward in fields and waste 
places; reported in grain fields in "Worth and a few other counties 
in the northern part of Iowa. It is said to have been largely dis- 
tributed with oats seed. 

Extermination. — Exterminated by cultivation. Sow only clean 
oats seed in clean fields. 



Mustard or English Charlock {Brassica arvensis (L.) Ktze.). 

Description. — Lower leaves nearly divided to the middle^ with 
divisions unequal, terminal lobe larger, upper leaves not stalked 
as a rule, much smaller than the lower; flowers yellow, large and 
very fragrant; pods 1-2 in. long, irr^ular in outline, appearing 
somewhat nodose, 3-7-seeded or occasionally more, upper part of pod 
forming a beak; seeds round, brownish black, darker than in B. 
nigra and minutely pitted, when moistened becoming mucilaginous. 

Distribution. — ^Mustard or charlock has been known as a pest of 
the grain fields from the earliest historical record, throughout the 
grain growing section of the world; common everywhere in Iowa, 
but most abundant in the grain growing section of northern and 
northwestern Iowa where it was introduced with flax. 

Extermination. — The first and' most important consideration in 
connection with the extermination of mustard is that the oats or 
wheat should be freed from mustard seed. Then this grain should 
be sown on clean fields, preferably fields that have been in pasture 
or meadow. Nothing has done so much to remove the weeds from 
the fields of northwestern Iowa as the pasture and meadow. If the 
grain is sown in a corn field there should have been no mustard the 



156 



WEED FLORA OF IOWA 




Fig. 88. Wild Mustard or Charlock {Brassica arvensis). Common in road- 
aides and grain fields. 
(After Clark and Fletcher.) 



DESCRIPTIVE MANUAL 



157 




Fig. 88-A. Distribution of "Wild Mustard. 

previous season. Having sown the small grain on a clean field there 
is always a chance that some of the seeds will retain tfieir vitality 
in the soil. If much of this mustard should come up it may become 
necessary to spi^y it with iron sulphate. Where the mustard is 
abundant this is a very effective means of destroying the weeds, 
using the sulphate at the rate of 100 pounds to a barrel of water. 

Chemdcal Composition. — According to the University of Minne- 
sota the chemical composition is as follows :* 



Dry Matter 


Crude Protein 


Ether Extract 


Nitrogen tree 

extract and 

fiber 


Ash 


91.79 


1B.75 


1.55 


TO.69 


7.11 



Black Mustard {Brassica nigra Koch.). 

Description. — ^A tall, coarse, much-branched annual, 2-5 ft. high ; 
leaves variously divided or only deeply cut, the terminal lobe the 
largest, sharply toothed, upper leaves small, simple, as a rule linear ; 
leaves as a rule not smooth, but somewhat bristly, at least on the 
veins ; flowers yellow, smaller than in charlock ; pods smooth, about 
y2 in. long, 4-comered, tipped with a slender beak; seeds black or 
reddish brown, smaller than in charlock; cotyledons incumbent; 
trichomes not stellate, simple, rough. 

•Snyder: Bull. Minn. Agr. Eixp. Sta., 101. 



158 



WEED FLORA OF IOWA 




Fig. 89. Black Mustard (.Brassica nigra). Fields, gardens and roadsides. 
(Photographed by Colburn.) 




Fig. 89-A. Distribution of Black Mustard. 



DESCRIPTIVE MANUAL 



159 



Distribution. — This weed is common in the northern states and 
extends across the continent. It is abundtot in Iowa, at times, in 
waste places and vacant lots; apparently, however, it is less com- 
mon than common charlock. 

Extermvnation. — This weed can he exterminated by the same 
method that is used with common charlock. 

Rocket {Eruca sativa L.). 

Description. — ^An annual or biennial herb with stout, 4-sided 
stem; lower leaves lyrate, incised or pinnatifid, upper leaves. 




Fig. 90. 



Rocket (Eruca sativa). Introduced with alfalfa seed. 
(Drawn by F. C. Collins.) 



160 



WEED FLORA OF IOWA 




Fig. 90- A. Distribution of Rocket. 

smaller, lobed, or entire ; flowers white or yellowish-wliite with dark 
veins; fruit an oval, elongated silique containing many, more or 
less compressed, seeds in 2 rows. 

Distribution. — ^A native of western Asia and the Mediterranean 
region, but cultivated as a salad plant and often an escape. Intro- 
duced into Iowa with alfalfa seed in Woodbury, Plymouth, 'Brien, 
Clay, Mitchell, Pottawattamie, Mills, Id.a, and Sac counties. 

Extermination. — The weed can be exterminated by cutting the 
plants off a few inches below the surface of the ground or by giving 
thorough cultivation. 



Hare 's-ear Mustard {Conringia orientalis (L.) Dumort). 

Description. — Slightly succulent annual ; leaves light green, ses- 
sile, obtuse, racemes becoming elongated in fruit; petals much 
longer than the sepals; pods long, linear 4-angled, spreading; coty- 
ledons incumbent. 

Distribution. — Common eastward and appearing in the Missis- 
sippi valley; occuri-ing in Woodbury, Webster and Page counties 
and probably in many other places in Iowa. 

Extermination. — Easily exterminated by cultivation. 



DESCRIPTIVE MANUAL 



161 




Fig. 91. Hare's-ear Mustard iConringia orientalis) . In grain fields, and waste 
places in northwestern Iowa. 
(After Clark and Fletcher.) 



11 



162 



WEED FLORA OF IOWA 




Fig. 91-A. Distribution of Hare's-ear Mustard. 




Fig. 91-B. Hare's-ear Mustard (.Cov/ringia oHentaUay . Flowering stem, seed 
and cross section of seed. Appearing In several counties in Iowa. 



DESCRIPTIVE MANUAL 
Ball Mustard {Neslia paniculata (L.) Desv.). 



163 



Description. — ^An erect, slender annual or biennial, 1-3 ft. high 
■with stem simple up to the inflorescence; stem and leaves, both 
being covered with stellate pubescence; sessile leaves oblong, very 




Fig. 91-C. Ball Mustard (Neslla paniculata) ; a^ flowering stem ; 6, pod ; c, seed. 
(Schuyler Mathews in Mich. Agr. Exp. Sta. Bull.) 



narrow, sagittate at base; racemes elongate; flowers small, yellow, 
about % in. in diameter; seed-pods nearly spherical, 2-celled with 
1 small yellow seed in each cell, sometimes but one developing. 

■ Distribution. — In grain flelds, Canada, the Dakotas and occa- 
sionally in northwestern Iowa. 

Extermination. — Clean seed; easily destroyed by cultivation. 



164 WEED FLORA OP IOWA 

Hedge Mustard {Sisymbrium officinale (L.) Scop.)- 

Description. — ^A slender, erect annual or winter annual, l%-2^ 
ft. high ; lower leaves divided, upper entire or hastate at base ; flow- 
ers small, yellow, borne in spikelike racemes; seeds small, brown; 
cotyledons incumbent. 

Distribution. — Found everywhere in the state, notably in Story, 
Boone, Polk, Clinton, Linn, Marshall, Hardin, Black Hawk, Wood- 
bury, Pottawattamie, Carroll, Jasper, Monroe, Scott, Lee, and Alla- 
makee counties. 

Exterminaition. — Easily exterminated by cultivation ; also by us- 
ing the formula 100 pounds of iron sulphate to one barrel of water. 




Fig. 92. Hedge Mustard ISisymbrium officinale). Common in gardens, fields 

and waste places. 
(General aspect of plant photographed by Hart. Drawing by Charlotte M. King.) 



DESCRIPTIVE MANUAL 



165 




Fig. 92-A. Distribution of Hedge Mustard. 

Chemical C omposition.-^ Aceovding to the University of Minne- 
sota it is as follows :* 



Dry Matter 


Crude Protein 


Ether Extract 


Nitrogen Iree 

extract and 

fiber 


Aeb 


94.5 


16.62 


1.43 


74;18 


7.87 



Tumbling Mustard {Sisymbrium aiUssimum L.). 

Description. — ^A leafy, branclied annual from 1-4 ft. high, lower 
leaves runcinate, pinhatifid, irregularly toothed, or wavy margined, 
upper leaves smaller, threadlike. 

Distribution. — This weed is native to east Europe. It has become 
widely scattered in the northern states, particularly in the west from 
Minnesota to Washington and in Canada. It is widely sca;ttered in 
Iowa in the vicinity of railroad watering tanks, elevators and stock- 
yards. It is less common in the southern half of the state. 

Extermination. — The young mustard plants are easily killed by 
cultivation. They are likely to occur in some commercial seed like 
timothy, therefore, sow only clean seed. 

•Snyder: Bull. Minn. Agr. Exp. Sta., 101. 



166 



WEED FLORA OF IOWA 




F"ig. 93. Tumbling Mustard (.Sisymbrium altissimum). In grain fields, rail- 
ways, etc. 
(After Clark and Fletcher.) 



DESCRIPTIVE MANUAL 



167 




Fig. 93-A. Distribution of Tumbling Mustard. 

Marsh Cress {Badicvia palustris (L.) Moench.). 
Description. — An annual or biennial; erect, smooth, or slightly 
pubescent herb; from 1-1% ft. high; leaves pinnately cleft, or 
parted, pinnaitifid; the lobes toothed; upper leaves sessile; flowers 
yellowish in racemes ; pods ellipsoid or ovoid. 




Pig. 94. Marsh Cress (Baddcula paUistris). Common in low grounds. 
(Photographed by Colbum.) 



168 



WEED FLORA OF IOWA 




Fig. 94-A. Distribution of Marsh Cress. 

Distribution. — In wet places or in low grounds; frequent in oat 
fields and meadows ; abundant in Iowa especially in northern Iowa ; 
common throughout the northern United States. Not infrequently- 
distributed with clover seed that is grown in Iowa. 

Extermination. — This weed may be exterminated by first drain- 
ing the soil and then giving clean cultivation. 



Horseradish (Baddcula armoracia (It.) Robinson) . 

Description. — ^A stout perennial with long, deep roots; leaves 
large, oblong, crenate or pinnatifid, the latter produced in the 
spring; stem leaves lanceolate, or oblong cordate; flowers with 4 
green sepials and 4 white petals, not' common ; pods short, globular, 
but fruit seldom found. At least I have never observed any in Iowa. 

Distribution. — Horseradish is native to eastern Europe and in- 
troduced in west Europe and the United States ; common from the 
Atlantic to the Pacific; largely an escape from cultivation; found 
in every part of Iowa. 

Extermination. — The horseradish is one of the most persistent 
of our weeds ; no other weed will stand such rough treatment. It 
may be hoed and cultivated and still it persists in coming up. Some 
years ago we tried the following plan : The land was plowed, then 
harrowed ; the roots were picked up and the process repeated after 
the lapse of a week, when young plants again made their appear- 
ance. After that, young plants were cut off with a hoe below the 
ground as soon as they appeared. This treatment was kept up for 



DESCRIPTIVE MANUAL 



169 




FiQ. 94-B. Horseradish (.Radicula armoracia). Escaped from cultivation; a 

rather persistent weed. 

(Drawing: by Charlotte M. King.) 




Fig. 94-C. Distribution of Horseradish. 



two years, and in this way most of it was removed. Quack grass 
near the horseradish received the same treatment and was killed in 
a single season, the season being dry. Yery little progress in de- 
stroying the plant would have been made in a wet season. 



170 



WEED FLORA OF IOWA 



Winter Cress {Barharea vulgaris R. Br.). 

Description. — ^A biennial, witli yellow "flowers 1-2 ft. high ; stem 
furrowed, simple or branched; lower leaves simple or pinnately 
parted, terminal lobe the largest, round or ovate; upper leaves obo- 
vate, cut, toothed or pinnatifid at the base ; flowers bright yellow ^ 
pods erect or slightly spreading ; cotyledons accumbent. 

Distribution,. — Eastern North America from Labrador to Mary- 
land, Iowa, Manitoba, Rocky Mountains, Pacific slope; common in 
northern Iowa. A cosmopolitan weed in Europe, Asia, Africa and 
Australia. 

Extermination.' — This perennial weed is not difficult to kill if the 
field is given an early plowing followed by a subsequent disking and 
harrowing, thus getting the field in a good state of tilth for a crop. 




Fig. 



95. Winter Cress (.Barharea vulgaris). 
(Photographed by Colbum.) 



DESCRIPTIVE MANUAL 



J71 




Fig. 95-A. Distribution of Winter Cress. 

CAPPARIDACEAE. CAPER FAMILY. 

This family contains the caper which is used for pickling, the 
Rocky Mountain bee plant, etc. 



Stinkweed {Polanisia gra/ueolens Baf.). 

Description. — A fetid annual with glandular hairs; leaves with 3 
oblong leaflets ; flowers in leafy racemes ; 6 petals, white, with claws, 
notched at the apex ; stamens about 11, scarcely exceeding the petals ; 
not elongated, bearing a gland behind the base of the ovary; pod 
short, stalked; seeds rough. The P. trachysperma T. & G. has larger 
flowers with long exserted stamens and sessile pods. 

Distribution. — Iowa to Kansas and eastward to New England; 
common in sandy soil, railroad embankments, Muscatine Island. 

Extermination. — Easily exterminated by cultivation. The land 
should be cultivated as soon as a fresh growth of the weed develops. 
Great care must be taken not to plow down any full-sized pods, even 
though they may be green, as it has been proven that in the dry 
climate of the west such seeds can ripen beneath the soil. The most 
important measure to be used in order to clear the land of stink- 
weed is harrowing the growing crop to kill the seedlings. The har- 
rowing should commence before the crop emerges from the ground 
and be repeated when the grain is about three inches high. 



172 



WEED FLORA OP IOWA 



/ 


^ s ^^^BR^Bs^''**' 






.J^^' 








Ife 


y 


j£id 


f 


I^^^^^^^R&^ZMi 


HH^?^ v'^*^^^^ fllH 


P / 


^w 




^' 



Fig. 96. Clammy Weed or Stinkweed (Polaniaia graveolens). In sandy places, 

gravelly soils, etc. 
(Photographed by Hart.) 




Fig. 96-A. Distribution of Stinkweed. 



DESCRIPTIVE MANUAL 



173 




Fig. 97. Stinkweed (Polaniaia trachysperma) . Common in sandy soils, rail- 
way embankments and gravelly soils. 
(Photographed by Colburn.) 



Rocky Mountain Bee-plant or Stinking Clover (Cleome serrulata 

Pursh.). 

Description. — A smooth annual; leaves of 3 lanceolate, oblong 
leaflets, somewhat fleshy; flowers in braeteate racemes; petals 
usually rose-colored, short-clawed ; stipe of pod as long as the pedicel. 

Distribution. — From western Iowa, Minnesota and northward, 
Utah, Colorado, Montana and westward; common in Iowa in Fre- 
mont, Mills, Pottawattamie, and "Woodbury counties, occasionally 
eastward in Polk county. 



Extermination. — Easily exterminated by cultivation. 



174 



WEED FLORA OF IOWA 




Pig. 98. Eocky Mountain Bee-plant CCleome serrulata). Fields, roadsides In 

western Iowa. 
(Photographed by Colburn.) 




Fig. 98-A. Distribution of Rocky Mountain Bee-plant. 



DESCRIPTIVE MANUAL 175 




Fig. 98-B. Rocky Mountain Bee-plant (.Cleome serrulata). 
(Drawing by Charlotte M. King.) 



ROSACBAB, ROSE FAMILY. ^ 

This family contains the well known rose, apple, pear, quince, 
plum, peach, almond, strawberry, blackberry, raspberry, spiraea, 
etc. 

Cinquefoil, False Strawberry {Potentilla monspeliensis L.). 

Description. — ^A hairy annual or winter annual from 1-21/^ ft. 
high; leaves 3-foliolate, leaflets obovate to oblanceolate, the upper- 
most toothed, nearly the whole length ; flowers in close cymes, calyx 
large, 5-cleft with 5 bractlets ; petals 5, yellow, small ; stamens 15-20 ; 
style terminal ; trichomes simple, long pointed, thick walled. 

Distribution. — ^Naturalized from Europe; eastern Canada, New 
England, to Kansas ; common in Iowa, in Story, Boone, Polk, Clin- 
ton, Lyon, Carroll, Woodbury, Kossuth, "Webster, Marshall, Cerro 
Gordo, Worth, Winnebago, Allamakee and other counties. 

Extenmnation. — ^Frequently introduced with clover seed. Sow 
only clean clover seed in a clean field. Cut the weed off below the 
surface of the ground and give thorough cultivation. 



176 



WEED FLORA OP IOWA 




Fig. 99. Cinquefoil, False Strawberry, Five-finger (Potentilla mons'geUenais') . 
Common In gardens, timothy meadows, etc. a. Plant hair ; i, showing cell-wall, 
(o and i, drawn by Charlotte M. King, general aspect of plant photographed 

by Hart.) 




Fig. 99-A. Distribution of Cinquefoil. 



DESCRIPTIVE MANUAL 
Silverweed {Potentilla anserina L.) . 



177 



Description. — Herbaceous perennial, spreading by slender run- 
ners; numerous white-tomentose and silky-villous leaves, all radi- 




Fig. 100. Silverweed (Potentilla artserina) . In marshes. 
(Drawing by Ada Hayden.) 




Fig. 100-A. Distribution of Silverweed. 



12 



178 



WEED FLORA OF IOWA 



cal ; pinnate leaflets, 7-21 with smaller ones between, oblong, sharply 
serrate, silky-4;omentose beneath ; flowers with 5 bright yellow petals ; 
peduncles elongated ; styles filiform. 

Distribution. — Common eastward in brackish marshes; also in 
the Dakotas and the Kocky mountains ; common in Wright county, 
Iowa ; perhaps in other places. 

Extermination. — Give a shallow cultivation; expose the roots to 
the sun. Care must be used to kill the weed on its first appearance 
as it is quite persistent. 

Wild Rose (,Bosa pratincola Greene). 

Description. — ^Low shrub with very prickly stem; compound 
leaves of 7-11 leaflets, broadly eUiptieal to oblong-oblanceolate, sub- 
cuneate at base, short stalked or sessile, serrate; stipule narrow, 




Fig. 101. Wild Rose (Rosa pratincola). Grain fields, roadsides. 
(Photograplied by Coibum.) 



DESCRIPTIVE MANUAL 



179 




Fig. 101-A. Distribution of Wild Rose. 




Fig. 101-B. Wiia Prairie-rose (Rosa pratincola). 
(Drawn by Ada Hay den.) 



180 WEED FLORA OF IOWA 

glandular toothed; flowers corymbose, calyx tube urn-shaped, 5 
sepals, smooth or occasionally hispid, petals 5, rose-colored; fruit 
oblong, ovaries hairy. 

Distribution. — Common in prairies and field from Texas to Min- 
nesota, west to Colorado. Common everywhere in Iowa; Story, 
Polk, Emmet, Dickinson, Palo Alto, Clay, Kossuth, Winnebago, 
Allamakee, Clinton, Muscatine, Scott, Decatur, and Pottawattamie 
counties. 

Extermination. — This weed often persists in grain fields of 
northern Iowa. Thorough cultivation for a few seasons will, how- 
ever, usually destroy the weed. 

Stickweed {Geum canadense Jacq.). 

Description. — ^A perennial herb from 114-2 ft. high; leaves pin- 
narte, the lower of 3-5 leaflets or undivided ; stem leaves 3-divided or 
3-lobed, sharply toothed ; stipules ovate-oblong ; flowers white ; calyx 
bell-shaped ; deeply 5-clef t ; petals 5 ; stamens many ; pistils numer- 
ous; styles jointed and bent near the middle, the upper part falling 
away and the lower part hooked. 

Distribution. — Widely distributed in northern United States, and 
frequently found in woods or fields adjacent thereto ; common espe- 
cially in northeastern Iowa. 

Extermination. — This weed is easily scattered by animals because 
of the hooked achenes ; thorough cultivation will, however, destroy 
it. 

LEGUMINOSAE, PULSE FAMILY. 

This family contains the clover, pea, beans, eowpea, soybean, 
honey locust, lupines, vetches, coffee bean, senna, and ornamental 
plants as red bud, sweet pea, caragana, etc. 



DESCRIPTIVE MANUAL 



181 




Fig. 102. Stickweed, White Avens iOeum canadense) . Wliite flowers with bur- 

lilce fruit scattered by animals. In pastures and fields. 

(Photographed by Hart.) 




Fig. 102-A. Distribution of Stickweed. 



182 



WEED FLORA OF IOWA 



Rattle-box {Crotalaria sagittalis L.). 

Description. — ^A hairy annual from 3 in-1 ft. high, with a small 
tap root; stem branched, villous, terete or wing-margined; leaves 
oval or oblong-lanceolate, from ^4-% in- wide, edge of the leaf en- 
tire or somewhat wavy and hairy; stipules united and decurrent 
on the stem, becoming inversely arrow-shaped; peduncles produce 
a few yellow flowers about % in. in diameter; calyx 5-cleft, stand- 
ard of the flower large, heart-shaped ; keel scythe-shaped ; stamens 
monadelphous, anthers of two sizes, 6 smaller and roundish; pod 
large, inflated, bears a close resemblance to that of the garden pea, 
greenish at first, becoming blacMsh varying in size from %-l in. 
in length and about 1 in. in diameter ; seeds from i/^-l/lO in. in 
diameter, flattish, kidney-shaped, when mature breaking away from 
the point of attachment and rattling in the pod, hence the name 
"rattle-box". 




Fig. 103. Rattle-box (.Crotalaria sagittalis). Common in sandy soil, Missouri 

river bottoms. 
(Photographed by Colburn.) 



DESCRIPTIVE MANUAL 



183 




Fig. 103-A. Distribution of Rattle-box. 

Distribution. — Common from New England to Minnesota, south- 
west to North Texas. In Iowa abundant only along Missouri river, 
the Des Moines near Ft. Dodge, and at other points along sandy 
beaches of o.ur streams. 

Extermination. — This weed occurs mostly in the Missouri bot- 
toms, generally on more or less sandy soil. It succumbs readily to 
cultivation. The raw sandy prairies on which it occurs should be 
broken up and sown to some leguminous crop, like alfalfa, which 
will crowd the weed out. 



The Yellow Clover {Tri folium agrarium L.). 

Description. — A smoothish annual, usually upright, with obovate- 
oblong leaflets, all 3 from the same point (palmate) and nearly ses- 
sile ; stipules narrow ; corolla yellow, persistent. 

Distribution. — Common in sandy fields and roadsides from east- 
ern Canada west to Wisconsin and Minnesota and to Iowa ; common 
along roadsides in northeastern Iowa. 

Extermination. — Same as for low hop-clover. 



184 



WEED FLORA OF IOWA 




Fig. 104. Yellow or Hop Clover (Trifolium agrarium). Along roadsides. Tel- 
low flowers. 
(Photographed by Colbum.) 



Low Hop-elover {Trifolium procunibens L.). 

Description. — A pubescent annual with spreading or ascending 
stems; leaves of 3 leaflets pinnate, the lateral at a small distance 
from the other, obovate, notched at the end; stipules ovate, short; 
flowers yellow, persistent, becoming dry in age. 

Distribution. — Naturalized from Europe; common in eastern 
startes. 



Extermination. — Readily succumbs to cultivation. The seeds, 
however, may retain their vitality for some time in the soil. Sow 
clean seed in clean soil. 



DESCRIPTIVE MANUAL 



185 




Fig. 105. Low Hop-olover, Yellow Clover (Trifottum prooumiens) . Clover 
fields, meadows, waste places. 

(1. Drawn by Charlotte M. King, the general aspect photographed by Hart.) 




Fig. 105-A. Distribution of Low Hop-clover. 



186 



WEED FLORA OF IOWA 



Yellow Sweet Clover {Melilotus officinalis (L.) Lam.). 

Description. — An upright, usually tall, fragrant annual or bien- 
nial; leaves compound, leaflets obovate-oblong, obtuse, closely ser- 
rate; flowers yellow, pod smooth, prominently cross-ribbed. The 
M. indica also with yellow flowers has a gibbous and alveolate pod. 
This has recently been introduced. 

Distribution.— Yellow sweet clover is also native to Europe. 
Widely scattered throughout the United States, more abundant upon 
the Pacific coast, in the Great Basin country and the Rocky moun- 
tains. Not abundant in the northern Mississippi valley. More or 
less frequent in many parts of Iowa, however, as in Humboldt and 
parts of Greene and "Woodbury counties. 




Fig. 106. Yellow Sweet Clover (.MelUotus officinalis). 

some fields. 
(Photographed by Colburn.) 



Roadsides, streets and 



DESCRIPTIVE MANUAL 



187 




Fig. 106-A. Distribution of Yellow Sweet Clover. 

Extermination. — The seeds preserve their vitality for some time. 
The weed is easily destroyed by cultivation. 

Sweet Clover {MelMotus alba Lam.). 

Description. — ^An erect annual or biennial 2-4 ft. high ; rather dis- 
tant, compound leaves, leaflets obovate, oblong, obtuse, serrate, nar- 
rowed at the base, truncate, emarginate or rounded at the apex; 
flowers with white petals, small, fragrant; pod ovoid, reticulated 
and smooth. 

Distribution. — Sweet clover is native to Europe and abundant in 
all parts of the United States. It has been widely scattered by bee- 
keepers who sowed it as a honey-bee plant. Abundant now along 
highways, right of ways of railways; also in some fields; found in 
every part of Iowa. 

Extermination. — The only way to exterminate this plant is to 
prevent seed formation. This may be done by cutting the plants 
underneath the ground. In fact the young plants are easily ex- 
terminated in this way. The plants occur in the meadows and pas- 
tures, coming largely from the weeds left growing along the road- 
sides. Road overseers should see that these chance plants are re- 
moved. According to a recent investigation of Prof. Ewart of Aus- 
tralia some of the seeds retain their vitality for a long time, some- 
times more than half a century. It is imperative, therefore, to pre- 
vent the formation of seeds so as not to sow for a future generation 
to eradicate. Sweet clover is used as a forage plant and considered 
quite valuable. Mr. Coverdale of Maquoketa considers it a most 
valuable plant. Mr. "Westgate has recently brought together many 
valuable points in its favor. 



188 



WEED FLORA OP IOWA 




Fig. 107. 



White Sweet Clover (Melilotus alba). Common along roadsides. 
(Photographed by Colburn.) 



The Farmer's Review says regarding the plant: "In Minnesota, 
Wisconsin, and Ohio there are laws against the plant known as 
sweet clover. We fail to see why this plant should be singled out 
and denominated as a weed. It certainly is not objectionable as a 
cover for waste places, and is easily controlled where its presence is 
not desired. ' ' 

Chemicdl Composition. — The chemical composition according to 
the University of Wyoming is as follows.* 

•Bull. No. 70 compiled by Henry G. Knight, Franlt B. Hepner, chemists, and 
Aven Nelson, botanist ; Wyoming Experiment Station. 



DESCRIPTIVE MANUAL 



189 







Wi 













Fig. 108. White Sweet Clover (MeUlotus alba). Along roadsides. 
(Photographed by Charlotte M. King.) 




Fig. 108-A. Distribution of White Sweet Clover. 



190 



WEED FLORA OF IOWA 







§ 

o 

ffl 


Q 

'•5 


TO.36 


6.02 


2.10 


9.57 


0.53 


2.42 


4.78 


21.77 


8.96 


18.00 


9.28 


42.22 



Si 



Water 

Ash 

Ether extract 

Crude fiber 

Crude protein 

Nitrogen free extract 



10.18 
2.S2 
23.16 
19.16 
44.99 



Black Medio {Medicago lupulinaJj.). 

Description. — ^A proeumbent, pubescent, annual; compound 
leaves trifoliate; leaflets wedge-shaped, obovate, toothed at the apex; 
flowers yellow, in short spikes ; pods kidney-form, 1-seeded. 

Distribuiion. — ^Native from Europe, common in alfalfa fields in 
the Rocky mountains and on the Pacific coast; common in waste 
places in eastern North America; reported from a number of coun- 
ties in Iowa, as "Wright, Kossuth and Story. 

Extermination. — This annual is not difficult to exterminate by 
giving thorough cultivation ; care should be used in planting clover 
and alfalfa seed, because this weed seed is a common impurity of 
the latter. The seed also retains its vitality for some time. 

Chemical Composition.* 

FRESH OB AIR DRY MATERIAL,. 



Water 


Ash 


Protein 


Fiber 


Nitrogen free 
extract 


Pat 


78.62 


1.3Y 


3.40 


6.31 


0.20 


1.11 


WATER BBKR SUBSTANCE. 




6.4 


16.8 


29.S 


43.4 


6.1 



•Compiled by Jenkins and Winton, Bull. Off. Exp. Sta., Bull. 11. 



BESCRIPTIVE MANUAL 



191 




Pig. 109. Black Medic (Medicago lupuUna'). Clover and alfalfa meadows. 
(Photographed by Hart.) 




Fig. 109-A. Distribution of Black Medio. 



192 



WEED FLORA OP IOWA 



Pink Parosela {Dalea alopecuroides Willd.). 

Description. — An erect annual from 2-3 ft. high, with pinnately- 
oompoiind leaflets; smooth flowers, whitish or light rose-color, in 
cylindrical spikes; calyx villous; seeds kidney-shaped. 

Distribution. — From Minnesota to Alabama and the Rocky moun- 
tains, common in western Iowa and introduced eastward in Wright, 
Boone, and Story counties. 

Extermination. — It is sometimes found in clover seed grown in 
western Iowa, also in alfalfa seed from the west, therefore care 
should be used in the selecting of seed ; succumbs readily to culti- 
vation. 



¥1 1 


' I 




^M. , < 


9k 


^■^■%^; 




1 


% 




\ 


n 1 \ 


1 


\ \l8 ^ ^ 


>-/ 


lt'^ 


Mf 


\J 





Fig. 110. Parosela (Dalea alopecuroides). Common in western Iowa ana 

along railroads. 
(Photographed by Quade.) 



DESCRIPTIVE MANUAL 



193 




Fig. 110-A. Distribution of Parosela. 



Rattle-box or Milk Vetch {Astragalus eanadensis L.)- 

Description. — A tall, erect, smooth or pubescent perennial^ 1-4 
ft. high; leaves compound, leaflets , 21-27, oblong; flowers greenish 
cream-colored in spike of variable length; pods crowded, snvooth, 
terete, occasionally somewhat suleate; the seeds separate from the 
pod, rattling, hence the common name. 

Distribvrtion. — ^Common in the northern Mississippi valley, east 
to New York and south to Georgia. Common on'-iborders of thick- 
ets, woods and native meadows. 

Extermination. — This weed is easily exterminated by cultivation. 



13 



194 



WEED FLORA OF IOWA 




Fig. 111. 



Rattle-box {Astragalus canadensis'). Woodland pastures. 
(Photographed by Charlotte M. King.) 



Purple or Stemless Loco Weed {Oxytropis lamberti Pursh.). 

Description. — Nearly acg,ulescent, perennial herbs or shrubby 
plants, with tufts of very numerous short stems coming from a hard 
and thick root-stock containing many scaly stipules; Stems and 
leaves covered with silky and finely appressed hairs, or smoothish ; 
leaves pinnate; leaflets linear; flowers racemose or spicate, rather 
largie and elongated, purple, violet, or sometimes white ; stamens dia- 
delphous ; keel tipped with a sharp projecting point. This is one of 
the loco weeds, poisonous to cattle. 

Diitribution. — ^Western Minnesota, western Iowa, and Missouri to 
Texas, and New Mexico, north to British Columbia, and northwest 
territory. 

Extermination. — It seldom gives much trouble in cultivated fields. 



DESCRIPTIVE MANUAL 



196 




Fig ]]2. Purple Loco Weed {Oxytropia lamberti). A Weed poisonous to cattle. 
(Drawn by F. G. Collins.) 




Fig. 132-A. Distribution of Purple Loco Weed. 



196 



WEED FLORA OF IOWA 



Wild Liquorice (Glycyrrhiza lepidota (Nutt.) Pursh.). 

Description. — A branching perennial 2-3 feet high, leaves com- 
pound of 15-19 oblong-lanceolate leaflets with mucronate points; 
young leaflets sprinkled with a resinous material ; flowers in spikes ; 
short peduncled j whitish ; pods oblong, ■ covered with hooked 
prickles, resembling a cocklebur. 

Distribution. — Common in the west, western lowa^ to Rocky 
mountains, Utah, New Mexico, and Montana to Canada, also re- 




Flg. 113. 



Wild Liquorice (.Glycyrrhisa lepidota.") Occurs In western and cen- 
tral parts of the state. 



DESCRIPTIVE MANUAL 



197 




Ftg. 113-A. Distribution of Wild Liquorice. 

ported from the Great Lakes; eommonly reported from Story, 
Greene, Pottawattamie, Harrison, Monona, Fremont, and Decatur 
counties. 

Extenmnation. — This perennial plant whose burs resemble the 
cocklebur is easily exterminated by cultivation. Do not permit the 
seeds to mature. Cut off the plants at the surface of the ground 
to prevent flowering, if they occur in the pasture or meadow. 
Where the land can be cultivated, give the ordinary plowing, fol- 
lowed with harrowing to bring the. roots to the surface so they are 
exposed to the sun. A few days' exposure to the sun will kill them. 



Common Vetch {Vicia sativa Jj.) . 



Description. — A smooth or slightly pubescent annual from 1-21^ 
ft. high with simple stem ; leaflets 5-7 pairs, obovate-oblong to lin- 
ear, notched or mucronate at the tip ; 1 or 2 nearly sessile flowers 
borne in the axils of the leaves, corolla violet-purple; pod linear, 
several-seeded, seeds black. 

Distribution. — This weed has long been known as troublesome in 
the grain fields of Europe, and in the northern states. It is particu- 
larly abundant in northeastern and northwestern Iowa and in some 
of the grain growing sections of the southern part of the state. 

Extermination. — Clean seed sown in clean soil is the only method 
of displacing the weed. 



198 



WEED FLORA OF IOWA 




Fig. 114. Common Vetch iVioia sativa). Common in grain fields, especially 

wheat fields, frequently found in screenings from fiour mills. 

( I'hotographed by Colburn; ) 




Fig. 114-A. Distribution of Common Vetch. 



DESCRIPTIVE MANUAL 



199 



Chemical Composition. — The chemical composition of vetch {Vicia 
sativa) according to U. S. Dept. Agr., 1880; p. 152, is as follows : 



FRESH OR AIR DRY MATERIAL. 





03 


■s 

< 


■.a 

1- 


s 


M g 




Out S-4: in lull bloom 


86.20 


1.60 


4.14 


2.11 


5.34 


0.61 


WATER FREE SUBSTANCE. 




11.6 


S.OO 


15. a 


88.7 


4.4 



Wild Bean {Strophostyles helvola (L.) Britton). 

Description.— An annual, with prostrate stem; compound leaves 
ovate to oblong-^obovate, with a prominent rounded lobe at the base ; 
coroUa greenish white and purplish; pod 4:-8-seeded, large, usually 
pubescent. 

Distribution. — Common in sandy places in northern United 
States; from Wisconsin, Minnesota, and Texas east to Massachu- 
setts ; common in gravel pits on Muscatine Island, along Des Moines, 
Cedar and Iowa rivers. 

Extermination. — Easily exterminated by cultivation. 
OXALIDACEAE, WOOD SORREL FAMILY. 



This family contains the cultivated yellow and purple-flowered 
oxalis. Few of the plants are economic. i, 



200 



WEED FLORA OF IOWA 




Fig. 115. Wild Bean (.Strophostyles helvola). Common in sandy or gravelly 

soil, sandy river bottom. 

(Photographed by Colburn.) 




Fig. 115-A. Distribution of "Wild Bean. 



DESCRIPTIVE MANUAL 
Field Sorrel {OxaZis stricta It.). 



201 



Description. — ^A pale green pubescent annual or perennial ; leaves 
compound, with evident stipules; flowers pale yeUow, cymose, 1-4, 
at length deflexed ; in fruit columnar, short-pointed. 

Distribution. — Common in fields and waste places from New Eng- 
land to Dakota; common in Iowa probably over the entire state. 

Extermination. — ^Persistent cultivation and crop rotation will 
usually exterminate the weed. 




Fig. 116. Tellow Field Sorrel (.Oxalis stricta). Common in .fields, it, Trlchome 

or plant hair. 

(a drawn by Charlotte M. King. The whole plant photographed by Hart.) 



202 



WEED FLORA OF IOWA 




Fig. 116-A. Distribution of Yellow Field Sorrel. 

Field Sorrel {Oxalis corniculata L.). 

Description. — An erect or decumbent perennial herb, spreading 
by numerous slender, pale runners; leaflets 3; flowers in eymose 
clusters, yellow; peduncle ascending and sparingly pubescent. 




r^r 



Fig. 117. Field Sorrel (.Oxalis corniculata). Fields, gardens, etc. 
(Photographed by Colburn. 1. Drawn by Charlotte M. King.) 



DESCRIPTIVE MANUAL 



203 




Fig. 117-A. Distribution of Field Sorrel. 

Distribution. — A very common weed in dry or moist soil through- 
out eastern North America. 

Extermination.^-Apj)ly the same method as to the preceding 
species. 

ZYGOPHYLLACEAB, CALTROP FAMILY. 
A small family. 



Caltrop {Triiulus terrestris L.) . 

Description. — The caltrop is a hairy, procumbent annual, branch- 
ing from the base, producing a stem which is a foot or more long, 
branches bear numerous small, compound leaves with short pe- 
duncles and small stipules at the base; each compound leaf has ,4-8 
pairs of short-stalked leaves; small, yellow, axillary flowers about 
% in. across with peduncle much shorter than leaves; fruit very 
spiny and divided into two nearly equal parts, each part consists of 
2 long spines, 2 shorter and a row of very short ones, forming a 
crest on the back ; 5-angled, spiny fruit splits into 3-5 divisions. 

Distribution.— InivodcacedL from the Old "World and occurs from 
the Atlantic states to Nebraska and Kansas ; in Iowa has been found 
only on Muscatine Island. 

Extermination. — Caltrop is disseminated by wool, and hence the 
waste of woolen mills should not be thrown in fields. The v/eed is 
easily destroyed by cultivation. 



204 



WEED FLORA OF IOWA 




DESCRIPTIVE MANUAL 



205 




Fig. 118-A. Distribution of Caltrop. 

EUPHORBIACEAE, SPURGE FAMILY. 

Many of the plants of this family contain an irritating milky 
juice. Few are of economic importance. The poinsettia commonly 
cultivated in greenhouses, snow-on-the-mountain in gardens, and 
castor-oil bean belong to this family. 



Three-seeded Mercury {Acalypha virginica L.) . 

Description. — A smoothish or hairy annual from 1-2 ft. high, 
turning purple especially in the autumn; leaves ovate or oblong- 
ovate, sparingly serrate, long-petioled ; sterile spike, few-flowered, 
pistillate flowers 1-3 at the base of staminate peduncle surrounded 
by a large leaf -like bract j capsule 3-lobed, subglobular, 2-valved 
carpels. 

Distribution. — From Nova Scotia to Texas and northward to Min- 
nesota. Common everywhere in Iowa along roadsides and in fields. 
Especially noticeable in the fall on account of the purple bracts. 

Extermination. -^Three-seeded Mercury is not a difficult weed to 
exterminate. The small, reddish, striate seeds are expelled from 
the plant to some little distance in a manner similar to the dispersal 
of the castor-oil bean. Thorough cultivation by preventing the for- 
mation of seed will eradicate the Weed. 



20C 



WEED FLORA OF IOWA 




Pig. 119. Three-seeded Mercury (Aoalypha virffinioa). Common In many parts 

of the state. 
(Drawing by Charlotte M. King.) 



DESCRIPTIVE MANUAL 



207 




Pig. 119-A. Distribution of Three-seeded Mercury. 

Spurge {Euphorbia preslii Guss.). 

Description. — ^An annual from 1-1^2 ft. high ; erect or ascending ; 
leaves oblique at the base, ovate, oblong, or sometimes oblong-linear, 




F:g. 120. Spotted Spurge (.Etiphorbia preslii). Common evei?y#here in the 

state. 
(Drawing by Charlotte M. King.) 



208 



WEED FLORA OF IOWA 




Fig. 120-A. Distribution of Spotted Spurge. 

frequently falcate, serrate, generally with a conspicuous red spot, 
or margin ; flowers pedunculate in terminal cymes ; appendages en- 
tire ; pod glabrous ; seeds ovate sometimes wrinkled. 

Distribution. — In loose soils and fields from New England and 
Canada to Wisconan, Minnesota and Nebraska, also southward. 

Extermination. — This annual weed is easily exterminated by cul- 
tivation ; therefore practice rotation of crops and give thorough cul- 
tivation. Seeds of several species of this genus retain their vitality 
for some length of time. 

Milkweed or Creeping Spurge {Euphorbia maculata L.) . 

Description. — Slightly pubescent or hairy annual, with prostrate 
stems; leaves oblong-linear, oblique at the base; pubescent or some- 
times nearly smooth, usually with a brown-red spot in the center; 
serrulate above, stipules lanceolate ; flowers pedunculate in lateral 
clusters; glands of the involucre minute; appendages usually red; 
pods .acute-angled; seed sharply 4-angled with 4 shallow grooves 
across the sides ; trichomes several-celled, gradually tapering to apex. 

Distribution.— ¥ovoa.di in sandy fields, or generally in fields from 
New England and Canada westward; common in every part of 
Iowa. 



Extenmnation.- 
preceding species. 



-May be exterminated in the same way as the 



DESCRIPTIVE MANUAL 



209 




Fig. 121. Milkweed or Prostrate Spurge (.Euphorbia maculata). Sandy fields. 
(Photographed by Quade. a, drawn by Charlotte M. King.) 




Fig. 121-A. Distribution of Prostrate Spurge. 



14 



210' 



WEED FLORA OF IOWA 



Snow-on-the-mountain {Euphorbia margmata Pursh.). 

Description. — Stems stout, high, ereet, hairy or smoothish ; annual, 
from 2-3 ft. high; leaves sessile ovate-oblong, acute; uppermost 
leaves white, petal-like margins. 

The flowering spurge {Euphorbia corollatmJj.) with white flowers 
in forked umbels ; long peduncles ; invohicres showy, white append- 
ages appearing like petals; deep perennial root; is common in grav- 
elly and sandy soils in many parts of the state, arid it is often weedy. 

Distribution. — Snow-on-the-mountain occurs from Minnesota to 
Missouri and Colorado; also reported eastward to Ohio and South 
Carolina. A frequent escape from gardens in Iowa; common only 
in the western part. 




Fig. 122. Snow-on-the-MountaIn (Euphoriia marginata) . A frequent escape 
from gardens, a. Whole plant, one-third natural size ; 6, seed capsule, 
natural size. 



DESCRIPTIVE MANUAL 



211- 




Fig. 122-A. Distribution of Snow-on-the-Mountain. 




Pig. 123. Flowering Spurge (.Euphorbia corollata). Common In sandy fields, 
gravel knolls, and roadsides. 
(Drawing by Lois Pammel.) 



Extermination. — This annual weed is easily exterminated by cul- 
tivation. The young plant should be cut off below the surface of 
the ground. 



212 WEED FLORA OF IOWA 

Cypress Spurge {Euphorbia cyparissias It.). 

Description. — Plant with perennial running root-stocks and 
densely clustered steins from 6 in.-l ft. high ; linear, crowded leaves ; 
many-rayed umbel with glands crescent-shaped and granular pods. 

Distribution.^Common westward from New England to Nebraska 
usually in the vicinity of gardens and cemeteries. 

Extermination. — This perennial weed because of its running root- 
stocks is often difficult to exterminate. The ground should be given 
a shallow plowing and the root-stocks exposed to the sun. It may 
be necessary to repeat this process two or three times during the 
summer. In addition to its propagation by the running root-stocks 
it also propagates by its seeds. 




Fig. 124. Cypress Spurge (Euphorbia cyparissias). Yellow "flowered" plant 

with milky Juice and narrow leaves. Escaped from gardens to roadsides. 

(Photographed by Colburn.) 



DESCRIPTIVE MANUAL 



213 




Fig. 124-A. Distribution of Cypress Spurge. 

ANACARDIACEAE, SUMACH FAMILY. 

Many of the plants are poisonous. Many, like sumach, contain 
tannin. Some, as the smoke tree, are cultivated for ornamental 
purposes. 

Poison Ivy {Rhus toxicodendron L.). 

Description. — A climbing or trailing shrub sometimes erect, cling- 
ing to trees or other objects by aerial rootlets ; 3 leaflets ; inconspicu- 
ous flowers;; waxy fruit, frequently remaining on plant until late 
winter or early spring. It is often mistaken for Virginia creeper 
{Psedera quinquefolia (L.) Greene) "which, however, has 5 leaflets. 
Many persons are sensitive to poisoning from this plant, every part 
of which contains the poisonous principle. The usual remedy for in- 
fection from it is to wash the skin with a solution of sugar of lead. 

Distribution. — Poison ivy is abundant throughout eastern North 
America and the Rocky mountains. It is common everywhere in 
Iowa, in hedge rows, thickets or woods. 

Extermination. — Poison ivy is not easily destroyed because in 
most cases it is troublesome in wood lots along fences and in yards. 
It is difficult to destroy except by giving thorough cultivation. If 
persistently cut off below the surface of the ground it can be de- 
stroyed. Sodium arsenite at the rate of one and one-half to two 
pounds to 52 gallons of water will help to destroy the weed. It is 
not, however, safe to use this since it is a strong poison. 

MALVACEAE, MALLOW FAMILY. 
Cotton, hollyhock and okra are well known plants of the family. 



214 



WEED FLORA OF IOWA 



-^^ 


Ah 


*/w 


^^i^^^StSkA S^^^^KK^BI^^^^w ' 




|^^^Rl\^HHHF^--:- 


•\<5f^ 


^^^wKF 




s^^;. :^^ 


"^C 


ittB^Mf^*^^ ■ ■ ' ^y 


/I 


UK^^^HI^L 




H 


' , 1 


"^p. / 


J 


^ ■;.„ 


< 





Fig. 125. Poison Ivy (BTwts toxicodendron). Common in woods and along 

fences. 
(Photographed by Colbum.) 




Fig. 125-A. Distribution of Poison Ivy. 



DESCRIPTIVE MANUAL 



215 




Fig. 125-B. Poison Ivy (,Bhus toxicodendron), u, spray showing rootlets; 

6, fruit. 
(After Chesnut, TJ. S. Dept. Agr.) 



Indian Mallow or Velvet-leaf, Butter-prinl; {Abutilon theophrasti 

Medic.). 

Description. — ^A usually tall annual from 2-4 ft. high ; plant with 
strong odor; leaves velvety, roundish heart-shaped, taper-pointed; 
peduncles shorter than the petioles ; corolla yellowish ; carpels 12-15, 
hairy-beaked seeds rough, rather large and blackish. 

DisiributioTU. — Common in waste places, corn fields, vacant lots, 
barnyards, etc. Common throughbut eastern North America, 
naturalized from tropical regions, probably India. 

Extermination. — This plant propagates only by its seed, which 
retains its vitality for some length of time, having been known to 
germinate after a period of 60 years. The young plants are easily 
exterminated. The plant should be pulled up before it begins to 



216 



WEED FLORA OP IOWA 




Fig. 126. Indian Mallow, Velvet Leaf, or Butter-print (.Abutilon theophrasti) . 

Common in corn fields, waste places, barnyards. 

(Photographed by Colburn.) 



flower. Wallace's Farmer suggests the following treatment: "It 
has been seriously thought of by some persons as a substitute for 
manilla or sisal in the manufacture of binder twine. It is an an- 
nual, and if not allowed to go to seed, the farm can in time be 
cleared of it. But it will be a long time. The seeds have a most 
astonishing vitality. We have known cases where it has been pulled 
up for fifteen years, not a plant allowed to go to seed, and yet it 
makes its appearance every spring. Fortunately, it grows only on 
rich land, and is therefore found in evidence largely in hog yards 
and feed lots and other places where the land is exceedingly rich. 
In fact, in sections of the country where it is being introduced, it 
may be found in almost every farmyard. Why farmers allow it to 
mature seed passes our comprehension. It goes variously by the 



DESCRIPTIVE MANUAL 



217 







<u 






^ 


i ^I^ 


i 


{m 




i- kWM 


I't 


%jM 


■s^ 


\r^ ^i '^ 


«!JL> 


m 


w 




W 


# 


-,/~: 


■■;_",/ -s-'-S., . . „-":*■■- 


>^-M 








1^^^ 


sP^ 


'■■ .-Ci ** 






>... ^1 




■/ ■.■■■■:;•■ ■ 


'i«W hl^' iJfetjfi 


sr-|- 


^:-■, ^ . ...r*.- 




if^^^w'''' *"■ ** *,■ *^^W''-'^%'"* ' ^ ■'''■ 






...:,-: 4 
^-■r.:-'^ 


"1 ^m*--^'a m' . » 


*<* 



Fig. 126-C. Pigweed, Foxtail, arid Velvet Leaf, in a potato patch. Too many 

such garden patches in Iowa. 

(Photographed hy Panimel.) 




Fig. 126-B. Distribution of Indian Mallow. 



218 



WEED FLORA OF IOWA 



names of velvet weed, butter print and in the locality of one of our 
farms, Davis weed, from the fact that it was introduced many years 
ago by a man named Davis, who regarded it as a rather good orna- 
mental plant. ' ' 

Sida {Sida spinosa L.) • 

Description.— An annual from 10-20 in. high ; frequently much- 
branched; leaves ovate-lanceolate; serrate with a long petiole, pe- 
duncles in axils of leaves, 1-flowered; flowers small, yellow; 5 car- 
pels, each 2-beaked. 

Distribution. — CJommon in the southern states, as far north as 
Massachusetts to southern Iowa and Kansas. 

Extermination.— This weed propagates entirely by its seeds which 
retain their vitality for a considerable length of time, as the seed 
coat is hard. The growing plant is, however, easily destroyed by 
pulling the weed or by cultivation. 




Fig. 127. 



Sida (.Sida spinosa). Common in fields in southern Iowa. 
(Photographed by Hart.) 



DESCRIPTIVE MANUAL 



219 




Fig. 127-A, Distribution of Slda. 



Cheeses or Common Mallow {Malvarotundifolia L.). 

Description. — A procumben't biennial ; leaves round; heart-shaped 
on long petioles, crenate ; flbwers white, petals longer than the calyx ; 
a 3-leaved involucre at the base of the calyx ; carpels pubescent. 

Distribution. — A widely distributed weed in eastern North Amer- 
ica, native to Europe, common in eastern and central Iowa in door- 
yards, barn lots, etc., in Stoi-y, Mairshall, Polk, Marion, Linn, Clin- 
ton, Winneshiek and AUamakee counties. 



Extermination. — This weed is easily exterminated by cultivation. 
Do not permit any of the seeds to mature. The seeds retain their 
vitality for a considerable length of time. 



220 



WEED FLORA OF IOWA 




Fig. 127-B. Common Mallow or Cheeses iMalva rotundifolia) . Qommon In door- 
yards, barn lots, etc. 
(Mich. Agr. Exp. Sta.) 



DESCRIPTIVE MANUAL 



221 




Fig. 127-C. Distribution of Common Mallow. 

Shoo-fly {Hibiscus tricmum L.). 

Description. — ^A low, rather hairy annual from 1-2 fi. high ; upper 
leaves 3-parted with 3 lanceolate divisions, the middle longest ; ealyx 
inflated in fruit, membranous, 5-winged, with numerous dark 
nerves ; flowers sulphur-yellow with a blackish eye, ephemeral. 

Distribution. — Common in fields and waste groundsin the south- 
em states and eastward ; abundant in some places in Iowa, especially 
in gardens where it has become naturalized from cultivation. 

Extermination. — A growing plant is not diflieult to exterminate. 
A thorough cultivation and exposing the roots to the sun will de- 
stroy the plant. The seeds, however, retain their vitality for a con- 
siderable length of time. A correspondent of southeastern Iowa 
stated that this weed kept coming up in spite of constant and thor- 
ough cultivation. This was owing to the prolonged vitality of the 
seed. 



HYPERICACEAB. ST. JOHN'S-WORT FAMILY. 

This small family contains a few ornamental plants with yellow 
flowers, commonly found in northern states. 



222 



WEED FLORA OF IOWA 




Fig. 127-D. Bladder Ketmia or Shoo-fly (.Hibiscus trionum). Gardens and 
com fields. Large white 'flower with a, dark -Spot at the hase of each petal, 
o and 6 trichomes or plant hairs. 

(a and 6 drawn by Charlotte M. King. The general aspect photographed by 

■ ' Colburh.) 




Fig. 127-E. Distribution of Shoo-fly. 



DESCRIPTIVE MANUAL 



223 



St. John's-wort {Hypericum perforatum L.). 

Description. — A branched perennial, l%-2 ft. high with runners ; 
leaves elliptical, or linear-oblong, with pellucid dots; flowers 
numerous in cymes, petals deep yellow, black-dotted, twice the 
length of the lanceolate sepals. 

Distribution. — Common in eastern North America in clay soils. 
Abundant in Iowa only in eastern counties, especially northeast- 
ward. 

Extermination — This weed spreads both by seeds, and by runners. 
It is difficult to exterminate. Clark and Fletcher give the follow- 
ing methods: "Close cutting several times during the summer will 
reduce it in pastures. An application of salt— a small handful to 




Fig. 128. St. John's-wort (Hypericum perforatum). Old fields and woodland 

pastures, eastern and northeastern Iowa. 

(Photographed by Quade.) 



224 



WEED FLORA OF IOWA 




Fig. 128-A. Distribution of St. John's-wort. 

each plant after close cutting in hot dry weather — will kill it and 
may be practicable where the pest is not abundant and the land 
cannot be brought under cultivation. Prevent it from going to seed. 
St. John's-wort is easily suppressed on land that can be cultivated 
under a systematic rotation of crops. Where it is established, it 
would be well not to seed to grass until it is suppressed. ' ' 

ONAGRACBAE. EVENING PRIMROSE FAMILY. 

A small family, some plants with showy flowers, a few cultivated 
for ornamental purposes. 



Evening Primrose {Oenothera biennis L.). 

Description. — A stout, erect, pubescent or hirsute perennial, 3-5 
feet high, sparingly branched; leaves lanceolate, or rarely ovate- 
lanceolate, denticulate, acute, bracts shorter or as hmg as the cap- 
sule ; flowers yellow, petals obovate, stigma lobes linear, capsule sub- 
cylindrical; seeds small, brownish. 

Distribution. — Common everywhere in eastern North America, 
Rocky mountains and Utah. Occurs in every county in Iowa. 

Extermination. — Spreads by seed. This plant is not difficult to 
exterminate. Cut off the young plants a few inches below the sur- 
face of the ground. 



UMBELLIPERAE, CARROT FAMILY. 

Carrot, celery, parsnips and caraway are members of this family. 
It includes also many poisonous plants. 



DESCRIPTIVE MANUAL 



225 




Fig. 129. Evening Primrose (Oenothera biennis). Fences, gardens, meadows 

and pastures. 
(Photographed by Hart, a^ drawn by Charlotte M. King.) 




Fig. 129-A. Distribution of Evening Primrose. 



15 



226 WEED FLORA OP IOWA 

Caraway {Carum carvi It.). 

Description. — A smooth, erect, slender herb 1-2% feet high with 
fusiform roots; leaves pinnate with filiform divisions; flowers in 
umbels, white; ealyx teeth small; fruit ovate, or oblong with fili' 
form ribs. 

Distribution. — Common in eastern North America, the Rocky 
mountains, Utah and scattered in places in Iowa. 

Extermination. — Easily exterminated; cut off the plants below 
the surface of the ground. 




Fig. 130. Caraway (.Carum carvi). Commonly escaped from gardens. Flowers 

white. 
(Photographed by Quade.) 



DESCRIPTIVE MANUAL 



227 




Fig. 130-A. Distribution of Caraway. 



Wild Carrot {Daucus carota L.). 

Description. — A bristly, hirsute biennial from 2-2l^ feet high; 
leaves pinnately decompound; involucral bracts foliaceous; flow- 







Pig. 131. Wild Carrot (.Daucus carota). Common in clover meadows. Flowers 

in white umbels. 
(Photographed by Colburn.) 



228 



WEED FLORA OF IOWA 




Fig. 131-A. Distribution of "Wild Carrot. 

ers in compound umbels, white, or occasionally pink ; fruit oblong, 
flattened dorsally, carpel with 5 slender bristly primary ribs, and 
4 winged secondary ones, each of these bearing a single row of 
barbed prickles. 

Distribution. — Common in eastern North America, especially in 
dry fields. Becoming common in Iowa clover fields in Scott, Story, 
Polk, Fl-anklin, Linn, Clinton, Cerro Gordo, Boone, Webster, Sac 
and Clay counties. 

Extermination.' — Plant clean seed in a clean field. Easily kiUed 
by cutting ofE the plant a few inches below the surface of the 
ground. 



Parsnip {Pastinaca sativa li.) . 

Description. — A tall, stout, glabrous biennial with grooved stem; 
leaves pinnately compound, cut-toothed; flowers yellow, small; 
calyx teeth obsolete; fruit oval, flattened dorsally, the lateral ribs 
with broad wings. 

Distribution. — Common in eastern North America, Rocky moun- 
tains and the Pacific coast. Common on roadsides in every part of 
Iowa. 

Extermination. — Propagated by seeds. Easily exterminated by 
cultivation ; cut off the young planets a few inches below the surface 
of the ground. 



DESCRIPTIVE MANUAL 



229 



^»»i 




Pig. 132. Wild Parsnip iPasHnaca sativa). Common along roads. 
(Mich. Agr. Bxp. Sta.) 



230 



WEED FLORA OF IOWA 




Fig. 132-A. Distribution of Wild Parsnip. 



Cowbane {Cicuta maculata L.). 

Description. — A smooth, marsh perennial, 2-5 ft. high, with pin- 
nately compound leaves, 2 or 3 times pinnate; leaves with long 
petioles; coarsely serrate leaflets lanceolate to oblong-lanceolate, 
1-5 in. long; stalks of umbellets numerous and unequal; flowers 
white ; fruit broadly ovate to oval, small, 1^/^ in. long. The plant 
grows in marshes and in low grounds, the stems springing from 
thick fleshy underground roots tapering at the lower end, usually 
numbering from 3-8 although single specimens are also met with. 
On cutting the roots there is given off a sharp pungent odor, which 
becomes intensified on boiling. 

Distribution. — Common throughout the northern states, south- 
west to Louisiana, Rocky mountains and Utah. Very common in 
low grounds and swales in northern Iowa, less common in southern 
Iowa. 

Extermination. — The field where cowbane occurs needs drain- 
age; plow the field, break up the sod, and expose the fascicled 
roots to the sun. This will soon destroy the weed. 



DESCRIPTIVE MANUAL 



231 





.V..-. 


-* 


4^# - ■ 


^^ m 


w^ 


^^ 


mM 


\ 


i A 


^P 


^ 


-^^ 


p 




■ 



Fig. 133. Cowbane iCicuta maculata). In low moist meadows and roadsides. 
(Photographed by Colburn.) 







Fig. 1S3-A. Distribution of Cowbane. 



232, 



WEED FLORA OP IOWA 



^W 


* 






■ '■' •.'^' 


,' /- ■ 


i^ ' 




(0 ' '^■ 




A 




« 


m 




'mm ^ 


'•''5! 






■^ 


^ '^-'m^A 


f"' 






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:.44!R;^- ..«*^--'l 


f ■[■':--^l.- 


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1 


i 


feii' 






r 




4t'' 






^fjk 


ff 


^ 






^mj^ 


r 


w» 


3l^ 


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Wi9i 




^^^M^% 


Asf!^ ■■ '<■ • ■ 




^^m 


::^ 





Fig. 133-B. 



Cowbane (Cicuta maculata). In low woods. 
(Photographed by Caughey.) 



DESCRIPTIVE MANUALi 



233 









■^■' 




tf 


|t>N 








\ 








^ '-" 


i^m 


^SSj^sStS^Btl^Bs^^ ^'3 






r- 


'?•■ 


ji^MicidM^Mi*^^ ' ^tm 




H^^K? 






'IHI 


^ 


Ks, 


^% 




^i 









Fig. 133-C. Cowbane roots (Cicuta macv,lata)f in low places. 
(Photographed by Gardner.), 



-im;; 



234 WEED FLORA OF IOWA 

Cow Parsnip {Heracleum lanatum Miehx.). 

Description. — A stout, hairy, pubescent perennial 4-8 ft. high; 
leaflets broad and large, irregularly cut-toothed; flowers white, in 
broad umbels. 




I''!g. 134. Cow Parsnip (.Heracleum lanatum). Common in woodland pastures. 
(Photographed by Charlotte M. King.) 



Distribution. — From the Atlantic coast, Newfoundland, through 
the northern states and Allegheny mountains to California. Com- 
mon in the Rocky mountains. 

APOCYNACEAE, DOGBANE FAMILY. 

In the tropics several species are important rubber producing 
plants. They are commonly called milk-weeds in Iowa. 



DESCRIPTIVE MANUAL 235 

Spreading Dogbane {Apocynvm, androsaemifolium L.)- 

Description. — Root-stock horizontal, smooth, or rarely soft-tomen- 
tose, branched above, spreading, leaves ovate, petioled, cymes loose, 
spreading, both terminal and axillary; the latter pale rose color, 
open, bell-shaped; calyx segments shorter than the tubes of the, 
corolla. 

Distribution. — Common along borders of thickets from eastern 
Canada to British Columbia to Arizona and Georgia. Abundant 
in Iowa in grain fields near thickets. 




Fig. 135. Distribution of Spreading Dogbane (.Apooynum anchrosaemifoliiMn). 

Extermination. — Spreading dogbane produces long, creeping 
roots, which are quite tenacious of life. In order to destroy the 
weed, the field should be given a shallow plowing after the grain is 
harvested, followed by a disking in a week or ten days, depending 
on the character of the weather. This should be followed by a 
harrow. If the fall is dry dragging will probably get the larger 
number of these weeds. 



Indian Hemp {Apocynum cannabimim L.). 

Description. — Glabrous or more or less softly pubescent; 2-3 ft. 
,high, smooth, terminated by an erect, close, many-fiowered cyme; 
corolla lobes nearly erect, the tube not longer than the lanceolate 
segments of the- calyx, greenish white ; appears in July and August. 

Distribution. — Common species eastward and troublesome as a 
weed in northern Mississippi valley. Common in small-grain fields 
and pastures. 



236 



WEED FLORA OF IOWA 




Figure 136 Figure 136A 

Fig. 136. Indian Hemp (.Apocynum cannaiinum) . 

Fig. 136-A.'' Apocyniim cannabinum hppericifoUum. A low growing variety of 
the above, but witli leaves broader at base and more abruptly pointed 
at' apex. 

(Schuyler Mathews In Mich. Agr. Exp. Sta. Bull.) 



DESCRIPTIVE MANUAL 



237 




136-B. Distribution of Indian Hemp. 

Extermination. — This weed should be treated like spreading 
dogbane. 

ASCLBPIADACEAE, MILKWEED FAMILY. 

A few plants, only, are of economic importance. Some are cul- 
tivated for ornamental purposes. In Iowa they are commonly 
called milkweeds. 



Showy Milkweed {Asclepias speciosa Torr.). 

Description.- — A perennial 1-4 ft. high, white-tomentose or ca- 
nescent; leaves thick, broadly ovate or oval, petioled; pedicel 
glabrate above; flowers borne in dense umbels or rarely solitary, 
the pedicels stout; corolla purplish green, large, foUicle erect or 
spreading on the recurved pedicels. 

Distribution. — Showy milkweed is common from Minnesota to 
southern Iowa, Kansas, the Rocky mountains and Utah. In Iowa 
it is abundant in Emmet, Palo Alto and Dickinson counties. 

Extermination. — This weed should be treated like common milk- 
weed. 



238 



WEED FLORA OF IOWA 




Fig. 137. Showy Milkweed (.Asclepias speoiosa). In grain fields, meadows and 

roadsides, northern Iowa. 

(Photographed by Colburn.) 




Fig. 137-A. Distribution of Showy Milkweed. 



DESCRIPTIVE MANUAL 



239 



Milkweed {Asclepias syriaca L.) . 

Description. — A perennial herb with a stout stalk 2-5 ft. high, 
finely, softly pubescent or tomentose ; leaves oblong, oval or ovate, 
obtuse or roundish at the base, the young leaf somewhat pubescent 
above, soon becoming glabrate; petioles stout, flowers from a few 
to many, borne in umbels; peduncles pubescent or tomentose; co- 
rolla dull purple or greenish purple, occasionally pale in color; 
fruit a follicle and borne on erect pedicels ; trichomes multicellular 
from a single cell, somewhat floccose. 

Distriiution. — This milkweed is common from New England to 
North Carolina and Kansas. In Iowa it is abundant in oat fields, 
on highways and in gardens throughout the state. 




Fig. 138. Oommon Milkweefl (Asclepias syriaca). Fields, meadows, roadsides, 

etc. a trichomes or plant hairs. 

(Drawing by Charlotte M. King; general aspect photographed by Colburn.) 



240 



WEED FLORA OP IOWA 




Fig. 138-A. Distribution of Common Milkweed. 

Extermination. — Both milkweeds have the same habit of growth. 
The weed is perhaps known by its long roots which are frequently 
10-15 ft. ia length ; another important point is that it produces ad- 
ventitious buds at frequent intervals from which new shoots arise. 




Pig. 138-B. Common Milltweed (Asc!epias syrtaca). Grain fields, waste places. 
(Photographed by Charlotte M. King.) 



DESCRIPTIVE MANUAL 241 

Wallace's Farmer says eonceming this weed: "We would ad- 
vise our correspondent to plow this field as soon as possible 
and prepare his seed bed for winter wheat. By plowing it again 
next August he wiU undoubtedly weaken the stand. He will 
fail, however, unless in working his corn he uses surface cultiva- 
tion. These weeds have no doubt been distributed through the 
field during the three years it was in corn by using a shovel cul- 
tivator, which takes up the roots and carries them over the field 
in the same way that many northern farmers are now seeding their 
fields with quack grass and damaging them to the extent of from 
five to twenty dollars per acre. By giving these two thorough 
August plowings and taking care of the roots that may be thrown 
up, then preparing the seed bed very thoroughly for corn and 
giving it as far as practical surface cultivation, he will probably 
get rid of these noxious weeds. ' ' 



Climbing Milkweed (Gonolohus laevis Michx.). 

Description. — ^A climbing perennial; leaves oblong, cordate with 
a deep, narrow sinus; flowers borne in axillary umbel-like cymes, 
5-10 flowered, large greenish flowers; calyx 5-parted; corolla 5- 
parted, wheel-shaped, the lobes narrowly linear-lanceolate, obtuse, 
larger than the calyx; anthers horizontal under the flattened 
stigmas ; pollen masses 5 pairs, follicles with soft warty projections. 

Distribution. — Troublesome in woods and fields in the southern 
states. It is reported las troublesome from a few counties in south- 
ern Iowa. 

Extermination. — This perennial weed is as difficult to destroy as 
common milkweed. Give thorough cultivation. If this will not suf- 
fice get the field into a meadow. 

CONVOLVULACEAE, MORNING-GLORY FAMILY. 

Few economic plants. Sweet potato and cultivated morning glory 
are representatives. 



16 



242 



WEED FLORA OP IOWA 




Fig. 139. Climbing Milkweed (Gonolobus laevia). Troublesome in fields In 

southern Iowa. 
(Drawing by Ada Hayden.) 



BESCRIPTIVB MANUAL 



243 




Fig. 139-A. Distribution of Climbing Milkweed. 



Morning-glory {Ipomoea hederacea Jacq,). 
Description. — Stems retrorsely hairy; leaves heart-shaped, 
3-lobed, the lobes usually acute ; peduncle variable, in length ; 1-3 




Fig. 140. Blue Field Morning-glory (.Ipomoea hederacea). Fields, common 
southern Iowa and Missouri. 
< Photographed by Colburn.) 



244 



WEED FLORA OF IOWA 




Fig. 140-A. Distribution of Morning-glory. 

flowers; calyx densely hairy below; corolla funnel-form, white and 
purple or pale blue; lobes of stigma and cells 3. 




Fig. 141. Annual Morning-glory (Ipomoea purpurea). A frequent escape from 

gardens into fields. 
(Photographed by Colburn.) 



DESCRIPTIVE MANUAL 



245. 




Fig. 141-A. Distribution of Annual Morning-glory. 

The I. purpurea has heart-shaped leaves with retrorsely hairy- 
stem j peduncles long, umbellately 3-5 flowered, purple to white. 

Distribution. — Common in waste and cultivated grounds from 
New England southwestward ; abundant from Missouri southward ; 
native from tropical America ; rare in Iowa. The I. purpurea is- 
commonly cultivated and is a frequent escape from cultivation in 
Hardin, Story, Marshall, Wapello and Marion counties. 

Extermination. — It is an annual and is easily destroyed; how- 
ever, the seeds retain their vitality for some time, frequently 
springing up for several seasons after the most thorough cultiva- 
tion. 



Hedge Bindweed or Morning-glory {Convolvulus sepium L.). 

Description. — Smooth, occasionally, however, pubescent, twining 
around supports or trailing; leaves triangular, halberd or arrow 
shaped, the tip acute, or pointed, the basal lobes obliquely trun- 
cate or sinuate lobed ; flowering peduncles 4-angled with 2 leaf -like 
bracts which are commonly acute; corolla white or tinged with 
rose purple. 

Distribution. — Hedge bindweed or morning-glory is common in 
the northern states and in the southwest from Texas to Canada, 
also in the Great Basin country. A form of it is also found in 
Europe and Asia. Common in every section of Iowa not only in 
corn fields, but along highways and in small-grain fields. 



246 



WEED FLORA OF IOWA 




'•?Sa. 



Fig. 142. Morning-glory (.Convolvulus sepium). Common in grain, com fields 

and meadows. 
(Photographed by Colburn.) 




Fig. 142-A. Distribution of Hedge Bindweed or Morning-glory. 



DESCRIPTIVE MANUAL 247 

Extermination. — The morning-glory must be treated like horse 
nettle since it is a perennial. In addition to the usual methods of 
cultivation sheep have been recommended to destroy the weed. 
This method is certainly applicable where the weed occurs in pas- 
tures. 

In "Wallace's Farmer, Mr. L. C. Greene's experience in killing 
morning-glory is given as follows : "A large farmer had 145 acres 
of com. One piece of twenty acres, fall plowed, on a south slope, 
was planted to com the first of May, ,and by the time the plowing 
and planting were all done it was near the last of May. The early 
planted field was thick with morning-glories and had received no- 
cultivation since they commenced to grow. By the time the corn, 
was four inches high the morning-glories were eight or more inches, 
tall, growing in mats on the ground hunting for something to climb' 
upon. The proprietor viewed the field, and instead of sending out. 
the cultivator sent out three stirring plows and the planter soon 
followed. In two days the field was plowed and planted again and 
a fine crop of com was raised with very little bother from the vines, 
and even the following year the vines bothered but little. 

"Some years ago I fall plowed a small field that was badly in- 
fected with morning-glory vines and smartweeds. The 24th of the 
next May I was ready for that field, but from a little distance it 
looked as if a mowing machine and a rake would be the proper tools 
to use. I plowed rather deep to do a good job, the planter im- 
mediately followed, and in four days after the planter some corn 
could be seen, and it was eight inches high when the cultivator 
got to it. It was just a matter of stirring the soil all season, for 
there were no large weeds to kill. ' ' 

The Prairie Farmer makes these suggestions concerning the 
eradication of morning-glory: "Another way to fight the morning- 
glory is to grow two or three pasture crops a year on the land for 
sheep. One of them ought to be a cultivated crop. The morning- 
glory would not be able to hold out long against such treatment. 
The strong point in favor of this method is the profitable character 
of the work. ' ' 

Wallace's Farmer says concerning its destruction: "They do 
not spread rapidly except under cultivation, as they grow 
mostly from the roots, and these are distributed over the fields 
by cultivators. If when the farmer first discovers a patch out of 
cultivation for a year or two he plows it shallow and frequently 



248 WEED FLORA OF IOWA 

and harrows he can get rid of them. If he cultivates the plants 
with the rest of his field it is only a short time until he will find 
these weeds scattered all over his field. A great many ways have 
been suggested to get rid of this troublesome weed. Special at- 
tachments have been invented for the use on corn cultivators 
known as the morning-glory blades. These are designed to shave 
off the plants just below the surface of the ground." 

"We certainly would fence up this pasture, or part of it, and 
would sow a miKture of grains that would furnish hog feed, and 
while we were at it would sow clover and timothy, and when the 
grains were three or four inches high turn in the hogs. The only 
trouble is that there are not enough hogs to go around the whole 
tract. We had a field in that condition twenty years ago. We 
made a hog pasture of it, and while, the morning-glories are yet 
to be seen in the road alongside, there are none of them in the 
pasture, and have not been siace the first year." 

European Bindweed or Morning-glory {Convolvulus arvensis L.) 

Description. — The European bindweed or morning-glory is a 
deep-rooting perennial; stem procumbent, twining or creeping. 
Like the horse nettle, this species propagates freely by under- 
ground root-stocks; leaves 1-2 in. long, ovate, oblong, arrow-shaped, 
lobes at the base running to a point; flowers borne in 1-flowered 
peduncles with very small leaf-like bracts some distance from the 
flowers; flowers an inch or less long, short, broadly funnel-shaped, 
white or commonly of a rose tinge. 

Distribution. — European bindweed is a troublesome weed in Eur- 
ope and in eastern North America. It occurs also in the southern 
states and on the Pacific coast. It is scattered in many parts of 
Iowa in small- patches. 

Extermination. — A short rotation of crops should be practiced, 
including late sown roots or other cultivated crops : rape is useful 
for this purpose. Frequent use of a broad-shared cultivator will 
destroy new growths and exhaust the vitality of the plants. Sow 
no crop seeds containing those of field bindweed. Applications of 
salt or lime, sometimes recommended to kill this weed, are useless 
unless applied in large quantities. 



DESCRIPTIVE MANUAL 



249 




Pig. 143. European Morning-glory or Bindweed (.Convolvulus arvensis). Com- 
mon in gardens and becoming frequent in Iowa. 
(Photographed by Colburn. ) 




Pig. 143-A^ Distribution of European Morning-glory. 



250 WEED FLORA OF IOWA 

Prof. H. A. Hitchcock in Farmer's Review, says: "The black 
bind-weed or perennial morning-glory {Convolvulus arvensis), 
■which I suppose is the kind meant, is a great pest and difficult to 
eradicate. If a patch is not too large, heavy mulching is the best 
way to destroy it. Then watch the patch closely and cut off im- 
mediately any stray shoot that may appear above its surface. 
Nothing but persistent watching and the careful cutting off of 
all parts above the ground will eradicate this weed. ' ' 

Prof. Ten Eyek, quoted in Wallaces' Farmer, states that the only 
method of culture applicable to large areas which promises any 
great degree of control or destruction of the pest is very late fall or 
winter plowing. The plots which were plowed in November (no 
plowing was done later than November 20th) showed a. very scat- 
tering and feeble growth of bindweed on April 26th, the date of 
inspection. 

The weeds were thinner and more feeble also on the unplowed 
land which produced a crop of sowed cane or sowed kafSt last 
season, than they were on any of the lots cultivated in intertilled 
crops. 

Clover Dodder (Guscuta epHhymum Murr.). 

Description. — A spreading, climbing plant; yellowish or reddish 
with a few minute scales in place of leaves ; flowers whitish or pink- 
ish in heads, small, globular, urn-shaped; cylindrical tube longer 
than the nearly erect, acute sepals; scales large-toothed; stigma 
elongated; style longer than the ovary; stamens exserted, fruit in 
capsules. 

Distribution. — This weed has long been known as troublesome 
in Europe and has been more or less common in the Rocky moun- 
tains on clover and alfalfa. For some years also frequent in the 
east; becoming more abundant on clover and alfalfa. 

Extermination. — -Where the plant occurs cut down the clover at 
once and burn. Sow the patch or field to another crop, preferably 
to small grain or with corn. 

Clark and Fletcher recommend the following treatment: "As 
soon as the pest is noticed, the infected patches should be at once 
mown with a scythe and the refuse removed and destroyed. Fields 



DESCRIPTIVE MANUAL 



251 




Fig. 144. Clover Dodder ( CMSCMf a epithymum). A yellow twining plant on 

clover and alfalfa. 
(Photographed by Colburn.) 




Fig. 144-A. Distribution of Clover Dodder. 

badly contaminated should be plowed before the seed has formed, 
or the crop cut early for hay and the land then plowed. Clover 
seed should never be taken from fields infested with this pest. ' ' 

The Wisconsin Farmer states: "The problem of dodder control 
is strongly influenced by the character of the crop infested. Red 
clover remains but two, or at most but three, years without re- 
seeding. If the dodder is prevented from seeding it should be 
eradicated within this time, or at least not interfere with the 
course of crop rotation. Alfalfa should remain indefinitely, and 



252 WEED FLORA OP IOWA 

if dodder reseeds itself its control becomes much more difficult or 
impossible. This is the prevailing condition in the west. The fact 
that the small-seeded alfalfa dodder of the west has not become 
■established in the east is of special interest in this connection. 
Clover dodder appears likely to prove the most troublesome in 
alfalfa culture in the east. 

' ' If the dodder occurs only in patches in the field it usually can 
be controlled by hand methods. If it covers the greater part or all 
of the field, plowing under the stand will probably be found nec- 
essary. It then becomes important to know how far the crop can 
be utilized without reseeding the land to dodder." 

Field Dodder {Cuscuta arvensis Beyrich.). 

Description. — Stems pale and slender, filiform; "flowers rather 
small, in sessile clusters; calyx with 5 obtuse broad lobes; corolla 
with a short, wide tube, inflexed points, 5-lobed, acute or acumi- 
nate, about 1/2 as long as the tube, tips reflexed; scales large and 
deeply fringed; stigmas capitate; capsules globose, indehiscent. 
Occurs on shrubs, clover and other herbs. 

Distribution.- — Massachusetts to Wisconsin and westward. In- 
troduced with clover and alfalfa seed in Iowa. 

Extermination. — The dodders are largely spread through com- 
mercial seeds, like flax, clover and alfalfa. Alfalfa dodder is a 
somewhat troublesome weed in sections of the United States and 
Europe where alfalfa is grown; in this way it has made its way 
into the Mississippi valley in recent years. There has been much 
complaint about the appearance of clover and field dodder in the 
same region, largely spread, of course, through commercial seeds. 
The dodder may be exterminated in the following way: 

First by the herbicidal treatment. For this purpose a liberal 
application of a 10 per cent solution of copper sulphate will be 
found efficacious. 

In addition, the European investigators recommend a strong sol- 
ution of salt, sulphide of lime, carbolic acid, and sulphate of iron. 
These solutions will destroy the dodder when found in the vegeta- 
tive condition, but should seed occur, then it will be necessary to 
take the additional precaution of cutting the dodder after the ap- 
plication of the herbicide and burning it. It should be remembered 
that these solutions will not be effective unless they come in direct 
contact with the plant. They will injure the clover plant as well. 



DESCRIPTIVE MANUAL 



253 




Figure 145 Figure 145A Figure 145B 

Fig. 145. Field Dodder (.Cuscuta arvensis). 

Fig. 145-A. Flax Dodder (.Cuscuta epilmum). 

Fig. 145-B. Lesser Clover Dodder, Thyme Dodder (Cuscuta epithymuni) . 



254 



WEED FLORA OF IOWA 




Fig. 145-C. Distribution of Field Dodder. 

It is advisable to mom the patch if it is a small one, to rake the 
material into a pile, and after allowing it to dry to hum it. The 
field should he watched carefully, for if the seed is formed, young 
dodder plants wUl make their appearance upon the new growth of 
clover. It is hest therefore to follow the mowing hy hoeing if the 
spot is a small one and continuing this for several weeks until all 
danger of infection is passed. Dewey recormnends keeping the soU 
stirred for about two inches and not allowing any young plants to 
come in contact with the clover. 

Wallace's Farmer suggests the following treatment: "Where 
our readers find this yellow vine twining around their clover or al- 
falfa they must act promptly and effectively. If when they dis- 
cover dodder they will cut it off close to the ground before it seeds 
no damage will follow, as dodder is an annual. It will not do, how- 
ever, to trust to the scythe or mower, for the least particle of dod- 
der which remains attached to the stubble will grow much more 
certainly than any corn or wheat will grow. Where a whole field 
is infested perhaps the safest way is to mow it before the dodder 
goes to seeding, use it for hay, and then plow it up for a crop the 
next year. Or, if we would rather lose a crop of hay than lose the 
stand, mow it, let it dry, and burn it, so as to destroy the dodder 
in the stubble." 



HYDROPHYLLACEAE. WATERLEAF FAMILY. 

The common waterleaf belongs to this family. Eepresentatives 
of the family are more numerous in the west and south than in the 
east and north. 



DESCRIPTIVE- MANUAL 



255 



Common Ellisia {Ellisia nyctelea L.)- 

Description. — Minutely or sparingly roughish hairy; stems 
forked, 6-14 in. high"; leaves pinnately parted into 7-13 sparingly 
cut-toothed divisions; peduncles l-flowered, opposite the leaves; 
flowers with calyx lobes lanceolate; pointed corolla white. 




Fig. 146. Ellisia (Ellisia nyctelea). Common in early spring fields.' 
(Photographed by Colburn.) 




Fig. 146-A. Distribution of Ellisia. 



256 WEED FLORA OF IOWA 

Distribution. — Common in shady and damp places everywhere in 
Iowa and a weed in cultivated fields. It is distributed from New 
Jersey to Kansas, and in the northwest territory. 

Extermination. — This is a spring weed of waste, shady places. 
Sow thickly with some leguminous crop, like clover, or get blue 
grass started. The weed is easily destroyed by cultivation. 

BORAGINACEAE, BORAGE FAMILY. 

Comfrey, bugloss, alkanet, blueweed and borage belong to this 
family. Many of the plants are scattered by animals because of 
the burs. 



Hound's Tongue (Cynoglossum officinale L.). 

Description. — A coarse biennial herb, clothed with short, soft 
hairs; lower leaves oblong or oblong-lanceolate, the upper closely 
sessile with a slightly heart-shaped base ; racemes nearly bractless, 
elongated in fruit; divisions of the calyx ovate, lanceolate, acute; 
corolla reddish purple, rarely white; nutlets flat on the broad up- 
per face, splitting away at maturity. 

Distribution. — ^In fields and waste places, especially westward 
from New England to Quebec, Ontario, Minnesota, Manitoba and 
Kansas. 

Extermination. — This weed should be cut a few inches below the 
surface of the ground. It is easily killed. The "seeds" are, how- 
ever, widely scattered by animals; stray plants should be looked 
for. 



DESCRIPTIVE MANUAL 



257- 




Fig. 147. Hound's Tongue (.Cynoglossum officinale). In pastures. The burs 

are scattered by sheep. 

(Photographed by Colbum.) 




Fig. 147-A. Distribution of Hound's Tongue. 



258 



WEED FX,ORA OF IOWA 



Wild Comfrey {Gynoglosswm virginmnum L.)- 

Description. — ^Perennial . hirsute herb with simple stem 2-3 ft. 
high, leafless above; stem leaves lanceolate-oblong, clasping by a 
heart-shaped base; Bowers on long peduncles, pale blue, small; fruit 
broad, nutlets not margined, convex on the upper surface. 

Distriiutidn.-^GoT3imon in woods of the central Mississippi val- 
ley. New Brunswick to Ontario, Florida, Louisiana to Texas. Com- 
mon in eastern to central Iowa near woods. 

Exterminaiion. — Sometimes persistent in newly made fields in 
the northern states. Cultivation for a few seasons will remove the 
weed. 




Fig. 148. Wild Comfrey {Cynoglossum virginianum) . Woodland pastures. 
(Photographed by Colburn.) 



DESCRIPTIVE MANUAL 



259 




Pig. 148-A. Distribution of "Wild Comfrey. 



Beggar's Lice {Lappula virginiana L.). 

Description. — A coarse, pubescent biennial 2-4 ft. high; lower 
leaves ovate, orbicular, cordate, long-petioled ; stem leaves oVa,te- 




Fig. 149. Beggar's Lice (Lapyula virginiana). Common in woodland pastures. 
(Photographed by Colburn.) 



260 WEED FLORA OF IOWA 

oblong or oval; flowers nearly white; globose nutlets which are 
flattened and barbed on the back. 

,* ■■•■ *'~ 

Distribution. — Common especially in woods northward, from 
New Brunswick to Wisconsin and Minnesota, also from Kansas to 
Louisiana. Common on borders of woods and in wooded pastures 
in Iowa. 

Extermination. — Cut the plant the first season a few inches be- 
low the surface of the ground. When the plants shoot up the sec- 
ond season give the same treatment. The plants are disseminated 
by animals. Stray plants along fences should be looked for and 
destroyed. 



Stickseed (Lappvia echinata Gilibert). 

Description.— An erect annual 1-2 ft. high; pale, leafy, hispid 
with erect branches; leaves linear or Unear-oblong ; racemes 
1-sided; bracteolate; calyx segments lanceolate; corolla blue; nut- 
lets rough-granulate or tuberculate on the back, the margins with 
a double row of slender pri(3kles. 

Distribution. — ^Abundant in waste places along roadsides from 
eastern Canada and New England to Minnesota, Kansas and Brit- 
ish Columbia. Weedy in Europe, where it is native. Common 
along roadsides and gravelly places in eastern Iowa. 

Extermination. — Destroy the plant before the seeds form, by 
cutting off below the surface of the ground. 



DESCRIPTIVE MANUAL 



261 



I I 




Fig. 150. Stlckseed, Bur Seed (Lappula echinata). Along roadsides. 
(From Mich. Agr, Coll. Exp. Sta. Bull.) 



262 



WEED FLORA OF IOWA 




Fig. 150-A. Distribution of Stlqkseed. 



Com Gromwell {Lithospernmm, arvense L.). 
Description. — ^A pubescent aiinual with stems 6-12 in. high, 
with bright green, lanceolate, linear, or oblong, sessile leaves; 




Fig. 161. Corn Gromwell or Puccoon (.Lithospermum arvense). A common 
roadside and field weed of Europe. Southern Iowa and Missouri. Small 
white flowers. 

(Photographed by Colburn.) 



DESCRIPTIVE MANUAL, 



263 



flowers sessile or nearly so, white; calyx segme&ts longer than the 
corolla tube ; corolla f uniiel-form ; nutlets smooth. 

Distribution. — Common weed in fields in the east ; may be looked 
for in southeastern Iowa. One of the most common weeds in grain 
fields in Europe. 

Extermination. — The planis are easily destroyed. The seeds 
probably retain their vitality for some time as the coat is hard. 
VERBENACEAE, VERBENA FAMILY. 

The common cultivated verbena and lemon verbena belong to 
this family. 



Blue Vervain {Verbena hastata L.). 
Description. — A tall perennial 4-6 ft. high; leaves lanceolate, 
coming to a point, cut-serrate, lower leaves often lobed; flowers in 
erect, linear, corymbed spikes, violet-blue or rarely pink ; trichomes 
simple, long, acuminate. 




Fig. 152. 



Vervain (Verbena hastata). Common in low pastures and meadows. 

a Trichome. 
(Photographed by Quade. a drawn by Charlotte M. King.) 



264 



WEED ST,0RA of IOWA 




Fig. 152-A. Distribution of Vervain. 

Distribution. — In damp situations in every county in the state of 
Iowa; also to the Atlantic coast and westward and southward. 

Extermination. — This weed, though abundant in low grounds, 
seldom gives trouble where the field is drained and thorough culti- 
vation is given. Spreads chiefly by the seed. 



Hoary Vervain {Verbena strict a Vent.). 

Description. — A soft, .pubescent, perennial 1-3 ft. high; leaves 
downy, ovate or oblong, serrate and sessile ; large blue flowers borne 
in a dense sessile spike, 6 in.-l ft. long; trichomes several-ceUed, 
thick-walled, pitted. 

The white vervain (F. urticaefolia) grows much taller than 
V. striata and has very small white flowers on elongated spikes. 
It is a weed of thickets and waste grounds. 

Distribution. — In dry soil, prairies of Ohio to South Daktoa and 
Wyoming, New Mexico and Texas. Commonly naturalized east- 
ward. A common weed in every part of Iowa ; frequent in pas- 
tures. 

Extermination. — Easily destroyed by cultivation; rarely found 
in cultivated fields for that reason. 



DESCRIPTIVE MANUAL 



2g§' 




Fig. |153. Hoary Vervain (.Verbena stricta). Common In pastures. Plant with 

blue flowers. Plant hair, trichome, to the right. 
(General aspect photographed by Colbum. a, drawn by Charlotte M. King.) 




Fig. 153-A. Distribution of Hoary "Vervain. 



266 



WEED; FLORA,; OF IOWA 




Fig. 153-B. White Vervain, Nettle-leaved Vervain (Verbana urticaefotta). 
(Mich. Agr. Bxp. Sta.) 



DESCRIPTIVE MANUAL 



267 




Fig. 153-C. Distribution of Wliite Vervain. 



Common Vervain {Verbena bracteosa Michx.). 

Description. — A widely spreading, hairy annual; leaves wedge- 
lanceolate, eut-pinnatifid or sometimes 3-elef t ; flowers in spikes, 




Fig. 154. Prostrate Vervain CVerbena bracteosa). u. Plant hair or trichome. 

Common along roadsides, streets, and gravelly places ; small, blue flowers. 
(General aspect photographed by Quade. u. drawn by Charlotte M. King.) 



268 



WEED FLORA OF IOWA 




Fig. 154-A. Distribution -of Prostrate Vervain. 

with large bracts, small, purple ; triclionies few-celled from a broad 
several-celled base. 

Distribution. — Common in waste places, roadsides, walks, gravel- 
ly and sandy fields from Virginia to Wisconsin and Minnesota and 
southward. 

Extermination. — It is easily exterminated by cultivation. 

LABIATAE, MINT FAMILY. 

The common pepperment, scarlet sage, catnip, pennyroyal, thyme 
and basil belong to this family. All are aromatic plants. 



Mint {Mentha arvensis L.). 

Desdpption. — This perennial weed has freely branching stems 
1-1% ft. high, retrorsely pubescent, leaves oblong to ovate, rounded 
at the base, minutely pubescent, closely serrate, petioled or nearly 
sessile ;■ flowers white, pink or violet. The varity canadensis has 
lanceolate to oblong-lanceolate, pubescent leaves and is the common 
form in Iowa in low grounds. Several other species occur in Iowa, 
namely: peppermint {Mentha piperita) along brooks, a smooth 
and pungent-tasting herb with ovate-oblong leaves and running 
root-stocks, and spearmint {Mentha spicata) with oblong or ovate- 
lanceolate unequally-serrate leaves. 

Distribution. — This Eurasian species occurs from Newfoundland 
to Nebraska and the Pacific coast. 

ExtemmMiion. — Easily exterminated by giving thorough culti- 
vation and dragging the soil to bring the root-stocks to the surface 
of the ground. 



DESCRIPTIVE MANUAL 




Fig. 155. Mint (.Mentha arvensis var. canadensis). Common in low meadows; 

whitish flowers. Plant with odor of peppermint. 

(Photographed by Colburn.) 




Fig. 155-A; Distribution of Mint. 



270 



WEED FLORA OF IOWA 




Fig. 155-B. Peppermint (.Mentha piperita). In some gardens. 
(Photographed by Colburn.) 



Carpenter "Weed, Self-heal {Prunella vulga/ris L.). 

Description. — ^A low, perennial weed with ovate-oblong, entire or 
toothed leaves, hairy or smooth; flowers collected in heads of 
3-flowered clusters, corolla violet or flesh-color, or rarely pale in 
color, longer than the purplish calyx which is tubular bell-shaped. 

Distribution. — Widely distributed in northern United States, 
west across the continent in clay soils and woods, also from New- 
foundland to Florida. 



Extermination. — This weed is not difficult to exterminate by 
giving cultivation with a cultivator and hoe. The weed is mainly 
spread by seed. The seed of this is not uncommon in clover seed. 



DESCRIPTIVE MANUAL 



271 




Fig. 156. Self-heal (Prunella vulgaris). Common along roadsides, wooded 

pastures. 
(Photographed by Quade.) 




Fig. 156-A. Distribution of Self-heal. 



272 



WEED FLORA OP IOWA 



American Germander {^Teucrium canadense L.). 

Description. — ^A perennial, downy, erect herb 1-3 ft. high with 
running root-stocks; leaves pubescent, short-petioled, downy be- 
neath, ovate, lanceolate, serrate with a rounded base ;' floral leaves 
small; flowers in ample wandlike spikes; caljrx 5-toothed, the up- 
per lobes obtuse; corolla purple, rose or whitish. 

Distribution. — From New England -to Mexico and northwest to 
Manitoba. Common in Iowa .alluvial grounds in pastures, mead- 
ows, grain fields, etc. 

Extermination. — A very troublesome weed in the north. It is, 
however, an excellent bee-plant. Should have the same treatment 
as quack grass. The root-stocks should" be exposed and allowed to 
dry. After plowing the field follow with a disc and harrow once 
a week after the small grain crop is removed. 




Pig. 167. Germander or "Wood Sage (Teuchrium canadense). Common In fields 

and woods. 
(Photographed by Colbum.) 



DESCRIPTIVE MANUAL 



273 




Fig. 157-A. Distribution of Germander. 

Li. H. Pammel in the "Weekly Register says: "Germander is a 
troublesome weed found in many parts of northern Iowa. It pro- 
duces root-stock very much like mint and quack grass. Each sev- 
ered portion produces a new plant, and for this reason it is some- 
what difficult to destroy. The only way to exterminate this weed 
is by thorough cultivation. Plowing in the fall during the dry 
season, then plowing again in the spring and giving thorough cul- 
tivation during the growing season should destroy the weed with- 
out difficulty." 

Catnip {Nepeta cataria L.). 

Description. — A perennial, erect herb, 1-3 ft. high ; leaves ovate, 
corda,te, coarsely serrate, petiolate, whitish, downy underneath; 
flowers in cymose clusters; corolla whitish, dotted with purple; 
trichomes several-celled, rough, thick-walled. 

Distribution. — Native to Europe; widely naturalized in the 
northern states. 

Extermination. — Give the same treatment as to motherwort. 

Chemical Composition. — ^According to the University of Min- 
nesota*, it is as follows : — 



Dry Matter 


Crude Protein 


Ether Extract 


Nitrogen free 

Extract and 

Fiber 


Ash 


94.30 


22.25 


2.66 


63.07 


12.77 



•Snyder: Bull. Univ. Minn. Agr. Exp., 101. 
18 



274 



WEED FLORA OF IOWA 




Fig. 158. Catnip (.Nepeta cataria). Trichome or plant hair at the right. Com- 
mon in waste places. 
(Photographed by Colhurn. Drawing of hair by Charlotte M. King.) 





Figure 158A Figure 158B 

Fig. 158-A. Plant hair or trichome from leaf of catnip. 
(Drawing by Charlotte M. King.) 
Fig. 158-B. Distribution of Catnip. 



DESCRIPTIVE MANUAL 
Ground Ivy {Nepeia hederacea (L.) Trevisan). 



275 



Description. — A creeping, trailing perennial, with leaves all 
alike, petioled, round, Mdney-shaped, crenate, smooth, green on 
both sides; flowers light blue in axillary whorls of about 6, ap- 
pearing in early spring and summer. 

Distribution. — ^Native to Europe, widely naturalized in the 
northern states, especially in shady places. Common everywhere 
in Iowa. 

Extermination. — Somewhat difficult to exterminate in lawns, 
but thorough cultivation will destroy the weed. 




Fig. 159. Ground Ivy or Creeping Charley (Nepeta hederacea). Common in 

some gardens. 
(Photographed by Colburn.) 



276 



WEED FLORA OP IOWA 




Fig. 159-A. Distribution of Ground Ivy. 



Motherwort {Leonurus carcKaca L.). 

Description. — Tall perennial herb with erect stem, 2-6 ft. high; 
leaves long-pointed, the lower round and palmately lobed, the np- 




Viu 160. Motherwort (.Leonurus cardiaca). A common weed in waste place* 

and gardens. 
(Photographed by Colbum.) 



DESCRIPTIVE MANUAL 



277 




Fig. 160-A. Distribution of Motherwort. 

per crenate at the base, 3-cleft; flowers pale;,purple, in close axil- 
lary whorls; corolla bearded. ' . 

Distribution. — ^Native to Europe, widely naturalized in the north- 
ern states. 

Extermmation. — This perennial weed can be exterminated by 
plowing the field with frequent cultivation subsequently. 



Blue Sage {Salvia lanceaefolia Poir.). 

Description. — ^A slightly pubescent or nearly smooth annual, 
1-2% ft. high; leaves petiolate, lanceolate serrate or nearly entire; 
flowers in interrupted, erect spikdike clusters ; ■ calyx bilabiate, 
upper entire, the lower .2-cleft; corolla, blue, slightly exserted; 
stamens with long connective, attached to a sterile anther which 
blocks the throat of the corolla; pistil 1, deeply 4-lobed. Plant 
related to the cultivated garden salvias. 

Distribution. — Chiefly west 0^ Missouri river, Kansas, Nebraska, 
Texas, and Arizona, Missouri and Indiana, introduced in Ohio. 
Common in Pottawattamie, Fremont, Monona and Woodbury coun- 
ties, less common in Story, Boone, Polk and Muscatine counties. 

Extermination. — This weed is easily exterminated by cultivation. 
Do not allow the plant to produce seeds. 

SOLANACEAE, NIGHTSHADE FAMILY. 

Potato, tomato, tobacco, ground cherry, jimson weed, flowering 
tobacco and black henbane, belong to this family. 



278 



WEED FLORA OP IOWA 




Fig. 161. Lance-leaved Salvia, Blue Sage (Salvia lanceaefoKa') . 



DESCRIPTIVE MANUAL 



279 




Fig. 161- A. Distribution of Lance-leaved Salvia. 



Ground Cherry {Physalis lanceolata Michx.) . 



Description. — ^A hirsute perennial with short, stiff hairs, some- 
times nearly smooth; forms short and stout underground stems; 
leaves oblong-ovate to lanceolate, sparingly angulate-toothed or 
more often entire; flowers in axillary peduncles, calyx hirsute, co- 
rolla yellowish with a dark eye; berry reddish. The P. virginiana 
Mill., is also an erect perennial with narrowly ovate acutish leaves 
or acutish or rounded teeth, corolla pale yellow. The P- subgldb- 
rata MacKenzie and Bush, has ovate or ovate-oblong leaves, oblique 
at the base, entire or repand, and brownish corolla; berry, large, 
reddish or purple. The P. heteraphylla is perennial, leaves obtuse 
repand, or obtusely toothed; trichomes several-celled, glandular 
and non-glandular. 

Distribution. — The P. lanceolata in southern Iowa and south- 
ward, the P. virginiana common everywhere in Iowa, in dry grav- 
elly soil, from Connecticut to Iowa and southward; the P. suh- 
glahrata from Rhode Island to Minnesota and southward. 

Extermination. — ^AU of the perennial ground cherries are diffi- 
cult to destroy because of the strong underground root-stocks which 
freely spread the weed. These plants are also scattered by seed. 
To exterminate the perennial weeds plow shallowly and expose the 
plants to the sun ; give frequent cultivation. 



280 



WEED FLORA OF IOWA 




Fig. 162. Ground Cherry (Phiisalis lanceolata). Common in gravelly ami 
sandy soils » waste places and gardens. 1, Leaf ; 2, flower. . 
(Photographed by Quade. Drawing by Charlotte M. King.) 




Fig. 162A 




Figure 162B 



Fig. 162-A. Trichome or plant hair from leaf of Ground Cherry (.Phj/salis 

heterophylla) . 

(Drawing by Charlotte M. King.) 

Fig. 162-B. Distribution of Ground Cherry. 



DESCRIPTIVE MANUAL 



281 




Fig. 162-C. Distribution of Virginia Ground Cherry (Physalis virginiana) . 

Common Nightshade or Stubbleberry (Solanum nigrum L.)- 

Description. — Annual, low-branched and often spreading; glab- 
rous or hairy, hairs roughened on the angles ; leaves ovate, petioled, 




Fig. 183. Black Nightshade (.Solanum nigrum). Shady places, gardens and 

fields. 
(Photographed by Colburn.) 



2S2 



"WEED FLORA OF IOWA 




Fig. 163-A. Distribution of Black Nightsliade. 




Fig. 163-B. Black Nightshade (.Solanum nigrum). 



DESCRIPTIVE MANUAL 283 

flowers white in small, umbel-like, drooping, lateral clusters; calyx 
spreading, the lobes obtuse, much shorter than the white corolla; 
berries glabrous, globose, black ; occasionally large. 

Distrilmtion: — Pound in northern United, States; abundant 
everywhere in Iowa in shady grounds and fields. A cosmopolitan 
weed. 

Horse Nettle {Solanwm caralinense L.). 

Description. — A deep-rooting perennial, propagating freely by 
its underground root-stocks, the running roots often being 3 ft. 
long ; stem 1-2 ft. high, somewhat straggling, half shrubby at the 
base; stem hairy or merely roughish with minute hairs which are 
star-shaped, also armed with numerous stout, subulate, yellowish 
prickles ; leaves oblong or sometimes ovate, obtusely sinuate-toothed 
or lobed, or deeply cut, 2-4 in. long; flowers borne in one-sided 
racemes ; calyx consists of slender lobes, corolla light blue or whitej 
an inch or less in diameter ; flowers followed by yellow globose ber- 
ries %-% in. in diameter; small yellowish seeds, a little less than 
^/i2. in. long, minutely roughened. Flowers and yellow berries 
resemble those of the potato. The spiny- character of the leaves arid, 
the further resemblance of the. flower to the potato should render 
it easy of detection. 

Distribution. — Horse nettle is indigenous to the southern stat,es^ 
but now occurs from Connecticut to northern Iowa. This wieed 
is most abundant in southern Iowa and has been reported from 
Floyd, Story, Boone and Linn counties; in the north half of the 
state, howeverj it is a recent introduction. 

E xtermiiwition. -^THaere are two methods of propagation ; one'by 
seeds, the other by perennial roots'. It is so exceedingly tenacious' 
a weed, that it is almost impossible to remove it when fully estab- 
lished. The following very suggestive methods 'have been given. 

Smothering. This is an effective method of removing the plant. 
For this purpose probably rape or sorghum is the most suitable 
crop. If the soil is not already rich, a liberal dressing of barnyard 
manure should be applied during the winter or spring. The soil 
should be harrowed or cultivated frequently until the time of seed- 
ing, which may be any time during the months of May or June. 
This cultivation will prevent the weed growth, and will also assist 



284 WEED FLORA OF IOWA 

in the retention of moisture. If the rape is sown in drills about 
two pounds of seed per acre is sufficient quantity and three pounds 
if sown broadcast. When the crop has attained a rank growth it 
may be pastured or removed and fed to stock. Where land is lack- 
ing in vegetable matter it is good practice to plow the crop under 
when it is properly manured. The latter is not necessary when the 
object is to destroy the nettle, as the rank growth of the crop is 
very effective in completely smothering the weed. 

Hoed crops. Planting of corn or roots is a method much in 
vogue for the destruction of this vile intruder. As in the previous 
method the plant should be kept down before seeding time. When 
the crop appears above the ground the use of horse and hand hoe 
should not be sparing. When the welfare of the crop prohibits the 
use of the horse hoe, the hand hoe should be used at intervals until 
the crop is reinoved; even after this, it is sometimes necessary to 
give attention to the pest. There is no question about this mode of 
treatment being effective if properly carried out, but often failure 
results from negligence during the latter part of the season. 

The Iowa Homestead suggests the following treatment: "Com 
land that has grown up to horse nettles this year should be burned 
over, if possible, next spring, as this will destroy many of the 
seeds. Afterwards the land should be plowed lightly and kept cul- 
tivated at intervals until somewhat late in the season. A surface 
cultivator will be all that is necessary, and this need not be run 
deeper than two or three inches, just enough to effectively, cut the 
plants off below the surface. By checking the growth several times 
before planting com the root system becomes much weakened, so 
that ordinary cultivation the remaining part of the season wiU often 
keep them completely in check. Where nettles have been going to 
seed for a number of years it may require considerable tiine to free 
the land because these will germinate as they are brought near the 
surface by the various plowings. However, it should be kfept in 
mind that any perennial root system may be kiUed outright in one 
season if it is not allowed to develop roots or stems." 

Buffalo Bur {Solarium rostratum Dunal.). 

Description. — Herbaceous; woody when old, somewhat hoary or 
yellowish, 8 in. -2 ft. high, covered with copious stellate pubescence ; 
branches and main stems, when it begins to branch, covered with 
sharp yellow prickles; leaves somewhat melon-like, 1-3 times pin- 



DESCRIPTIVE MANUAL 



285 




Pig. 164. Horse Nettle CSolanum caroUnense) . Deep rooted perennial, roots 
sometimes extend 3-4 feet In the soil. Flowers and berries somewhat like 
the potato. Common In southern Iowa. ^ 

(Photographed by Colbum.) 




Fig. 164-A. Distribution of Horse Nettle. 



286 



WEED FLORA OP IOWA 




Fig. 165. Buffalo Bur (.Solanum rostratum). Pastures, gardens, railways, etc. 
.^ _. (Photographe.d by CQlbnrn.J 




Fig. 165-A. Distribution of Buffalo Bur. 



DESCRIPTIVE MANUAL 



287 



natifid, lobes roundish or obtuse and repand, covered with soft 
pubescence; hairs stellate, flowers yellow, corolla gamopetalous, 
about an inch, in diameter, nearly regular, the sharp lobes of the 
corolla broadly ovate; stamens 5, declined, anthers tapering up- 
ward, linear-lanceolate, dissimilar, the lowest much larger and 
longer, with an incurved beak, hence the technical name rostmtum; 
style much declined; fruit a berry but enclosed by the close-fitting 
or prickly calyx, which has suggested the common name buffalo 
bur; pedicels in fruit erect; seeds thick, irregular, round or some- 
what longer than broad, wrinkled, showing numerous small pits 
and surrounded by a gelatinous substance. 




Fig. 165-B. Buffalo Bur iSolanum rostratum) ; a, general sketch showing 

habit of plant ; T>, flower ; d^ seed natural size ; c, seed enlarged. 

(After Dewey, U. S. Dept. of Agr.) 



288 WEED FLORA OF IOWA 

Distribution. — Buffalo bur is originally native -of the plains 
region, between the Missouri river, and the Rocky mountains. It 
has spread eastward in the northern states and extensively in 
Texas, Mississippi and Arkansas. It is not infreqiient from 
Tennessee to New York. It has been found in Germany. This 
weed is widely scattered in small patches in many parts of the 
state of Iowa. 

Extermination. — ^Inasmuch as this weed is an annual, it can be 
easily exterminated by cutting off the young plants below the 
ground and this should be done before the pods are formed. If 
plants are older they should be cut off and burned. 

The Iowa Homestead says concerning this, weed : ' ' On account 
of the fact that the buffalo bur is an annual its destruction or 
eradication is simply a matter of preventing it from maturing its 
seed. Com fields that are badly infested may need but little at- 
tention after the regular time, for laying the. corn' by, for which 
purpose the one horse cultivator may .be pressed into use." 

Dr. C. E. Bessey in Breeder's Gazette recommends as follows: 
"To get rid of it the best thing is first not to allow the weed to 
get a good start, as its deep roots are hard to get out-. Second, if it 
has a good start, the plants Inust be. cut down frequently so as to 
prevent their seeding and thus starting new plants. In the third 
place, the deep roots must be killed by digging out or by smother- 
ing. This can be done by using a very heavy dense crop like some 
of the sorghums, or by covering the patch with wet manure. Of 
course constant stirring of the soil will kill them. It will pay to 
watch this weed wherever it appears. ' ' 

Purple Thorn-apple, Purple Stramonium, or Jimson Weed 
■ .{Datura tatula L.). 

Description. — A glabrous annual from a few inches to 5 feet 
high; stem purplish; leaves thin, ovate, acute or acuminate; flowers 
consisting of a 5-toothed calyx and a 5-lobed funnel form corolla, 
with stamens included; filiform filaments inserted below the mid- 
dle of the corolla tube; capsule globular, prickly, 4-valved and 
2-celled. The common thorn-apple {Datura stramonium) is a glab- 
rous annual with green stem, sinuate-toothed leaves and white 
corolla. 



DESCRIPTIVE MANUAL, 



289 




Fig. 166. Purple Jlmson "Weed (Datura tatubi). Barnyards, roadsides. 
(Photographed by Colbum.) 




Fig. 16 6- A. Distribution of Jimson Weed. 



19 



290 



WEED FLORA OP IOWA 



Distribution. — ^Both species abundant in field and waste places 
from New England to North Dakota and Texas and naturalized 
from Europe ; originally native to India. 




Fig. 166-B. Jlmson Weed or Thorn-apple iDatura stramonium), a, flowering 

spray ; i, fruiting capsule. 

(U. S. Dept. Agr.) 




Pig. 166-C. Distribution of Thorn-apple. 



DESCRIPTIVE MANUAL 291 

Extermination. — Botli of the jimson weeds are easily destroyed 
by cultivation. They produce an enormous amount of seed which 
probably retains its vitality for a considerable length of time. How 
long, however, has not been determined. 

SCROPHU'LARIACEAE, MULLEIN FAMILY. 
Snapdragon and Simpson honey plant belong to this family. 

Mullein {Verhascwm thapsus L.). 

Description. — A tall, densely woolly annual or biennial herb 2-6 
ft. high; leaves oblong, thick, covered with branched hairs, the 
basal leaves margined, petioled; flowers in long dense spikes; coroUa 




l^'ig. 167. Mullein (Verbascum thapsus). A hairy biennial, common road- 
side weed ; gravel hills along Mississippi river, old fields. 
(Photographed by Colbum.) 



292 



WEED FLORA OF IOWA 





Figure 167A 



Figure 167B 



Fig. 167-A. Glandular triohoiiie from viscid pod of Moth Mullein (.Terbascvm, 

blattaria) . 
(Drawing L, H. Pammel and Charlotte M. King.) 

Fig. 167-B. Distribution of Mullein. 



rotate, yellow or rarely white; stamens unequal, the 3 upper 
shorter, woolly, with short anthers ; the 2 lower smooth with larger 
anthers ; trichomes many-celled, branched with central axis. 

Distribution. — From Nova Scotia west across the continent. 
Southwest to Missouri and Kansas and Utah. Common in waste 
places, especially in eastern Iowa. 

Extermination. — Mullein is easily destroyed by cutting the plant 
off a few inches below the surface of the ground. This may be 
done in the autumn after the appearance of the root leaves, or in 
the second season when the plant shoots up. 



Toadflax -{Linwria vulgaris Hill.). 

Description. — ^Persistent, deep-rooted perennial, 1^2-2^^ ft. high, 
with erect, slender stem ; leaves smooth, sessile, crowded, alternate- 
linear, somewhat fleshy ; flowers in racemes, showy, pale yellow and 
orange lips; corolla 2-lobed, closed; seeds small, dark brown to 
black and roughened ; flowers from June to October. 

Distribution. — Introduced from Europe first as a cultivated 
plant from whence it has spread to roadsides, meadows, and waste 
places. Somewhat widely distributed in this state, but particularly 
common in Clayton, Allamakee and Winneshiek counties; local in 
Story county. 



DESCRIPTIVE MANUAL 



293 




Fig.. 168. Toadflax or Butter and Eggs (Linaria vulgaris). Roadsides, gardens, 

etc. 
(After Clark and Fletcher.) 



294 



WEED FLORA OP IOWA 




Fig. 168-A. Distribution of Toadflax. 

Extermination. — Fletcher and Clark recommend as follows: 
"Short rotation of crops with deep, thorough cultivation in spring 
and fall will suppress it. Hand-pulling when the soil is wet is 
effective ia pasture lands that cannot be cultivated. Badly in- 
fested meadows or pasture lands should be brought under cultiva- 
tion by plowing in July, summer-fallowing until autumn, and 
planting with hoed crop the following spring." 



Simpson Honey Plant {Scrophularia marilandica L.). 

Description. — ^A glabrous, somewhat glandular, pubescent peren- 
nial, 3-5 ft. high; stems 4-angled; leaves thiu, ovate, or ovateJan- 
ceolate, sharply serrate; flowers eymose; calyx lobes ovate, about 
the length of the tube, corolla brownish purple; capsule subglpb-- 
ular; seeds small, numerous. 



Distribution. — Common in woods and thickets from Maine 
the Eocky mountains. Abundant in woods and adjacent fields. 



to 



Extermination. — Simpson honey plant produces a large number 
of small seeds. However, but little is known of their vitality. The 
weed is easily killed by cultivation and easily crowded out by 
clover and small cereals. 



The Scrophularia leporella Bicknell, is similar as regards the 
foliage, the rudimentary stamen is, however, yellowish-green in- 
stead of brownish-purple as in the S. WMrilandica. 



DESCRIPTIVE MANUAL 



296 




Fig. 169. Simpson Honey Plant (.Scrophularia marilandica). Woods and 

waste places. 
(Photographed by Colburn.) 




Fig. 169-A. Distribution of Simpson Honey Plant. 



296 



WEED FLORA OF IOWA 



Purslane Speedwell, Neekweed {Veronica peregrino L.). 

Description. — A glabrous, glandular, or nearly smooth, branch- 
ing annual 4-9 in. high; leaves petioled, upper oblong, linear and 
entire; floral leaves like those of the stem but reduced; flowers 
axillary and solitary, white; capsule orbicular. 

Distribution. — A common weed in fields in Iowa and in eastern 
North America from Nova Scotia southward ; also west to Texas and 
the Pacific coast. Found in South America and in Europe; cos- 
mopolitan. 

Extermination. — The seeds are produced abundantly, but young 
as well as older plants are easily killed by cultivation. 




Fig. 170. Speedwell (.Veronica peregrina'). Common in gardens and fields in 

early spring. 
(Photographed by Quade.) 



PLANTAGINACEAE, PLANTAIN FAMILY. 

The family contains few plants of economic importance. The 
seeds of a few species are used as medicine. 



DESCRIPTIVE MANUAL 



297 




Fig. 170-A. Distribution of Speedwell. 

Common Plantain {Plantago major L.). 

' Description. — A smooth, glabrous perennial with short root- 
stocks ; leaves with a long channeled petiole, ovate, oblong or oval ; 
spike long, linear, cylindrical, capsule circumscissile near the mid- 
dle; flowers proterogynous ; seed smooth, angled, reticulated; tri- 
e^omes short, several-celled, from a broad base. 

, Distribution. — Common plantain is widely distributed in North 
America from the Atlantic to the Pacific. Perhaps native far 
northward; probably naturalized in Iowa. It is found in every 
county in the state; frequent in dooryards, fields and pastures. 

Extermination. — Usually not a difficult weed to exterminate in 
cultivated fields. 



Clark and Fletcher recommend the following treatment: "Hoed 
crops every four years will keep this weed in check. Working 
with a broad-shared cultivator, followed by a harrow, to drag the 
plants with their fibrous roots to the surface, is recommended for 
spring cultivation. Plantain in lawns may be weeded out when 
the soil is firm by forcing a small implement like a chisel, with 
a half-round blade having a point like the tip of a spoon, between 
the soil and the fleshy crown of the weed to a depth sufficient to 
break the plant away from its fibrous roots without disfiguring the 
turf. A teaSpoonful of salt applied to the crown of small plants 
in hot dry weather will kill them without seriotisly injuring the 
grass. ' ' 



29S 



WEED FLORA OF IOWA 




Fig. 171. Common Plantain (.Plantago major). Common In dooryards, wasl» 

places, etc. 
(After Clark and Fletcher.) 



DESCRIPTIVE MANUAL 



299 





Pig. 171A 



Figure 171B 

Fig. 171-A. Hairs of Common Plantain. 
(Drawing by L. H. Fammel. and Charlotte M. King.) 

Fig. 171-B. distribution of Common Plantain. 



Chemical Composition. — According to the report of the Bussey 
Institution* the ■chemical composition is as follows : 



FRESH OR AIR DRY MATERIAL. 



Water 


Ash 


Protein 


Fiber 


Nitrogen free 
Extract 


Fat 


81.44 


2.ie 


2.es 


2.09 


11.19 


0.47 


WATER FREE SUBSTANCE. 




11.7 


14.S 


11.3 


60.2 


.25 



Rugel's Plantain {Plantago Bugelii Dec); 

Description. — Perennial, much like the preceding, Ibut leaves and 
petioles cbmmo^y purplish; spikes less dense; sepals oblong; cap- 
sule about twice as long as the sepals; circumscissile much below 
the middle ; flowers proterogynous ; seed oval or oblong, not reticu- 
lated. 

Distribution. — Common in fields and waste places from Maine to 
Texas, South Dakota and Ontario. Common in Iowa. 

Extermination. — This weed may be exterminated in the same 
manner as the preceding species. 

•Bull. 1877:117, Jenkins & Winton. Office of Experiment Stations, Bull It 



300 



WEED FLORA OP IOWA 




Fig. 172. Rugel's plantain (.Plantago rugelii Decne.) 
(Mich. Agr. Exp. Sta.) 



DESCRIPTIVE MANUAL 



301 




Fig. 172-A. Distribution of Rugel's Plantain. 



Rib Grass {Plamtago lanceolata It.). 

Description. — ^A hairy, scapose, perennial with flowering heads, 
l-2l^ ft. high; leaves lanceolate or lance-oblong; spike thick, at 
first- capitate, becoming cylindrical ; bracts and sepals scarious ; seed 
smooth, brownish, hollowed on the face; trichomes simple, lo:pg, 
slender-pointed. 

Distribution. — ^Buckhorn or rib grass is native to Europe and 
has long been known as a troublesome weed in the eastern states; 
it is particularly abundant in Ohio and New York and is frequent 
in the east; in the Rocky mountains and on the Pacific coast. In 
Iowa it has been distributed widely with clover and will be found 
in clover meadows in m,any parts of the state. 

Extermination. — This weed is a persistent perennial in fields, 
lawns and clover meadows. Nothing but thorough cultivation will 
destroy it. In seeding to clover use only pure and clean seed. 

Clark and Fletcher recommend as follows: "Sow clean seed. 
In common with other species of plantain, this weed is easily sup- 
pressed by hoed crop and short rotation. It is prevalent almost ex- 
clusively in clover crops, in which it increases rapidly by the dis- 
tribution of its seeds with commercial clover seed, the market value 
of which is depreciated by this impurity. Farmers who use only 
first quality red clover seed and who pull the first plants of this 
weed that occur in the clover seed crop will soon rid their farms 
of this pest. ' ' 



3( 302 



WEED FLORA OF IOWA 




Fig. 173. Buckhorn (Plantago lanceolata). Common in clover meadows. 
(Photographed by Coibum.) 




Fig. 173-A. Distribution of Buckhorn. 



DESCRIPTIVE MANUAL 



303 



Chemical Composition. — The chemical composition of rib grass, 
grown in New Hampshire, according to Eept. U. S. Dept. Agr., 
1879,, p. 121, is as follows:* 



FRESH OR AIR DRY MATERIAL. 



Water 


Ash 


Protein 


Fiber 


Nitrogen free 
Extract 


Fat 


7.85 


e.90 


9.80 


20.24 


61.10 


4.U 


WATER I-BEH SUBSTAITOB. 




■ 

7.4 


10.7 


21.9 


m.s 


4.5 



Prairie Plantain {Plantago pursMi R. & S.). 

Description. — A silky, green annual with slender scapes; leaves 
linear, acute, with marginal petioles; spikes usually cylindrical, 
villous with rigid bracts ; flowers of two kinds on different plants ; 
most of them cleistogamous ; sepals oblong, obtuse; corolla lobes 
broadly ovate; stamens 4; capsule oblong, obtuse, eircumseissile at 
about the middle ; seeds convex on the back, deeply concave on the 
face. 



Distribution. — Common westward from Ontario and Illinois to 
British Columbia, Texas and Mexico. Sometimes a troublesome 
weed in Missouri and Nebraska. Found along railways in Iowa. 

Extermination. — ^.This little plantain is not likely to give much 
trouble unless the seeds are able to retain their vitality for a con- 
siderable length of time. The plant is easily destroyed by culti- 
vation. 



•Jenkins and Winton. Bull. Off. Exp. Sta. 11 :79. 



304 



WEED FLORA OF IOWA 




Fig. 174. Prairie Plantain (.Plantago purshii). 
(Drawing by Ada Hayden.) 



DESCRIPTIVE MANUAL 



303 




Fig. 174-A. Distribution of Prairie Plantain. 



Bracted Plantain {Plant ago aristata Miehx.). 

Description. — ^A loosely hairy, green annual, becoming glab- 
rous with age, leaves 1-3-nerved, oblong, linear, or filiform; spike 
slender, cylindrical, with narrow linear bracts, much longer than 
the flowers. Flowers of two kinds with reference to the length of 
anthers and filaments on different plants, mostly cleistogamous ; 
corolla lobes broad and rounded; seeds 2, smooth, light brown, 
with a ring on the hollowed portion. The P. purshii is much like 
bracted plantain except that its leaves are silky villous and slender ; 
spike dense. 

Distribution. — The bracted plantain is common in southern Iowa 
and is spreading to many other parts of the state with clover seed ; 
on prairies, Illinois to Louisiana, naturalized eastward. The P. 
purshii is found chiefly along railroads where it has been intro- 
duced; common; native from western Minnesota and Iowa to the 
Pacific coast. 

Extermination. — Only clean clover seed should be used. Easily 
exterminated by cultivation. Practice rotation of crops, oats, corn 
and clover. 

Wallaces' Farmer says concerning its extermination: "The en- 
tire southern country seems to be infested with bracted or lance- 
leaved plantain, and seed coming from the south should always be 
regarded with suspicion. It is one of the worst weeds that can get 
on the farm. Cut the hay, plow up the land, put it in wheat, and 
don't undertake to take a crop of clover seed from that land 
20 



306 



WEED FLORA OF IOWA 




Fig. 175. Bracted Plantain (.Plantago ariatata). A common weed in clover 

fields in southern Iowa and In waste places. 

(Photographed by Colbum.) 




Fig. 175-A. Distribution of Bracted Plantain. 



DESCRIPTIVE MANUAL 307 

Wlien this weed grows over the whole field the only thing to do 
is to put it through a course of rotation. "Where there is only a 
stalk here and there it may be taken out with a 'spud,' which is 
simply a two-inch chisel with a handle, by means of which the 
farmer can cut out rapidly many of these weeds, but where it is 
scattered over the field the only way is to put it through a course 
of rotation." 

CAPRIFOLIACEAB, WOODBINE FAMILY. 

Contains a number of cultivated ornamental plants like the coral 
honeysuckle, bush honeysuckle, elder, etc. 



Indian Currant, Coralberiy (Symphoricarpos orhiculatus Moeneh.). 

Description — ^A shfub 2-4 feet high; purplish, usually pubescent 
branches ; leaves oval or ovate, entire or undulate, nearly glabrous 
above, pubescent underneath ; flowers in short axillary clusters ; 
corolla bell-shaped, sparingly bearded; pinkish, stamens included; 
fruit a purplish berry. 

Distribution. — Rocky woods and along streams ; from New Jersey, 
Illinois, South Dakota, Nebraska to Texas and Georgia. This weed 
is common throughout the southern part of the state of Iowa and 
is often most troublesome; 

Extermination. — ^Fields that' are infested with this weed must be 
broken up with a breaking plow and subsequently disked so that 
the roots may be brought to the surface and exposed to the sun. It 
may be necessary to disk once or twice more before planting the 
crop. 

COMPOSITAE, SUNFLOWER FAMILY. 

• Includes comparatively few economic plants, such as lettuce, arti- 
choke, pyrethrum, sunflower; quite a number such as gumweed 
(Grindelia), tansy and absinth, are used in medicine; several, like 
daisy, cosmos, coreopsis, aster and goldenrod, are' ornamental. 



308 



WEED FLORA OF IOWA 




Fig. 176. Indian Currant (.Symphot-icarpus orbiculatus') . 




Fig. 176. Distribution of Indian Currant. 



DESCRIPTIVE MANUAL 



309 



Ironweed {Veronia haldwmi Torr.). 

Description. — A roughish, pubescent, perennial 3-5 ft. tall; 
leaves lance-oblong or ovate, denticulate; heads in open, cymose 
clusters, about 25-fl.owered; involucre hairy-tomentose ; bracts 
squarrose, purplish or greenish ; involucre acuminate. 

Distribution. — Common from Maine to Missouri and southward. 
It is found in central Iowa, from Webster county southward and 
along Missouri river to Council Bluffs. 

Extermination. — Frequently a troublesome weed. Usually not 
difficult to exterminate in cultivated fields. 




Fig. 177, Ironweed (Vernonia T}aldwinl). Common in low pastures. 

in heads. 
(Photographed by Colburn.') • 



Flowers 



310 



WEED FLORA OF IOWA 




Fig. 177-A. Distribution of Ironweed. 

"Western Ironweed {Vemonia fasciculata Miehx.). 

Description. — ^A bushy perennial 3-6 ft. high; leaves linear to 
oblong-lanceolate, long,, acuminate, smooth or nearly so, denticulate ; 
heads short-peduncled, 20-30-flowered, bracts of the involucre ap- 
pressed, ovate or oval, acute, ciUate, the uppermost somewhat 
mucronate. 

Distribution. — Common in the Mississippi valley, especially on 
low, alluvial grounds from Ohio to North Dakota, south to Ken- 
tucky and Texas; frequent in all parts of Iowa. 

Extermination. — This perennial weed, though abundant in pas- 
tures and low meadows, soon succumbs to cultivation. 



Wallaces' Parmer says concerning its destruction: "An occa- 
sional cutting of ironweed is useless. If you are to keep it down 
by strangulation, then you must keep at it until the weed is 
strangled. 

"If we had some permanent pasture that was covered with iron- 
weed, we would try sheep. There are a few weeds that sheep 
will not eat. They will probably not make a very good living on 
ironweed alone, although we recently saw some sheep that ap- 
parently had nothing else to live on trimming up ironweed alone. 
But sheep will eat almost any weed that grows out of the ground, 
barring thistles, mullein and buffalo berry. It requires about two 
years of sheep pasturing to get rid of ironweed. We know of no 
other way in which it can be done so easily." 



DESCRIPTIVE MANUAL 



311 




Fig. ]78. Common or Western Ironweed CTernonia fasciculata) . A perennial 

weed with purple flowers. In low pastures and meadows. 

( Pliotographed by Colburn.) 




Fig. 17 8- A. Distribution of Western Ironweed. 



312 WEED FLORA OP IOWA 

"White Snakeroot {Ewpaioriwm urticaefolium Riech.). 

Description. — Perennial, with smooth, branching stem 15-40 in. 
high; broad, ovate, coarsely and sharply toothed, pointed, long- 
petioled leaves ; flowers in compound, eymose clusters, white. 

Distribution. — Pennsylvania, Virginia, westward; reported from 
many places in Iowa. 

Extermination. — This perennial weed is easily killed by cultiva- 
tion. It is common in woodlands. It is mentioned here because 
of its supposed poisonous nature. 




Fig. 179. Bcneset or White Snakeroot (Bupatorium urticaefolium,). Wood- 
land pastures. 
(Photographed by Quade.) 



DESCRIPTIVE MANUAL 



313 





Figure 179A Figure 179B 

Fig. 179-A. Distribution of White Snakeroot. 

Fig. 179-B. Boneset (Eupatoriwrn rotundifoUum) . 
(Drawing by Lois Pammel. ) 



Goldenrod {Solidago canadensis L.). 

Description. — A rough, hairy, pubescent perennial 3-6 ft. high; 
lanceolate, pointed, sharply serrate leaves, especially pale in color, 
pubescent beneath and rough above; heads in recurved racemes 
forming panicles ; ray flowers yellow ; triehomes several-celled ; cells 
short, walls pitted. 

Distribution. — Most widely distributed of the goldenrods from 
the Atlantic to the Rocky mountains; common in every part of 
Iowa, especially in Story, Boone, Clinton, Linn, Allamakee, Potta- 
wattamie, Woodbury, Cerro Gordo and Marshall counties. 

Extermination. — This weed is quite largely spread by "seeds," 
but is not difficult to kill by cultivation, although it sometimes 
persists in fields for some years. Prevent the carrying of "seeds" 
and give thorough cultivation. 



314 



WEED FLORA OP IOWA 




Fig. 180. Canadian Goldenrod iSoUdago canadensis). Roadsides and woods. 

a, hairs of leaf. 
(Photographed by Colburn, a, hairs drawn by Charlotte M. King.) 




Fig. 180-A. Distribution of Canadian Goldenrod. 



DESCRIPTIVE MANUAL 
Goldenrod {Solidago serotina Ait.). 



315 



Description. — ^A tall, stout perennial 4-6 ft. high ; often glaucous ; 
leaves smooth on both sides, lanceolate to oblanceolate, taper- 
pointed, sharply serrate; heads in open panicles, pubescent, bracts 
linear ; ray flowers 7-14, yellow. 

Distribution. — Common from New England southward and west- 
ward to the Rocky mountains and Colorado; common in all parls 
of the state of Iowa. 

Extermination. — Succumbs readily 'to cultivation, spreads by its 
seeds and root-stocks. 




Fig. 181. Smooth Goldenrod (Solidaao serotina). Abundant in low grounds 

along streams. 
(Photographed by Colburn.) 



316 



WEED FLORA OP IOWA 




Fig. 181-A. Distribution of Smooth Goldenrod. 



Large Yellow- flowered Goldenrod {Solidago rigida L.). 

Description. — A rough and somewhat hoary perennial, minutely 
pubescent; stems stout, 2-5 ft. high, very leafy; leaves oval or ob- 




Flg. 182. Large-flowered Goldenrod (.SoUdago rigida). In pastures and road- 
sides. 
(Photographed by Colbum.) 



DESCRIPTIVE MANUAL 

\ - 

MAM ^ 



317 




Fig. 182-A. Distribution of Large-flowered Goldenrod. 

long, feather-veined, thick and rigid, the upper sessile; heads 
large, collected in a large compound corymb, terminating the stem. 

Distribution. — Abundant in dry soils from New England to 
Manitoba, Dakota, Nebraska and Missouri; common in pastures in 
Iowa, in Story, Boone, Polk, Linn, Marshall, Hardin, Cerro Gordo, 
Winnebago, Emmet and Woodbury counties. 

Extermination. — Though it is often a very troublesome weed in 
pastures it is easily killed by cultivation; spreads largely by 
"seeds." 



Many-flowered Aster {Aster muttiflorus Ait.). 

Description. — ^A pale or hoary pubescent, branched perennial, 
9 in-li/^ ft. high; heads on spreading, racemose branches; leaves 
rigid, crowded, spreading, with ciliate margins; ray flowers white, 
small. 

Distribution. — Common along roadsides and fields, gravelly 
knolls, etc. 

Extermination. — Though abundant in fields readily succumbs to 
cultivation. 



318 



WEED FLORA OP IOWA 




Fip. 183. White or Many-flowered Aster (.Aster multiflorus) . Common on road- 
sides. 
(Photographed by Quade.) 




Fig. 183-A. Distribution of White Aster. 



DESCRIPTIVE MANUAL 



319 



Willow-leaved Aster {Aster salicif alius Ait.). 

' Description. — -A branched, leafy perennial 2-8 ft. high ; leaves ob- 
long to narrowly lanceolate, pointed, entire, or slightly serrate, firm, 
often scabrous ; heads racemose, clustered ; ray flowers purplish. 

Distriiution. — Common in low grounds, thickets or borders of 
fields from New England to "Wisconsin and Minnesota. An allied 
species, A. paniculatus Lam., is much like A. salicif alius except that 
the leaves are more pointed, serrate and less scabrous. It is a very 
variable species, with distribution similar to that of A. multiftorus. 

Exterminatian. — Easily exterminated by cultivation. 




Fig. 184. 



Willow-leaved Aster (Aster salicifoKus'). Common In low gvounfls. 
(Photographed by Quade.) 



320 



WEED FLORA OF IOWA 




Fig. 184-A. Distribution of Willow-leaved Aster. 




Fig. 185. Aster paniculatua. a. Plant Hair. Common in low grounds every- 
where in Iowa. White ray flowers, sometimes purplish. 
(Photographed by Colburn. Drawing by Charlotte M. King.) 

The Aster tradescanti L., is closely related to A. paniculatus, but 
has smaller leaves and shorter rays. The leaves are lanceolate to 
linear. The bracts are linear or acutish. 



DESCRIPTIVE MANUAL 



321 



Whiteweed or Fleabane (Erigeron annuus Pers.). 

Description. — A sparingly pubescent annual 3-5 ft. high; leaves 
thin, coarsely and sharply toothed, the lower one ovate, or ovate- 
lanceolate, acute, and entire on both ends; heads corymbed; rays 
white, tinged with purple. 

Distribution,. — This weed occurs from New England to Texas. 
Common in the Mississippi valley. Common throughout the state 
of Iowa, particularly in timothy and clover meadows. This weed 
is also naturalized in Europe. 

Extermination. — Both this and E. ramosus are easily exter- 
minated by thorough cultivation. They are seldom troublesome out- 
side of meadows, though in some parts of Iowa the meadows and 
pastures are white with flowers of these species. 




Fig. 186. Whiteweed or Daisy Fleabane (Erigeron annuus). Common in clover 
and timothy meadows. 
(Photographed by Colburn. Drawings a and 6 by Charlotte M. King.) 
21 



322 



WEED FLORA OP IOWA 




Fig. 186-A. Distribution of Whiteweed. 

Wallace 's Farmer states concerning its eradication : ' ' One of the 
worst enemies of the meadow, and especially the timothy 
meadow in the west, is a peculiar form of daisy to which farmers 
give the name of whiteweed. It may be seen in full bloom about 
the time timothy heads out, and if not dealt with on its first ap- 
pearance in the timothy field it is only a question of time when 
the hay will be from one-fourth to one-half whiteweed. If the 
farmer is vigilant and goes through and pulls out these weeds on 
their first appearance, he can protect his timothy meadows. If he 
fails to do this, it is only a question of time when he will have to 
plow them up." 



Daisy Fleabane {Erigeron ramosus (Walt.) B S P). 



Description. — This resembles the preceding species except that 
the stem and leaves are somewhat more hirsute and hairy; leaves 
roughish, entire or nearly so, the upper lanceolate, the lowest ob- 
long or spatulate; flowers white and smaller than in the preceding 
species. 

Distribution. — Daisy fleabane is native from New England to 
Arkansas. Common in Iowa, particularly in drier situations, clover 
meadows and timothy flelds. 

Extermination. — This weed is common in timothy and clover 
meadows. The seed is often found in clover and timothy seed. 
Care should be used to sow only clover and timothy seed that does 



DESCRIPTIVE MANUAL 



323 




I'is. 187. Daisy Fleabane {Erigeron ramosus) . 
(Mich. Agr. Coll. Exp. Sta. Bull.) 



324 



WEED FLORA OP IOWA 




Pig. 187-A. Distribution of Daisy Fleabane. 

not contain these weed seeds. This weed is easily destroyed by cul- 
tivation. The meadows are sown from seed coming from the neigh- 
boring roadside or field. The weeds should, therefore-, be cut in 
waste places. 

Horseweed (Erigeron canadensis L.). 

Description.— Bristlj, hairy, or sometimes glabrate stem, 1-6 ft. 
high, simple or paniculately branched ; leaves usually pubescent or 
ciliate, the lower spatulate, incised or entire, obtuse or acutish, 
the upper generally linear and entire ; heads- numerous, with in- 
conspicuous white ray flowers shorter than the pappus; pappus 
simple; trichomes several-celled, straight with long cells, curved 
with short cells. 

Distribution. — ^Horseweed is common throughout eastern North 
America; naturalized in Europe, the Rocky mountains and along 
the Pacific coast. Everywhere in Iowa in waste places and in cul- 
tivated fields. 



Extermination. — This weed is an annual and is very easily de- 
stroyed. Cutting off just below the surface of . the ground will 
exterminate it, provided, of course, that the new seeds are not per- 
mitted to re-seed the soil. The weed is common everywhere and 
the fact that it is so easily blown by the wind makes it difficult to 
keep it in check. 



DESCRIPTIVE MANUAL 



S25 




Pig. 188. Horseweed (.Erigeron canadensis). In fields and waste places. 
(Mich. Agr. Exp. Sta.) 



326 



WEED FIX)RA OP IOWA 




Fig. 188-A. Distribution of Horseweed. 



Great Ragweed {Ambrosia trifida L.)- 

Description. — A stout, scabrous, hispid or nearly glabrous an- 
nual, 3-12 ft. high; leaves all opposite. and petioled, 3-nerved, deeply 
3-5-lobed; lobes ovate-laneeolate and serrate, upper leaf sometimes 
ovate and undivided ; flowers monoecious, staminate, borne in spikes 
surrounded by the larger bract-like leaves ; involucre turbinate to 
obovoid, 5-7-ribbed, beaked, each rib bearing a tubercle near the 
summit ; involucre enclosing a single oily seed. 

Distribution. — This North American weed is most abundant in 
the Mississippi valley from Texas to Minnesota and in the Da- 
kotas; however, it also occurs east from New England to Quebec. 
It is abundant in every part of Iowa, especially along highways, in 
grain fields and com fields. 



Extermination. — It is certain that cultivating the young plants 
followed by three or four other similar treatments will remove the 
weed in a single season. 



DESCRIPTIVE MANUAL 



327 




Fig. 189. Greater Ragweed (AmBrosto trifida) , sometimes, but Incorrectly, 

called Ironweed. Common in fields, along roadsides, etc. 

(Photographed by Colbum.) 




Fig. 189-A. Distribution of Greater Ragweed. 



328 WEED FLORA OP IOWA 

Smaller Eagweed (Ambrosia wrtemisii folia L.). 

Description. — A puberulent or hirsute annual, branched, 1-3 ft. 
high; leaves thin, 1-2 pinnatifid; upper leaves alternate, lower 
usually opposite, pale or caneseent beneath; flowers monoecious, 
staminate above and pisillate in lower axils of the leaves; fertile 
heads obovoid or globose ; short-beaked, 4-6 spined ; trichomes sev- 
eral-celled, cells short or long. 

Distribution. — Ragweed or hogweed is originally from Europe 
but is common throughout eastern North America; also found in 
the Rocky mountains, the Pacific northwest, and in Mexico, West 
Indies and South America. It is common throughout the state of 
Iowa in gardens and fields and is abundant in pastures. 

Extermination. — This weed is too common in pastures, along 
roadsides and in waste places. The weed is easily exterminated by 
cutting the plants off below the surface of the soil. The commonly 
used cultivator will destroy most of the young plants in a corn 
field. 

Clark and Fletcher recommend the following treatment: "Sow 
clean red clover seed. Stubble lands where this weed is prevalent 
should be shallow plowed directly after harvest, or, if seeded, the 
autumn growth should be closely cut with a mowing machine 
within two weeks after the grain crop is cut. ' ' 

Wallaces' Farmer says concerning this serious pest of the pas- 
ture: "We suggested that the reason why the ragweed grows in 
the blue grass pastures is because for some reason the stand of 
grass has been weakened and thus the ragweed seeds, which are 
present in all cultivated soils in the west in great abundance, have 
a chance to grow. We suggested further that the stand of grass 
may have been weakened by overpasturing in a dry time', thus giv- 
ing the sun opportunity to burn the roots and lower their vitality. 
We suggested also that it may have been weakened by the ravages 
of larvEe of the various insects known as the white grub worms. 
We suggested still further that blue grass, not being able to ob- 
tain nitrogen from the atmosphere, was nitrogen hungry, and there- 
fore weak. 

To meet all these various suggestions we proposed that farmers 
who have blue grass pastures of long standing should re-seed them 
next year with one or other of the various kinds of clover, filling 



DESCRIPTIVE MANUAL 



329 




Fig. 190. Small Ragweed or Hogweed (.Amlirosia artemisUfoUa) . In pastures, 

waste places, gardens and clover meadows. 

(After Clark and Fletcher.) 



330 



WEED FLORA OP IOWA 





Figure 190A • Figure 190B 

Fig. 190-A. Plant hairs or trlchomes of ragweed. 

(Drawing by Charlotte M. King.) 

Fig. 190-B. Distribution of Small Ragweed. 



up the land with a preferred food for stock and at the same time 
restoring the nitrogen content to the soil, enabling the blue grass 
to make more rapid growth. 




Fig. 191. A weedy Iowa field ; Ragweed, Foxtail, Barnyard Grass, etc. The 

seeds are sown in the field for ne:tt year. 

(Photographed by Pammel.) 



DESCRIPTIVE MANUAL 331 

We did try it on a neighbor's farm under the most disadvantag- 
eous eireumstanees imaginable. The field was a pasture of blue 
grass and wool grass with a very little white clover. The ground 
was dry; as dry as we have ever seen it at that time of the year. 
"We found it easy even under these hard conditions to drill in clover 
on this tough sod and cover it from an inch to an inch and a half, 
using a Hoosier drill with two horses. 

We found that the clover was dropped in the very bottom of 
the slit made by the disk, a seed every two or three inches, using six 
pounds to the acre. It lay there until the 23d of May, apparently 
as dry as it came out of the drill, except in some of the lower spots, 
where it had sprouted. The 23d of May there was a two-inch rain 
on that field, and -at once the clovers began to grow." 



Perennial Ragweed {Ambrosia psilostachya D C). 

Description. — A branched hairy and rough perennial with slen- 
der running root-stock, 2-3 ft. high; leaves once pinnatifid> acute 
iobes, lower leaves incised; monoecious flowers, staminate flowers 
with flattish involucres, involucre of fertile flowers, obovoid, tuber- 
eles absent or very small. 

Distribution. — Common on gravel hills and sandy plains from 
Illinois, Wisconsin to the Saskatchewan to the Rocky mountains, 
common gravel knolls and sandy plains; Clinton, Muscatine, Car- 
roll, Kossuth, Pottawattamie counties. 

Extermination. — Succumbs readily to cultivation. 



332 



WEED FLORA OF IOWA 




Pig. 192. Perennial Ragweed (Ambrosia psilostachya) . 

roadsides. 
(Photographed by Quade.) 



Pastures, drift soils. 



Marsh Elder {Iva xanthifolia Nutt.). 

Description. — An annual 1-8 ft. high; stem frequently pubescent 
when young ; leaves opposite, rhombic, ovate, or lowest heart-shaped, 
doubly serrate, or cut-toothed, obscurely lobed; upper surface 
minutely scabrous, caneseent beneath, especially when young; 
petiole frequently ciliate at its upper end ; flowers borne in spikelike 
clusters forming a compound panicle ; heads small, crowded ; outer 
bracts of the involucre broadly ovate, greenish; inner membrana- 
ceous; achenes glabrate. This plant is also known botanieally as 
Cyclachaena xanthifolia Fr. 

Distribution. — Common in the eastern Eockies, to Saskatchewan 
and western "Wisconsin, most abundant in Iowa along Missouri 
river where it is troublesome in fields, along highways, and in 



DESCRIPTIVE MANUAL 



333 




1% , \ Air 




Fig. 193. Half breed Weed, Marsh Elder (.Iva xanthifoHa) . Common in western 
Iowa, fields and roadsides. 
(Photographed by Colbum.) 




Fig. 193-A. Distribution of Marsh Elder. 



334 WEED FLORA OP IOWA 

yards, spreading into north and northeastern Iowa, Mason. City and 
Allamakee county and also in central Iowa, in Boone and Story 
counties. 

Extermination. — Marsh elder is an annual and hence thorough 
cultivation for a single season will destroy it, provided it is not 
allowed to form seeds. 

Coeklebur {Xanthium canadense Mill.). 

Description. — A coarse, rough annual from 1-2 ft. high, stem 
marked with brown punctate spots; leaves alternate, cordate or 
ovate, 3-nerved, long petioled; flowers monoecious, staminate and 
pistillate flowers in different heads, the pistillate clustered below; 
iuvolucre of staminate flowers somewhat flat, of separate scales; re- 
ceptacles cylindrical; scales of the fertile involucre closed; fruit 
2-beaked, containing 2 achenes; bur densely prickly and hispid, 
achenes oblong, without pappus. 

The spiny clotbur X. spinosum has spines in the axils of the 
lanceolate leaves. 

Distribution. — Common in Mississippi valley from Texas to Min- 
nesota and eastward. Common in fields in many parts of the 
state, but more common in southern than in northern Iowa. 

Extermination. — -The best method of combating this weed is the 
rotation of crops and clean culture. Where a field is in corn, the 
field should be thoroughly cultivated and none of the plants al- 
lowed to mature seed. If they cannot be caught by the cultivator, 
it may pay to kill the remaining plants with a hoe, or to pull them 
by hand. The corn should be followed with winter rye, and then 
oats, using the oats as a nurse crop for clover and timothy. Leave 
the field in meadow for at least two years and then if possible turn 
it into pasture. 

Mr. E. B. Watson found in soil badly infested with coeklebur 
that clover seed would not germinate as well, and it is rather dif- 
ficult to get clover to start in fields of this kind. 

The Homestead says concerning the eradication of coeklebur: 
"Needless to say there is no easy way of eradicating the pest. 
Where the winter wheat can be grown the following plan can be 
depended upon. Start on fields that have been in small grain and 
plow the land as soon as the crop is removed. Harrow as often 



DESCRIPTIVE MANUAL 



a35 




Fig. 194. Cocklebur (Xanthium canad^nse). Corn fields, roaflsides, alluvial 

bottoms. 
(Photographed by Colbum. ) 




Fig. 194-A. Distribution of Cocklebur. 



336 



WEED FU)RA OP IOWA 



as necessary to kill weeds and put in wheat when the time comes. 
The next season as soon as the wheat is harvested remove from the 
field and go on with the mower. This will clip all or most all of 
the young cocklebur plants, as well as other weeds, and following 
this operation the stubble should he plowed as rapidly as possible 
and prepared for another crop of wheat. Another season's treat- 
ment of this sort will generally reduce the burs to such an extent 
that very few will be left and these can be pulled by hand. 




Fig. 195. Spiny Clotbur (.Xanthiwm spinosutn). Waste places from Maine to 

Kansas. Perhaps in southern Iowa, 

(Photographed by Colbum.) 



' ' One of our Nebraska subscribers, Mr. J. J. Bishop, stated some 
time ago that he succeeded in almost clearing out a badly infested 
field of cockleburs in two years by employing the following 
method : Just as soon as the removal of the oat crop the soil was 
plowed and prepared for winter wheat, this crop being sown at 



DESCRIPTIVE MANUAL 337 

the proper time. Mr. Bishop stated that before plowing this ground 
after removing the oats the surface was covered with burs just 
about as thick as they could grow. After harvesting the first crop of 
winter wheat the soil was again plowed and seeded for the second 
time to winter wheat. After this it was followed by corn and 
other crops, with the result that even in the corn crop a very short 
time spent in pulling burs freed the field entirely of these pests. ' ' 

Mr. Albert Wiltz says in Wallaces' Farmer : "When I moved to 
this farm nine years ago the land was very badly infested with 
cockleburs, and farmers told me that each bur had two seeds, one 
growing one year and the other one the next year. I left a patch 
of ground where the cockleburs were lying thick without a crop, 
plowed in June once, and again in August. That settled the cockle- 
burs. That year was a good corn year, with plenty of moisture. 
Now, would not that way be the cheapest way to deal with them — 
to put three years, yes, sometimes ten years ' fighting into one year ? 
That is, take a field one year to fight cocklburs, and finish it ; next 
year take another, and so on, if the farmer is -a renter on a long 
term lease or owns the land." 

Wallaces' Farmer states concerning the extermination of cockle- 
bur : " If it is desirable to put some of this kind of land in alfalfa, 
we would not put it in com, but disk it every week or two during 
the summer to sprout the burs, and then kill them by subsequent 
disking, and keep on that way all summer, missing the crop for the 
first year. Then in the fall, when the ground has sufficient mois- 
ture, say in August or in the first part of September, seed it to al- 
falfa alone, we would not sow .alfalfa in the spring on that kind of 
land; but by continuous summer cultivation it can be gotten in 
shape to grow alfalfa and thus avoid not only cockleburs but also 
erabgrass, another great foe to alfalfa in that part of the country. 

' ' Speaking now on the subject of cockleburs generally. Where the 
land is not so badly infested with them as this farm seems to be, 
and it is not desirable to grow spring grains and seed to clover, we 
would make the stand of grain rather thin, put in a good seeding 
of clover, put the clover deep enough to insure germination, use as 
early a variety of grain as possible, get it off the land as soon as 
possible, and then keep the cockleburs mowed down by clipping the 
clover until a good stand is secured." 

22 



3K8 



WEED FLORA OP IOWA 
Ox-eye {Heliopsis scabra Dunal.)- 



Description.— A rough, pubescent, perennial with opposite, 
petioled, triple-nerved leaves; heads large, peduneled; scales of 
involucre in 2-3 rows, nearly equal; ray flowers yellow, 10 or 
more, fertile; achenes smooth, thick, 4-angled, tnmcate; pappus 
chaffy or 2-3-toothed. 

Distribution. — ^From New York west to Wisconsin, Minnesota 
and British Columbia and southwest to Missouri, Kansas and 
Arkansas. 

Extermination. — Though this weed is perennial, it is rather 
easily destroyed by cultivation. 




I''ii.' 196. Ox-eye (Heliopsis scabra). a, plant hair or trichome. Common in 
orchards, waste places. Ratl:er large yellow heads, and rough, oppositii 
leaves. 

(Photograph by Colburn. a, drawing by Charlotte M. King.) 



DESCRIPTIVE MANUAL, 



339 




Fig. 196-A. Distribution of Ox-eye. 

Black-eyed Susan, Nigger-head, Cone-flower {Budheckia hirta Ij.). 

Description. — A rough, hairy biennial 1-2 ft. high with stems 
simple, or branched, bearing a long pedunculate head; leaves 
nearly entire, the upper sessile, oblong or lanceolate, the lower 




Fig. 197. Blacl5-eyea Susan (Rudbeckia hirta). Common in sandy fields. 
(Fliotographed by Colbum. ) 



340 



WEED FLORA OF IOWA 




Fig. 197-A. Distribution of Black-eyed Susan. 

petioled and spatulate; heads many-flowered, radiate, neutral; 
receptacle columnar or conical; chaff hairy at tip, acutish; ray 
flowers yeUow, disk dull brown ; aehenes 4-angled ; pappus none. 

Distribution. — This weed is indigenous to the northern Missis- 
sippi valley but has been naturalized eastward ; is common through- 
out the state of Iowa, occuring not only in meadows but in some- 
what sandy fields in Linn and Muscatine counties. 

Extermination. — This weed succumbs to cultivation but care 
should be used in the sowing of clover seed as seed of this weed 
is sometimes found with it. It is largely in this way that it has 
been spread in the east. 



Common Sunflower {Helianthus a/nnuus L.). 

Description. — A tall, rough annual, 6-8 ft. high, leaves 3-ribbed, 
ovate or the lower cordate, serrate; large. heads with yeUow ray 
flowers, disk flowers brownish. 

Distribution.— 'WiAAj distributed west of Missouri river from 
Saskatchewan to Texas, California and Mexico. Common in west- 
ern Iowa, from Woodbury to Fremont county, occurring in fields 
along highways, meadows, vacant lots and com fields ; widely scat- 
tered, but not abundant in many other sections of the state, as 
Boone, Story, Polk, Cerro Gordo, "Webster, Lyon, Linn and Mus- 
catine counties. 

Extermination. — The seeds of this plant do not retain their vi- 
tality very long. The young plants are easily destroyed by cultiva- 
tion. The plant should not be permitted to go to seed. 



DESCRIPTIVE MANUAL 



341 




Fig. 198. Cornmon Sunflower (.Helianthus annuus). Common in western Iowa 

fields, roadsides. 
(Photographed by Colburn.) 




Fig. 19 8- A. Distribution of Common Sunflower. 



342 



WEED FLORA OF IOWA 









''-.k*.' 


f - 


ji 






,,- ;. ,' 


-. •'v^q 


■*',■*? 


u^J^MS^^^^ferifl 


■'^T > . 




H^ 


£l^w«^%tiS)B^^? 


•; 4^** 


'■^s-,^ 


:^% 


V- &-^.%'3V'--'JN 


»*.. JftSfk*. . 


f ■ T^Jk.'^^S 


•*?» , 


;sJ*(^■-^<^\:^^v.1 


•"-'.V^g^nR' 


mm 


;?\g 


^M 


_! ! 1 --L. 




i 


« 


f,^);r^^-^*<:i\i 



Fig. 198-B.- A patch of Wild Sunflowers (.Helianthus annuus). 

western Iowa. 
(Photographed by Pammel.) 



Common In 



Prairie Sunflower {Helianthus petiolaris Nutt.). 

Description. — The prairie sunflower is an annual 1-3 ft. high ; 
lower branches rough; stem leaves 1-3 in. long, oblong to ovate- 
lanceolate, sparingly toothed, lower leaves abruptly contracted into 
a long slender petiole; ray flowers yellow, disk flowers brownish; 
bracts lanceolate or oblong-lanceolate, usually not ciliate; head 
flowers smaller than in common sunflower; flowers half an inch 
or more in diameter. 

Distribution. — Prairie sunflower is most abundant in dry prairies 
from Minnesota to the northwest territory and Oregon and south 
to Missouri. It has become naturalized more or less in Iowa. 
It is not uncommon from Council Bluffs to Sioux City and 
around Muscatine. 

Extermination. — This weed is easily exterminated by cultivation. 



DESCRIPTIVE MANUAL 



343 




Fig. 193. Prairie or Western SunHou-er (Helianttius petiolaris). In Muscatine 

Island and western Iowa. Similar to large Sunflower. 

(Photographed by Colbum.) 




Figv J'J'J-A. Distribution of Prairie Sunflower. 



344 



WEED FLORA OF IOWA 



Meadow or Saw-toothed Sunflower {Helianthus grosseserratus 

Martens) . 

Description. — ^A tall, glabrous perennial 6-10 ft. high, bear- 
ing numerous short peduncled heads; lower stem leaves 8-10 in. 
long and petiole 1-2 in. long; leaves opposite or alternate with a 
slender petiole, oblong, lanceolate, acuminate with sharp teeth, or 
the upper merely denticulate, somewhat scabrous above, whitish 
below ; heads % in. high with deep yellow rays about an inch long ; 
bracts of the involucre slender. 

Distribution. — Common in the central states and northward, also 
westward to Texas. Abundant throughout the state of Iowa in 
corn fields, low swales and roadsides, particularly in northern 
Iowa. 




Fig. 200. Meadow Sunflower (.Helianthus grosseserratus'). Common in meadows, 

pastures and fields. 
(Photographed by Colbum.) 



DESCRIPTIVE MANUAL 



345 




Pig. 200-A. Distribution of Meadow Sunflower. 




Fig. 200-B. Meadow Sunflower (BeUanthus grosseserratus) ■ In meadows and 

flelds. 
(Photogt'aphed by Pammel.) 



346 



WEED FIX)RA OP IOWA 



Extermination.— It is certain that cultivating the young plants 
followed by three or four other similar treatments will remove the 
weed in one or at most two seasons. It would be well to use clover, 
planted as a rotation after the field had had clean cultivation. 



Artichoke (Helianthus tikberosus L.). 
Description. — A pubescent or hirsute perennial with tuberous 
underground stems; leaves oblong-lanceolate or ovate-acuminate, 
scabrous, minutely pubescent; flowers yellowish, large. 

Distribution. — Common from New York to Minnesota; in Iowa 
most abundant in the northern counties; particularly troublesome 
in Mitchell, Howard and Cerro Gordo counties. However, it is 
not infrequent along highways and fields in many other parts of 
the state. 




Fig. 201. Artichoke (Helianthus tuberosus). Common in corn fields, road- 
sides, etc., north Iowa. 
(Photographed by Colbum.) 



DESCRIPTIVE MANUAL 



347 




Fig. 202. Artichoke (Helianthus tuberosus) . In grain fields, roadsides and 

waste places. 




Fig. 202-A. Distribution of Arlichcke. 



34S 



WEED FLORA OF IOWA 



Extermination. — This is a most troublesome weed in com and 
smaller grain fields of northern Iowa. The somewhat thickened 
underground stems spread the plant freely by cultivation. The 
small-grain field should be plowed after the grain is removed, 
then dragged so as to expose the "roots" to the sun. Before 
planting corn in the spring run a disk over the field, then har- 
row, plant to corn, and give thorough cultivation. When the weed 
is very bad it may be well to get the field .into meadow or pas- 
ture. 

Maximilian's Sunfiower {Heliantkus maximiliani Sehrad.). 

Description. — Stem scabrous and hispid, 2-12 ft. high, the latter 
height being obtained in alluvial bottoms ; leaves usually alternate, 
thick, becoming rigid, scabrous above, hairy beneath, lanceolate, 




Pig. 203. Maximilian's Sunflower. (.Helianthus maximUianil. Common In 
meadows and fields of northern Iowa. Yellow flowers, hairy elongated 
leaves. 

(Photographed by Colbum.) 



DESCRIPTIVE MANUAL 



349 




Fig. 203-A. Distribution of Maximilian's Sunflower. 

narrowing at both ends, nearly sessile, entirely or sparingly dentic- 
ulate ; heads large, %-% in- high ; short peduncle terminating the 
simple stem and later appearing in the axils of lower leaves; invo- 
lucre consisting of rigid bracts about 1% in- long; ray flowers 
golden yellow, disk flowers brownish, flowering in late summer 
and early autumn. 

Distribution. — This weed is common in places from Alberta 
and Manitoba to Texas. In Iowa it is most abundant in the 
northwestern and western counties, in the alluvial bottoms of 
Missouri river and on high prairies of Pocahontas, Dickinson, 
Emmet and Palo Alto counties ; also found east in Worth, Howard 
and Cerro Gordo counties. 

Extermination. — This perennial weed has the habit of the arti- 
choke. The more or less thickened underground stems freely prop- 
agate the plants. Give the field a shallow plowing then drag and 
expose the roots to the sun for a few days. This will destroy the 
most of the plants. If the field is put into corn give thorough cul- 
tivation and follow corn with a small-grain crop and then clover. 



Boot-jack (Bidens discoidea (T. & G.) Britton). 

Description. — A diffusely branched annual with alternate, di- 
vided leaves and slender petioles ; leaflets ovate-lanceolate, pointed, 
■coarsely serrate, small heads of yellow flowers surrounded by a 
double involucre, the outer of 4 bracts; aehenes linear, wedge- 
shaped, smooth or tuberculate, bearing a pair of short, upwardly 
barbed awns. 



350 



WEED FLORA OF IOWA 




FiB. 204. Tall Boot- jack or Spanish Needle (Bidens discoidea)- Commcii in 

corn fields, pastures, and meadows. 

(Photographed by Colbunti) 




Pig. 204-A. Distribution of Tall Boot-Jack. 



3SESCKIPTIVE MANUAL 



351 



Distribution. — ^Moist sitnations from New England to Missouri. 
Common in southern Iowa. 

Extermination. — This annual is most abundant in low fields. It 
succumbs readily to cultivation. The plants should not be allowed 
to go to seed as the seed is scattered by animals; its spreading, 
therefore, can be prevented by cutting the plant off close to the 
surface of the groBsid when it begins to blossom. 



Beggar-ticks, Stick-tight, Boot- jack {Bidens frondosah.) . 

Description. — A branching, hairy or smooth annual 2-6 ft. high; 
leaves petioled, 3-o-divided, terminal leaflet lonc;-stalked, pointed, 
coarsely toothed, frequently divided again; rays small, yellow invo- 




Hg. 205. Boot-jack, Spanish Needle, (.Bidens frondosa). Common in gardens. 

The "seeds", more properly aehenes, are scattered by animals. 

(Photographed by Collmm.) 



352 



WEED FLORA OF IOWA 




Fig. 205-A. Distribution of Boot-jack. 

lucre double, the outer foliaceous; bracts ciliate, longer than the 
head; receptacle flattish with deciduous chaff; achenes narrowly 
acuminate, 2-awned, the awns downwardly barbed. 

Distribution. — ^Widely distributed in moist places throughout 
the northern states ; often a very troublesome weed in gardens. It 
is widely scattered because of the "seeds" adhering to clothing, 
pelts of aijimals, etc. 

Extermvnation. — Boot-jack is easily exterminated by cultivation. 
The weed is disseminated- by animals and man. It would be well 
to cut off the plant close to the surface of the ground when in 
flower. 



Tickseed {Bidens aristosa (Michx.) Britton). 

Description. — A smoothish, slightly pubescent, annual 2-4 feet 
high ; leaves 1-2-pinnately, 5-7-divided, petioled ; leaflets lanceolate, 
cut-toothed or pinnatifid; heads panicled-eorymbose ; scales of the 
involucre in 2 series, the outer about as long as the inner, ciliate; 
ray flowers conspicuous, yellow; achenes obovate with ciliate mar- 
gins, usually with 2 divergent teeth ; a somewhat showy plant with 
yellow flowers. 

Distribution. — From Michigan and southern Iowa to Kansas 
and Texas. Abundant in Missouri; probably indigenous to south- 
ern Iowa; in recent years has made its appearance in Wapello, 
(Pammel) Marion, (Pammel) Polk (Bakke) and Decatur (Ander- 
son) counties. 



DESCRIPTIVE MANUAL 



353 




Fig. 206. Tickseed (Bidens aristosa). 
(Mich. Agr. Exp. Sta.) 



23 



354 



WEED FLORA OP IOWA 




Fig. 206-A. Distribution of Tickseed. 

> 



Exterminatibn. — ^TMs weed is easily exterminated by cultiva- 
tion. Do not permit seeds to mature;. 



Sneezeweed {Helenium autumnaleh.). 

Description. — A smooth, angular, branching perennial, 1-5 ft. 
high ; mostly toothed, lanceolate-ovate oblong ; heads yellow, ap- 
pearing in autumn; involucre of the head or flower consists of 
small reflexed scales ; ray and disk flowers yellow and fertile ; seeds 
top-shaped and ribbed; pappus consisting of 5-8 thin, 1-nerved, 
chaffy scales. 

Distribution. — ^Native to the northern states, particularly from 
Missouri and Illinois to Wisconsin and Minnesota; in the Dakotas 
as well as in the Kocky mountains, Utah and the northwest. 

Extermination. — This weed occurs only in low grounds. The 
soil should be drained. Then sow to some useful legumibous crop 
like alsike clover. The weed succumbs readily to cultivation. 



DESCRIPTIVE MANUAL 



355 




Fig. 207. Sneezeweed (.Belenium autumnale) . Common in low grounds, pas- 
tures and along streams. 
(Photographed by Colbum.) 




Fig. 207-A. Distribution of Sneezeweed 



356 



WEED FLORA OF IOWA 




P^G. 207-B. Sneezeweed (.Helenium autum/nale) . 



Fetid Marigold {Dyssodia pUpposa (Vent.) Hitch.). 

Description. — ^A nearly smooth or somewhat pubescent, branched 
annual with strong odor, 6 in.-2 ft. high; leaves opposite, sessile, 
pinnately parted, bristly-toothed, with large pellucid glands; 
heads many-flowered ; disk and ray flowers small, yellow ; involucre 
with a few scales at the base, one row of scales united to form a 
cup ; achenes slender, 4-angled, pappus a row of chaffy scales fine- 
ly divided into numerous rough bristles. 

Distribution. — Common from western Iowa and Minnesota to Il- 
linois and to the southwest. Common in western Iowa along right 
of ways, streets, barnyards and fields. 



Extermination. — This weed is not difficult to destroy by cultiva- 
tion. It sometimes occurs in clover seed and alfalfa seed. 



DESCRIPTIVE MANUAL 



357 



1 ^l/kV 


^mttSSllm^^ 


?i 




1 


P^vy .^^mA^^U 


^ 


5 



Fig. 208. Fetid Marigold (Dj/ssocMo papposo). Pungent smelling herb. Road- 
sides, fields, waste places, etc. Especially in western Iowa. 
(Photographed by Hart.) 




Fio. 208-A. . Distribution of Fetid Marigold. 



358 



WEED FLORA OP IOWA 




Fig. 209. Fetid Marigold (.Dyssodia papposa). 
(Drawing by Charlotte M. King.) 



Yarrow {Achillea millefolium lu). 

Description. — ^A perennial with simple stem 1-2^ feet high; 
leaves twice-pinnately parted, the divisions linear ; 3-5-«lef t flowers 
in corymbose heads, flat-topped ray flowers tisually white, 4-5, 
sometimes pink; plant with a somewhat pungent odor. 

Distribution. — ^Widely distributed in fields, especially gravelly 
knolls and drift soils through the state; particularly common in 
northeastern Iowa, found from the Atlantic to the Pacific, also 
in Europe and Asia. 

Extermination. — The weed is not difficult to destroy by cultiva- 
tion. It is not uncommon in clover seed. Practice rotation of 
crops ; when in the pasture where it is apt to be very common cut 



DESCRIPTIVE MANUAL 



359 




Fig. 210. Yarrow (.Achillea millefolium). Common in pastures, especially 
northwestern Iowa. "White flowers." 




Fig. 210-A. Distribution of Yarrow. 



360 WEED FLORA OF IOWA 

the roots off with a small spade. This will effectually destroy the 
plant. In Europe, it is sometimes recommended as a forage plant 
but it is of doubtful value. 



Mayweed or Dog Fennel {Awthemis cotula L.). 

Description. — ^An acrid, branching, strong-scented perennial, 
white ray flowers; plants 1-2 feet high; leaves pinnately dissected; 
solitary and many-flowered, outer ray flowers pistillate, fertile, or 
neutral ; disk flowers yellow, small, and tubular ; involucre of num- 
erous, small, dry scarious scales;, achenes small, tuberculate; pap- 
pus roughened, none, or merely a minute crown. 

Distribution. — This weed is native to Europe; early introduced 
in the United States, now. common from the Atlantic to the Pacific. 
In Iowa more common in n6rth,ea§tem part than westward; es- 
pecially abundant in some gaxdeiis and along roadsides. 

Extermination. — ^A weed easily exterminated by cultivation. It 
is especially common in clover seed in eastern United States. 

Clark and Fletcher recommend as follows : ' ' Clean up the waste 
J)l4feefe about the farmyards and seed to permanent grass that will 
take full possession of the soil to the exclusion of this and other 
weeds. This plant is usually prevalent in gardens fertilized with 
manure from city stables." 



DESCRIPTIVE MANUAL 



361 




STlNKfNC MAYWeeD 

(Anrhcm-is Cotuia / ) 



Fig. 211. Mayweed or Dog Fennel (Anthemis cotula). Barnyards, roadsides, etc. 
(After Clark and Fletcher.)' 



262 



WEED -FLORA OF lOWlA. 




Fig. 211-A. Distribution of Mayweed. 



Ox-eye Daisy {Chrysanthemum leucanthemum L. var. piwnatifdum 
(Leeoq) Lamotte). 

Description. — ^A perennial herb with erect stem; spatulate, peti- 
oled, root leaves, those of the stem partially clasping, all leaves 
cut or pinnatifld-toothed ; nearly simple stem bearing a large, 
many-flowered head with numerous white rays ; scales of involucre 
with scarious margins, both disk and ray flowers producing 
achenes, marked with longitudinal lines; pappus absent. 

Distribution. — This European weed has long been known as a 
troublesome weed in New England and the central states. It is 
not abundant 'in Iowa except in a few places. 

Exterm,ination. — This weed is not troublesome as yet in Iowa. 
There is much danger, however, that it may be introduced with 
clover seed, as it frequently occurs in eastern and European 
grown clover seed. Sow only clean clover seed. It succumbs quite 
readily to cultivation. 

Clark and Fletcher miake the following recommendations : ' ' Shal- 
low plowing of sod in August, with thorough cultivation from time 
to time until frost, will suppress it. This pest does not give trouble 
on lands worked under a short rotation of crops. Clover for hay 
in which this weed is plentiful should be cut early. ' ' 



DESCRIPTIVE MANUAL 



363 




Fig. 212. Ox-eye .Daisy. (Chrysanthemum leucanthemum var. pinnatifidum') . 

Pastures occasionally. 

(After eiark and Fletcher.) 



364 



WEED ET,ORA OF IOWA 




Fig. 212-A. Distribution of Ox-eye Daisy. 

Chemical Composition. — Its chemical composition according to 
Me. Bull. Agr. Ex. Sta. 26:6 (1888), is as foUows.* 

FRESH OP AIR DRY MATERIAL. 



Water 


Ash 


Protein 


Fiber 


Nitrogen free 
Extract 


Fat 


9.63 


6.85 


8.44 


29.00 


a.72 


i.36 


WATEB PBEB SUBSTANCE. 




7.6 9.S 


ffi.l 


i6.2 


«.8 



Tansy {Tcmacetum vulgare L.). 

Description. — ^A bitter, acrid, strongly scented, poisonous herb 
or branched perennial 2-4 ft. high; leaves pinnately divided into 
linear-pinnatifid divisions, lobes serrate; heads many-flowered, few 
ray flowers, disk yellow ; marginal flowers fertile ; scales of the invo- 
lucre in several series; receptacle flat or convex, naked; branches 
of the style brush-like at the summit; achenes S-angled or 5-ribbed, 
truncate or obtuse ; pappus none or a short crown. 

Distribution. — Common throughout the southern states from the 
Atlantic to the Pacific but more common in eastern North America. 
Common in many parts of the state of Iowa, especially in some 
communities, in gardens and along roadsides. 

Exfermmation. — ^Easily exterminated by cultivation. 

•Compiled by Jenkins and WVnton; Bull. Off. Exp. Sta. 11:78. 



DESCRIPTIVE MANUAL, 



365 




Fig. 213. Tansy (Tanacetum vulgare') Common in old gardens, roadsides, etc 
(Photographed by Colbum.) 




Fia. 213-A. Distribution of Tansy. 



366 



WEED FLORA OF IOWA 



Western Mugwort {Artemisia ludoviciana Nutt.). 

Description. — ^A branching perennial with inconspicuous flow- 
ers; leaves and stems white, woolly; leaves lanceolate, the upper 
usually entire, the lower cut- toothed ; heads in narrow panicles, ray 
flowers absent; involucre of dry scarious scales; receptacle naked; 
flowers small, yellowish; achenes obovoid; no pappus; trichomas 
long, simple, cylindrical, tortuous. 

Distribution. — This weed is common from Illinois north to Sas- 
katchewan, southwest to Texas, and west to Utah. It is quite 
widely distributed in the state of Iowa. 

Extermination. — This weed is easily exterminated by cultivation. 
After the crop has been removed the field should be plowed thus 
leaving the soil in good condition. 




Fio. 214. Western Mugwort, or White Wormwood (Artemisia ludoviciana). 

Common In gravelly places, fields and pastures, a, plant hairs. 

(Photographed by Colburn. u. Drawn by Charlotte M. King.) 



DESCRIPTIVE MANUAL 



367 




Fig. 214-A. Distribution of Western Mugwort. 



Wormwood {Artemisia biennis Willd.). 
■ Description. — ^An aromatic, somewhat bitter, smooth amiual, or 
biennial herb, 1-3 ft. high, with leafy stems and erect branches ; 




Fig. 215. Biennial Wormwood. (Artemisia iiennis). Pungent smelling herb, 

fields, woods, etc. 
(Photographed by Colbum.) 



3^8 



WEED FLORA OF IOWA 




Fig. 215-A. Distribution of Biennial Wormwood. 

lower leaves twice pinnately parted, the upper pinnatifid, the 
lobes linear or linear-oblong, serrate or cut-toothed; inconspicuous 
flowers; ray flowers absent; heads numerous in short axiUary 
spikes; bracts of involucre green, scarious, margined. 

Distribution. — Common in the northern Mississippi valley; now 
widely scattered east to Nova Scotia and south to Kentucky. It 
occurs in many parts of the state of Iowa. 

Extermination. — ^Readily succumbs to cultivation. The plant 
should be cut off close to the surface of the ground. 



Fireweed {Erechtites Meracifolia L. Raf.). 

Description. — ^A coarse, annual weed of rank odor and grooved, 
often hairy stem; leaves simple, lanceolate or oblong, acute, eut- 
topthed, the upper with aUricled base; heads many-flowered; re- 
ceptacle naked; flowers tubular and perfect; achenes oblong, tap- 
ering; soft, white, capillary bristles. 

Distribution. — This weed is common in moist woods; in the 
north especially in recent clearings which have been burned over, 
hence the common name fireweed; also occurs in the Rockies, and 
Kansas; common in many parts of Iowa, especially along streams. 



Extemvmation. — Easily exterminated by cultivation, 
should b« cut off close to the surface of the ground. 



Plants 



DESCRIPTIVE MANUAL 



369 




Fig. 216. Fireweed (JBrecfttites hieracifolia). Common in clearings, woodland 

pastures. 
(Photographed by Colbum.) 




FlQ. 216-A. Distribution of Fireweed. 



24 



370 



WEED FLORA OF IOWA 



Burdock (Arctium lappa L.). 

Description. — A coarse, branched biennial 1-3 ft. high; hairy; 
leaves large, roundish or heart-shaped, thin, obtuse, entire or den- 
tate, floccose, tomentose beneath; petioles deeply furrowed, heads 
of purplish or whitish flowers, clustered or somewhat corymbose; 
involucre surrounding ■ the flowers lengthened into hooked tips, 
glabrous or slightly cottony; trichomes simple, long, twisted. 

Distribution. — Burdock has long been known as a troublesome 
weed in the northern states and in Europe. Quite common from 
New Brunswick to Alabama and the Rocky mountains, the Great 
Basin country and on to the Pacific coast. Common in grain 
fields and waste places in many parts of the state. 




Fio. 217. Burdock (,ArcUum lappa). Common in waste places. A biennial 

weed ; "seeds" scattered by animals. 

(Photographed by Gardner.) 



DESCRIPTIVE MANUAL 



371 





Figure 217B 



Fig. 217-A. Trichome or plant hair from leaf of Burdock. 
(Drawing by Charlotte M. King.) 

Fig. 217-B. Distribution of Burdock. 



Extermination. — Burdock is easily destroyed. Since it is a 
biennial, cut off below the crown during spring or summer. If it 
comes up again, cut off once more, or as often as may be necessary. 

Dr. 'Vasey says : "It may also be killed by being mowed when 
ithe seed has fully formed, and the tops burned." - 

Prof. Shaw says : ' 'Farmers who go over their fields twice a 
year with the spade will soon have no burdock." 

Prof. Goff says: "During the first year of growth the plant is 
readily destroyed by pulling out 'by the roots when the ground is 
very wet." 

The important thing is not to allow it to go to seed; it will then 
die if left to itself. But we may always expect an abundance of 
the weed as long as it is allowed to grow in waste places. Then 
add to this its iexcellent means of dispersal and no wonder it is con- 
stantly coming up in out-of-the-way places. 



372 WEED FLORA OF IOWA 

Bull Thistle {Cirsiwm lanceolatum (L.) Hill). 

Description. — Branching biennial, 3-4 ft. high, tomentose, be- 
coming dark green and villous or hirsute with age, branchlets 
bearing large heads; leaves lanceolate, decurrent on the stem with 
prickly wings deeply pinnatifid, the lobes with rigid prickly points, 
upper face roughened with short hairs, lower face with a cottony 
tomentum ; heads l%-2 in. high ; bracts of the involucre lanceolate, 
rigid when young, more flexible with age, long-attenuated, prick- 
ly, pointed, spreading tips, wholly arachnoid; flower hermaphro- 
dite ; tube of the corolla 10 lines long ; anther tips acute, filaments 
pubescent; aehenes smooth, 1% in. long; pappus of numerous 
plumose bristles. 

Disiribution. — Bull thistle is native and indigenous to Europe. 
It has long been an inhabitant of the northern states and now ex- 
tends across the continent. In Iowa it is abundant in every county, 
frequently found in fields and particularly in pastures and wood- 
lots. 

Extermination. — This weed should be treated like all other bien- 
nials. The most important point is to prevent the seeds from 
forming. For this purpose the plant should be cut off in early 
spring below the surface of the ground. The seeds germinate in 
the spring and during the first season produce a flattened mass of 
leaves. The second season, a flowering stem shoots up rapidly; 
early in August the flowers begin to appear and these are continued 
tiU frost. 

The only method of treating is to cut down and remove aU the 
"roots" as far as it is possible to do so. If this is done frequent- 
ly and thoroughly the weed can be exterminated. If the patch is 
a small one, cutting off the parts as soon as they appear above the 
ground, several times during the season, will certainly destroy 
this thistle. In larger patches, plow the ground, harrow and re- 
move the thistle, either burn the material, or put into compost 
heaps. This should be done five or six times during the season or 
as often as occasion may require. 



DESCRIPTIVE MANUAL 



373 




Fig. 218. Bull Thistle (.Cirsium lancealatum) . Common In woodland pastures 
roadsides and waste places. 
(Photographed by Colbum.) 




Fig. 218-A. Distribution of Bull Thistle. 



374 



WEED FLORA OP IOWA 



Woolly Thistle {Gi/rsium canescens Nutt.). 

Description. — ^Branching perennial, 2-4 ft. high, woolly through- 
out, branches bearing single, medium-sized heads ; . stem angled, 
white-woolly; leaves, radical, 8 in.-l ft. long, the division usually 
2-lobed, prominently ribbed, ending in stout spines; stem leaves, 
except the lower, 1-4 inches long, pinnatifid, the upper sessile, 
slightly roughened, with a slight cottony down, the lower white- 
woolly; heads 11^-2 in. high; bracts of the involucre somewhat 
arachnoid; lower scales with a broad base, glutinous ridge, and 
ending in a minutely serrated spine, inner scales long, attenuated, 
tips straw-colored; flowers purple. 

Distribution. — This species is distributed from Mason City and 
southwestern Minnesota, west to the Rocky mountains. It was 
collected by Chas. A. Geyer in 1839 and described by Nuttall. The 




PlO. 219. 



Woolly Thistle (.Oirsium canescens). Common in western Iowa fields 
and roadsides. 
(Photographed by Quade.) 



DESCRIPTIVE MANUAL 



375 




Fio. 219-A. Distribution of Woolly Thistle. 

writer has seen it v^ry abundant in both Wyoming and Colorado. 
The species occurs in Emmet, Dickinson, Sioux, Plymouth, Wood- 
bury, Cerro Gordo, Worth, Ida and Carroll counties in Iowa. 




Fig. 220. Woolly Thistle (.Cirsium canescens) . In pastures and fields of 

northwestern and western Iowa. 

(Photographed by Pammel.) 



Extermination. — Correspondents sending this weed frequently 
refer it to Canada thistle. It occurs not only in pastures and mead- 



376 



WEED FLORA OP IOWA 



ows, but also in com and grain fields. It grows in patches like the 
C5anada thistle. These patches increase in size from year to year. 
It was described as a doubtful perennial by early botanical writers 
and so far as I have been able to determine, it is a perennial It 
may be exterminated by thorough cultivation, plowing well and 
then following with the cultivator. 

Prairie Thistle (CirsivMi ddscolor (Muhl.) Spreng.). 

Description. — ^Tall, branching, leafy biennial, 5-7 ft. high, with 
heads larger than in Canada thistle; stem striate, slightly hirsute; 
leaves radical, 12-14 in. long, deeply pinnatifid, the divisions fre- 
quently divided, pricMy-toothed, the upper surface smoothish, and 
the lower white ; woolly single heads terminating the branches, with 




Fia. 221. Prairie or Wood Thistle (.Cirsium discolor). Common border of 

woods, etc. 
(Photographed by Colbum.) 



DESCRIPTIVE MANUAL 



377 




rig. 221A Figure 221B 

Fig. 221-A. Triohomes or plant hairs of wood thistle. 
Fig. 221-B. Distribution of Prairie Thistle. 

purple flowers ; heads 1-1% in. long ; bracts of the globose involucre 
somewhat suppressed, slightly arachnoid, lower bracts ovate with a 
broad base and a weak prickly recurved bristle, slight dorsal gland, 
inner linear-lanceolate with a nearly colorless entire appendage; 
flowers purple, tube of the corolla 11-12 lines long, lobes of the 
corolla terminating in clavate tips; anther tips acute, filaments 
pubescent; bristles of pappus plumose; achene 22 lines long, 
smooth, Tipper part yellow. . . ■ . . . . 

Distribution. — Common in many portions of Iowa; Marshall, 
Johnson, Winnebago, Lee, Winneshiek, Allamakee, Greene, and 
Emmet counties ; at Keokuk, Muscatine, Ames, Cedar Rapids, Car- 
roll, Des Moines, Polk City, Steamboat Eoek, Mason City, Belle 
Plaine and Iowa City. 

Extermination.^This field thistle should be treated like all other 
biennial weeds. The flattened masses in the spring should be cut 
off below the ground and hone of the plants allowed to go to seed. 
We have received numerous inquiries in regard to this weed from 
western and northwestern Iowa. 



Iowa Thistle {Cirsium iowense (Pammel) Fernald). 

Description. — Biennial with downy, branching stem; leaves 
roughly hairy above but white-woolly beneath, oblong-ovate to nar- 
rowly lanceolate, sinuate-toothed, or somewhat pinnatifid, lobes or 



378 



WEED- FLORA OF IOWA 




PlO. 222. Iowa Thistle CCiravum iowenae). Common In pastures and meadows. 
(Photographed by Colbum.) 




Pio. 222-A Distribution of Iowa Thistle. 



DESCRIPl'IVE" MANUAL 379 

teeth with weak prickles; rather large heads; involucre l-ll^ in. 
long; bracts with broad glandular back, the inner with a some- 
what attenuated colorless tip. 

Distribution. — Common in borders of woods and in fields. From 
Iowa to South Dakota and Kansas. In Story, Emmet, Kossuth, 
Marshall, Boone, Linn, Clinton, Webster and Carroll counties in 
prairie meadows. 

Extermination. — This biennial is readily destroyed by cutting 
the plants off below the surface of the ground. When left to 
flower it dies but in meadows where cut off above the surface of the 
ground it acts like a perennial. 

Canada Thistle {Cirsium arvense (L.) Scop.). 

Description. — Smooth perennial, spreading by roots and root- 
stocks, 1-3 ft. high, corymbosely branched at the top ; stem smooth ; 
leaves lanceolate, sessile, and deeply pinnatifid, lobes and margins 
of leaf with spiny teeth; heads small, %-l in. high, bracts ap- 
pressed, the outer with a broad base, inner narrow, all with an 
acute, never spiny, tip; somewhat arachnoid flowers purple, di- 
oecious; in staminate plant, flowers exserted with abortive pistils, 
in pistillate less so, scarcely exceeding the bracts; tube of the 
corolla 6 lines long; stamens with abortive anthers, anther tips 
acute, filaments minutely pubescent; young aghene pubescent; all 
of the bristles of the pappus plumose- trichomes simple, long, 
floecose. 

Distribution.— This European weed is widely distributed in Can- 
ada to the Pacific coast; found in Iowa in many counties, more 
common in northern counties than in the southern. It is more or 
less abundant in Hardin, Pocahontas, Clinton, and Worth coun- 
ties, frequently in cloveir meadows and in pastures. 

Extermination. — The Canada thistle can be treated with sodium 
arsenite. No other chemicals, so far as our experiments extend, 
will entirely destroy this weed. Carbolic acid only partially de- 
stroys the roots and the plants shoot up again from below the point 
of injury, but by repeating the process the Canada thistle can ulti- 
mately be exterminated. A good method of eradicating the weed 
is to plow shallow and cultivate frequently during the summer. 
The roots of the Canada thistle extend deeply down into the soil, 
hence for this reason deep cultivation will be of no avail. After 



380 



WEED FLORA OF IOWA 




Fig. 223. Canada Thistle (.Cirsium arvense). Common and widely dlstrllnited 

in Iowa. 
(After Clark and Fletcher.) 



DESCRIPTIVE MANUAL 



381 





Figure 223A 
Fie. 223-A. 



Figure 223B 

Trlchome or plant hair from leaf of Canada Thistle. 
(Drawing by Charlotte M. King.) 
Fig. 223-B. Distribution of Canada Thistle. 



plowing, the soil should be dragged and the roots exposed to the 
sun and removed, when possible. It may be necessary to run 
over the field with a hoe to cut off the stray plants which appear. 
This method was tried on a patch several years ago and no 
Canada thistles have since made their appearance in this place. 
Various crops, such as clover and sorghum, are said to be ef- 
fective in subduing the thistles. 

Of the various chemicals which have been used to exterminate 
Canada thistles none are more effective than sodium arsenite. It 
is applied at the rate of l%-2 pounds to 52 gallows of water. 

Carbolic acid at the rate of one part to one part water destroys 
the root when it comes in contact with the mixture, and for a little 
distance beyond. This is not an effective method, as the roots 
sprout out from below. 

In response to circulars of inquiry sent out by the Iowa Experi- 
ment Station, the majority of correspondents recommend shallow 
plowing, disking, and harrowing ; and continuing cultivation and 
hoeing as long as the thistles make their appearance. Some report 
successful treatment with salt when scattered -thickly about the 
thistles, especially if cattle or sheep are given access to it. Some 
report success with carbolic acid when it is applied directly to the 
stem. Tarred paper in a few cases gave success, as did also the 
method where the thistle was covered thickly with straw or ma- 
nure. The depth of covering was not, however, given. 



382 WEED FLORA OF IOWA 

Clark and Fletcher recommend the foUowiiig treatment: 
"The chief safeguard against the Canada thistle and all similar 
deep-rooted perennials is undoubtedly a regular short rotation. A 
three-year rotation, including two cuttings of early red clover for 
the first year, followed by a deep fall plowing for hoed crops with 
clean cultivation, and a cereal crop for the third year, will sup- 
press it." 

A correspondent in The Prairie Farmer on the resisting quali- 
ties of Canada thistle says: "I have been debating in my mind 
and endeavoring to determine whether or not root-stocks or por- 
tions thereof have to some extent the hibernating qualities of the 
seed. For instance, take two seeds of the cocklebur — one hiber- 
nates for one season and the other for two seasons, with growth 
always present. Now the question is may not a Canada thistle 
with its root-stock or a portion of it lie dormant for a season or 
more? If this be true, then some of the best known methods of 
extermination are useless." 

To this Prof. R. A. Moore says : "In regard to Canada thistle 
roots hibernating and retaining their vitality for several years, 
will say, that I think your correspondent's version seems reason- 
able, and it is quite conclusive from this fact that the eradication 
of the pest is all the more difficult. It seems that many of the 
seeds and plants are given this power of remaining dormant when 
subjected to adverse conditions. In the lower order of plants, 
many of the species of bacteria when subjected to adverse environ- 
ments are transformed into resistant spores and will not vegetate 
until the conditions are favorable." 

Wallace's Farmer says concerning its eradication: "We 
believe if we had a quarter of an acre of Canada thistles 
we would let them alone until August, when the thistle will put 
forth its utmost efforts to produce seed. While the thistles are in 
full blossom we would mow them, rake them up and burn them, 
and then plow the ground about eight inches deep, throwing the 
furrow flat. Letting them put forth their full strength to produce 
seed and thwarting that by mowing and burning would weaken the 
roots materially. Then by plowing them under eight inches deep, 
if possible, you would attack them at their weakest point. 



DESCRIPTIVE MANUAL 



383 



Knapweed {Centaurea solstitialis L.). 

Description. — Annual erect, branched, cottony stem ; lower leaves 
lyrate, deeply pinnatifid, upper leaves, linear, entire or nearly so, 
decurrent wings on the stem; outer bracts, with long spreading 
spines, those at base few and smaller; flowers yellow, with soft 
pappus. 




Fig. 224. Knapweed, Star Thistle (Centaurea solstitialis). In alfalfa fields. 
(Mich. Agr. Exp. Sta.) 



384 



WEED FLORA OF IOWA 




Fig. 224-A. Distribution of Knapweed. 

Distribution. — ^Massachusetts to Ontario and Iowa; introduced 
with alfalfa seed into other western states. 

Extermination.— This annual weed has been introduced largely 
with alfalfa seed. Sow clean seed. Use seed coming from the 
Rocky mountains or Kansas where the weed is not common. It is 
an extremely objectionable weed because of the spiny heads. It 
is easily killed by- cultivation. 



CJiicpry or Succory {Cichorium intyJnCs It:). 

Description.^— A branching perenjiial with deep roots, alternate 
leaves; blue flowers, or sometimes pink or purple; basal leaves 
spreading on the ground; stem leaves oblong or lanceolate, 
partly clasping. 

Distribution.— It is common alonfe roadsides in fields and waste 
places from N^w England to Canada to Nebraska, especially com- 
mon where chicory has been cultivated; it has become a trouble- 
some weed in Wisconsin and Minnesota. It is allied to endive, cul- 
tivated as a salad plant. 

Extermination. — Chicory is not difficult to destroy where ro- 
tation of crops is practiced. Though a perennial, the roots are 
easily killed by repeated cultivation. 

Clark and Fletcher recommend the following treatment: 
"A short rotation of crops will soon suppress it. Chicory is not 
often seen in good farming districts except as a wayside weed. 
Individual plants may be destroyed by close cutting and applying 
salt to the root in hot, dry weather." 



DESCRIPTIVE MANUAL 



385 




CHICORY 



Fig. 225. Chicory iCichorium intyius). In clover and alfalfa fields, some- 
times in waste places. 
(After Clark and Fletcher.) 



25 



3^6 



WEED FLORA OP IOWA 




Fig, 225-A. Distribution of Chicory. 

Dandelion (Taraxacum ojjicmale Weber). 
Description. — ^A smooth, or at first pubescent, biennial or per- 
ennial ; the many-flowered head borne on a slender hollow scape ; 
root leaves pinnatifid or mneinate ; involucre double, the outer of 




F^G. 226. Dandelion (Taraxacum officinale). Long root, sometimes to a deptlJ 

of three and one-lialf feet in the soil. 

(Photographed by Gardner.) 



DESCRIPTIVE MANUAL 



387 




Fig. 226-A. Distribution of Dandelion. 

short scales, the inner of long, linear, erect scales in -a single row ; 
after flowering the inner involucre closes, the fru^ is ripened 
close to the ground, and when ripe the hollow scape elongates and 
the whole involucre is reflexed permitting the wind to scatter the 
"seeds;", "seeds" oblong, long-beaked, the beak being 2 or 3 times 
as long as the remainder of the achene, bearing at the end the 
pappus. ,V,, 

■k 




Fig. 226-B. A patch of Dandelion in a lawn, early in June. 
(Photographed by Charlotte M.. King.) 



388 



WEED FLORA OF IOWA 



Distribution. — The dandelion is cosmopolitan. It is quite as 
common in Europe as in the United States, being common and 
abundant at high elevations, as in the Rocky mountains. Found 
everywhere in Iowa on lawns and pastures. 




Fig. 227. Common Dandelion ITaraxacum officmale). 

lawns, pastures, etc. 
(Photographed by Colbum.) 



A weed common in 



Hxtermination. — The dandelions are not difficult to exterminate 
in cultivated fields but in garden crops it is more difficult to do 
so, especially in strawberry beds. As the dandelions are perennial 
herbs, seed formation should be prevented. Where they occur in 
small patches a spud may be used successfully. "Where they, are 
abundant in lawns it is only necessary to keep the lawn closely 
cropped and dig them up with a small spud to prevent seeding. 
Blue grass and clover, especially the latter, will crowd them out. 
It is rare that dandelions give trouble after the middle of June. 



DRSCRIPTIVB MANUAli 



389 




Fig. 227-A. Common Dandelion (.Taraxaoum officinale). 1, head; i, single 
flower ; S, achene ; i, receptacle and seed with pappus. 



Experiments have been made with herbicides and the one most 
commonly used is iron sulphate which is usually applied at the 
rate of 100 pounds to one barrel of water. The weed where prop- 
erly sprayed will be destroyed, but owing to the fact that the dan- 
delion possesses a long perennial root, sometimes 4 feet long, it 
will sprout again. The spraying must be kept up until fall. 

Chemical Composition. — According to the report of the Bussey 
Institution the chemical composition of the dandelion is as follows : 

FBESH OB AIB DRY MATEEIAI/. 



Water 


Ash 


Protein 


Fiber 


Nitrogen free 
Extract 


Fat 


85.S4 


1.99 


2.81 


1.82 7.« 


0.«9 


WATEB FEEE 8UBSTAN0E. 




13.8 


19.4 


lO.S 61.5 


4.8 



•Bull. 1877. Compiled by Jenkins and Winton ; Bull. 11, Off. Exp. Sta., U. S. 
Dept. Agr. 



390 WEED FLORA OF IOWA 

Eed-seeded Dandelion (Taraxacum erythrospermum Andrz.). 

Description.-— A perennial weed with long root; leaves deeply 
runcinate-pinnatifid or pinnately divided into narrow segments; 
heads somewhat smaller than in common dandelion, sulphnr yel- 
low; involucre glaucous, the inner bracts comiculate, appendaged 
at tip; the outer short, spreading or ascending; achene reddish, 
tuberculate above. 

Distribution. — Eed-seeded dandelion is a much more recent in- 
troduction than common dandelion. It occurs from Maine to 
Kansas. Naturalized from Europe, in similar situations to com- 
mon dandelion in Iowa; sometimes less abundant and sometimes 
more abundant than the latter. 

Extermination. — ^May be exterminated in the same way as the 
common dandelion. 




Fia. 228. Red-seeded dandelion (.larhxacum erythrospermum). Common In 

lawns. 
(Photographed by Colbum.) 

Clark and Fletcher recommend the following treatment: 
"It is important to prevent dandelions from seeding in lands 
adjacent to lawns. Though entailing much labor, the most satis- 
factory way to deal with them, when deeply rooted in lawns, is to 
loosen the soil with a digging fork and pull them up. The use of 



DESCRIPTIVE MANUAL 391 

the fork may not be necessary in some wet and soft soils. The ap- 
plication of kerosene to the crown of the plant, in the centre of 
the rosette of leaves, is recommended. Sulphate of ammonia or 
sulphate of iron in excess is also recommended. A small table- 
spoonful of salt applied in the morning of a hot day, when the soil 
is dry, will Mil them. 



Annual Sow-thistle {Sonchus oleraceus L.). 

Description. — Annual, succulent herb with leafy, smooth stems, 
and pale yellow flowers in corymbose or umbellate clusters ; leaves 
of stem dentate, runcinate-pinnatifid, terminal with a large seg- 
ment; heads numerous; blossoms in late summer and fall. 

Distribution. — This weed is common in fields and waste places 
throughout North America, especially in the north. It is common 
in Europe and also occurs in Mexico and South America. 

Extermination. — Sow thistle is easily exterminated by cultiva- 
tion. It can also be exterminated by the use of iron sulphate at the 
rate of 100 pounds to a barrel of water; where it is abundant it 
may be necessary to make two or three applications. 

Clark and Fletcher recommend as follows: "Prevent them 
from seeding in waste places by cleaning them up and seeding them 
to permanent, vigorous grasses. This annual weed, with its rela- 
tively small, pale yellow flowers, when compared with perennial 
species is not diiScult to control by ordinary methods of cultivation 
and alternation of crops. Sheep, if sufficient in numbers, will pre- 
vent sow thistles from seeding in pasture lands." 

The Iowa Homestead says concerning its eradication: "We 
have seen the sow thistle take complete possession of a soil, 
growing so thickly that other crops were entirely choked out. Nec- 
essarily the best way to destroy it is to cultivate freely. If it 
makes its appearance in stubble ground we would advise plowing 
as early as possible after harvest and the cultivation of surface at 
intervals tJuring the late summer and fall in order to keep the 
thistles below the ground. 



892 



WEED FLOfeA OF IOWA 




P lalo 67 
COMMON nRANNimi SOW T 



Pia. 229. Common Sow Thistle (.Sonchus oleraceus). Waste places. 
(After Clark and Fletcher.) 



DESCRIPTIVE MANUAL, 



393 




Fig. 229-A. Distribution of Annual Sow Thistle. 

Sow Thistle (Sonchus asper (L.) Hill). 
Description. — ^Like the preceding species except that stem leaves 
are less divided and more spiny-toothed, with auricles of the 





w 




'^o^^' 


f 


r^- 


/ 


"■-: 






Fig. 230. Sow Thistle (Sonchus asper'). Waste places, yellow flowers and milky 

juice. 
(Photographed by Colbum.) 



394 



WEED FLORA OF IOWA 




Fig. 230-A. Distribution of Sow Thistle. 

clasping base rounded; achenes 3-nerved on each side and 
margined, smooth. 

Distribution. — Common with the. preceding species, in waste 
places. 

Extermination. — This annual is not difficult to exterminate by 
giving thorough cultivation. 



Perennial Sow Thistle {Sonchus arvensis L.). 

Description. — ^A perennial with creeping root-stock, and milky 
juice; leaves runeinate, pinnatifid and spiny toothed, heart-shaped 
base ; flowers yellow ; peduncle and involucre bristly ; achenes ob- 
compressed, wrinkled on the ribs. 

Distribution. — Common from Nova Scotia west to Saskatchewan, 
North Dakota, Minnesota, occasional in Iowa to New Jersey and 
New England. 

Extermination. — ^A most difficult weed to exterminate and should 
be treated like the Canada thistle. Summer fallow with frequent 
cultivation is the only successful method. Clark and Fletcher of 
Canada, recommend the following: 

"Small patches may be eradicated by digging out the roots as 
thoroughly as possible and destroying them. This may have to be 
done several times during a season. Great care must be taken not 
to distribute pieces of the rootstocks over the fields by harrows or 
other implements. To exterminate Perennial Sow Thistle, some 
ayst,ei!a,must, be adopted which will prevent the development of 
leaves for a period sufficiently long to kill the roots by smothering 



DESCRIPTIVE MANUAL 



395 




Fig. 231. Perennial Sow Thistle (.SonofMs arvensis). Plants with 'brlsrht yel- 
low flowers, milky juice. Not common in Iowa. A difficult weed to exter- 
minate. 

(Photographed by Colbum.) 




Fig. 231-A. Distribution of Perennial Sow Thistle. 



396 WEED FLORA OF IOWA 

them. "When a field is badly infested it requires special treatment 
for a season and cloSe attention for a number of years. One of 
the most effective methods is to plow lightly immediately after 
the hay or ^ain 'crap is removed and follow with frequent use of 
a broad-shared cuffivator. Late in the fall plow again, somewhat 
deeper. In the spring give frequent cultivation, so as to prevent 
the development of any leaves and thus weaken the roots to the 
greatest possible extent. |.' ^About the middle of June or first of 
July sow rape in drills M the rate of about 1% lbs. per acre. 
Cultivate between the drills as soon as possible and repeat at short 
intervals until the "rape completely covers the ground. Some hand 
hoeing may be necessary to keep all the thistles down. This should 
pretty well exterminate the pest but if some plants still remain 
when the rape is cut or pastured off, the field may be fall plowed 
and put into hoed crop the iiext season, when special attention can 
be given to any small patches that may appear. Buckwheat is 
sometimes used instead of rape for a smothering crop." 

Prickly Lettuce (Lactuca scariola L. var. integraia Gren. & Godr.). 

Description. — Tall, erect herbs, glaucous, green, 2-5 ft. high, 
simple or branched except the lower part of stem which has stiff 
bristles; leaves glaucous, green, smooth except the midrib which 
is beset with weak prickles lanceolate to oblong in outline, with 
spinulose, denticulate margins, occasionally sinuate-toothed; flow- 
ers pale yellow. The leaves of L. scariola are pinnatifid and more 
prickly; trichomes multicellular. 

Distribution. — Prickly lettuce was introduced into Massachu- 
setts about 1863 from Europe. It is quite widely distributed in 
northern Africa and Europe and has become frequent throughout 
the northern Mississippi valley to the Pacific coast. It is com- 
mon everywhere in Iowa particularly along roadsides, highways 
and in gardens. The L. scariola is becoming more frequent in 
Iowa, in Ames, Des Moines, Boone, etc. 

Extermination. — The weed is easily exterminated from culti- 
vated fields and in waste places by cutting off young plants below 
the ground. Where the stem is cut off below the surface of the 
ground it will give no trouble, but in meadows and lawns where 
the plants are cut off above the ground the weed will continually 
■reappear, producing from 3-6 branches. The following excellent 
suggestions are made by L. H. Dewey : 



DESCRIPTIVE MANUAL 



397 




P.ale 68 
PRICKLY LETTUCE 



Fig. 232. Prickly liettuce (.Lactuca scariola var. integrata). Common road- 
sides and gardens. 
(After Clark and Fletcher.) 



398 



WEED FLORA OF IOWA 





FigTire 232A 



Figure 232B 



Fig. 232- a. Bristles on Prickly Lettuce (.integrata) . 

(Drawing by Charlotte M. King.) 

Fig. 232-B. Distribution of Prickly Lettuce. 

"Sheep and sometimes cattle will eat the young prickly lettuce, 
and in some localities their services have been found very effective 
in keeping it down, especially in recently cleared land where culti- 
vation is impossible. Repeatedly mowing the plants as they first 
begin to blossom will prevent seeding and eventually subdue them. 
Thorough cultivation with a hoed crop, by means of which the 
seed in the soil may be induced to germinate, will be found most 
effective. The plowing should be shallow so as not to bury the 
seeds tod deep. Under no circumstances should the mature seed- 
bearing plants be plowed under, as that would only fill the soil 




Fig. 232-C. Distribution of Prickly Lettuce (Lactuca scariola). 



DESCRIPTiyB MANUAL 399 

with seeds buried at different depths to be brought under condi- 
tions favorable for germination at intervals for several years. Ma- 
ture plants should be mowed and burned before plowing. The 
seed appears as an impurity in clover, millet and the heavier grass 
seeds, and the plant is doubtless most frequently introduced by 
this means. As the seeds may be carried a long distance by the 
wind, the plants must be cleared out of the fence rows, waste land 
and roadsides." 

Clark and Fletcher recommend as follows: "The seed is 
short-lived and if the plant is kept closely cut and prevented 
from seeding in waste places for two or three years it will soon 
disappear from cultivated areas. Clean waste lands and seed 
to permanent vigorous grasses. Ordinary methods of cultiva- 
tion will suppress it in the fields. ' ' 



Wild Lettuce (Lactuca canadensis L.). 

Description. — Stem leafy, glabrous or nearly so, glauepus; lower 
leaves sinuate, pinnatifid, upper entire; heads numerous, in a 
rather long, open panicle ; flowers yellow. 

Distribution. — ^Nova Scotia to Ontario, Ohio and westward; fre- 
quently found in Iowa. 

Extermination. — This perennial is not difficult to destroy by 
cultivation. 



400 



WEED FLORA OF IOWA 




Fig. 233. Wild or Canadian Lettuce iLactuca canadensis). Fields, roadsides 

and meadows. 
(Fhotogiaphed by Quade.) 



DESCRIPTIVE MANUAL 



401 





4 


^ ;• 


• ^ 


s 




m^ 


^ 


^^^^ i 


. ^ 


i 




^ 


y 


'Y^ 


^ 




I ^ 



Fig. 233-A. Wild or Canadian Lettuce (Lactuca canadensis). Plant with milky 
juice and yellow flowers. 
(Photographed by Quade.) 



\ : JiA' 




36 



Fig. 233-B. Distribution of Wild Lettuce. 



402 



WEED FLORA OF IOWA 



Blue Lettuce (Lactuca pulchella (Pwsh.) DC). 

Description. — Perennial plant, deep-rooted, pale or glaucous; 
stem simple, about 1 foot high; leaves sessile, oblong or linear- 
lanceolate, glabrous, entire, or lower leaves somewhat pinnatifid; 
racemose heads large, erect ; peduncles with scaly bracts ; bracts 
of involucre imbricated in 3-4 ranks ; flowers blue. 

Distribution. — ^Northern Michigan and Ontario southward; re- 
ported from several localities in Iowa. 

Extermmation. — Prevent from distributing seed by continued 
cutting before flowering. If it becomes established in a field, try 
thorough summer fallow with deep cultivation so as to check 
growth of long rootstocks. 




Fill. 234. Blue Lettuce (.Lactuca pulchella). Blue flowered lettuce, 
milky juice. Common In western Iowa. 
(Photographed by Quade.) 



Plant with 



DESCRIPTIVE MANUAL 



403 




Fig. 234-A. Distribution of Blue njettuce. 



. Rushlike Lygodesmia {Lygodesmia juncea (Pursh.) D. Don.). 

Description. — ^A tufted, smooth, frequently glaucous perennial a 
foot or more high, coming from a thick woody root, with copious 




Fig. 235. liygodesmia or Skeleto/i Weed (.LygocCesmia juncea). A deep rooted 

perennial with a yellowish milky juice. 

(Photographed by Colbum.) 



'404 



WEED FLORA OF lOWA 




Fig. 235-A. Distribution of Lygodesmia. 

yellowish juice; lower leaves rigid, linear-lanceolate, small, entire, 
the upper scalelike; flowers purple in erect heads; achenes nar- 
row-ribbed, pappus light brown. This weed is sometimes called 
skeleton weed. 

Distribution. — This weed is common from Missouri river to west- 
ern Montana and east to St. Croix river in Wisconsin. A some- 
what troublesome weed in northwestern Iowa; easily recognized by 
the yellowish juice and rushlike stems. 

Extermination. — This plant produces a long root which enables 
the plant to spread rapidly. It also produces a large number of 
"seeds." Where the weed is common, plough the field after 
harvest and disk the plants. It is a good plan to follow up with 
a hoe, cutting off the plants. 



CHAPTER 11. 

THE GENERAL CHARACTERS 
OF SEEDS 



By 

L. H. PAMMEL 

and 

CHARLOTTE M. KING 



CHAPTER II. 



CYPERACEAE, SEDGE FAMILY. 
Sedge {Car ex vulpinoidea Mx.). 

Achene enclosed by an utricle called the perigynium, hardly 3- 
angled, somewhat flattened, tipped by lanceolate 2-toothed beat, 
the persistent base of the flower-style; achene flask-shaped, about 





Figure 236A 
Fig. 236. Forms of Sedges. 



Figure 236B 

Oj Eleqcharis palustris; b, Carex vulpinoidea. 
(After Gray.) 



one-sixteenth of an inch in length, light brown; surface incon- 
spicuously nerved; whitish, projecting scar. 



Spike Rush {Eleocharis paitistris R. Br.). 

Achenes slightly flattened, somewhat lenticular, with 2 or 3 ob- 
tuse angles one-twelfth to one-tenth in. long, brown, smooth, shin- 
ing, minutely cross-striated ; seed with persistent tubercle from tip ; 
tubercle conical, triangular, constricted; bristles pale, longer than 



408 



WEED FLORA OF IOWA 







FiQ. 237. Achenes, "seeds," of common forms of Sedges (.Carer). 
(After Hillman, Bull. Nevada Agr. Bxp. Sta.) 

aehene; seed may appear with or without tubercle and bristles. 
Seed occasionally found in seed of alsdke and red clover from wet 
grounds. 

GRAMINEAE, GRASS FAMILY. 

Johnson Grass {Sorghum halepen^e (L.) Pers.). 

Sessile spikelet broadly lanceolate, acute, 4-6 mm.* long, be- 
coming dark at maturity ; callus small, obtuse, shortly and sparsely 
barbate ; first glume coriaceous, slightly pubescent on the flattened 
back, 5-7 nerved; second similar, equal to first, with hyaline, ciliate, 




Fig. 238. Spikelet of Johnson Grass (.SorghMm halepense'). 
(Drawn by Charlotte M. Kins.) 

inflexed margins; the third glTime shorter, membranous, faintly 
2-nerved, with ciliate, infolded margins; fourth glume broad, ob- 
tuse, shorter than second, 2-lobed at apex, ciliate, awned; awn 
10-16 mm. long ; palea shorter than glumes, without nerves, ciliate. 

Smooth Crab Grass {Digitaria humifusa Pers.). 

Spikelets lanceolate or elliptical, one-twelfth in. in length, acut- 
ish; glumes usually present, first glume wanting, sometimes rudi- 
mentary, 3-nerved; the first and second, hairy on the margins; 

•1 mm. = 0.0394 Inch, or nearly one-twenty-fifth Inch. 



THE GENERAL CHARACTERS OP SEEDS 



409 









Fig. 239. Seeds of Smooth Crab Grass (.pigitaria humifusa). A and B, spike- 
lets ; A showing the second glume, B' showing the third glume. ' C, D' and E, 
florets ; D, bearing a portion of the second glume, E, the inner face, showing 
the edges of the flowering gliime. F, a spikelet of Digitaria fiUformts, show- 
ing the shorter second glume. G-, the natural size of both of these Species. 
(After Hillman, Bull. Nevada Agr. Exp. Sta.) 

the third, T-nerved; the fourth, dark purplish brown. Occurrence 
very frequent in alfalfa clovers and commercial grass seed. 

Crab Grass {Digitwria sanguinalis (L.) Scop.). 

Spikelets one-seventh in. in length with usually persistent scale- 
like glumes, lanceolate,, pedicellate; second glume usually ciliate 
on margins, short ; fourth glume silky-villous along marginal nerves, 
5-nerved, color pale. Frequently occurs in red and alsike clover, 
as well as in timothy. 





f.O- 



Fig. 240B Figare 2400 

FiQ. 240. Common Crab Grass {Digitaria sanguinalis). 
of Crab Grass. B, with small glume attached. C. 



A, 
A, 



an enlarged view 
spikelets showing 

the second glume, floret, and edges of the third glume. B, the opposite 
face, showing the minute first glume and third glume. D and B, the two 
faces of the floret. F, seeds, natural size. 
(A and B, Drawings by C. M. King; C, after Hillman, Bull. Nevada Agr. 

Exp. Sta.) 



410 WEED FLORA OP IOWA 

Tickle or Hair Grass (Pamicum capillar e L.)- 

Spikelets small, ovate or acute, one-fifteenth to one-twelftli in. 
long, acuminate-pointed, smooth, shining; sterile glumes usually 
absent, when present not shining ; first glume 1-3-nerved, obtuse to 






Figure 241A 



Pipire 241B 



Fig. 241. A. Tickle or Hair Grass {Panicum capillare'). At the left a spllielet 
opened, at the right various views. A, B and C, the outer, inner and edge 
views, respectively, of a floret. D and B are views of the spikelet, D 
showing the second glume and the first in part, and B the first and third 
and the second In part. F, a group showing the natural size of the pre- 
ceding. 

B. Sprouting Crab Grass. Various views of spiltelets. 

(A, at the left, drawn by C. M. King ; A, at the right, after Hillman, Bull. Mich. 
Agr. Bxp. Sta. ; B, drawn by C. M. King.) 



acute; second and third glumes 5-7-nerved, tips acute; flowering 
glume shining, smooth, elliptical, obtuse, or subacute. Often found 
in clovers and in timothy. 

Sprouting Crab Grass {Panicum proliferum Lam.). 

Spikelet lanceolate, ovate, acute, one- tenth in. in length, smooth; 
lower glume obtuse, nerveless or 1-3-nerved ; second and third glume 
equal, acute, 5-7-nerved ; flowering glume smooth and shining ; pedi- 
cels scabrous. Rarely found in clover. 



Switch Grass {Panicum virgatum L.). 

Spikelets ovate, acuminate, 3-5-nerved; flowering glume shorter 
than the outer glumes, smooth, shining, minutely striated; with 
outer glumes removed, the spikelet resembles a small jassid. Barely 
found in clovers. 



THE GENERAL CHARACTERS OP SEEDS 



411 





Figure 242A 



Figure 2i2B 



a, b, c, 



Figure 242C 
various views of 



Fig. 242. A. Switch- Grass (.Panicum virffatum') 
splkelet ; d', "seeds," natural size. 

B. A single splkelet. . ;. 

C. lillUet ^Pantcum miliaceurh'i . 

(A, after HlUman, Bull. Mich. Agr. Exp. Sta. ; B and C, ' drawings by ' Char- 
lotte ^BJ. King.) - - 

Millet {Panicum miiiaceum h,) . ■* 

Spikelets acuminate, one-eighth to one-fifth in. long, lower 
gluine acuminate, 5-7-nerved ; third glume subtending the empty 
palet, 7-13-nerved ; flowering glume indurated, obtuse, shining, min- 
utely cross-striated; the hulled seeds ovoid, yellowish. Found in 
clover and alfalfa seed. ^ . ," * - 



"' Barnyard Grass {Echinochloa cfusgalli (L.) Beauv.). 

Spikelets with hispid or piibeseent nerves; first glume shorter 
than the third, awned; second awnless or short-awned; third with 
long rigid awn ; flowering glume generally ovate ; one-tenth to one- 
ninth iji. longitudinally striate; palet smooth. Not infrequently 
found in clovers. 



\m 




HHflP^ 


m 


f^ 


B 






■ '1 


F 




hdM. 



Fig. 



243. A. Barnyard (Jrass (Echinochloa crusgalU). A, a floret, back view 
of the glume. B, front view of floret, showing the palea. C, edge view of 
the same. D, the stlkelet, showing the small first glume, the awned third 
glume, and the _ tip of the second. E, a group showing the natural size of 
the preceding. 



412 



WEED FLORA OF IOWA 




Fig. 243. B. Sandbur (.Cenchrus tnbuloides) . a. bur enlarged; b, spine; e and 

d, splkelet ; e, seed. 
(After HlUman ; A, Bull. Nevada Agr. Exp. Sta., B, Bull. Michigan Agr. Exp. 

Sta.) 

Sandbur (Cenchrus tribidoides L.). 

Burs with sharp, straight, pubescent prickles; each bur with 
6-20 globose spikelets. 

Green Foxtail (Setwria viridis (L.) Beauv.)- 

"Seeds" about one-twelfth in. in length, biconvex, color light 
green, or greenish; with flowering glume rounded, slightly granu- 





Figuie 244A 



Figure 2MB 



Figure 2440 



Fig. 244. A. Green Foxtail (Setaria viridis). A and B, views of the floret; 
A, the back of the glume ; B, showing the palea, its shining edges partially 
covered by the edges of the glume. C, a floret covered by the empty 
glumes (a spikelet), the figure showing the first and third glumes. D, a 
group showing the natural size, 

B. Slightly enlarged spikelet. 

C. Whorled Millet (Setaria verticillata) . 

(A, after Hillman, Bull. Nevada Agr. Exp. Sta. ; B and C, drawings by Char- 
lotte M. King.) 



THE GENERAL CHARACTERS OF SEEDS 413 

lar, striate lengthwise and with cross-ridges ;'. palea shining ; com- 
monly brownish or greenish. In alfalfa, clovers and grass seed. 

, Whorled Millet {Setcuria verticillata (L.) Beauv.). 

Spikekts elliptical-ovate, one-twelfth in. long;_ first glmne tri- 
angular-ovate, acute or obtuse, 3-nerved; second glume ovate, ob- 
tuse, 5-7-nerved; third glume, 5-7-nerved, bears short palet in its 
axil ; flowering glume about one-fifteenth in. in length, striate, near- 
ly smooth; bristles about the fiower, 1 or 2, retrorsely scabrous, 
one-twelfth to one-third in. long. Found in clover seed. 

Yellow Foxtail {Setaria glauca (L.) Beauv.). 

"Seeds" about one-eighth in. in length, very variable; color, 
yellowish, brownish, or even palej; perfect flower with flowering 
glume plano-convex, partially ' covering edges of palet; back of 





Figure 245A 



Figure 245B 



Fig. 245. Yellow Foxtail or Pigeon Grass (.Setaria glwuca). A and B, the 
outer and inner faces, respectively, of a floret ; B, showing the palea. C 
and D, the same showing the empty glumes of the spikelet ; C, showing the 
second glume, and the first and third in part ; D, showing the first and 
third glumes and the second slightly. E and F, the grain ; E, the convex, 
embryo-bearing face ; F, the plane face. 6, a, group showing the natural 
size. 
Slightly enlarged spikelet. 

(A, after Hillman, Nevada Agr. Exp. Sta. Bull. ; B, drawing by Charlotte M. 

King.) 



B. 



flowering glume with prominent transverse branching ridges ; flow- 
ering glume minutely granular. In alfalfa, clovers and grass seed. 



Mexican Dropseed {Muhleniergia mexicana (L.) Trin.). 

Spikelet about one-twelfth in. long, on very short pedicel ; empty 
glumes nearly equal, acuminate; flowering glume lanceolate, 3- 
nerved, scabrous on keel, pilose near base; sterile and flowering 



414 



WEED FLORA OP IOWA 



glumes marked by dark, longitudinal lines ; seed brown, about one- 
twelfth in. in length, marked at embryo by darker elliptical area. 
Occurs in alfalfa and the clovers. 

Marsh Muhlenberg {Muhleniergia racemosa (Mx.) B. S. P.). 

Spikelets one-sixth to one-quarter in. long; lower glume acumi- 
nate-pointed ; flowering glume acute, densely bearded at base, min- 
utely pubescent and marked by black lines; seed slender, cylindri- 






Pigure 246B 



Fie.. 2460 



Pig. 246. Dropseed Grasses. A. Seed of Mexican Dropseed Grass (.Muhlen- 
bergia inexicwna) . B. Spikelet of Marsh Muhlenberg (Jf. racemosa). C. 
Nimble Will iM. schreberi). 

(Drawings by Charlotte M. King.) 

cal, brown, with black area at one end. Found in timothy and 
clover seed. 



Nimble Will {Muhlenbergia schreberi J. F. Gmel.). 

Spikelet one-twelfth in. in length, as long as or longer than pedi- 
cel ; empty glume minute ; lower sometimes absent ; flowering glume 
lanceolate, slender, awned, scabrous on nerves. Found in clover 
seed. 



Timothy {Phleum pratense L.). 

Flowering glume or larger scale marked by several veins, truncate 
at top, shorter scale or palet also prominent; seed usually with 
flowering glume; one-sixteenth to one-twelfth in. long; color light 



THE GENERAL CHARACTERS OF SEEDS 



415 





Figure 247B 



Fig. 247. A. Timothy (.Phleum pratense). Hulled and unhulled seed. B. Red 

Top (.Agro^is alba). 
(A, drawing by Charlotte M. King; B, after Hillman, U. S Dept. Agr.) 



gray; seeds somewhat transparent with darker elongated area' at 
lower end, marking the location of the embryo. 



Red Top {Agrostis alba L.). 

Spikelet one-twelfth to one-eighth in. long, empty glumes 
lanceolate, acute ; the first scabrous on the keel ; the second a little 
shorter, and smooth or scabrous near the apex; flowering glume a 
little shorter than the empty ones, obtuse or truncate; palet one- 
half to three-quarters as long as glume ; rachilla frequently present 
in seed, roughened ; fruit brownish, ovate. 



Wild Oats {Avena fatua L.). 

Fruit spindle shape, and of a light yellow color on the tip, bal- 
ance darker yellow to blackish brown; bears one long geniculate 
awn with lower end twisted ; basal scar oval, sloping, with a bunch 
of soft hairs just above ; size 15 mm. 



416 



WEED FLORA OF IOWA 




%^ 




Figure 248B 

Pig. 248. Wild Oats (Avena fatua).- a, spikelet; b, floret; c, natural size. 
(A, after Hillman, Bull. Nev. Agr. Exp. Sta. ; B, Bull. Mich. Agr. Exp. Sta.) 

Crowfoot or Goose Grass {Eleusine indica Gaertn.). 

Spikelets closely imbricated, l%-2 lines (3%-5 mm.) long, 3-6- 
flowered ; glumes obtuse, the first small, 1-nerved, the second larger, 
with flowering glumes 3-5-nerved; seeds rugose, enclosed within a 
thin, loose pericarp. 




Figure 249A 




Figure 249B 




Figure 2490 



Fig. 249. A. Crowfoot or Goose Grass (.Eleusine indica). a, florets; b, c, d, 

views of seed. 

B. Tufted Bragrostis (Eragrostia pilosa), a, spikelet; b. fruit. 

C. Candy Grass (Eragrostis megastachya) . A. Seeds enlarged. B. Seeds 

natural size. 



THE GENERAL CHARACTERS OF SEEDS 



417 



Candy Grass {Eragrostis megastachya (Koeler) Link.). 

Spikelets ovate to linear, many-flowered, one-sixth to two-thirds 
in. long; empty glumes nearly equal, ovate-lanceolate, one-twelfth 
in. long, prominently nerved, scabrous on keel; palet ciliate on 
keel ; seed small, ovoid to elliptical, one-thirty-second in. in length, 
color brown. Found in commercial grass seed and alsike clover. 

Southern Spear Grass {Eragrostis pilosa (L.) Beauv.). 

Spikelet narrow, lanceolate, 3-15-flowered, equaling or exceeding 
the capillary pedicels, one-sixth to five-twelfths in. long; empty 
glume ovate, acute, scabrous on keel ; flowering glume broadly ovate, 
obtuse, 3-nerved, scabrous on keel, one-seventh in. in length; palet 
ciliate on keel ; seeds small, elliptical or ovoid ; one-twenty-eighth in. 
in length. Found in commercial grass seed. 

Orchard Grass {Dactylis glomeratoi L.). 

Spikelets compressed, 3-5-flowered, in crowded, 1-sided clusters; 
flowering glumes lanceolate, acute or awn-pointed, one-sixth to one- 
quarter in. in length, ciliate on keel, and otherwise minutely pu- 




FiG. 250. Orchard Grass (.Dactylis glomerata). 
(After Hillman. XJ. S. Dept. Agr.) 



bescent ; callus at base ; palet serrate on margin near upper end and 
minutely pubescent. 



418 



WEED FLORA OP IOWA 



Wire Grass (Pooi compressa L.). 

Spikelets lanceolate, 5-9-flowered, one-sixth to one-quarter in. in 

length, flowering glumes about one-seventh in. in length, obscurely 

5-nerved ; marginal teeth of palet continue to extreme apex. Found 

with seed of Kentucky blue grass and other commercial grass seed. 





Figure 251A 



Figure 251B 



Fig. 251. A. Wire Grass (Poo compressa). a,, b, two views of seed; c, 
natural size ; d, upper portion of palet showing marginal spines. B. Ken- 
tuclcy Blue Grass (.Poa pratensis). a, b, two views of seed; o, natural 
size ; d, upper part of palet showing marginal spines. 
(Hillman, Bull. Mich. Agr. Exp. Sta.) 

Kentucky Blue Grass {Poa pratensis L.) . 

Spikelet 3-5-flowered, one-sixth in. long, on short scabrous pedi- 
cels; empty glumes slightly unequal, lower nea,rly lanceolate, 1- 
nerved, upper glume broader, 3-nerved; flowering glume ovate, 
scarious towards the apex, base cobwebby, rachilla slender; palet 
with marginal teeth disappearing short of the apex. Pound oc- 
casionally in fescue grass seed and the commercial grass seed. 

Meadow Fescue {Festuca elatior L.). 
Spikelet lanceolate, 5-10-flowered ; empty glume lanceolate, acute, 
one-quarter in. long, smooth, faintly striate ; indistinctly 5-nerved ; 
rachilla slender. Occasionally found in brome grass and rye grass 
seeds. 




FiQ. 262. Meadow Fescue (Festuca elatior). 
(Drawing by Ada Hayden.) 



THE GENERAL CHARACTERS OF SEEDS 419 

Soft Chess {Bromus hordeaceiis L.). 

Flowering spikelet 7-9 mm. in length, obtuse and awned; awns 
6-8 mm. in length ; roughened ; glume with 3 nerves on each side ; 
glume bearing numerous hairs upon the surface; caryopsis 5 mm. 
long, 2 mm. wide, light brown, scar at base, extending one-third 
length of seed. 




Figure 253B 

Fig. 253. A. Soft Chess (.Bromus hordeaceus) . a, b, views of enlarged seed; 

0, natural size. 
B. Chess (.Bromus secalinus). a, h, c, d, views of seed, enlarged; e, natural 

size. 
(After Hillman.) 



Smooth Brome or Hungarian Brome Grass (Bromus inermis Leyss.) . 

Empty glumes unequal; flowering glumes awnless or short- 
awned, with broad searious margin at obtuse or emarginate apex; 
veins of flowering glume conspicuous, roughened; veins of palet 
roughened; seed flattened, boat-shaped, one-third in. in length, 
one- twelfth in. in width. 



420 



WEED FLORA OP IOWA, 




Figure 234B 



Figure 254A 



Fig. 254. A. Smooth Brome CBromus inermls). B. Awned Brome (.Bromus 

tectorum) . 
(A, after Hillman ; B, drawn by Ada Hayden.) 

Awned Brome Grass (Bromus tectorum L.). 

Spikelet with unequal, acuminate-pointed, hirsute empty glumes, 
and rough or hirsute flowering glumes 8-12 mm. long; awn 12-16 
mm. long. 



Chess (Bromus secalinus It.). 

Spikelets tinged, 6-12-flowered, pendulous in fruit, one-twelfth 
to two-fifths in. long ; empty glume oblong-lanceolate ; flowering 
glume ovate-oblong, obscurely 7-nerved, nearly awnless, or short- 
awned from the back of apex ; pubescent along margins and toward 
the apex; palet obtuse, strongly nerved; toothed or fringed with 
distant bristles; seed brownish. Pound in oats and other small 
grain. 



Perennial Rye Grass {Lolium perenne L.). 

Spikelets about one-half in. in length, 5-12-flowered ; empty 
glume much shorter than the spikelet; flowering glume obscurely 
nerved, obtuse, cuspidate, or very short awn-pointed, bearing callus 
at base ; palet granulate ; serrulate on margin. 



THE GENERAL CHARACTERS OF SEEDS 



421 




Figure 255A 



fig. 255A 




Figure 255B 



Fig. 255B 



Fig. 255. A. Perennial Rye Grass {Lolium perenne). B. Italian Rye-grass 

(Lolium italicum), 
(A, after Hillman ; B, drawn by C. M. King.) 



Italian Eye Grass (Lolium italicum A.). 

Spikelets two-fifths to three-fifths in. long, 6-15-flowered ; flower- 
ing glume scabrous near the summit, awned; awn slender, about 
length of glume ; margin of palet serrate. 



Quack Grass {Agropyron repeiis (L.) Beauv.). 

Spikelets 4-8-flowered; empty glumes 5-7-nerved, obtuse or 
notched, acute or acuminate; flowering glume awned near apex; 
two-fifths in. in length; 5-7-nerved above the middle, finely rough- 



422 



WEED FLORA OF IOWA 






Figure 2560 



Fig. 256, A and B. Quack Grass (Agropyron repens) showing various forms. 
C. Slender Wheat Grass (Agropyron tenerum). 



THE GENERAL CHARACTERS OP SEEDS 423 






%^Mi1 iiv/. A/ 





4 

-4- 



Figure 256D 

Fig. 256. D. Western Wheat Grass (.Agropyron smithii) ; a, large spikelet ; 

b and d, small spikelet ; c, edge view of spikelet ; e, empty glumes ; f , empt y 

glume attached to axis of spikelet. 
(After Hillman. A, Cir. U. S. Dept. Agr. ; B. Bull. Mich. Agr. Exp. Sta. ; C. 
Cir. U. S. Dept. Agr.; D, Cir. U. S. Dept. Agr.) 

ened, granular-serrate on margins, finely pubescent at apex ; 
rachilla prominent, hairy, minutely roughened. Occasionally oc- 
curs in clovers. 

Western Wheat Grass {Agropyron smithii Rydb.). 

Fruit similar in shape and size to A. repens, but the broadest 
portion nearer the tip, giving it more of the characteristic outline 
of brome grass; tip generally awned, surface finely pubescent; 
toothing on edge of palea seems finer than in A. repens. 

Poison Darnel (Lolium temulentum) . 

Flowering glume about three-tenths in. long, awned or awnless, 
smooth, obscurely nerved; margins folded in over the palet; tur- 
gid ; shorter than in Lolium perenne. 

Wild Barley (Hordeum juba-tum L.). 

Spikes narrow, 1-3 in. or more long; empty glumes rigid; the 4 
internal ones of each group dilated above the base, those of central 
sublanceolate, all awn-pointed; outer glumes of lateral spikelets 
setaceous; flowering glume of central spikelet awned; florets of 
lateral spikelets awnless. 



424 



WEED FLORA OF IOWA 




Figure 257a 



A 8 

Figure 267B 



Figure 2570 



Fio. 257. A. Seed of Darnel (.LoUum temulentum) . a, b, with awns enlarged, 

c, natural size. 
B. Wild Barley (.Bordeum juhatum.) C. Little Barley (Hordeum pusillum). 
( A, after Winton ; B, after Hillman, Bull. Mich. Agr. Exp. Sta ; C, drawn by 

C. M. King.) 



Little Barley {Hordeum pusillum Nutt). 

Spikelet 1-3-flowered; empty glumes rigid, the 4 internal ones 
of each group dilated above the base, those of the central spikelet 
sublaneeolate, all awn-pointed; outer glumes of the imperfect lat- 
eral spikelets setaceous; flowering glume of the central spikelet 
awned, awn equaling those of the empty glumes; florets of the 
lateral spikelets awnless, or nearly so. 



URTICACEAE, NETTLE FAMILY. 

Hemp {Cannabis sativa L.). 

Achene ovoid, brown with more or less light markings, 4 mm. 
in diameter; surface smooth. 



THE GENERAL CHARACTERS OF SEEDS 



425 





III 




Figure 258A 




Figure 258B 

Fig. 258. A. Hemp (Cannabis sativa). I. Seed in envelope. II. Seed witlioui 

envelope. III. Cross section of seed. F. pericarp ; S. testa ; B. endosperm. 
B. Nettle CUrtica gracilis), a, seed in envelope; b, seed enlarged; d, natural 

size, 
(A, after "Winton ; B, after Hillman, Bull. Mich. Agr. Exp. Sta.) 



Nettle {Urtica gracilis Ait.). 

The fruit enclosed in membranous calyx ; seed pale straw-color, 
1 mm. long, flattened, ovate, slightly pointed toward the ends, 
smooth; point of attachment at broader end. 

POLYGONACEAE, BUCKWHEAT FAMILY. 

Sour Dock {Bumex acetosa L.). 

Inner sepals of calyx in fruit, with wings; aehene convex be- 
tween angles; one-twelfth in. in length, variable, smooth, shining; 
dark reddish brown. Probably occurs in European grown clover 
seed. 



Sheep Sorrel (Bumex acetosella L.). 

Calyx usually persistent, not wing-mar^ned in fruit, roughened, 
with prominent veins; closely fitting aehene, elliptical or ovate 



426 



WEED FLORA OF IOWA 




ft 



« a 







% 



Figure 259A 






Figure 2S9B 

FiQ. 259. A. Sour Dock (Rumex acetosa). A, various achenes. B, diagram 

of the calyx. C, achenes and calyx, natural size. 
li Sheep Sorrel (.Bumex acetosella) . A, seeds bearing the calyx segments. 
B, one having the segments partially broken away. C, achenes from which 
the calyx is removed. D, seeds, natural size. 

(After Hillman, Bull. Nev. Agr. Exp. Sta.) 

with blunt angles, one-twenty-fourth to one-twentieth in. in length; 
color of fruit grayish to brownish. Common in red, white and 
alsike clover. 



Curled Dock {Eumex crispus L.). 

Perianth frequently persistent, consisting of thin veined lobes 
of the calyx, winged in fruit; wings cordate or notched at base; 







9 4 




Figure 260 

Fia. 260. Curled Dock (Rumex crispus). A, views of achenes. B, a cross- 
sectional view of the same. C, diagram of the calyx. D, achenes and 
calyces, natural size. E, a shrunken achene. 

(After Hlllman, Bull. Nev. Agr. Exp. Sta.) 



THE GENERAL CHARACTERS OP SEEDS 



427 



margins entire, each with tubercle on the back; color brown; 
aehene triangular, elliptical, with pointed apex ; one-twelfth to one- 
eighth in. in length; color brown; surface smooth, shining; mar- 
gins minutely roughened. 

Tall Dock {Eumex altissinms Wood). 

Usually but one wing of fruiting calyx bearing tubercle ; pedicel 
as long as .wings; perianth segments veined; margins nearly en- 
tire ; aehene triangular, widened at the base ; one-sixteenth to one- 
twelfth in. in length; soar prominent. 





Fig. 261A 



Figure 261B 




6 e> 



Figure 26".0 




Fig. 261. A and B, Tall Dock (Rumex altissimus) . C and D, Broad-leaved 

Dock (Bumex obtusifoUus). C, tubercle and calyx. 
(A, drawn by L. R. Collins ; B and C, drawn by Ada Hayden ; D, after Hill- 
man, Bull. Nev. Agr. Exp. Sta.) 



Broad-leaved Dock (Rumex obtusifolius L.). 

"Wings of the fruit small, only 1-tubereled; margins of wings 
deeply toothed, backs rugose; fruit three-sixteenths in. long; 
aehenes convex between angles, one-twelfth to one-eighth in. in 
length; conspicuous scar at base. 



428 WEED FLORA OF IOWA 

Water Smartweed (Polygonum acre HBK.). 

Achenes oblong, thick, generally 3-angled, somewhat lenticular, 
one-tenth to one-eighth in. in length, smooth, finely reticulated; 
color dull; base of perianth adhering. 

Dooryard Knotweed {Polygonum awiculare L.). 

Achenes 3-angled, ovoid, acute, sides deeply concave, one-eighth to 
one-seventh in. in length; color light to dark and reddis'h brown; 
surface finely granulated and striated lengthwise. 





Figure 262A 



Figure 262B 





Figure 2620 Figure 262D 

FiQ. 262. A. Water Smartweed (.polygonum acre). 

B. Dooryard Knotweed (.Polygonum aviculare). A, group of seeds (achenes) 
showing the usual forms ; that at the right is one of the smooth, light 
colored specimens ; B, a, group showing the natural size ; G, a cross section 
showing the relative positions of embryo and endosperm. 

C. and D. Prince's Feather (.Polygonum orientale). 

(A and D, drawn by C. M. King; C, drawn by Ada Hayden ; B, after Hillman.) 



Prince's Feather {Polygonum orientale L.). 

Achenes usually orbicular, flattened, with prominent remnant of 
style, one-ninth in. in length, finely reticulated; color dull brown- 
ish to black; base with large scar; remnant of colored calyx at 
base. 



THE GENERAL CHARACTERS OF SEEDS 



429 



Black Bindweed {Polygonum convolvulus L.). 

Achenes large, prominently 3-angled, ovoid-pyramidal, one- 
eighth to one-sixteenth in. in length; surface dull, with minute 
striae; color blackish; perianth usually removed, when present 
straw-colored. 





Figure 263 B 

Fig. 263. A. Black Bindweed (.Polygonum convolvulus). A and B, views of 
two seeds, the latter bearing a portion of the perianth about the base. C, 
a view of an entire perianth covering a, seed. D, a group showing the 
natural size. 

B. Erect Knotweed (Polygonum erectum). 

(After Hlllman, Bull. Mich. Agr. Exp. Sta.) 

Erect Knotweed {Polygonum erectum L.). 

Achenes 3-angled, ovoid, less deeply concave between the angles 
than in preceding (P. aviculare) ; one-ninth to one-tenth in. in 
length ; dull, minutely reticulated. 





Figure 264A Fig 264B 

Fig. 264. A. Water Pepper (Polygonum hydropiper). Seeds enlarged and 

natural size ; the embryo at C. 
B. Mild Water Pepper (Polygonum hydropiperoides) . 

(A, after Hlllman; B, drawing by Ada Hayden.) 



430 



WEED FLORA OP IOWA 



Water Pepper {Polygonum hydropiper L.)- 

Achene lenticular, triangular; form broadly oblong or ovoid, 
slightly gibbous; one-tenth in. in length; dull, color light. 

Mild Water Pepper {Polygonum hydropiperoides Mx.). 
Achenes 3-angled, ovoid, angles between flattened, sides rounded, 
one-eighth to one-tenth in. in length ; smooth, shining. 

Slender Pink Smartweed {Polygonum, lapathifoUum L.). 
Achenes ovoid-oblong, lenticular, edges slightly angled along the 
center, with a prominent remnant of the style at upper end, one- 





Figure 265A Figure 265B 

Pig. 265. A. Slender Pink Sniiartweed (.Polygonum lapathifoUum) . A, a side 
view of an acliene bearing a part of the perianth at the base, enlarged. B, 
a. group showing the natural size, one shown edgewise. C, a cross section 
of an achene. 

B. Lady's Thumb iPolygonum perslcaria). A, B and C, side views of com- 
mon forms of achenes ; C, a three-angled specimen. D, one covered by the 
perianth (reduced from the size of A, B and C). B, a group showing the 
natural size. F, a cross section of an achene. 

(After Hillman, Bull. Nev. Agr. Exp. Sta.) 

twelfth to one-tenth in. long; color light brown to dark brown, 
shining; base of achene with remnant of perianth adhering. 

Pennsylvania Smartweed {Polygonum pennsylvanicum L.). 
Achenes orbicular, usually broader than long, with edges as in 
P lapathifoUum, remnant of style short, one-seventh to one-sixth 
in. long; color blackish, dull, base of achene with perianth ad- 
hering. 

Lady's Thumb {Polygonum persicaria L.). 

Achenes broadly ovate, lenticular, often somewhat 3-angled at 
base, one-eleventh in. in length; surface smooth, shining; color 
dark; remnant of perianth present at base. 



THE GENERAL CHARACTERS OF SEEDS 



431 




# 



# 



A ••(. B 

Fig. 266. Pennsylvania Smartweed (Polygonum pennsylvanicum). A, a side 
view of a seed (achene). B, one surrounded by the calyx; the opposite side 
has two segments between those on the edges. C, a cross section of a 
seed. D, seeds, natural size. 

(After HlUman, Bull. Nev. Agr. Exp. Sta.) 

Bushy Knotweed {Polygonum ramosissimum Mx.). 

Achenes sharply 3-angled, sides less deeply concave than in 
P. aviculare, one-eighth in. in length; color blackish, dull; calyx 
greeni&h, light straw-colored in dried specimens. 





Figure 267A 



Figure 267B 





Figure 267C 



Fig. 267. A. Pennsylvania Smartweed (.Polygonum pennsylvanicum.). B. Tan- 
weed (Polygonum, muhlenbergii) . C. Bushy Knotweed (Polygonum ramos- 
issimuTii ) . 

(A and B, drawings by Charlotte M. King; C, drawings by L. R. Collins.) 

CHENOPODIACEAE, GOOSEPOOT FAMILY. 

Cycloloma {Cycloloma atripUd folium (Spreng.) Coult.). 

Fruit enclosed by the calyx, lower surface prominently rayed, 
upper surface depressed, wing-margined, one-tenth to one-eighth in. 
in diameter; seed nearly spherical, somewhat flattened, one-twelfth 
in. in diameter, blackish ; scar whitish ; embryo slender,, forming a 
ring about the endosperm. 




Fig. 268. Cycloloma (Cyclolom,a atriplicifolium) . a, b, seed in envelope; 
d, enlarged views ; e, seeds, natural size ; f, cross section. 
(After Hillman, Bull. Mich. Agr. Exp. Sta.) 



432 WEED FLORA OP IOWA 

Lamb's Quarters {Chefiopodium album L.)- 

Seeds one-twentieth in. in diameter, often surrounded by thin 
glandular utricle which varies from grayish to straw-eolor; seed 
dark brown, shining, firmly attached to pericarp, edge rounded, 
lower, convex with a curved groove; seed somewhat irregular in 
shape ; some seeds also surrounded by the pericarp and star-shaped 
calyx. In seed of small grains, clover and grasses. 





Figure 269A 



Figure 269B 




a 




Figure 2690 

Fig. 269. A. Lamb's Quarters (Chenopodium album), a to b, different views of 
seed ; d, g, f, seed with utricle ; 1, calyx attached. 

B. Maple-leaved Goosefoot (Chenopodium hybridum). a, seed in envelope; b, 
c, general view of seed ; d, cross section ; e, natural size. 

C. Western Lamb's Quarters (Chenopodmm murale). A, B and C, views of 
seed ; D, the natural size. 

(After Hillman, A and B, Bull. Mich. Agr. Exp. Sta. ; C. Bull. Nev. Exp. Sta.) 



Maple-leaved Goosefoot {Chenopodium hyhridum L.). 

Seeds dark grayish black, circular, 2.5-3 mm. in diameter, flat- 
tened double-convex, with distinct margin, slightly indented by a 
notch; scar on middle of one face; seed shining, black, when en- 
velope is entirely removed. 



Spinach {Spinacia oleracea L.). 

Fruit broadly ovate, one-sixth in. in length, size variable ; 
unarmed, wrinkled, sometimes tubereulate, straw-colored; 
closely enveloped by utricle; scar elevated. 



utricle 
achene 



THE GENERAL CHARACTERS OF SEEDS 



433 





Figure 270A 
Fia. 270. A. Spinach iSpinacia oleracea). 



a, b, 



Figure 270B 
different views of seed in 



B. Orach (Atriplex patula var. hastata) 

envelope ; d, e, f, views of seeds. 
(A, drawing by Charlotte M. King; B, after Hillman, Bull. Mich. Agr. Exp. Sta. ) 

Orach {Atriplex patula var. hastata (L.) Gray). 

Fruiting bracts ovate-triangular, entire toothed, often murieate 
on the back, united to near the middle ; seed jet black, shining, 
nearly circular, edge bluntly rounded, bearing a notch; a groove 
leads from protuberance on the margin part way to center of face. 

Russian Thistle {Salsola kali var. tenuifolia G. F. W. Mey.). 

Calyx persistent, 5-parted, membranaceous, enclosing the flat- 
tened utricle by a broad, flat, membranaceous wing; seed conical. 





Figure 271A 



Figure 271B 



Fig. 271. A. Russian Thistle (Salsola kali var. tenuifolia), a, seed in envelope; 

b, d, e, views of seed enlarged ; c, natural size. 
B. Kochia or Mexican Fireweed (.Kochia scoparia). 

(A, after Hillman, Bull, Mich. Agr. Exp. Sta.; B, drawing by Miss King.; 

upper end truncate, with a depression one-eighteenth in. in 
diameter, brownish; seed without endosperm, embryo coiled in a 
spiral; cotyledons slender. 
38 





434 WEED FLORA OF IOWA 

AMARANTHACEAE, AMARANTH FAMILY. 

Spreading Amaranth {Amaranthus blitoides Wats.)- 

Seeds lenticular or round to broadly egg-shaped, one-sixth in. in 
diameter, both sides convex with distinct margin, glossy, black; 



3 a 



Fig. ,272. Spreading Amaranth (.Amaranthus blitoides). A, seeds. B, a broken 

specimen. C, an edge view. D, the natural size. 

(After Hillman, Bull. Nev. Agr. Exp. Sta.) 

seeds borne in ovoid-oblong utricle, 2-3-beaked by the persistent 
style. Eeported in western alfalfa seed. 

Tumbleweed {Amaranthus graecizans h.) . 

Seeds lenticular or roundish, one-twenty-fourth in. in diameter, 
glossy black, much like the preceding but smaller. In grasses and 
lawn mixtures. 




9 % 



•".. 



FiH. 273. Tumbleweed (.Amaranthus graecizans). A, seeds. B, a broken one. 

C, the natural size. 
(After Hillman, Bull. Nev. Agr. Exp. Sta.) 



Rough Pigweed {Amaranthus retro flexus L.). 

Seeds from one-eighteenth to one-twentieth in. in length; oval, 
spherical or nearly spherical, both sides convex with a continuous 
ring on the margin ; scar small ; smooth, black, shining ; seeds much 
like A. blitoides but somewhat smaller. In seeds of red clover, 
alsike, and timothy. 



THE GENERAL CHARACTERS OF SEEDS 



435 






Fig. 271. Rough Pigweed (,Ainaranthu3 retroflexus) . A, seeds; B, one having 

the seed-coat broken ; C, the natural size. 

(After Hillman, Bull. Nev. Agr. Exp. Sta.) 

Water Hemp {Acnida fuberculata ^loq.). 

Seeds erect, lens-shaped, one-fifteenth in. in diameter, smootli, 
bhining. black, 2-5 remnants of stigmas, sometimes ^vith the at- 




FiG. 275. "Water Hemp (.Acnida tuberculata) . a, b, e, different views of seed; 

d, cross section ; e, in seed envelope ; f, natural size, 

(After Hillman, Bull. Mich. Agr. Exp. Sta.) 

tached calyx and mucronate bracts; utricle longer than bracts; 
ciremnscissile, not angled. In seed of clover and alsike. 

CARYOPHYLLACEAE, PINK FAMILY. 

Chickweed {Stellaria media (L.) Cyrill.). 

Kidney-shaped, broadly egg-shaped, to wedge-shaped, one- 
twentieth in. in length, finely and closely tubercled; color grayish 






Fig. 276. Chickweed IStellaria media'). A, seeds, side view. B, one shown 
in edge view. C, a sectional view showing the embryo and endosperm. 
D, group showing the natural size. 

(After Hillman, Bull. Nev. Agr. Exp. Sta.) 

to light brown ; scar marked by a longitudinal groove at basal end. 
Occasionally found in clover. 



436 WEED FLORA OP IOWA 

Corn Cockle {Agrostemma githago L.). 

Seeds large, angular, broadly wedge-shaped, one-eighth in. in 
length ; tubercles prominent, lines of tubercles beginning at basal 
end of seed ; color brown to black ; size of seed variable ; according 





Fig. 277. Corn Cookie (Agrostemma githago), a, seed enlarged; b, seed in 

cross section ; c, natural size. 

(After Hillman, Bull. Nev. Agr. Exp. Sta.) 

to Dewey the larger ones hard to screen out. Most commonly found 
in wheat; seed has poisonous properties. "Pest in grain fields." 
Found in wheat and in chicken feed. 



Bladder Campion {Silene latifolia (Mill.) Brit. & Rendle). 

Seed kidney-shaped, more nearly spherical than in Silene nocti- 
flora, one-fifteenth in. in length; shape of seed more nearly or- 
bicular than in S. noctiflora. Found in some clovers. 





* 



Fig. 278. Bladder Campion (Silene latifolia). A, common forms of seeds, 
side view. B, edge view of a, seed, showing the scar-cavity. C, the nat- 
ural size of the seeds. 

(Alter Hillman, Bull. Nev. Agr. Exp. Sta.) 



Forked Catchfly {Silene dichotoma Bhrb.); 

General shape of seed roundish triangular, somewhat flattened, 
about 1.5 mm. in breadth; color dull reddish brown; 5-7 rows of 
tubercles on each side in curved rows following the rounding out- 
line of the shape of the seed ; scar on the straight side of seed. 



THE GENERAL, CHARACTERS OF SEEDS 



437 




.» « 

» ft 

« 



3** 



Figure 279A 





Figure 279B 

Fig. 279. A. Forked Catchfly (.Silene dichotoma) . a, seed enlarged; b, nat- 
ural size. 

B. Night-flowering Catchfly (Silene noctiflora) . A, side view of a seed; B, 
edge view of the same, showing the scar-cavity. C, a longitudinal section 
of a seed, showing the embryo curved about the endosperm. D, the nat- 
ural size of the seeds. 

(.\fter Hillman ; A, Bull. Mich. Agr. Exp. Sta., B, Bull. Nev. Agr. Exp. Sta.) 



Xight-flowering Catchfly {Silene noctiflora L.). 

Seeds kidney-shaped, thick, with rounded edges, one-fifteenth to 
one-tenth in. in length ; surface roughened by peculiar tubercles ; on 
shorter side a black elevated scar; immature seeds red. Found in 
clover and grass seed. 





Figure 280A 

Fio. 280. A. Evening Catchfly (.Silene vesrertina). 
B. Evening Catchfly (Lychnis alba). 

(Drawings by L. R. Collins and Ada Hayden.) 



Evening Catchfly {Silene vespertina Sibth.). 

Seed smaller than that of S. noctiflora, which resembles it, one- 
fifteenth of an in. in length; ash-colored. Found in alfalfa and 
clover seed. 



438 WEED FLORA OF IOWA 

Cowherb {Saponaria vaccaria h.) . 

Seed nearly spherical, one-twelfth in. in length, minutely tu- 
bercled; color black; immature seeds reddish; scar whitish, in de- 
pression. Occurs in wheat and in red clover. 




Fig. 281. Cowherb (Saponaria vaccaria). A, different views of the seeds; 
the one at the left and the lower one show the scar ; the light spots show 
the minute surface-projections. B and C, parts of a broken seed, B re- 
taining a part of the embryo. D, a sectional view of a seed. E, seeds, nat- 
ural size. 

(After Hillman, Bull. Nev. Agr. Exp. Sta.) 

PORTULACACBAE, PURSLANE FAMILY. 

Purslane (Portulaca oleracea h.) . 

Seeds broadly ovate, inclined to kidney-shaped, flattened, one- 
thirtieth in. in length, roughened by minute tubercles in concentric 
rows: small scar at smaller end, whitish. 





Fig. 282. Purslane (.Portulaca oleracea). A, a side view of a seed, enlarged, 
showing the whitish scar ; B, a group, natural size ; C, section of a. seed, 
taken parallel with the faces. 

(After Hillman, Bull. Nev. Agr. Exp. Sta.) 

RANUNCULACEAE, CROWFOOT FAMILY. 

Meadow Rue (Thalictrum dasycarpum Fisch. and Lall.). 

Fruit an achene, ovoid, one-fifth in. in length, with remnant of 
curved style, prominently ribbed, with from 6-8 wings, short- 
stalked, glabrous or pubescent ; seed elongated, ovoid, one-tenth in. 
long, brownish, smooth, with prominent veins near base of seed. 
Ocoasionally found in clover seed. 



THE GENERAL CHARACTERS OF SEEDS 



439 





Figure 283A Figure 283 B 

FiQ. 283. A. Meadow Rue (Thalictrum dasycarpiim) . 
B. Long-fruited Anemone (.Anemone cylindrica). 

(A, drawing by L. R. Collins, B, by Ada Hayden.) 

Long-fruited Anemone (Anemone cylindrica Gray) . 

Aehenes one-quarter in. in length and one-fifth in. in width, flat, 
compressed, 1-seeded, nearly orbicular, greenish, covered by dense 
pilose mass of whitish hairs. 

Prairie Larkspur {Delphinum Penardi Huth.). 

Seeds somewhat flattened, upper end wider, nearly square, 4- 
angled or triangular, one-sixteenth to one-twelfth in. long, surface 
scabrous, becoming rougher on angles; color grayish. 






Figure 284A Figure 284B Figure 2840 

Fig. 284. A. Prairie Larkspur (.Delphinium Penardi). 
B. and C. Field Larkspur (Delphinium consolida). 

(A, drawing by Ada Hayden; B, drawn by L. R. Collins; C, drawn by C. M. 

King.) 



Field Larkspur (Delphinium consolida L.). 

Seed angular, somewhat convex on back, one-twelfth in. long 
and equally wide, surface scabrous or scaly, with whitish margins ; 
color blackish, brownish or grayish; seed with sharp bitter taste. 
Reported as of frequent occurrence in Russian clover seed. 



440 



WEED FLORA OF IOWA 



Small-flowered Crowfoot {Ranunculus ahortivus L.)- 

Achene flattened-circular, with 2 convex faces, orange-brown in 
color, smooth and shining, very slightly impressed with wrinkles'; 
remnant of style present as a short curved point on margin. 





Figure 285A Figure 285B 

Fig. 285. A. Small-flowered Crowfoot {Ranunculus abortivus). a, 

enlarged ; b, end view ; c, achenes natural size. 
B. Tall Buttercup (Bdnunculus acris). a, b. different views of seed; 

section ; d, natural size. 

(After HlUman, Bull. Mich. Agr. Exp. Sta.) 



achenes 
c, cross 



Tall Buttercup (Ranunculus acris). 

Carpel 1-ovuled; achene flattened, tipped by remnant of curved 
style, one-tenth to one-eighth in. long; color greenish to brownish; 
surface apparently smooth, minutely pitted; scar minute, in a 
whitish depression at base of achene. 

PAPAVERACEAE, POPPY FAMILY. 

Pop-py {Papa/ifer somniferum h.) . 

Seed about 1 mm. in length, kidney-shaped, one end being slightly 
larger than the other; hilum and chalaza in a notch, connected by 
a short raphe; surface covered with fine, beautiful reticulations; 
embryo straight; considerable endosperm. 





Figure 286A 

P'lGS. 286. A. Poppy (Papaver somniferum) 
B. Prickly Poppy (.Argemone intermedia). 

(A, after Winton. B, drawing, C. M. King.) 



Figure 286B 
To the left embryo of seed. 



THE GENERAL CHARACTERS OP SEEDS 441 

Prickly Poppy {Arg&mone intermedia Sweet). 

Pod ellipsoid, prickly; seeds spherical, crested, about 2 mm. in 
diameter; dark brown, surface reticulate and deeply pitted. 

CRUCIFERAE, MUSTARD FAMILY. 
Pennycress {Thldspi arve')ise L.). 

Seed oblong, flattened, one-twelftb to one-tenth in. long; sur- 
face marked by curved ridges, simple or occasionally forked, which 
curve from base to apex in regular rows; color brownish to dark 
reddish brown; funicle sharp pointed. Found largely in wheat, 
barley and o'a,ts. "A pest of grain (wheat) fields of Manitoba." 




Fig. 287. 



Figure 287A 




Figure 287B 



A. Pennycress (TMasvi arvense). A, side view of a seed; B, 
natural size ; C, the embryo. 
B. Cress {Lepidvuin sativum). 
(After Hillman, Bull. Mich. Agr. Exp. Sta.) 



seeds, 



Cress {Lepidium sativum L.). 

Seed oval, one edge nearly straight, the other convex, one-tenth 
in. in length, apparently slightly marginate at basal end, basal 
portion bearing scar, also with white projecting 'tip, and end of 
funicle prominent, smooth, brownish. 

Small Peppergrass {Lepidium apetalum Willd.). 

Seeds oblong, flattened, margin colorless, prominent ridge on 
one side, one-sixteenth to one-twelfth in. long, minutely rough- 
ened ; cotyledons incumbent ; seed coat becomes mucilaginous when 
wet; funicle prominent. Generally found in small grains and 
commercial grass seed. 



442 



WEED FLORA OF IOWA 






J '*. o M 



e 
E 6 ^ 




Figure 288A 



Figure 288B 



Fig. 288. A. Small Peppergrass (iepiiimm opetaZum). A, seeds shown in side 
view ; B, a half -section of a pod ; C, a seed in cross section, showing the 
three parts of the embryo, the caulicle being at the right ; D, the embryo, 
the caulicle at the left ; E, group of seeds, natural size. 

B. Lepidium apetalum, with section of seed coat showing action of mucilagin- 
ous cells after moistening. 
(A, after Hillman, Bull. Nev. Agr. Exp. Sta. ; B, drawn by C. M. King.) 



Large Peppergrass {LepidHum virginicum L.). 

Seed elongated with prominent ridge on one side, one-twelfth in. 
in length; color light reddish brown; cotyledons incumbent; seed 




Fig. 289. Large Peppergrass (.Lepidium virginicum). A, three seeds shown 
in side view. The upper two show the narrow, curved groove of one face, 
the lower one shows the broader, shallow depression of the opposite face. 
The one immediately at the right of A shows the widened border and its 
light colored edge. B, entire pod. C, a seed showing the mucilage as it 
appears while wet. D is a cross sectional view of a seed, showing the 
flattened form of the cotyledons and the edgewise position of the caulicle. 
E, the embryo in side view. F, seeds, pod, and half-pod, natural size. 
(After Hillman, Bull. Nev. Agr. Exp. Sta.) 

coat becomes mucilaginous when wet. Generally found in small 
grains and commercial grass seed. Frequent in timothy. 



THE GENERAL CHARACTERS OP SEEDS 443 

Shepherd's Purse {Capsella bursa-pastoris (L.) Medic). 

Seed small, flattened, oblong, with 2 longitudinal grooves; one- 
twenty-fourth to one-twentieth in. in length ; color light brown ; scar 
whitish, funicle prominent. In alsike clover. 




Fig. 290. Shepherd's Purse (.Capsella bursa-pastoris). A, seeds showing var- 
ious forms and degrees of color. B, showing the mucilage while wet. C, 
a seed showing the appearance of the dried mucilage. D, a seed in cross 
section. E, seeds, natural size. 

(After Hillman, Bull. Nev. Agr. Exp. Sta.) 



False Flax {Camelina sativa (L.) Crantz). 

Seeds one-twelfth in. in length, light brown, minutely pitted; 
eauliele prominent, running lengthwise with conspicuous groove 




Fig. 291. False Flax (Camelina sativa). A, various forms of seeds. B, a seed 

showing the mucilage. C, a. seed in cross section. D, seeds, natural size. 

(After Hillman, Bull. Mich. Agr. Exp. Sta.) 

between it and the cotyledons which are incumbent. On addition 
of water the seeds become mucilaginous. In seeds of clovers and 
grasses. 



444 



WEED FLORA OF IOWA 



Radish {Baphanus sativus L.). 

Seed spherical, ovate to oval, frequently angular, one-eighth to 
one-fifth in. in length, minutely pitted, brownish with glaucous or 
shining surface; sear inconspicuous, usually surrounded by small 
dark area ; radicle near sear, prominent. 




Fig. 292. Radish (Raphanus sativus^, two different views. 
(Drawn by C. M. King.) 

White Mustard {Brassica alba Boiss.). 

Seed nearly spherical, occasionally somewhat oblong, one-twelfth 
to one-ninth in. long, light colored, reticulations inconspicuous; 
scar whitish, projecting; seed coats mucilaginous when wet. 






^^« b e 

Figure 293A Figure 293A Figure 293B 

Pig. 293. A. White Mustard (.Brassica alba). B. Charloclc (Brassica arven- 

sis). a, tip of i5od ; b, seeds enlarged, and natural size; c, cross section. 
(A, drawings by Ada Hayden and L. R. Collins; B, after Hillman, Bull. Mich. 

Agr. Exp. Sta.) 

English Charlock {Brassica arvensis (L.) Ktze.). 

Seed nearly spherical, sometimes oblong, one-fourteenth to one- 
twelfth in. in diameter, marked with fine ridges, reticulated or 
honeycombed in appearance, light brown or grayish, with paler 
appearance; scar whitish, an elevated point at one end of the 
seed ; embryo large ; cotyledons conduplieate. Only a small amount 
of mucilage produced in presence of water. 



THE GENERAL, CHARACTERS OP SEEDS 



445 



"Wild Turnip {Brassica campestris L.). 

Seeds generally nearly spherical or oblong; the caulicle and 
radicle usually conspicuous along the middle, one-twentieth to ono- 
twelfth in. in diameter, cultivated forms larger, roughened and 



^^ 








Fig. 294. Wild Turnip (Brassica campestHs). A and B, various forms o( 
seeds. C, a seed in cross section showing cotyledons and caulicle. D, the 
embryo. E, seeds, natural size. 

(After Hillman, Bull. Mich. Agr. Exp. Sta.) 

more finely ridged than in B. nigra and B. arvensis; color grayish 
or brownish; scar at one end. With clover and grass seed. 

Eape {Brassica napus L.). , 

Seed nearly spherical or sometimes oblong, one-fourteenth to one- 
twelfth in. in length, prominently reticulated; closely resembles 
B. arvensis. Found in mustard and clover seed. 





o 9 



Figure 295A Figure 295B 

Fig. 295. A. Rape (Brassica napus). B. Black Mustard (.Brassica nigra). A, 
seed enlarged, showing the surface network of dark lines. B, a group of 
seeds, natural size. 

(A, drawings by Ada Hayden; B, after Hillman, Bull. Mich. Agr. Exp. Sta.) 



Black Mustard {Brassica nigra (L.) Koch.). 

Seed nearly spherical, more generally broadly oblong, one-twen- 
tieth to one-fifteenth in. in diameter; surface marked with fine 
ridges; frequently whitish sear at one end; embryo as in B. 



446 



WB^D FLORA OF IOWA 



arvensis; taste pungent. Generally found in seed of clover and 
alfalfa. 

Indian Mustard {Brassica juncea). 

Seed about the size of wild mustard seed ; surface rather coarsely 
reticulated. Color dark reddish brown. 



^e^^A^^i^^^^-^&j^M. 



^^s^sG-sija^Si^'^ '/v,^ 




e 3 

-1 

c 



^0-. 




Figure 296A Figure 296B 

Fig. 296. A. Indian Mustard (.Brassica junoea). B. Hare's-ear Mustard 
(Conringia orientalis). a, b, different views of seed; c, cross section; d, 
natural size. 

(After Hillman, Bull. Mich. Agr. Exp. Sta.) 

Hare 's-ear Mustard {Conringiat orientalis (L.) Dumort.). 

Pod rigid, 4-angled; seeds brown, oblong narrowed to rounding 
at the ends, 2-2.5 mm. long; surface finely reticulated in checks; 
sear at end of seed lighter in color; position of caulicle indicated 
by two distinct, lengthwise grooves. 

Tumbling Mustard {Sisymbrium altissimum L.). 

Seed oblong flattened, one-twenty-fifth in. in length ; color reddish 
yellow; radicle prominent, variable in shape; form of embryo 
marked by deeper color, by lines; seed coat becomes mucilaginous 
when wet. A tumbling weed. Distribution wide, reported as a 
serious weed in commercial seeds of the northwest and Canada. 



Hedge Mustard {Sisymbrium officinale (L.) Scop.). 

Seed oblong, sometimes with upper end truncate, some almost 
trapezoidal in outline, one-twenty-fourth to one-sixteenth in. long; 
color yellowish, or brownish, variable ; caulicle evident from promi- 
nent white sear; funide sometimes present and pointed; seed coat 
mucilaginous. Found in alsike and white clovers. 



THE GENERAL CHARACTERS OP SEEDS 



447 




Fig. 



B. 



Figure 297A 




Figure 297B 



> 



297. A. Tumbling Mustard (.Sisymbrium altissinmm). A, a group of 
seeds indicating the usual forms ; .a, one showing the hairy appearance due 
to the mucilage, either when wet or after drying. B, several seeds, natural 
size. 

Hedge Mustard (.Sisymbrium officinale). A, a group of seeds showing the 
prevailing forms ; a, one showing the fine hairlike mucilage as it appears 
when wet or after drying. B, group showing the natural size. 
(After Hlllman, Bull. Mich. Agr. Exp. Sta.) 



Marsh Cress {Badicitla palustris (L.) Moeneh.). 

Pod ovoid; seed pale reddish brown, oval, finely reticulated, 

length about .6 2-3 nun. ; sear near one end, occupying a deep 
notch in the contour of the margin. 




Fig. 298. Marsh Cress (Radicula palustris). 
(Drawing by Ada Hayden.) 

Winter Cress {Barbarea vulgaris R. Br.). 

Seed oblong, flattened, one-sixteenth in. in length ; surface finely 
reticulated ; the scar a light-colored appendage at one end ; position 





m 









a 



Fig. 299. W^inter Cress (Barbarea vulgaris). A, various forms of seeds, 
seed in cross section. C, seeds, natural size. 
(After Hillman, Bull. Mich. Agr. Exp. Sta.) 



448 WEED FLORA OF IOWA 

of eaulicle marked by groove ; color light brown ; seed coats do not 
develop mucilage in water. Occasionally with clover. 

CAPPARIDACBAE, CAPER FAMILY. 

Rocky Mountain Bee-plant (Cleome serrulata Pursh.). 

Roughly wedge-shaped to triangular in outline, and wedge- 
shaped in cross section; mature seeds of a grayish brown color, 
immature seeds a creamy yellow ; size 3 by 2.5 mm. ; basal scar ex- 




FiG. 300. Rocky Mountain Bee-plant (.Cleome serrulata). 
(Drawing by Ada Hayden.) 

tends from the edge of the wedge, well up on both flat faces; 
most of the surface of the seed roughly tubercled. 

ROSACEAE, ROSE FAMILY. 

Silver Weed {Potentilla anserina L.). 

Seed pointed, egg-shaped, unsymmetrieal, about 1.6 mm. in 
length ; color yellowish to brown ; surface furrowed throughout its 
length. 




Fig. 301. Silver Weed {Potentilla anserina). 
(After Burchard.) 



Cinquefoil {Potentilla canadensis L.). 

Seed small, about 0.5 mm. in length, short, obliquely egg-shaped ; 
light brown. 



THE GENERAL' CHARACTERS 0^ SEEDS 



449 





t 



Figure 302A 



Figure 802B 



FiQ. 302. A. CinquefOil (.Potentilla eaHddensis)'. B; Five-linger (.Potentilla mon- 
• speli^nsis var. riorvegica) . A, tWQ seeds (aohenes), side "view- B, a seed 
in edge view. C, group showing the natural size. 
(After iliUraan- A, Bull. Mich. Agr. Exl). Sta:; B; Bull. Nev. Agr.' Exp. Sta.). 



Five Finger {Potentilla monspeliensis L. var. ncirvegica (L.) 

Rydb.). ■, 

Achertes small, ovate or kidnejNsliiaiped, one-twenty-fourth in, im 
kngth, prominently ridged ; the ridges simple or branched, starting 
from base of seed ; color light brown or straw-colored. Frequently 
•ecura in alsike clover and timothy, as well as in red clover. 



Ayens {Geum cqMadeiise.J&cq.). 

Achene pale greenish brown, length 3 mm., width 1% mm., gen- 
eral shape ovate, tapering to base, rounded at apex which bears 
persistent hooked style 5 mm. in length tipped with a hook; achene 
slightly flattened, with a narrow ring along each edge. 



.f^^n 





Figure 303A Figure 303B 

Fig. 303. A, Avens (.Geum oanadense) . B, Rose (.Bosa pratincqla). 
(Drawings by C. M. King.) 
29 



450 



WEED FLORA OF lOWA 



Prairie Rose {Bosa prati/ncola Greene). 

Achenes dark to light brown, smooth, shining; length 3-5' mm., 
width 2-3 mm., general shape ovoid, modified by some flattening of 
portions at the surface, and corresponding angulation of the seed's 
form; sear at broader end, with dark line extending ^t& the apex 
which is tipped with a slight remnant of the style. * 

LEGUMINOSAE, PULSE FAMILY. 

Rattlebox (Grotalafia sagittalis L.). 

Pod blackish, cylindrical, inflated, many seeded; seed greenish 
brown, shining, smooth, somewhat flattened, circular-kidney-shaped. 




Fig. 304. Rattlebox (,Crotalaria sagittalis). 
(Drawing by Ada Hayden.) 

with one side interrupted by a deep rouiided notch, bearing the 
conspicuous sear with dark center and light rim; width of seed 
2.5 mm. 



White Clover (Trifolvum repens L.). 

Seeds;varying from nearly square to triangular, margins rounded, 
flattened'^ often concave on one margin, one-twentieth to one-thir- 
tieth in. long; smooth; color dull yellow to light reddish brown, or 
slightly green; radicle slender club-shaped, about as long as the 
cotyledons. 

Alsike Clover {Trifolium hyiridiim L.). 

Seed more nearly round than that of alfalfa or red clover ; one- 
twentieth to one-sixteenth in. in length; color a peculiar yellowish 
green, often brown and mottled, individual seeds even yellow or 
brown ; the projecting radicle gives the seed the appearance of hav- 
ing a nearly square top. 



THE GENERAL CHARACTERS OF SEEDS 



451 





Figure 305B 





Figure 3050 Figure 305D 

FiQ. 305. A. White Clover (.Trifoliwm repens). a, enlarged; b, natural size. 

B. AJsike Clover (.TrifoUum hyhridum). a, enlarged; b, natural size. 

C. Red Clover (.TrifoUum pratense). a, enlarged; b, natural size. 

D. . Low Hop Clover (.TrifoUum ptocurnbens) . a, enlarged; b, opposite face; c, 

flower; d, seeds, natural size. 

(After Hillman, Bull. Nev. Agr. Exp. Sta.) 

Red Clover {TrifoUum, pratense L.). 

Seeds roughy triangular, with angles rounded ; no two sides equal 
length, sides somewhat convex with rounded edges, one-sixteenth 
to one-tenth in. long ; color light yellow, purple, or of yellow and 
purple; old seeds more brownish; scar near radicle, which is not 
so prominent as in other clovers ; the seeds of mammoth clover re- 
semble those of red clover but are usually larger. 

Low Hop Clover {TrifoUum procumiens L.). 

Seed light brown, shining, oval, length 1-1.3 mm., width 0.6 mm. ; 
scar in a notch a short distance from one end. 



Sweet. Clover, Bokhara Clover {MeUlotus alba Desv.). 

Seeds contained in an ovoid pod, one-twelfth to one-fifteenth in. 
long, reticulated, nearly smooth, elliptical, somewhat triangular, 
variable ; color yellowish to greenish, scar brown in color ; micropi- 
lar processes near scar, not conspicuous. Found in seeds of alfalfa 
and clover. 



452 



- ' %gfeD PtORA OF tOWA v 




Fio. 306. White Sweet Clover (.Melilotiia alba). A, a group of seeds. B, the 
pods ; tlje central one without the calyx. C, the embryo. D, a group of 
seeds alia, pods, natural Size. * ,, -i 

, ' '■ (After Hillman, , Bull. Nev. Agr. E!xp. Sta.) ... jP 

\j Yellow Sweet Clover {Melilotus officinalis (L.) Lam.)^ {h, 

Pods one-seventh in. in Ito^; rugose, mor^ evenly, transverselj 
mrrinkled than in M. alba; seeds subspherical or elliptical to Mdney- 







''■' ^ '^ " ' ■ . ■ 

Pig. 307. Yellow Sweet Clover (Welilotus officinalis). A, seeds, B, pods; the 

ohe at the -right wiifioiif^the calyx, and showing the contracted Base. C, a 
i. . view of a .seed in cross -seotionj showing cotyledons and cauliclE. D, a group 

of seeds and pods, natural size. 
■■'' ; (After Hillman, Bull.' Nev. Agr. Shcp. Sta.) "- 

shaped, one-twelfth to one-tenth in. in length, smooth ; yellowish or 
brownish to greeilish;, with Siiiall micropilar processes. 



Bur Clover ^{MeMcUgo hispida Gaertn.). 

Seed^ kidney-shaped, occasionally sausage-shaped, both sides con- 
vex, one-sixth in. in length, larger than alfalfa, variable in size; 
color lighter than in alfalfa seed; scar about middle of seed, close 
to prominent micropilar processes ; pods large, spirally twisted into 
several flat coils, covered by pointedprojeetions; the prickles eithel" 
straight or curved; each pod several-seeded; seeds have general re- 
semblance to alfalfa seed in form and color. ^-. - -i 



THE GBNERALi CHARACTERS OF SEEDS 



US3 




inc 





308. Bur Clover (Jfedicaffo hisptda). A, seed; B, 
(Drawings by Ada Hayden and L. R. Collins.) 



pod. 



i3i.>,') j:^.' Yellow Tre£oir(Me<iica£fo .iMp«J*j«iL.). ■ 

Seeds kidney to egg-shaped, much shorter than bur clover seed, 
one- twelfth to one-tenth. in. long; about the size of alfalfa, which 
it ^jlosely resembles ; color yellowish, reddish, or greenish ; sear near 




Fig. 309. Teliow Trefoil (Medicago Vu/pulina.) . A, seeds showing the prevail- 
ing forms. B, pods ; the central one with the calyx removed ; the one at 
the left an inmiature, lighter colored specimen. C, a view of a seed in cross 
section, showing cotyledons and caulicle. D, the embryo. E, seeds and 
pods, natural size. 

(After Hillman, Bull. Nev. Agr. Exp. Sta.) 



r 



one end; micropilar processes prominent; the pods clustered at, the 
end of the peduncle small, black, wrinkled, and coiled at tip, marked 
by prominent veins and hairs ; each pod contains one j^eed. ) 



Dalea ( Z>aZea aiopeeiiroi^ies Willd.). 

Seeds triangular to kidney-shaped, one-tenth in. in length ; mi- 
cropilar scar prominent,, with whitish border and 2 micropilar 
processes; surface shining, slate-Colored. Pound in clover seed, 
f rtim which it is separated with difficulty. 



454 



WEED FLORA OF IOWA 






Figure 810A Figure 310B Figure SIOC 

Fig. 310. A, Dalea (.Dalea alopecuroides) . B, seed of Fink Dalea iDalea 

laxiflora). C, seed-pod of the same species. 

(A, drawing by L. R. Collins ; B and C, by C. M. King.) 

Pink Dalea {Dalea laxiflora Pursh.). 

Seeds one-tenth in. in length, generally triangular, somewhat 
kidney-shaped, one end projecting beyond sac, which is circular 
and has two micropilar processes on one side ; yellowish or brownish 
in color ; leaves have pellucid dots. This should enable one to recog- 
nize the impurity. Occasionally found in clover seed. ' 

Stemless Loco Weed (Oxyiropis lamberti Pursh.). 

Pods coriaceous, silky pubescent, cylindrical; seed flattened, 
brown, about 2 mm. broad and 2.5 mm. long. 






Figure SUA 
Fig. 311 



Figure SUB 



Figure 311C 

A, Stemless loco Weed (Oaiytropis lamierW) . B, Bush Clover 
ILespedesa capitata), pod and seed. 
(Drawings A, by Ada Hayden ; B, by Charlotte M. King.) 



Bush Clover (Lespedeza capitatm Michx.). 

Pod ovate-oblong, one-sixth in. in length, sessile, 1-ovuled, pu- 
bescent, brownish, reticulated, indehiscent, seed scarcely kidney- 
shaped, one-tenth in. in length, greenish to purplish. 



THE GENERAL, CHARACTERS OF SEEDS 455 

Common Vetch {Vicia satwa L.). 

Pod linear, several-seeded ; "seeds nearly spherical or compressed 
on the sides, variable, blackish to brownish. 




Pio. 312. Common Vetch (.Ticia sativa). 
_ (After Hillman, Circular U. S. Dept. Agr.) 

Hairy Vetch {Vicia viUosa Roth.). 
Seeds spherical to subspherical ; one-tenth to one-sixth in. in diam- 
eter; bla;6tish or brownish, surface smooth; scar elongated, repre- 






Fig. 313. Hairy Vetch (Ticia villosa'). 
(Hllhnan, U. S. Dept. of Agriculture.) 

sented by a narrow line slightly elevated, with depressed center, 
light in color, brownish to straw-colored. 

Trailing "Wild Bean {Strophostyles helvola (L.) Britton). .■ 

Pod terete, 5-7.5 cm. long, nearly glabrous, 4-8-seeded, dark 
brown; seed eylindrioal, rounded, truncate at both ends; length 
6 mm., width 4.5 mm.; color dull brown slightly mottled; narrow 
white sear along inner angle, nearly the entire length of the seed; 
seed strongly angled longitudinally on side opposite scar. 




Fig. 314. Wild Bean (Strophostyles liejvola). 
(Drawing by L. R. Collins.) 



456^ 



WEED FLORA OF IOWA 



LINAOEAE, PliAX FAMILY. 

, Common Vlax {Lmum u$itatissimum Jj-} . ''. 

Seeds ovate, flattened; one-fifth in. long, one-tenth in. wide, basal 
end curved on one side ; color brown, margins with whitish luster, 





Figure S15A Figure 315B 

Fig. 315. Common Flax (Liniim usitatissimum) . A, seed. B, cross section 

of seed. 
(A, drawing by Ada Hayden; B, after Winton.) 

smooth, shining ; scar on one ' side, near lower end, small, incon- 
spicuous; embryo, large, straight. 



OXALIDACEAE, SORREL FAMILY. 

Lady's Sorrel {Oxalis comiculata L.). 

Pod prismatic, cylindrical, seeds 1 mm. in length; shape and 
markings similar to preceding. 

Oxalis {Oxalis stricta L.). 

Pod angled, awl-shaped ; seeds 1 mm. in length, elliptical, pointed 
at one end; surface marked by broken transverse lines of white; 
seed longitudinally ribbed, slightly flattened. 



THE GENERAL, CHARACTERS OF SEEDS 



457 





Figure 316A 



Figure 316B 



Figure 316B 



Fig. 316. A, Storksbill or Alfllaria (.Erodium cicutarium) ; A, a seed-vessel 
with a portion of its spirally coiled awn. B, a seed-vessel and its awn, 
natural size. (In many the awn is smaller.) C, a seed, magnified. D, a 
line showing the length of the seed. B, the embryo removed from the seed 
coats, the parts spread. 

B. Lady's Sorrel or Yellow Field Sorrel (.Oscalis cornioulata) . 

(A, after Hillman, Bull. Mich. Agr. Exp. Sta. ; B, drawings by C. M. King.) 

GERANIACEAE, GERANIUM FAMILY. 

Storksbill {Erodiwm cicutarium L'Her.). 

Lobes of. capsule l-sepded, with elastic, dehiscent style, coiled at 
maturity, villpus inside ; hairs at base pointing obliquely upwardly ; 
awn coiled for half its length; seed broadly club-shaped, one-fifth 
in. in length without awn ; soar removed one-'thifd length of seed 
from base; groove from scar to tip of seed. 



:.!;o 



EUPHORBIACEAE, SPURGE FAMILY. 



Three-seeded Mercury {Acalypha virginica Ij.).> 

Seeds ovoid; one-twelfth to one^twentieth in. long; reddish, min- 
utely striate, line running from apex to base ; soar at smaller end. 
Pound in clover seed. 





h ^- 



Figure 317A 



Figure 317B 



Fig. 317. A. Three-seeded Mercury (.Acalypha virginica). a and b, different 

views of seed ; c, sectional view showing embryo and endosperm ; d, seed, 

natural size. . ■ ' ' - 

B. Prostrate Spurge or Milk Spurge (EupJiQrbia maculata)., A, Piffierent 

views of seed. B. Seeds, natural size. 

(After Hillman, Bull. Mich. Agr. Exp. Sta.) 



468 



WEED FLORA OF IOWA 



Upright Spurge {Euphorbia preslii Guss.)- 

Seeds lead-colored, obovoid-oblong, with 4 unequal sides ; surface 
pitted and transversely wrinkled ; a narrow dark raphe along one 
edge; length 1-1.3 mm. 




Fig. 318. Seeds of' Spotted Spurge (.Ettphorbia preslii). A and B, different 

views of seed. D. Fruit; B. Seed, natural size. 

(After Hillman, Bull. Mich. Agr. Exp. Sta.) 

Flowering Spurge (Euphorbia corollata L.)- 

Seeds ovoid, one-tenth in. in length, smooth, brownish, a line 
extending from apex to base on one side, with whitish bordered 
depression at base; apical point on larger end; seed coat mucilagin- 
ous. 





Figure 319A 

Fig. 319. 

B. Snow-on-the-Mountaln (Suphorbia niatginat^) 



Figure 319B 
A. Flowering Spur§;e (.Euphorbia coroUata.) 



(Drawing by Ada Hayden.) 

Milk Purslane (Euphorbia maculata L.). 

Seeds ovoid or oblong, obtusely angled, one-twentieth in. in 
length, minutely pitted and transversely wrinkled ; grayish. 

Snow-on-the-mountain (Euphorbia marginata Pursh.). 

Seed ovoid, slightly flatj;ened at apical end, length 4 mm., width 
3 mm. ; color light brown ; surface roughly tuberculate ; one side 
marked by la dark longitudinal line. 



THE GENERAL. CHARACTERS OP SEEDS 459 

MALVACEAE. MALLOW FAMILY. 

Velvet-leaf, Butterprint {AbutUon theophrasti Medic.)- 

Carpels 2-valved, beaked, each usually 2-seeded; seeds somewhat 
triangular, kidney-shaped, one-eighth in. in length, minutely granu- 
lar and pubescent; color blackish gray; funicle extending to notch 
of seed. May occur in small grain. 





c 

Figure 320A Figure 320B 

Fig. 320. A. Indian Mallow or Butterprint {Abntilon theophrasti). a, b, c, 
different views of seed ; d, cross section showing embryo and caulicle ; e, 
seeds, natural size. 

B. Seeds of Bladder Ketmia. a and b, different views, u, naturEH pize, 

(After HUlman, Bull. Mich. Agr. Exp. Sta.) 



Prickly Sida {Sida spinosa L.). 

Seeds oval, one-sixteenth to one-twelfth in. long, one face con- 
vex, the other with a prominent ridge across its length ; scar at 
broad end ; surface dull, smooth ; color brownish. Reported in seed 
of Missouri red clover. 







» 



«■ 



Fig. 321. Prickly Slda ^Sida spinosa). A, different views of seeds. B, a. seed 
in section taken midway between tbe two extremities, showing embryo and 
caulicle. C, seeds, natural size. 

(After Hillman, Bull. Nev. Agr. Exp. Sta.) 



4§0 -" WEED FLORA OB" lOWA : 

Common Mallow {Malva roiundifoUa L.). 

Commonly called cheesed. Carpels arranged about a center, flat, 
bealjless, indehiscent ; each carpel a single seed, kidney- shaped, one-' 
si?;teenth, to on6-twelfth in. /in diameter, flattened, with a prominent 




Fig. 322. Common Mallow (.Malva rotundifoUa) . A, two seeds in side view. 
B, a seed retained by a carpel of the seed-vessel. C, a seed in cross section 
taken midway between the Scar and the opposite edge. D, seeds, showing 
!■ the natural size. 
t • (After Hillman, Bull. Mich. Agr. Exp, Sta.) 

notch at base; seeds brownish or gray, minutely granular; sear 
small, frequently containing spongy tissue; embryo curved; small 
am<5lint of en^ospenp. Reported in alfalfa and red clover seed. 

/ Bladder Ketmia {Hibiscus trionum L.). •"—- 

Qa,psule 5-valved, globose-ovoid, hairy; seeds kidney-sihaped,' one- 
fifteenth in. in length, blackened, roughened by short tubercular 
processes, minutely granular; basal end of seed of much smaller 
diameter; scar brownish; funicle extending to the notch. 

ONAGRACEAE, EVENING PRIMROSE FAMILY. 

-aoo r,:r.'t ?:i:- , : - " ■-, r'^r-. 

*" '.:■"■:: ;- Evening Primrose {Oenothera iiennisli.). 



1 T q : i T r" 



Seeds prismatic, 4 or 5-sided, sometimes curved, variable, one- 
sixteenth in. in length, slightly wing-margined, rugose, brown, scar 
indistinct at- due end, embryo straight. 

■■ UMBELLIFpRAE, PARSLEY FAMILY. 

Water Hemlock {Cicuta maculata L.). 

Fruit ovate to oval, curved or nearly straight, one-eighth in. in 
length, smooth, with longitudinal brown and straw-colored lines; 
apex widened with 2 styles; ribs corky; oil-tubes solitary, in the 
intervals. 



THE GENERAL CHARACTERS OF SEEDS 



461 




Pigure'323A 




Figure 323B 

Fig. 323. A. Kvening Primrose ^Oenothera bfennis). A, different views of 

seed. B, cross section of seed. C, natural size. 

B. Water Hemlock (.Cicuta macalata). 

(After Hillman, Bull. Mich. Agr. Exp. Sta.) 



Wild Parsnip {Pastinaca sativa L.). 

"Seeds", carpels one-quarter in. in length, thin, eireidar or 
oblong; color light or dull yellowish brown; lighter conspicuous 
margin, ribs brownish or reddidi ; apex notched, with a conspicuous 
remnant of the style; oil tubes four, alternating with the ribs; 
inner face concave, with a central longitudinal ridge and one oil- 
tube on each side. 



Wild Carrot {Dauciis carota It.). 

Fruit one-eighth in. long,^^ oblong, flattened dorsally ; carpel with 
5 slender, bristly, primary ribs bearing numerous spines, and 4 
secondary wings; color whitish yellow; oil tubes one under each 
row of spines, and two between the ridges of the inner face ; seeds 
commonly found with spines broken off. In alfalfa and clover 
seeds. 



462 



WEED FLORA OF IOWA 




Figure 324B 

Fia. 324. A and Al. Wild Parsnip (Paatlnaca sativa). B. 'Wild Carrot 
iDaucua carota). A, the outer (at left) and inner (at right) faces of a 
seed (carpel). The spines occupy the margin and two rows along the 
outer face. The slender, hairy ridges alternate with the rows of spines. 
The' Inner face bears two, separated by a slender ridge or line which is not 
hairy. B, an oblique view of the outer face of a seed found with clover 
seed. C and D, views of the inner face of seeds similarly found. E, seeds, 
natural size. 

(A, after Hillman, Bull. Nev. Agr. Exp. Sta. ; Al, drawing by I* R. Collins ; 

B, after Hillman.) 

ASCLEPIADACJEAB, MILKWEED FAMILY. 

Swamp Milkweed (Asclepias incarnata L.). 

Seeds oval, wing-margined, three-tenths in. in length ; surface less 
prominently veined than in A. syriaca; raphe marked by distinct 
ridge; coma attached to smaller end of fine silky hairs. Probably 
never in commercial seed. 



Common Milkweed {Asclepias syriaca). 

Seeds flattened, oval or elliptical, apical end truncate, three- 
tenths in. in length, wing-margined; seed and vnng distinctly 
veined ; the raphe occurs in form of a distinct ridge on inner face of 
seed ; coma a tuft of silky hairs attached to apical end, easily sepa- 
rated from seed. Not apt to be found in commercial seed. 



THE GENERAL CHARACTERS OF SEEDS 



463 




_ J ^ ^ 

Figure 325A Figure 325B Figure 325C Figure 325D 

Fio. 325. A. Swamp Milkweed (.Asclepias incarnata). B. Common Milkweed 
(.Asclepias syriaca). a, b, different views of seed; c, cross section; d, e, 
natural size. C. Butterfly Weed (Asclepias iuherosa). D. Whorled 
Milkweed (Asclepias verticillata') . 
(A, drawing by L. R. Collins; B, after Hillman ; C, D, by C. M. King.) 



Butterfly Weed {Asclepias tuberosa L.). 

Seed ovate or eliptieal, three-tenths in. in length ; surface rough- 
ened by ridges on, both back and inner faces; winged margin, 
lighter brown than middle part of seed ; raphe marked by a distinct 
ridge; coma fine, silky, smooth. 

"Whorled Milkweed {Asclepias verticillata L.) . 

Seeds ovate, one-sixth in. in length, margin distinct, lighter in 
color than the rest of the reddish brown seed ; surface veined, but 
not ridged or roughened; raphe a distinct ridge on inner face; 
coma soft, silky; very smooth. 

CONVOLVULACBAE, CONVOLVULUS FAMILY. 
Common Morning-glory {I pomoea purpurea (L.) Both.). 

Seed dark brown, with one convex ^de opposite to 2 flattened 
faces meeting at an angle, length 5 mm., width 4 mm. at the base 
of the seed; at lower end of the angle between the two flattened 
faces is the scar, also dark brown ; surface dull, finely roughened. 



Small Bindweed {Cowvolvulus arvensis L.). 

Seeds large, oval, one side convex, the other side with a broad 
ridge; one-sixth in. long, a depression at one extremity representing 
the scar; surf ace of seed roughened, dark brown in color; embryo 
large, surrounded by the fleshy endosperm. Found in cereal grains. 



464 



WEED FLORA OF IOWA 





Figure 326A 



c ""^^ d 

Figure 326B 



Figure 8260 



Fig. 326. A. Common Morning-glory (.Ipomoea purpurea). B. Small Bind- 
weed (.Convolvulus arvensis). a, b, different faces of seed, c, cross section, 
d, natural size. C. 'Wild Morning-glory (.Convolvulus sepiwm). a., b, dif- 
ferent faces of seed, c, natural size. 

• (A, drawing by Charlotte M. King ; B and C, after Hillman.) 

Wild Morning-glory {Convolvuhis sepiumh.). 

The outer surface rounded ; inner face with prominent ridge and 
a depression on each side ; seed one-quarter in. long ; smooth, brown- 
ish or blackish, with minute projections over the surface; hilum 
prominent, light brown, in semicircular depression. 

Field Dodder {Cuscuta arvensis Beyrich.). 

Capsule globose, indeliiseent ; seed spherical to kidney-shaped, or 
ovate, occasionally with, prominent angles; one-twenty- fourth to 
one-sixteenth in. long; roughened but not pitted, dull yellowish, 
grayish or light brown; sear at one extremity, frequently elevated 
and prominent ; Mr. Hillman finds field dodder seeds usually lighter 
than those of Chilean dodder; in some samples the Chilean dodder 
seeds are the lighter in color. Appears in clover seed, in many cases 
abundantly. 





Fio. 327. Field Dodder (Cuseuta arvensis). 
(A, after Hillman, Bull. Nev. Agr. Exp. Sta. ; B. drawing by C. M. King.) 



THE GENERAL. CHARACTERS OP SEEDS 



465 



Clover Dodder {G'uscuta epithymvm Murr.). 

Seed spherical or subspherical, one-thirtieth to one-twenty-fourth 
jfi. in diameter ; surface roughened, with appearance of sponginess, 
dull, usually ashy, yellowish to light or dark brown, or purplish; 
embryo coiled, without cotyledons, consisting of slender tapering 




Pig. 32S." ' Clover Dodder (Cuscuta epUJiymum) . A, a, group showing various 
forms and vi^ws of seeds. B and C, seeds having, the scurfy appearance. 
D and E shove the angled, scar-bearing face, B, being one of the light- 
colored, sterile seeds. F, a, torn, dried flower having the seed-vessel intact. 
G, the embryo. H, group of seeds showing the natural siie. 
(After Hlllman, Bull. Nev. Agr. Exp. Sta.) 

body, with cauliele and i*adicle embedded in fleshy endosperm. 
Commonly distributed in seed of clovers and alfalfa. Brown and 
Hillman state that this dodder is almost entirely confined to Euro- 
pean grown seed, since the plant does not generally produce seed 
in this country. 

Chilean Dodder {Cuscuta sp.) 

Seeds spherical to subspherical or oval, inclined to be more angu- 
lar than the preceding,spe,cies, flattened on one side, one-seventeenth 
to one-fifteenth in. in diameter, about the size of large field dodder 
seeds; dull brownish, minutely roughened; scar prominent, at end 
of^ flattened surface, lighter in color than rest of seed. Found in 
both clover and alfalfa seed, from which it is screened with dif- 
ficulty; 




Fig. 329. Chilean Dodder .( CitsoMSo chUensis).. 
CDrdwing, after Burotiard.) 



80 



466 WEED FLORA OF IOWA 

BORAGINACEAB, BORAGE FAMILY. 

Coniinon Hound's Tongue {Cynaglossum offk-maie L,.). 

Ovary dividing into 4 achenes, each 5-7 mm. in length., ovate to 
round, flattened; lower side bearing large ovate sear; surface cov- 
ered with straight, stiff, barbed prickles. 




Fig. 330. Common Hound's Tongue iCynoglossum officinale'), a, b, views of 

different faces of seed ; e, natural size. 

(After Hillman, Bull. Mich. Agr. Exp. Sta.) 

Wild Comfrey {Gynoglosswm boreale Femald.). 

Nutlets convex on the upper face, somewhat triangular, one- 
seventh in. in diameter, bearing short barbed prictles on convex 
surface; color brown. 




Fia. 331. Wild Comfrey (.Cynogloasum boreaie). 
(Drawing by Ada Hayden.) 

Stickseed (Lappula echinata Gilibert). 

Ovary separating into 4 achenes, 2.5 mm. long, slightly flattened 
from ovate, under surface tubereulate, bearing straight ridge from 
point to middle ; on the upper side, the margins bear a double row 
of slender barbed prickles. 

Beggar's Lice {Lappula virginiana (L.) Greene). 

Achenes 3 mm. long, borne in clusters of 4, broadly ovate, flat- 
tened on outer side; the outer surface bearing short stiff barbed 
prickles, the inner side cone shaped, free from hairs, and bearing 
a trmngular scar. 



THE GENERAL CHARACTERS OF SEEDS 



467 




h ^- 




Figure 332B 



Figure 332A 

Fig. 332. A. Stickseed (.Lappula echinata). a, b, views of different faces of 

seed ; c, natural size. 
B Beggar's Lice (Lappula virginiana) . a, b, views of different faces of seed; c, 

natural size. 
(After Hillman, Bull. Mich. Agr. Exp. Sta.) 



Narrow-leaved Pueeoon {Lithospermum angustifolium Michx.). 

Nutlets ovoid, keeled on inner face, one-eigMh in. long; surface 
smooth., shining, pitted; color white to yellowish white; base irre.p- 
ular with projecting margin; bearing base with projecting ridges. 





Fig. 333A 

Fig. 333. A Narrow-leaved Puccoon (.lAthospermum angustifolium). 

B. American Gromwell (IAt}U)Spermuni latifolium). 

(Drawings by L. K. Collins). 



American Gromwell {lAthospermum latifolium Michx.). 

Nutlets ovoid to globose, one-sixth in. in diameter, white, shining ; 
glabrous but prominently pitted ; base oblique. 

Com Gromwell (Lithospermum^ wrvense L.). 

Ovoid nutlets 4 or fewer, convex on back, inner face with distinct 
ridge ; one-sixteenth to one-twelfth in. in length ; color from whitish 
to dark brown, surface glabrous, but wrinkled and pitted; base 
obliquely flattened, bearing the scar. Reported to occur with 
grain seed. 



468 



WEED FLORA OF IOWA 




^ 




Figure 334A 



Figure 334B 



Fig. 334. A, Corn Gromwell (.Lithospermum arvense). A, difterent views of 
nutlets, B, one bearing the flower-receptacle and portion of the stem, C, 
the natural size of the larger nutlets. 

B, Viper's Bugloss {Echmm vulgare). 

(A, after Hillman, Bull. Mich. Agr. Exp. Sta. ; B, dra-«vn by L. R. Collins.) 

Viper's Bugloss {Echmm vulgare L.). 

Nutlets ereet, ovoid, one-eleventh in. in length, back distinctly 
convex ; seed straight or curved ; outer f ac& with distinct ridge ; 
surface rugose ; color white, base flattened. 

VERBENACEAB, VERVAIN FAMILY. 

Large-bracted Vervain {yerbena bracteosa Mx.). 

Nutlets cylindrical, 3-sided, outer face convex, one-tenth in. in 
length, outer face rugose at upper end, lower end marked by lines, 
inner face pitted, scar somewhat elevated, whitish. In seeds of 
clovers and grasses. 





Da b 

; Figure 336A Figure 335B 

Fio. 335. A. Large-bracted Vervain (.Verbena bracteosa). B. Blue Vervain 
(.Verbena hastata). A, the outer face, and B, the inner face of a nutlet; the 
latter shows the whitish, spongy scar at the base. C, a group showing the 
natural size. D, a section of a nutlet, taken lengthwise. 
(A, drawing by C. M. King; B, after Hillman, Bull. Nev. Agr. Exp. Sta.) 



THE GENERAL, CHARACTERS OF SEEDS 



469 



Blue Vervain (Verbena) hastata L.). 

Nutlets 3-sided, with a distinct line of separation, back' convex, 
rugose, inner face 2-sided; one^^fifteenth to one-thirteenth in. long; 
color light brown; sear slightly elevated, whitish, at base of nut- 
let. Often found in seed of clover. 

Hoary Vervain [Verbena striata Vent.). 

Nutlets cylindrical, 3-sided, one-eighth in. in length, outer face 
convex, back with 4 prominent veins, upper portion slightly pitted ; 
color dark brown; whitish scar at base. Seed found in clover. 





Fig. 336. A. Hoary Vervain (.Yeriena strtcto). B. White Vervain iVertena 

urticaefolia). 
(A, drawing by Li. R. Collins; B, after Hillman, Bull. Mich. Agr. Exp. Sta.) 

"White Vervain (Fer&ewa itrftcae/oKa L.). 

Nutlets cylindrical, convex on back, 2-faeed on inner sdde, with 
prominent central line; one_-tenth to one-eighth in,, in, length; back 
somewhat rugose, with 2 or 3 prominent lines extending from base " 
to apex and some cross lines; inner face somewhat grajQular; scar 
a whitish elevated point. Found in seeds of clovers. 

LABIATAE, MINT FAMILY. 
Catnip (Nepeta cataria L.). 

Oval, dark brown seeds, about 1.5 mm. in length, slightly flat- 
teiied, surface smooth ; one face bears a broad central, longitudinal 
ridge, the base of which is marked by two white characteristic 
spots, which are a part of the scar. 

American Germander (Teucrium canadense L.). 

Nutlets obovoid, one-tenth in. in length, outer surface convex ; 
color brown ; surface prominently rugose, reticulated except the scar 
at the lower end. Common in commercial seed. 



470 



• 



WEED FLORA OP IOWA 



• t 




c 




Figure 337A Figure 337B 

Pig. 337. A. Catnip (Nepeia cataria'). A, views of vartous seeds (nutlets), 
tliree showing the scar-marldng. B, one having the nutlet wall partially 
broken away, exposing the seed proper. C, a nutlet in longltudiiial section, 
showing the embryo. D, group showing the natural size. 
B. American Germander (.Teucrium canadenae). 
(A, after Hillman, Bull. Nev. Agr. Exp. Sta. ; B, drawn by L. R. Collins. ) 

Horehiotmd (Marrubium vulgar e L.). 

Seed ovate, one side convex, flattened side divided into 2 faces 
by strong, central ridge ; one-twelfth of an inch in length ; brownish 





Figure 338A 



Figure 338B 



Fio. 338. A. Giant Hyssop (.Agastache scropTmlariaefoUa'). 

B. Common Horehoimd (.MarruMum vulgare) ; a, angled face; !>, convex face; 

c, longitudinal section ; d, transverse section ; e, natural size of seed. 

(A, drawing by L. R. Collins; B, after Hillman, Mich. Agr. ESxp. Sta.) 

or blackish, with straw-colored markings; scar inconspicnous, in a 
slight depression somewhat paler in color than seed. 

SeM-heal {Prwnella vulgaris L.). 

Nutlets ovoid, faces convex, marked by longitudinal grooves; 
one-twelfth of an inch in length; smooth, shining; color brown; 
small bud marked by white sear appendage. Found in red clover. 

Motherwort {Leonurus cardiaca L.). 

Nutlets 3-sided, occasionally flattened, 1.10 in. long, smooth ex- 
cept upper end, which is papillose ; minutely roughened ; straw- 
colored to brownish. Pound in cultivated grass seed. 



THE GENERAL CHARACTERS OF SEEDS 



471 






* 9 





Figure 339A 



a b 

Figure 339B 



I'ls. 339. Ai Self-heal (Prunella vulgaris). A, a group of seeds, enlarged, the 
lower left-hand one with the scar-appendage broken away ; the upper left- 
hand one showing the outer face. B, a group showing the natural size ; C, 
a longitudinal section of a seed, showing the embryo. 

E Motherwort (Leonurus carMaca). a and b, different views of seed, c, seed, 

natural size. 

(After Hillman, A, Bull. Nev. Agr. Bxp. Sta. ; B, Bull. Mich. Agr. Elxp. Sta.) 



SOLANACBAE, NIGHTSHADE FAMILY. 

Horse Nettle (Solanum carolinense L.). 

Berry orange-yellow, 1.6 to 2. cm. in diameter; seeds pale dull 
yellow, much flattened, obovate, 2 to 3 mm. in length ; finely granu- 
lar, or indented over whole surface. 

Black Nightshade {Solamum nigrum, L.). 

Berries black, globular, smooth; seed asymmetri'cally ovate, flat- 
tened, pale yellowish brown, finely granular; diameter about 
1.5 mm. 

Buffalo Bur {Solanum rostratum Dunal.). 

Black berry enclosed in spiny yellow calyx ; seeds nearly circular, 
bearing a dent on one side of the margin; fiattened, pitted on the 
surface; both sides irregularly indented with depressions; color, 
dull dark brown ; seed about 2.& mm. broad. 



Jimson "Weed {Datura stramonium L.). 

Seed one-eighth in. in length, brownish or blackish, kidney-shaped, 
elliptical or nearly spherical, with numerous large depressions and 
smaller pits; hilum with a small depression. 



472 



WEED FLORA OF IOWA 






Figure 3400 



Fro. 340. A. Horse Nettle (Solanum. carolinense) . a, b, c and d, different 
views of seed ; e, fruit. 

B. Black Nightshade (Solanum nigrum"), a, two seeds, side view, enlarged; h, 
group showing the natural size ; c, a section of a seed, parallel with the 
faces, showing the spirally curved embryo imbedded in the endosperm. 

C. Buffalo Bur (Solanum rostratum). a, prickly calyic ; b, seeds with pits; c, 

' seed, natural size; d, cross section of seed with embryo. 

D. Jimson Weed (Datura stramonium), a. and b, seeds from different views; 
between a and b, seeds, natural size ; c, cross section of seed showing 
embryo. 

(After Hillman, A, C, D, Mich. Agr. Exp. Sta. Bull; B, Bull. Nev. Agr. Exp. Sta.) 

SCROPHULARIACBAE, FIGWORT FAMILY. 

Moth MiiUein {Verbasawm blattaria L.). 

Seeds light to dark brown, 0.5 to 1 mm. in length, prismatic, 
6-sided, base truncate, broader than the rounded apex; each side 
face pitted in longitudinal rows. 

Mullein {Veriascum thapsus L.). 

Seeds eoliiiiiiiBr, 4-6-sided, top usually truncate, base nearly so ; 
one-thirtieth in. in length ; faces deeply transversely pitted ; surface 
duU; color brown; scar in middle of flattened base. Reported as 
frequently found in seeds of timothy and similar grasses. 



THE GENERAL CHARACTERS OF SEEDS 



473 






Figure 341A 




r 




' < ' - Pigure 341C 

Pis. 341. A. Moth\ Mullein (Terbascum blattaria) . A, a group of seed's, e»- 
larged, showing different forms, and kinds of surface markings, a, b an* 
c were produced from seeds of V. Hattaria,.a,n& d from T. tftopsu*. B rep- 
resents a group natural size. C, a section taken lengthwise through th« 
center of a seed, showing the embryo and surrounding endosperm. 

B. Commo(i Mullein (.Terbascum thapsus). 

C. Toad Flax (Linaria vulgaris). A, a side view of a seed niuch enlarged, the 
scar within the notch on the upper right-hand margin. B, a group show- 
ing the natural size. C, a section through the center of a seed showing 
the embryo. 

(A, after Hillman, Bull. Mich. Agr. Exp. Sta. ; B, drawing by L. R. Collins ; 

C, after Hillman, Bull. Mich. Agr. Exp. Sta.) 



Toad-flax {Lmaria vulgaris Hill.). 

Seeds flattened, wiiigrma^giiied, orbicular in outline, wing wavy, 
notched at one end; one-twelfth in. in diameter; surface rugose; 
wings one-thirtieth to one-twenty-flfth in. wide; embryo slender, 
curved. Commonly occurs in grass seed and occasionally in clover. 



Speedwell {Veronica peregrinaJj.). 

Seeds oblong to egg-shaped, flattened, one-thirty-second to one- 
thirtieth in. long, slightly curved, the outer face with a central 
ridge; embryo straight, surrounded by the endosperm; raphe on 
the inner face; sca,r projecting. 



474 



WEED FLORA OF IOWA 




Fio. 342. Speedwell iTernonla peregrina). a, b, d, different views of seeds; c, 

seeds, natural size. 
(After Hillman, Mich. Agr. Exp. Sta.) 



PLANTAGINACEAB, PLANTAIN FAMILY. 

Bracted Flantain (Plcmtago aristata Mx.). 

Seeds oval or oblong, back of seed convex with, transverse ring 
across the middle or nearly so, one-twelfth to one-eighth in. long; 
inner face with white marginal ring, in center of inner face. 2 pit- 
like markings each surrounded by whitish area, giving appearance 
of 2 rings, or 2 links of a chain. 





Figure 343A 




Figure 343B 

Fig. 343. Bracted Plantain (Plantago aristata). A, group of seeds. B and C, 

the convex and grooved faces, respectively. 
(A, after Hillraan, Bull. Nev. Agr. E!xp. Sta. ; B and C, drawings by Char- 
lotte M. King.) 



THE GENERAL CHARACTERS OF SEED'S 475 

Ribgrass, BuckhorB {Plantago lanceolata It.). 

Seeds oblong, convex on back, one-twelfth to one-seventh in. in 
length, edges folded inwardly to deep central longitudinal groove 




Fig. 344. Buckhom (.Plantaffo lanceolata). A and B, group of seeds showine 
both the convex and grooved faces. C, a sterile seed. D, a seed In cross 
section. E, seed showing the mucilage. P, the natural size. 
(After Hillman, Bull. Nev. Agr. Exp. Sta.) 



on inner face; brown, smooth, shining; scar at center of groove 
frequently of dark color. 

Dooryard Plantain {Plantago major L.). 

Seeds oblong to trapezoidal in shape, usually 4-sided, some of 
them 3-sided, one-twenty-second to one-sixteenth in. long; brown- 
ish to black ; surface bearing 5 ridges radiating from scar ; scar on 
middle of inner face, often with white markings. 



Eugel's Plantain (PloMtago rugelii Dene.). 

Seeds oblong, rhomboidal, generally trapezoidal with flattened 
edges, one-eighteenth to one-twelfth in. in length ; color brownish to 
black ; surface minutely roughened, ridgelike markings absent ; scar 
circular, whitish. 



476 



WEED FLORA OF l6WA 



:/ cv 




Figure 345A 




^^r j^r 





*«*« . » 



• ^ 



Mgure 345B. 



Fig. 345. A. doirimon' Plantain iPlantdgo inaiov'). a, a^ group of seeds, en- 
larged, showiilg the relative form -arid size, " also the Surface ridges as dark 
lines ; b, a group showing the natural size ; c, a cross section of a seed. 
B. Plantago rugeUi. A, seeds, the upper two showing the scar. B, seed show- 
: Injg t5i§ mucilage. ,; C, a seed-vessel. :D, seeds, natural size; ::■) 

(After Hillman, Bull. Nev. Agr. Exp., Sta.)-^ , ^ 

RUBIACEAE, MADDER FAMILY. 

Cleavers {Galium aparine L.). 

Fruit iridehiscent, spherical, bne-tenth to one-eighth in. in diam- 
eter, roughened with prickles, tuberculate when prickles are rubbed 
off ; color blackish ;' embryo Curved ; endosperm horny ; fruit covered 
with hooked trichomes. 




Fig. 346. Cleavers, or Bedstraw (Oalium aparine). 
(After Wlnton.) 



THE GENERAL CHARACTERS OP SEEDS 477 

COMPOSITAE, COMPOSITE FAMILY. 

/ 
Baldwin's Iron weed {Vernonia baldwini Torr.). 

Achenes practically indistinguishable from those of the follow- 
ing species. 





Pieure 347A Figure 347B 

Fig. 347. Ironweed' seeds. A. Vernonia fasciculata. B. Ternonia baldwini. 
, ■ . Achenes with pappus. 
(Drawings Charlotte M. King.) 

Ironweed {Vernoma fasciculata Mx.). 

. Achenes 3-3.-5 mm. long, land 1 mm. broad; general form slender, 
cylindrical, often slightly curved; strongly 9-10-ribbed, ribs of 
same color as achene, pale brown; tuft of purplish brown pappus 
bristles attached at larger end ; length of pappus hairs 6 mm. 

"White Snakeroot {Eupatonumurticaefolium Reichard). 

Achene long, 5-angled, prominently grooved between the angles 
oue-twelfth to one-tenth inch; generally blackish except at the 
base where it is yellowish ; the scar at base with a small circular 
opening, and whitish border; smoothish (see figure), pappus of fine 
white capillary bristles; the upper part of beak expanded into 
candelabra form> bearing the ."^omewhat fragile pappus. 

Joe-Pye Weed (Eupatorium purpureum L.). 

Achenes smooth, prominently ribbed; 5-angled, truncate; about 
one -eighth of an inch; long; base white; pappus with numerous 
tawijy-colored, capillary bristles. Miss Mary Nichols, who studied 
the achenial hairs of E. villosum, finds that they are short with 
lateral canals. The achenial hairs of- E. purpureum, according 
to Mr'. Fracker, are simple, in E. villosum duplex. 



478 



WEED FLORA OF IOWA 






Figure 348A , Figure S48B Figure, 3480 

Pio. 348. Seeds of Snakeroot (.E'miatorium urticaefolhim') arid Joe-Pyeweed 
(.Eupatorium purpureum). A. Eupatormm purpureum. B. Achenlal hairs 
of same. C. Ev/patorivM, urtioaefoUwm. 
(A and C, drawings by Ada Hay den; B, drawing by S. B. Fracker.) 





Figure 349 1 



Figure 349 2 



Fig. 349. 1. Hairs from aohenium of Eupatorium villosum. 
achenlum of Ev/patorium urticaefoUum. 
(Drawings by S. B. Fracker.) 



2. Surface of 



False Boneset (Kuhnia eupatorioides L.). 

Achenes oblong, columnar, 10-15-ribbed ; blackish or reddish, base 
with prominent disklike area marked by circular, somewhat bulging 
ring; from one-eighth to one-tenth inch in length; pappus of 
fine tawny colored capillary, somewhat brittle, bristles. The achenial 
hairs of Kuhma eupatorioides, according to Miss Mary A. Nichols, 
are mostly simple and short ; a few duplex hairs also occur. 



Blazing-star {Liatris punctata Hook.) . 

Achenes 10-ribbed; slender, tapering to the base; one-quarter 
to one-third inch long; grayish, pubescent, almost pilose; apex 
brownish; scar at base indistinct; pappus or numerous plumose 
bristles. The achenial hairs of Liatris groicilis, according to Miss 
Nichols, are duplex with an indistinct wall arising from the base. 
The hairs of L. punctata, according to Mr. Fracker, are duplex 
and simple. 



THE GBNBRAX. CHARACTERS OF SEEDS 



479 





Figure 350A Figure 350B 

Fie. 350. Seeds (achenes) o£: A. Blazing Star (,Liatris punctata). 
Boneset (Kuhnia eupatorioides) . 
(Drawings by Ada Hayden.) 



B. False 





Figure 351A Figure 351B 

Fig. 351. Aohenial hairs of: A. Euhnia eupatorioides. B. lAatris punctata. 
(Drawings' by Fracker.) 

Broad-leaved Gum-plant. ( Grindelia squarrosa Dunal) . 

Aehenes short, tliickeried, faintly 4-angled, with veins between 
the angles ; curved ; one-twelfth to one-eighth of an inch in length ; 
straw-colored; apex truncate; base with light scar. The related 
Bigelovia nuSata, according to Mr. Ftacker, has duplex hairs. 



Canadian Goldenrod {SoUdago canadensis L.). 

Achenes minute, nearly terete, obovate, many-ribbed; brownish 
or greenish, somewhat pubescent; pappus of numerous fine capillary 
equal bristles. 



4S0 



WEED FLORA' OF IOWA 






Figure 352A 



We. 852* 



Figure 352C 





ng. 352D 

Fig. 352. Seeds (achenes) of: A. Gum Weed (GrindeKa aguarrosa), enlarged 
and natural size. The one at the top shows the wrinkled appearance of the 
corky-thickened angles. B, Canadian Goldenrod (.SoUdago canadensia) . C, 
Stiff Goldenrod (.Solidago rigida). D, late Goldenrod (.SoUdago aerotina). 

(A, after Hillman, Bull. Nev. Agr. Exp. Sta. ; C, drawing by Charlotte M. King; 
B and D, drawings by Ada Hayden). 

Stiff Goldenrod {SoUdago rigida L.). 

Achenes ribbed, somewhat 4-angled, with minute ribs between 
the angles; sear at base small, whitish, one-sixth to one- twelfth jn. 
long, pale straw-colored; pappus of minute capillary bristles of 
nearly equal size, spreading. 

Late Goldenrod {SoUdago serotina Ait.). 

Achenes minute, somewhat teretish, many-ribbed, minutely pu- 
bescent, straw-colored, one-twentieth in. in length; small obovoid 
scar at base, whitish; pappus spreading, of fine white capillary 
bristles. 



THE GENERAL CHARACTERS OF SEEDS 



481 



Willow-leaved Aster {Aster saUdf alius Ait.) . 

Achene slender, pale brown, about 1.5 mm. long and .25 mm. 
broad ; 5 longitudinal ribs at angles of seed ; pappus straw-colored, 
hairs or bristles 6 mm. in length. The aehenial trichomes are long, 
the duplex character very pronounced, according to Mr. Fracker. 




Fig. 353A . Pig. 353B Fig. 3530 Fig. 353D 

Fig. 353. Seeds of Aster, Whiteweed and Horseweed. A, Aster salicifoUus. B, 
Daisy Fleabane or Whiteweed (Erigeron annuus). C, Horseweed iErigeron 
canadensis). D, Whiteweed (Brigeron romosus). 

(A and B, drawings by Charlotte M. King; C and D, after HlUman; C, Bull. 
Nev. Agr. Exp. Sta. ; D, Bull. Mich. Exp. Sta.) 

He found much variation in the trichomes of the genus. The hairs 
of A. drummondii are shorter. The trichomes of A. tradesccmti 
and A- macrophyllus are longer and more slender than in A. drumi- 
mcmdU. The duplex hairs of Aster laevis, A. dblongif alius, A. navae- 
wngliae and A. mvltiflorus are slender. 




Fig-. 354A Fig. 354B Fig. 8540 Pig. 354D Fig. 354E 

Fig. 354. Aohenial hairs of Asters. A. Aster novae-angliae. B. Aster 
salicifoUus. C. Aster tradescanti. D. Aster oVlongifolms. E. Aster 
multiflorus. 

(Drawings by Mary A. Nichols and S. B. Fracker.) 
31 



482 



WEED FLORA OF IOWA 



Daisy Fleabane {Erigeron a/rmuus (D.) Pers.)- 
Achenes pale straw color, smooth, shining, flattened, oboTate; 
length 0.7-0.9 mm.; the apex bears a row of small straw-<jolored 
bristles. 

Horseweed {Erigeron ccmadensis L.). 

Achenes one-twenty-fourth to one-twentieth in. long, white or 
whitish, oblong lance-shaped, much flattened, one side often more 
convex than the other; scar of seed witli small, whitish, raised 




Fig. 355D 

Aster laevis. B. Aster 
macrophyllus. . C. Aster drummondii. T>. Bigelovia nudata. 
(Drawings by Mary A. Nichols and S. B. Fracker.) 



Fig. 355A Fig 355B , Fig. 3550 

Fig. 355. Achenial hairs of Asters and Bigelovia. A. 



border, pubescent; pappus small, of numerous, fragile, capillary 
bristles, usually breaking away. With grass seeds and lawn mix- 
tures. 

Cup Plant {SUphium perfoUatwm L.). 

Achenes large, two-fifths in. in length, dorsally flattened, 2- 
winged, notched at apex, grayish or bronze-colored, margins thin. 

Marsh Elder {Iva xanthifolia Nutt.). 

Achenes obovoid, brown to black, with somewhat flattened longi- 
tudinal faces 1.5 to 2 mm. in length, longitudinally striate with 
fine markings. 

Small Ragweed {Ambrosia wrtendsiaefolia L.). 

Involucre containing a single achene one-twelfth to one-sixth in. 
long, obovoid or globular, tipped by a tapering beak one-quarter 
length of involucre; ridges several (4-10), prominent, with pro- 
jecting tubercles, short, acute ; color grayish or brownish, pubescent ; 



THE GENERAl. CHARACTERS OF SEEDS 



483 











Fig. 356A Fig. 356B 

FiQ. 356. Seeds of Small Ragweed and Cup Plant. A. Single achene of Cup 
Plant (.Silphium perfoUatum). 

B. Achenes, various views of Small Ragweed (.Ambrosia artemisiaefoUa) ; A, 
five specimens having the outer covering, and showing the crown of teeth, 
or spines ; B, one having the covering partially broken away, exposing the 
achene ; C, aohene, the covering persisting only at the base ; D, a sectional 
view of a fruit; E, a group showing the natural size. 

(A, drawing by Ada Hayden; B, after- HlUman, Bull. Nev. Agr. EScp. Sta.) 

involucre reticulated, somewliat brittle, achene with thick, rather 
hard wall ; cotyledons 5, large, thick, fleshy, oily ; eaulicle short. 
In clovers and alfalfa. 

Liance-leaved Ragweed {Ambrosia hidentata Miehx.). 
Involucre top-shaped (turbinate) , closed, yellowish or brownish ; 
length, exclusive of the spine, one-tenth to one-eighth in. ; 1 very 
prominent lobe and .6 or more prominent tubercles; surface of in- 
volucre rough and. hispid, pubescent. 






Fig. 357A Fig. 357B Fig. 3570 

Fig. 357. Seeds of some Ragweeds. A. Ambrosia bidentata. B. Ambrosia 

psilostachya. C. Ambrosia trifida. 
(Drawings, A, Charlotte M. King ; B, Ada Hayden ; C, after Hillman. Bull. 

Mich. Exp. sta.) 



484 



WEED FLORA OF IOWA 



■Western Ragweed {Ambrosia psilostachya DC.)- 

Bur teretish, one-eighth to one-fifth in. long, obovoid, with beak 
less prominent than in preceding species; tubercles when present, 
short ; ridges 4-5 ; color grayish ; pubescent ; involucre pitted, readily 
removed leaving brown achenium, with short beak; cotyledons large, 
fleshy, oily. In clover seed. 

Large Ragweed {Ambrosia trifida L.). 

Achene one-fifth to three-tenths in. in length, one-sixth in. across 
at widest portion near upper end, containing seed one-fifth to three- 
tenths in. long, or in extreme cases nearly one-half in.; width at 
upper end 1.6 in., involucre obovate, narrow below, gradually 
widening toward top, tipped by tapering beak; fruit prominently 




Fig. 358A 




Fig. 358B 

Fig. 358. A. White-leaved Franseria (.Franseria discolor'). B. Franaeria 

Hookeriana. A, bur enlarged ; B, natural size ; C, bur cut lengthwise. 

(A, drawings by Ada Hayden and Cliarlotte M. King; B, after HlUman, Bull. 

Nev. Agr. Exp. Sta.) 

ridged, forming rather long projecting tubercles, 4-10 in number, 
near upper end ; involucre pitted or marked by cross ridges ; color 
grayish or brownish ; pubescent or nearly smooth ; encloses a single 
achene, commonly oalled seed ; outer portions of achene blackish or 
brownish; embryo with large thick cotyledons; seed oily, eaulicle 
thick, short. In uncleaned clover seed. 



THE GENERAL CHARACTERS OF SEEDS 485 

White-leaved Franseria {Franseria discolor Nutt^.) . 

Involucre with burs from a little less than one-quarter in. to 
slightly more in length, with 2 achenes, each in a separate cell, 
oblong, with 2 pointed spines usually incurved at apex land tapering 
base ; several prominent ridges ; 3 or more tubercles, furrowed ; light 
straw color, surface pubescent; achene slightly reticulated. 

Hooker's Franseria {Franseria hookeriana Nutt.). 

Involucre lanceolate or oval, two-fifths in. in length, with a promi- 
nent conical spine and numerous, straight or recurved rigid spines, 
variable in number, as long as the width of the bur ; surface wrin- 
kled; involucre with one elongated achene; color yellowish, slightly 
pubescent. 

Cocklebur {Xamthivrnt, canadense Mill.). 

Involucre containing 2 seeds; three-quarters to one in. or more 
long, each in a separate cell, the lower placed further down in the 
bur than the upper ; bur hard, woody, thick-walled, bearing numer- 
ous hispid recurved spines, the 2 spines at the end thicker, heavier, 
and incurved ; surface of achene blackish in color, thin-walled ; and 
embryo slender with 2 long cotyledons and a thick caulicle; each 
seed cavity connects with a channel, frequently may also show 
styles connecting with this channel; odor of seed strong. 





A B * 

Fig. 359A Fig. 359B 

Fig. 359. Burs of Cockleburs. A. Common Cocklebur (Xanthium canadense), 
with view of entire bur, and of cross section showing the pair of seeds in place. 
B. Spiny Clotbur or Cocklebur (Xanthium spinosum). 

(After Hillman, Bull. Mich. Agr. Exp. Sta.) 

Cocklebur {Xamihiwm spinosum Kearney) . 

Involucre one-third to one-half in. long, cylindraeeous, obtuse, 
armed with short prickles, inconspicuous, 2-beaked, or pointless, 
occasionally a single straight spine; bur oblong or somewhat flat- 
tened ; surface sparingly covered with slender hooked prickles one- 



486 



WEED FLORA. OF IOWA. 



twelfth in. long; color dull; smooth or covered with yellowish 
hairs ; achenes 2 in each bur. 

Cocklebur {Xcmthium strumarmm L.). 

Involucre one in. long; brownish in color; prominently bristly 
spines curved; achenes 2 in each bur; closely resembles- Z*. can- 
adense. 

Rough-Ox-eye (Heliopsis scabra Dunal). 

Achenes thick, obtusely 3-4-angled, with truncate summit; one- 
eighth to one-seventh in. long; margins pubescent; blackish; apex 
somewhat depi-essed; scar at base light or straw-colored; pappus 
none. 









Fig. 860A Fig. 860A1 Fig. 360B Fig. 3600 

Fig. 360. Seeds of Heliopsis and Kudbeckia. A, Al, Ox-eye (.Heliopsis scabra'). 
B. Black-eyed Susan or Nigger-head (.RudhecTcia hirta") ; a, two views of 
achenes, b, achenes, natural size. C. Coneflower (.Budbeckia laciniata). 

(A, C, drawings by L. Collins; Al, Charlotte M. King; B, after HiUman, Bull. 
Mich. Agr. Exp. Sta.) 

Nigger-head {Budbedkia hirta L.). 

Achene purplish black, 1.5-1.8 nun. long,' tapering slightly from 
base to apex ; a distinct ridge at each of the 4 angles of the achene ; 
each side with fine longitudinal strips; no pappus. 

Cone-flower {Rudbeckia laciniata L.). 

Achenes 4-angled, brownish, truncate, one-fifth in. long; min- 
utely roughened; upper end with projecting truncate point; apex 
with an inconspicuous scar. 

Gray-headed Cone-flower (Lepachys pinnata Torr. & Gray). 

Achene short, flattened or angular, one-tenth of an inch long, ,2 
slightly marginal wings, and 2 intermediate ones, or only 1, convex ; 
apex whitish, depressed with slight projecting scar; base with 



THE GENERAL CHARACTERS OF SEEDS 



487 



inconspicuous scar of nearly the same color as the rest of the 
achene. 

Sunflower {Helianthus annuus L.). 

Achenes obovate, oblong, somewhat flattened, one-fifth to one- 
quarter of an inch long; with appressed pubescence (see figure) 
especially at upper end, grayish and mottled with brown ; marked 
by longitudinal lines; more prominent ridge in center; lower end 
of achene notched, containing the sear; the apical scar with a 
slightly elevated circular margin ; cotyledons large and fleshy. The 
achenes, according to Mr. Fracker, are long, slender, and duplex ; 
B. iuberosus has simple and several-celled trichomes but not duplex. 
H. occidentalis has short, thick, duplex hairs. 





Fig. 361A 



Fig. 361B 



Fig. 3610 



Fig. 361D 



Pig. 361. Seeds of Cone-flower and Sunflower. A. Coneflower (.Lepachys pi»- 
nata). B and C. Common Sunflower (Helianthus annuus), D. Meadow 
Sunflower (.Helianthus grosse-serratus) . 

(A, drawing by Ada Hayden ; B and D, drawings by C. M. King ; C, after 
Hillman, Bull. Mich. Exp. Sta.) 

Saw- toothed Sunflower {Helianthus grosse-serratus Martens). 

Achenes oblong, narrowed at base and broad at apex, flattened, 
with 2 edges, and 1 prominent ridge, sometimes 2 on each side; 
one-sixth to one-fifth in. long ; pappus of 2 lanceolate awns ; smooth 
or slightly hairy; brownish or lighter color, mottled with brown; 
the scar at the end is in the form of a small notch; the remnant 
of a corolla tube at the apex; cotyledons fleshy. 

Prairie Sunflower {Heliamthws petiolaris Nutt.). 

Achenes obbvate-oblong, but slightly flattened, villous pubescent, 
(see figure), a prominent longitudinal ridge and several lines on 
each side; grayish, mottled with brown; scar in notch at the lower 
end; sear on upper end circular; cotyledons 2, large and fleshy. 
According to Mr. Fracker, the aeheniial hairs are long and slender 
and duplex. 



48S 



WEED FLORA OF IOWA 





Fig. 362A Pig. 362B 

Fie. 362. Seeds of Sunflowers. A. Prairie Sunflower (.BeUantJms petiolaria). 

B. Wood Sunflower (.HelUmfhua atrumoaus) . 

(Drawings by I* R. Collins.) 

Wild Sunflower {Helianthus strumosus L.)- 

Achenes obovate, flattened, several fine lines and a longitudinal 
ridge on each side, one-sixth to one-fifth in. long, nearly glabrous: 
yellowish or light brown, finely mottled, except near apex and base 
which are lighter in color; lower end marked by small distinct 
soar, occurring in a notch; upper end bearing large circular scar; 
cotyledons 2, large,, fleshy. 




Fig. 363A 






Fig. 363B Fig. 3630 

Fig. 363. Achenial hairs of Sunflower seeds. 



Fig. 363D 



A. Artioholte (.Helianthus tuber- 
osua). B. Prairie Sunflower (.BeUanthua occidentalis) . C. Common Sun- 
flower (.Helianthua annuua). D. Prairie Sunflower (.HeUanthua petiolaria). 
(Drawings by S. B. Fracker.) 



THE GENERAl, CHAEACTERS OF SEEDS 489 

Spanish. Needles {BideTis hipinnata L.). 

Achenes exclusive of awns one-half to three-fifths in. long, linear, 
4-angled, slightly pubescent ; pappus consisting of usually 4 diver- 
gent downwardly barbed awns, lighter in color than the achene; 
base of seed with a lightish ringed border and a small depression. 





'i'^ 



Fig. 364A Fig. 364B 

Fig. 364. A. Seeds of Spanish Needles, Pitchforks, or Bootjacks, a, Spanish 

Needle (Bidens frondosa), b, Bidens Mpinnata,. 

B. Bidens discoidea. 

(Drawings by Charlotte M. King.) 



Small Stick-tight {Bidens discoidea (T. & G.) Britten). 

Achenes small, flat, narrowly acuminate, upwardly strigose; 
pappus of upwardly hispid, rarely downwardly barbed awns. 



Beggar-ticks {Bidens frondosa L.). 

Achenes flattened, oval or obovate, three-tenths to two-fifths 
inch exclusive of the awns; slightly ciliate on the margins (see 
figure) ; awns generally diverging, downwardly barbed ; corolla 
tube, whitish, with small opening in the center; basal portion of 
achene with a prominent depression with a light border. The 
aehenial hairs, according to Miss Mary A. Nichols and Mr. Fracker, 
are duplex. In B. cernua they are simple. The related species 
{B. aristosa) formerly called Coreopsis has duplex hairs, although- 
some hairs are simple. 



490 



WEED FLORA OF IOWA 




JUii 



Pig. 365A 




Pig. 3660 

Fig. 365. Achenial hairs of Beggar-ticks. A. Bidens frondosa. B. Bidens 

cernua. C. Bidens aristosa. 

(Drawings by Mary A. Nichols.) 

Sneezeweed {Helenium autumnaie L.). 

Achenes straw-colored, with several longitudinal ribs, length 1 
mm., breadth 0.3 mm. at apex, toward which the achene widens; 
surface bears scattered appressed hairs; pappus several chaffy 
points on margin of truncate apex. 



Fetid Marigold {Dyssodia papposa (Vent.) Hitchc). 

Achene slender, 4-angled; length 3 mm., width at truncate apex 
.75 mm. ; black, with numerous, scattered, appressed black hairs ; 
pappus a row of chaffy scales, dividing into numerous, rough, 
bristly hairs ; 3 mm. long. According to Mr. Fracker, the achenial 
hairs are simple and duplex, the tip in duplex hairs deeply cleft. 



THE GENERAL, CHARACTERS OF SEEDS 



491 





Fig.SeeA Fig. 366B Kg. 8660 

Fig. 366. Seeds and achenial hairs of Sneezeweed and Fetid Marigold. A. 

Sneezeweed (.Belenmm dutizmnale) . B. Fetid Marigold (.DyssocUa papposa). 

C. Achenial hairs of Fetid Marigold. 
(A and B, drawings by Charlotte M. King; C, from drawing by Mary A. Nichols.) 

Yarrow {Achillea mMefolwrn L,). 

Aehenes one-twelfth to one-tenth in. long, ohlong to obovate, 
somewhat compressed; light on the margin, the remainder some- 
what brownish ; sometimes slightly curved, base with prominent sear 
with slightly raised border ; apex larger with a notch in the center 
and a projecting knob; surface of the achene marked with fine 
lines; pappus absent. 








B A 

Fig. 367A Fig. 367B 

FiQ. 367. Seeds of Yarrow and Mayweed. A, Yarrow (Achillea millefolium) ; a, 
seeds (aehenes) in side view, the two at the left showing the minute, cir- 
cular scar ; b, group showing the natural size. ' ■' 
B. Mayweed (.Antheinis cotuhi) ; .i, a t;roup of pe^rlj: slicving the prevailing 
lorms ; b, a grouii showing the nitural bize. 
(After Hillman, Eul]. Nev. Agr. Exp. Sta.) 

Mayweed {Antliemis cotula L.). 

Aehenes one-twentieth to one-sixteenth in. long', rblnnj: \\\'A\ 
prominent tubercled ribs, or occasionally siroothish curved, tl:i' lia^c 
tipped with smooth nipple-like projections; pappus nbsrnt ; slr;iw- 
colored to light brown; bearing a projection scar; baso with round, 
light-colored scar. Common in clover and grass seecs. 



492 WEED FLORA OF IOWA 

Ox-eye Dai^ {Chrysa/nth&m/um leucanthemum L.). 

Achenes flattened, club-shaped, straight or slightly curved, one- 
twentieth to one-tenth in. long, oblong; angles white, with brown 
interstices ; 5-10-ribbed ; small scar at basal end ; pappus wanting. 







Fig. 368. Seeds of Ox-eye Daisy (Chrysanthemum leucanthem.um,') . A, pre- 
vailing forms of seeds (achenes) ; B, one in cross section ; C, a group 
showing the natural size. 

(After Hillman, Bull. Nev. Agr. Exp. Sta.) 



Wormwood {Artemisia hie^nnis Willd.). 

Achenes brown, smooth, from 3-4 flattened faces, angled between 
longitudinally; length .8 mm., width .3 mm., broader at apex than 
at base. 







^• 




'6 

1i^ 



Fig. 369A Fig. S69B 

Fig. 369. Seeds of Wormwood and Fireweed. A. Wormwood (.ArtemAaia 

Mennis) ; a, achenes, b, natural size. 

B. Fireweed (Erechtites hieracifolia) ; a, achenes, b, natural size. 

(After Hillman, Bull. Nev. Agr. Exp. Sta.) 



Fireweed {Erechtites Meracifolia (L.) Raf.). 

Achene linear-oblong, straight, or curved, prominently striate, 
pubescent, beakless, one-sixth in. in length ; upper end with a white 
ring, within the ring a slight depression ; sear at the lower end with 
whitish ring, and a small depressed opening ; pappus of numerous 
white soft, capillary bristles. 



THE GENERAL CHARACTERS OF SEEDS 493 

Indian Plantain {Cacalia tuber osa Nutt.). 

Achenes oblong, straight, or slightly curved, one-fifth in. in 
length; brown; prominently ribbed, the ribs minutely roughened; 
the apex of the seed with a slightly projecting rim or border to 
which the, pappus is attached; the base with a circular ring; pappus 
with numerous fine, white, capillary bristles. 




Fig. 370A Pig. 370B 

Fig. 370. Seeds of Indian Plantain and Groundsel. A. Indian Plantain (.Cacalia 

twberosa). B. Groundsel (.Senecio vulgaris). 

(Drawings by Charlotte M. King.) 



Groundsel {Senecio vulgaris L.). 

Achenes teretish or those of marginal flowers compressed, narrow, 
cylindrical; 5 or 10-ribbed, pubescent; one-half in. long; upper 
part expanded, extending beyond narrow portion of upper part of 
achene; lower portion with a depression; color reddish; pappus of 
fine, white, capillary bristles. 

Burdock (Arctium lappa L.). 

Achenes 3-5-ridged, upper portion truncate, one-fifth to one- 
fourth in. long, compressed or oblong, nearly straight to slightly 
curved, 3-angled; surface mottled in appearance, due to the small 
serrulate scales with projecting tips of ridges beyond the border; 
scar surrounded by a circular lighter colored area; scar at base 
lighter in color; pappus of numerous short scales. In commercial 
seeds, occasionally. 



494 



WEED FLORA OP IOWA 







^. 



Fio. 371. Seeds of Burdock (.Arotimm, lappa), a, a side view of one of the Inner 
achenes of a bur; b, showing the Inner surface of a curved, outer achene, 
and exhibiting the character of the apex, both enlarged; c, a group show- 
ing natural size. 

(After Hlllman, BuU. Nev. Agr. Exp. Sta.) 

Tall Thistle {Cirsimn altissirmum, Willd.). 

Achenes lanceolate-obovate, tapering toward lower end, and some- 
what narrowed toward the apex, wider in the middle, one-eighth in. 
in length ; width one-twelfth in. ; duU brown or grayish excepting 
light colored ring at upper end; numerous fine ridges; apex con- 
cave, with the remnant of corolla tube projecting from the center; 
color uniform; not marked by light and dark areas as the bull 
thistle. 





Fig. 372. 



v.liat tl 

sli.-ipi'rl 

I'lirvcil 
V. i;li :i 
sued ol' 



Pig. 372A 

Seeds of Thistles. A. Different views of Canada Thistle ICiraium 
arveme). B. BuU Thistle {Ciraium, lanceolatum') . 
(Drawings by Charlotte M. King.) 

Cacada Thistle {Cirsium arvense (L.) Scop.). 

•v.r I.-niM" I Vio, inricv.pil r.t lower pnrl. tapering from some- 
lii Icind U.,-\ oi'c-tv, cirik to ()i:c-fi.'l.;!i i-i. Iniii:: i!ii- i-i;i- 

lop witli a ],rc}ifctw'4 (■(•!:!•.• I |ri)-li-i;. sliriirlit n-- s!i}:litly 
: r;!;ii''c^'(l willi It ngiliulinal (iiiik li"is m- r;:;Tci\vs ; -mi-k 
li'jlit 'olii.'id b(ir''r'r. giving' apicr'r; n; c oT a ring. I'ouihI in 

sin:;!! g!-ai!:3, clovers am'. y;;;£st.'s. 



THE GENERAL CHARACTERS OF SEEDS 



495 



Field Thistle {Cirsiwiu discolor (Muhl.) Spreng.)- 

Achenes obovate, inner edge nearly straight, outer curved, convex ; 
one-seventh to one-sixth in. long, tapering from narrowed base 
to apex, upper p9,rt longitudinally striated, slightly pigmented; 




Fig. 373. Seeds of Thistle. 3. Cirsium alUssimum. I. Cirsium discolor. 5. 

Cirsiwm undulatum. 6. Cirsium ioense. 

(Drawing by Charlotte M. King.) 

grayish, upper part yellowish for one-third length of the achene. 
Found in seed of alfalfa and red clover. 



Iowa Thistle {Cirsium ioense (Pammel) Femald). 

Achenes obovate, lanceolate, one side of seed straight, outer side 
slightly convex, one-fifth to one-fourth in. long, one-twelfth to one- 
sixteenth in. in width, gradually tapering from lower end toward 
upper end, prominently widened just below the apex, marked by 
longitudinal striations and dark areas, upper part yellowish, promi- 
nent rim glossy; apex concave, with the prominent projecting rem- 
nant of flower center. 

Bull Thistle {Cirsiwm lanceolatum (L.) Hill). 

Achene lanceolate, curved, tapering, in many oases somewhat 
angular, one-eighth to one-sixth in. long; brownish, not darkly 
striated, marked with definite grooves, upper part lighter, ringed, 
also showing at center of concave apex; apex with projecting point. 
Found in red clover and in alfalfa seed. 



Wiavy-leaved Thistle {Cirsium undulatum (Nutt.) Spreng.). 

Achene in general outline lanceolate, tapering from base, inner 
edge slightly convex, several prominent ridges, light brown, not 
pigmented; upper part yellowish; apex with prominent rim and 
prominent remnant of corolla tube; achene slightly thicker than 
that of C. discolor. Found in seeds of red clover and alfalfa. 



496 . WEED FLORA OF IOWA 

Chicory {Cichoriwm intyhus li.). 

Achenes oblong, ribbed, 5-iaiigled, spotted, grayish or straw- 
colored, with darker spots, one-twelfth to one-eighth in. in length 
apex with the bale of the pappus scales extending beyond the scar ; 




Fig. 374. Chicory (.CichoHum intyhus). A, B, two views of seeds; C, seeds, 

natural size. 
(After HlUman, Bull. Mich. Agr. Exp. Sta.) 

mdniitely, transversely roughened ; base of seed lighter in color, with 
small depressed scar ; achenes from the inner part of the flower more 
slender and straight than from outer part. Found with various 
commercial seeds. 



Corn-flower {Gentcnrea cycmus L.). 

Achene oblong or obovoid, compressed, one-sixth to one-flfth in. 
long; smooth, shining; with inconspicuous veins or nerves; lower 
part of achene oblique ; ivory-white ; the elliptical or somewhat cir- 
cular scar at base with whitish rimmed border, depressed, made up 
of soft tissue; pappus of several series of scaly bristles; brownish 
in color. The achenial trichomas, according to Mr. Fracker, are 
long and simple. 

Bamaby's Thistle {Centcmrea solstitiaiUs L.). 

Involucre ovoid, 1.5 cm. in diameter, with stout straw-colored 
spines, widely spreading ; achene cream or pale brown after matted ; 
length 2 mm., scar of attachment in a notch above rounded base; 
apex truncate, bearing tubercle in the center. 



THE GENERAL. CHARACTERS OF SEEDS 



497 




Fig. 375A 



Fig. 375B 



Fig. 3750 '■ 



Fig. 375, Seeds of Corn-flower and Knapweed. A. Bamaby's Thistle or 
Knapweed (.Centaurea solstitialis) ; a, achene with pappus, c, pappus re- 
moved, b and d, achenes, natural size. 
B. Corn-flower (.Centaurea cyanus). C. Achenial hairs of Corn-flower. 

(A, after Hillman, Bull. Nev. Agr. Exp. Sta. ; B, after Nobbe; C, drawing by 

S. B. Fraoker.) 



Bristly Ox-tongue (Picris ■ echioides L.). 

Aehene elliptical, narrowed at base, with projection at tip ; one- 
tenth in. in length ; light brownish red ; wrinkled transversely, espe- 
cially toward apical end. Found in seed of alfalfa and clover. 

Oyster Plant, Salsify {Tragopogon porrif alius L.). 

Achenes linear, terete, beaked or long, covered with scalelike 
tubercles, on the ribs, or igerely roughened, light straw-colored or 
darker pappus of numerous plumose bristles ; smialL scar at apex, 
whitish with a depression sear at base with an oval depression. 
Reported as a "weed of alfalfa meadows." 



Meadow Salsify {Tragopogon pratensis L.) . 

Achenes linear, terete, one-half in. or little more long, exclusive 
of beak ; scar at base, whitish, with an oval depression ; beak one- 
third in. long; scar at end of beak whitish, with a depression, 
striate, smooth or slightly roughened, light straw-colored or darker ; 
pappus of numerous soft, brownish, plumose bristles. 
32 



498 



WE3ED FLORA OF IOWA 







Pig.376A rig.376Al Fig. 376B Fig. 376C 

Fig. 376. Seeds of Picria and Tragopogon. A and Al. Bristly Ox-tongue 
(Picris ecMoides). B. Oyster Plant (.Tragopogon porrifolius) ; a, achenes 
enlarged, b, achenes natural size. 

C. Meadow Salsify (.Tragopogon pratensis). 

(A, drawings by L. R. Collins ; B, after Hillman, Bull. Mich. Agr. Exp. Sta. ; 

C, drawing by C. M. King.) 

Dark-seeded Dandelion {Taraxacum erythrospermum Andrz.). 

Achenes one-sixth to one-fifth in. long; lance-shaped, or spindle- 
shaped, 5 longitudinal ridges, upper end with rough tubercles, per- 
sistent long beak about two-fifths in. long, brownish, somewhat 
pointed, prominently ribbed ; pappus of numerous capillary, fragile, 
white bristles ; color reddish ; toothed at apex ; beak and pappus both 
shorter; achenes more prominently tubercled than in T. officinale. 





m 

a * A 

Fig. 377A Fig. 377B 

Fig. 377. Dandelion seeds. A, Red Seeded Dandelion (.Taraxacum erythroa- 
perrmim') ; a, seed enlarged, b and c, seed, natural size, c, with pappus. 
Common Dandelion (Taraxa^cum officinale). A, an enlarged view of one 
of the two similar faces of an achene, in which no attempt Is made to show 
the minute surface-scales which are not evident under the ordinary lens. 
B, a group of seeds, natural size, b, one bearing the beak and pappus. C. 
a group showing common variation in the form of the achenes. 

(After Hillman: A, Bull. Mich. Agr. Exp. Sta.; B, Bull. Nev. Agr. Exp. Sta.) 



B. 



THE GENERAL CHARACTERS OF SEEDS 



499 



Dandelion (Taraxacum officinale Weber). 

Achenes two-fifths in. long including persistent beak, fusiform in 
shape, prominent ribs, and projecting teeth at ribs, especially at 
upper end ; beak four-fifths to one in. in length ; achenes light gray in 
color, otherwise like preceding; pappus capillary, whitish, fragile. 
With grass seeds. 

Field Sow Thistle (Sonchus arvensis L.). 
Achenes dark reddish brown, duU, ends slightly truncate, length 
2.5-3 mm., width 0.8 mm., somewhat flattened, with 4 strong ribs or 
angles, between which lie smaller ridges ; numerous transverse ridges 
on the ribs. 




B A 

Fig. 3780 

Fig. 378. Seeds of Sow Thistles. A. Field or Perennial Sow Thistle (Sonchus 

arvensis) ; B, natural size, showing pappus on one acUenc. 

B. Sonchus oleraceus, different views of achenes. 

C. SoncTviis asper, A and B, different views of acliene?, C, ac!-enes, natural size. 

(After Hillman, Bull. Mich. Agr.- E.Kp. Sta.) 

Spiny Sow Thistle {Sonchus asper Vill.). 

Achenes broadly oblcng or lance-sliaped, similar faces, many- 
fibbed, one-tenth in. long, slightly pubescent, prominent ridges 
minutely roughened; base with a minute sear, brownish; the apex 
with projecting point and iine, capillary, white, bristles. Found 
with grass seeds. 



r,oo 



WEED FLORA OF IOWA 



Sow Thistle {Sonchus oleraceus L.)- 

Achenes light brown, flattened, ribbed, the prominent ribs rough- 
ened ; one-eighth in. long ; pappus of white capillary bristles, much, 
like the preceding. "Apt to occur among grass seeds." 

Wild Lettuce {Lactuca canadensis L.). 

Achene three-twentieths in. in length, straight or curved, sides 
somewhat unequal, transversely wrinkled, blackish brown, beak one- 
twentieth ia. long, shorter than in L. floridana; one faint rib on each 
side of prominent midrib ; decidedly convex on each side of midrib 
to the flattened margin ; sear with whitish ring and small depression ; 
pappus white, capillary. Much like L. floridana, beak: smaller and 
shorter. With commercial seed. 





Fig. 379A Fig. 379B 

Seeds of Lettuce. A. Lactuca canadensis; a, enlarged achene, b, 
natural size. B. Lactuca floridana. 
(A, after Hillman, Bull. Mich. Asr. Exp. Sta. ; B, drawing by Charlotte M. Bang.) 



Pig. 379. 



False Lettuce (Lactuca floridana (L.) G-aertn.). 

Achene brown, transversely wrinkled, three-twentieths to seven- 
fortieths in. in length, straight or slightly curved; beak light 
brown, about one-fifth in. long, generally persistent, convex; ribs 
rather faint, 1 on each side of prominent midrib, strongly convex 
on each side of midrib, margin flattened; pappus white, capillary. 

Prickly Lettuce {Lactuca scariola var. integrata Gren. & Godr.). 

Achenes brownish, margin somewhat lighter, surface roughened, 
one-ninth to one-sixth in. long ; beak one-tenth to one-eighth in. long, 
lance-shaped, straight or slightly curved, upper end tapering 



THE GENERAL, CHARACTERS OF SEEDS 



501 





Fig. 380B 

Pig. 380. Lettuce Seeds. A. Lactuoa scariola; A, side view of an achene, en- 
larged. B, a group of the same, natural size. C, an achene bearing Its 
beak and fragile pappus. 

B. Prickly Lettuce (.Laotuca scariola var. integrata.) 

(A, after Hillman, Bull. Nev. Agr. Exp. Sta. ; B, drawing by L. R. Collins.) 

toward the beak, somewhat flattened, on one side margined, faces 
convex, with 5-7 longitudinal nerves; scar circular, with a small 
depression. 



Rattlesnake Root {Prenanthes alia L.). 

Achene oblong or columnar, truncate, somejvhat flattened, 4-5 
angled, brownish; upper part with a projecting ring to which the 
bristles of pappus are attached ; scar at the base whitish, not prom- 
inent; one-eighth in. in length; pappus tawny. 





Fig. 381A Fig. 381B 

Fig. 381. Seeds of Rattlesnake Weed and False Calais. A. Rattlesnake Weed 

(.Prenanthes alba). B. False Calais (Agoseris cuspidata). 

(Drawings by Charlotte M. King.) 



502 



WEED FLORA OF IOWA 



False Calais {Agoseris cuspidatcn (Pursh.) Steud.). 

Achenes fusiform, slightly contracted at the apex, with 10 
prominent ribs; one-half in. long, or little longer; pappus of soft, 
white, capillary bristles ; scar at base, whitish, with a small opening. 

Orange Hawkweed {Mieracvwm aurantiacum It.). 

Achene oblong, columnar, one-tenth in. long; blackish or dark 
brown, marked with prominent longitudinal ridges, minutely 
roughened; base of achene with small circular raised border, lighter 
than remainder of achene; pa;ppu8 of numerous somewhat brown- 
ish bristles, frequently breaking away near the top of the achene, 
then showing short bristles. 






Kg. 382A 



Fig. 382A1 



Fig. 382B 



Fig. 382. Seeds of Hawkweeds. A and Al, Orange Hawkweed CHieracimn 

aurantiacum). B, Hawkweed (Eieraoiv,m canadense). 

(A, after Hillman, Bull. Mich. Agr. Exp. Sta. ; Al, drawing by L. R. Collins ; 

B, drawing by Charlotte M. King.) 



Hawkweed {Hieracium canadense Mx.). 

Achenes one-tenth to one-eighth in. long, oblong, columnar, 
10-15-ribbed ; blackish or reddish; base with prominent disklike 
area marked by circular ring; apex with somewhat fine tawny- 
colored capillary bristles; below point of attachment is an area 
bulging outward; capillary bristles have tendency to break. 



CHAPTER III. 

MICROSCOPIC STRUCTURE OF 
SOME WEED SEEDS 

By 

L. H. PAMMEL 

and 

CHARLOTTE M. KING 



CHAPTER III. 



GRAMINBAB,* GRASS FAMILY. 
Smooth Crab Grass {Digitaria humifusa Fers.) . 

A cross section of seed shows but slight development of the 
pericarp and testa. The epidermal cells of the former are smaller 
than the underlying rows of cells of the waU of the ovary. The 
testa is reduced to a single layer of cells, longer than broad. The 
aleurone layer is filled with protein grains. The starch cells of 
the endosperm are larger and densely packed with polygonal 
grains. 




Fig. 383. Structure of the grain fruits of some Grasses (.Gramineae) . 
Wild Barley (Hordeum jubatum). II. Timothy (Phleum pratense). III. 
Smooth Crab Grass (.Diffitaria humifusa). IV. Sandbur (.Cenohrua tribu- 
loides). V. Millet (.Setaria italica). VI. Corn (.Zea mays). VII. Barn- 
yard Grass (Echinochloa crusgalli). 

t=testa. al=aleurone. en=endosperm. n=nucellus. 
(Drawings by L. H. Pammel.) 



•The material for this family has been taken from the accounts by Pammel 
and Winton. 



506 WEED FLORA OF IOWA 

Broombom Millet {Paniciim, miUaceum L.). 

The walls of the ovary are siniilar to those of Digitaria hurmfusa 
except that they are wider. The testa is much compressed and 
consists of several layers of small cells. The ceUs of the aleurone 
layer are small, somewhat longer than broad. The cells of the 
starch layer are similar to those of D. humifusa. 

Barnyard Grass (^Echinochloa crusgalU (L.) Beauv.). 

The adherent glumes in this species consist of several rows of 
parenchyma cells, the inner portion, of one row of thick-walled 
sclerotic cells with pore canals. The cells of the pericarp and testa 
are much as in the other species, thin-waUed and compressed. The 
protective features are preserved in the coriaceous glumes. The 
starch and aleurone layers are similar to those of Digitaria 
humifusa. 

Hungarian Grass or Millet {Setaria italica (L.) Beauv.). 

The colorless smooth pericarp is but slightly thickened and con- 
sists of three or four rows of elongated cells. These in colored 
seeds contain the pigment. The testa is but slightly developed. 
The cells of the aleurone layer are not much longer than broad, 
and are densely filled with protein grains. 

Green Foxtail (Setaria viridis (L.) Beauv.). 

Dr. A. L. Winton describes the microscopic structure as foUows: 
Empty Glumes and Glume of Sterile Flower.. The lower empty 
glume is three-nerved and le^ than 1 mm. long; the upper empty 
glume and the glume of the staminate flower are five-nerved and 
2 mm. long. In microscopic structure the three are practically 
identical. 1. Outer Epidermis. Characteristic of this layer are 
the elongated cells with sinuous side walls and longitudinal rows 
of pits so arranged that one pit occurs in each concave bend of 
the wall. On the middle portion of the mature glume each of 
these pits is so large that it fills completely the bend of the wall, 
and in addition has a thickened border, half of which coincides with 
the cell wall, thus giving the tissue a lacelike appearance. This 
structure is optically delusive, the pit borders often appearing to 
be the cell walls, but is resolved by careful focusing and comparison 
with the tissue in earlier stages of growth. In addition to these 



MICROSCOPIC STRUCTURE OF WEED SEEDS 



507 




FiQ. 384. Green Foxtail (Setarip, viridis). I, spikelet with ripe fruit, g', lower 

empty glume; g^, upper empty glume; gP-, glume, and pS, palet of- the 

staminate flower ; gf^ glume, and p', palet of fertile flower ; c, caryopsis ; h, 

bristles. II and III. caryopsis enclosed by flowering glume and palet. X 8. 

(After Winton, Conn. Agr. Exp. Sta.) 

elongated cells, pairs- of sliiDrt cells, one isodiametric, probably a 
hair-sear, the other more or less' crescent-shaped, occur here and 
there, and less frequently stomata and thin-walled one to three- 
jointed hairs. 2. Mesophgl. Only about the nerves and the basal 





Pig. 385A Pig. 385B 

Fig. 385. Green Foxtail. A; Outer epidermis of the staminate flower; I, at 

the edge ; II, in the middle. X 300. 
B. Outer epidermis of the glume of the fertile flower, showing the wrinkled 

central portion and the smooth edge. 

(After Winton, Conn. Agr. Exp. Sta.) 



508 WEED FLORA OF IOWA 

portions of the glumes is this coat evident. It has no diagnostic 
importance. 3. The Inner Epidermis is composed of elongated cells 
with straight walls. 

Palet of Stammate Flower. Within the glume of the staminate 
flower is the palet, a hyaliae scale only 1 mm. or less long with 
a notch at the end. In general structure, it is much the same 
as the other thin envelopes, but the cell walls are thinner. 
1. Outer Epidermis. The narrow, elongated ceUa are wavy in out- 
line, but pits are lacking or are indistinct. Isodiametric cells are 
thin-walled ; jointed hairs also occur. 2. Inner Epidermis. Except 
at the base, where traces of mesophyl are sometimes evident, the 
inner epidermis immediately underlies the outer epidermis. 

Glumes <md Palet of Perfect Flower. Both the glume and the 
palet of the fertile flower closely envelop the grain at maturity, 
the former being strongly convex, the latter flat except on the 
edges, which clasp about the caryopsis. At the time of flowering 
these envelopes are thin and of a green color, but at maturity they 
are coriaceous, silicified and of a brown or mottled color. Under 
the lens, numerous transverse wrinkles are evident on the glume 
and on the middle or flat portion of the palet, the lateral portions 
of the latter which clasp the caryopsis being smooth and shining. 

1. Outer Epidermis. Throughout the glume and on the middle 
portion of the palet, the cells are isodiametric or moderately elon- 
gated and are arranged not only in longitudinal rows but also in 
irregular transverse rows, the wrinkles being formed by the out- 
bending of the cells at the end walls and the inward bending 
half way between. At the time of flowering, it may be seen that 
at the outer surface the end walls are sinuous and the side walls 
are compoundly sinuous, but farther inward the end walls are 
nearly straight and the side walls are simply, not compoundly 
sinuous. At the end of each cell nearest the apex of the envelope, 
a cuticular wart bearing a group of pits is usually evident, par- 
ticularly on the palet. About these warts the adjoining end walls 
are more or less curved and the side walls are not so deeply sinuous. 
At maturity the cell cavity beneath the wart is conspicuous (on 
the palet nearly circular), but at the other end of the cell is nar- 
row or not evident at all owing to the encroachment of the strongly 
thickened walls. The cell contents during the early stages of devel- 
opment are colorless, but later on usually become dark brown. The 
epidermal cells on the lateral or smooth portions of the palet which 



MICROSCOPIC STRUCTURE OF WEED SEEDS 



509 




Fig. 386. Green Foxtail. Outer epidermis from the middle of the glume of the 
fertile flower. I, outer surface, and II, inner surface soon after blooming. 
Ill, outer surface when in fruit. X 300. 

(After "Wlnton, Conn. Agr. Exp. Sta.) 



clasp about the caryopsis are longer, narrower, and less complex 
than those already described. At maturity the wrinkles are usually 
from 0.03 to 0.06 nun. apart. 2. The Eypodermal Fibers may be 
readily isolated by treatment on the slide with caustic alkali. They 
vary in length up to 0.6 mm. and are often toothed at margin. 
3. Mesophyl. Rectangular parenchyma cells without intercellular 
spaces make up this layer. Numerous chlorophyl granules are 
present at the time of flowering. 4. The Inner Epidermis is com- 



510 WEED FLORA OF IOWA 

posed of rectangnlar cells resembling those of the mesophyl. Both 
of these layers become more or less obliterated at maturity and are 
of no diagnostic importance. 

Pericarp. The ventral side is flat and has a darker colored spot, 
the remains of the hUum, near the base. Extending half way from 
the base to the apex on the dorsal side is a groove, which marks 
the position of the embryo. Vogl describes minutely the histology 
of the caryopsis of common millet {Panicum miliaceum L.) and 




Fio. 387. Green Foxtail. Outer epidermis from the edge of the glume of the 

fertile flower. X 300. 

(After Winton, Comi. Agr. Exp. Sta.) 

states that German millet {Setaria panis Jessen) has practically 
the same structure. I find that his description applies also to the 
caryopsis of both green and yeUow foxtail. 1. Epidermis. As in 
the outer epidermal layers of the floral envelopes the cells axe 
elongated and wavy in outline. On the dark colored spot already 
referred to, the epidermal cells are more or less rectangular. 

2. The Cross-Cells are similar to the tube-ceUs in form but are 
usually shorter, broader, and more irregular in shape. 3. Tube- 
Cells. These are 0.002 to 0.004 mm. wide and often reach the 
length of 0.3 mm. a. Nucellar or Hyaline Layer. After treatment 
with alkali, this layer is clearly seen in surface view. The cells 
are of large size and have beaded walls, h. Endosperm. 1. Aleurone 
Layer. The cells vary in diameter from 0.01 to 0.02 mm. 



MICROSCOPIC STRUCTURE OF WEED SEEDS 



511 



2. Starch-Cells. Polygonal starch granules with conspicuous hilums 
fill the parenchyma cells of the endosperm. In the outer layers 
they are from 0.004 to 0.008 mm. in diameter but farther inward 
they reach the maximum diameter of 0.018 mm. After dissolving 
the starch with potash, there remains a network of threads con- 
taining conspicuous granules. In this respect, however, this fruit 
cannot be distinguished from the fruits of S. glauca Beauv., 
S. panis Jessen, Panicum mUiaceum L. (see Vogl) and all the 
other species of Panicum which I have examined. Detection in 
Powder Form. The membranous glumes with pores in the bends of 




FiQ. 388. Green Foxtail. Transverse section of caryopsis. F, pericarp con- 
sisting of the epidermis ep and the tube-cells sch ; N, nucellar layer ; B, 
endosperm consisting of the aleurone-cells al and the starch cells s. X 300. 
(After Winton, Conn. Agr. Exp. Sta.) 

the walls and the coriaceous, transversely wrinkled, more or less 
spotted, envelopes of the fertile flower with compoundly sinuous, 
thickened cell walls are highly characteristic of both green and 
yellow foxtail. These tissues are usually present in all stages of 
development. The fruit elements are like those of common millet 
and German millet. Treatment with caustic alkali brings out the 
structure of the fruit coats and nucellar layer, and serves to dis- 
tinguish this fruit from the common cereals. The starch is hardly 
distinguishable from the starch of bindweed. 

Dr. A. L. Winton describes the microscopic character of yellow 
foxtail (Setaria glauca Beaxiv.) as follows: 

The fruit of this species is larger than that of green foxtail, the 
envelopes are also proportionately larger (with the exception of 
the upper empty glume which is but half the length of the 



512 



WEED FLORA OF IOWA 



spikelet) and the wrinkles on the glume of the fertile flower are 
more pronounced. In microscopic structure the fruits of the two 
species are identical. The floral envelopes are also much alike, 
the only distinction being in the distance apart of the wrinkles on 
the mature flowering glumes. In green foxtail this distance is 
usually from 0.03 to 0.06 mm., but in yellow foxtail it is often 
from 0.08 to 0.12 mm. Since this distinction does not apply to 
the mature glumes and since the wrinkles on the palets of the two 
species are practically the same, it is often difficult to identify the 
species in ground mixtures. Fortunately, identification of the 
genus is all that is usually required. 

sch -N 




Fig. 389. Green Foxtail. Caryopsis in surface view. Significance of letters 

same as in Fig. 388. 
(After Winton, Conn. Agr. Exp. Sta.) 



Broom Corn {Andropogon sorghum var. technicus Koern). 

Dr. A. L. Winton describes the microscopic structure of the 
pericarp and testa of broom com as follows: 

Empty Glumes. — Both glumes are from 4 to 6 mm. long, equal- 
ing and closely enveloping the fruit. They vary in color from 
yeUow-brown to red-brown. The soft hairs, which nearly cover 
the outer surface, are loosely attached and most of them are re- 
moved during the threshing and cleaning of the seed, leaving the 
glumes smooth and shining. 1. The Outer Epidermis consists of 
strongly selerenchymatized cells several times as long as they are 
broad, with wavy contour, interspersed here and there with iso- 
diametrie hair-scars, each accompanied by a crescent-shaped ceU 



MICROSCOPIC STRUCTURE OF WEED SEEDS 
c 



513 




Fig. 390. Broom-corn. Fruit with chaff, i-, two staminate apikelets ; gS lower 
empty glurae ; g'^, upper empty glume ; g*, glume of rudimentary flower ; gf , 
flowering glume with awn ; p, palet ; c, caryopsis. X 4. 
(After Wlnton, Conn. Agr. Exp. Sta.) 

with granular contents. The hairs, which are almost invariably 
detached in preparing the mount, if not in cleaning the seed, are 
often 1.0 mm. long and 0.012 mm. broad in the middle but taper 
toward both ends. Invariably the lumen is much broader than 
the walls. 2. The Hypoderm Fibers, of which there are several 
layers, have thick walls and narrow cavities. They vary in length 




Fig. 391. Broom-oorn. Transverse section of caryopsis and an empty glume. 
Sp, empty glume, consisting of the outer epidermis aep, the fiber layer f, 
the spongy parenchyma p, and the Inner epidermis iep ; g, bundle ; sto, 
stoma; Fs, pericarp, consisting of the epidermis ep with the cuticle o, the 
hypoderm hy, the starchy mesocarp mes, the cross-cells q, and the tube-cells 
sch ; N, nucellar or hyaline layer with swollen inner walls s ; E, endosperm, 
consisting of the aleurone layer al and the starch-cells with starch 
granules st and proteid network a. X 160. 

(After Winton, Conn. Agr. Exp. Sta.) 

33 



514 



WEED FLORA OF IOWA 



up to 0.5 mm. or more. 3. Spongy Parenchyma. As seen in sur- 
face view, the cells of this layer are more or less rectangular with 
circular intercellular spaces and resemble those of rice and barley 
glumes. 4. Inner Epidermis. In cross section this layer is not 
readily studied since the radial walls are usually collapsed; but 
in surface preparations, the large elongated cells, often 0.15 mm. 
long and 0.05 mm. wide, interspersed with stomata and hairs, are 
clearly displayed. 

TMn, Glume. — ^Within the lower or first glume and nearly equal- 
ing it in length, is the third or thin glume, the remnant of an 
abortive flower. This glume is exceedingly thin and membranous 
and bears numerous hairs, particularly in the margin. 1. Outer 
Epidermis. In general form the eeUs are similar to those of the 
outer epidermis of the thick glumes, but are narrower and much 
thinner-wialled. The marginal hairs are long (often 0.5 mm.) 
single-celled and pointed; but on the surface shorter hairs, with 
two or three joints and blunt ends, also occur. Both of these 




Pig. 392A Fig. 392B 

Fig. 392. Broom-corn. A. aep, outer epidermis and f, fiber of an empty glume 

In surface view. X 300. 

B. p, spongy parenchyma and lep, Inner epidermis of an empty glume in surface 

view; sto, stoma; h, hair. X 300. 

(After Winton, Conn. Agr. Exp. Sta.) 



MICROSCOPIC STRUCTURE OF WEED SEEDS 515 

forms have exceedingly thin walls. 2. The Inner Epidermis is dis- 
tinguished from the outer by the straight walls and almost entire 
absence of hairs. 

Flowering Glume. — The fourth or flowering glume, situated be- 
tween the upper or second glume and the grain, is also mem- 
branous and bears lan upwardly barbed awn 5 to 7 mm. long. This 
awn, with the larger part of the flowering glume, being readily de- 
tached by threshing, it is seldom found in the grain on the market. 




Fig. 393. Broom-corn. Glume of rudimentary flower in surface view, aep, 
outer epidermis with h, one-celled hair and h, two-celled hair ; lep. Inner 
epidermis. X 300. 

(After Winton, Conn. Agr. Exp. gta.) 

Palet. — This is membranous and hairy like the third or thin 
glume, but is much smaller. 

Pericarp. — The grain or caryopsis is about 5 mm. long and from 
2 to 3 mm. wide, tapering to a blunt point at both ends. It varies 
in color from yellow-brown to red-brown. 

Harz, Hassack and particularly Mittlaeher have described so 
fully the histological elements of the caryopsis, that only a brief 
description, essential for a clear understanding, need here be given. 
1. Epidermis. The cells are longitudinally extended and have 
thick wavy side walls, with more or less distinct pores. Hassack 
has noted that the cuticle is of uneven thickness, due to minute 
granules or crystals, which may be seen in either section or sur- 



516 



WEED FLORA OF IOWA 
q sen, 



hy. mes 




N 






si^ 



FiQ. 394. Broom-corn. Layers of the pericarp in surface view, 
of letters same as in Fig. 391. X 160. 
(After Wlnton, Conn. Agr. Exp. Sta.) 



Significance 



face view. 2. The Hypodermi consists of from one to three layers 
of cells, with walls somewhat thinner than those of the epidermis. 
3. Starchy Mesocarp. Several layers of thin-waUed parenchyma 
cells, filled usually with small round or rounded polygonal starch 
granules seldom over 0.006 mm. in diameter, make up this coat. 
In all the varieties here described the starch appears during the 
early stages of growth and persists until the fruit nearly or quite 
reaches full maturity. As the caryopsis, even when nearly mature, 
is intensely green owing to chlorophyll grains in the outermost 
layers of the mesocarp, it may be inferred that this starch is a 
direct product of photosynthesis in the pericarp. So far as I have 
observed, the presence or absence of a starchy mesocarp in the 
grain at the time of harvest is not a definite varietal peculiarity, 
but is dependent on the ripeness of the fruit or other conditions. 
Some kernels of the same variety may possess it, while others show 
only empty, obliterated cells. Whether or not the starch is present 
in a given seed may often be determined by careful scraping and 
observation with the naked eye. 4. Cross-Cells. These cells are 
usually long and narrow, being distinguished from the tube-cells 
only by their transverse arrangement. Near the extremities of 
the seed they are, however, shorter and of more irregular shape. 
5. Tuie-Cells (sch). The cells of this layer lie at right angles to the 
cross-cells. They are about 0.005 mm. wide and often reach a 
length of 0.20 mm. a. Nucellar or Hyalme Layer. This layer is 
frequently 0.05 mm. thick. The outer radial walls are thiu, but 
the inner wall is greatly swollen. In surface view the large ceUs 



MICROSCOPIC STRUCTURE OF WEED SEEDS 517 

are conspicuous, not only because of their size, but because of their 
yellow or brown color, b. Endosperm. 1. Aleurone Layer (al). 
The individual cells of this layer are characterized by their 
great variation in size (0.01 to 0.04 mm. in diameter) and form. 
2. Starch^Gells (st). In the outer layers the starch granules, if 
present, are much smaller than in the interior of the seed, where 
they sometimes reach a diameter of 0.03 mm. They are usually 
sharply polygonal, with a distinct hilum land radiating fissures. 
The starch is surrounded by small protein granules, forming a 
network which is especially evident after removing the starch by 
reagents. In some specimens, one or more of the outer cell layers 
are filled with these protein granules to the complete exclusion of 
the starch. 

Sandbur {Cenchrus tribuloides L.). 

The pericarp is divided into two portions. The cells of the 
outer portion are thick-walled and short; of the inner portion, 
elongated, thick-walled and fusiform. The testa consists of one to 
two rows of thin-walled cells, much compressed. The aleurone 
cells are much larger than in Paniciom and Setaria, thick-walled, 
densely filled with protein grains. Walls of the starch cells thick- 
ened; starch grains larger and loosely arranged. 

Timothy (Phleum pratense L.). 

The testa and pericarp are dark colored! The epidermal cells 
are thin-walled, elongated, sometimes slightly irregular. The 
testa consists of several rows of thick-walled dark brown cells 
much longer than broad. The aleurone layer consists of a single 
row of cells relatively thin-walled, somewhat variable in size, 
solidly packed with aleurone grains. The nucellus is very evident 
as a remnant in some places. The cells of this layer are thick- 
walled, clear and colorless. The starch cells are much larger than 
the aleurone, and contain angular starch grains. 

Cheat or Chess {Bromus secdlinus L.). 

Dr. A. L. "Winton describes the microscopic structure as follows : 
Flowering Glume. — The structure throughout is much the same 
as in darnel, but the cells of the outer epidermis are much more 
conspicuously thick-walled, and the wavy-walled cells throughout 
much longer than broad. The circular cells also have wavy walls. 
The cells on the margins, interspersed with lance-shaped hairs, are 
the same as in darnel. 



518 



WEED FLORA OF IOWA 




Fig. 395. Chess (Bromus secalinus). Outer epidermis of flowering glume in 

surface view. X 160. 

(After Winton, Conn. Agr. Exp. Sta.) 

Palet. — The flowering glume and palet of chess are very similar 
in structure, but the outer epidermis of the latter is barbed on the 
keel, the stiff hairs often reaching 45/* in length. 

Pericarp (F). — The pericarp consists of two layers with rudi- 
ments of another layer in parts. 1. The Epidermal Cells (ep) are 
large, elongated-polygonal, and have thin, non-porous walls. 
2. Mesocarp. As a rule, the cross-cells immediately underlie the 




at— 



Fig. 396. Chess. Transverse section of fruit. F, pericarp consisting of 
epidermis ep, and cross-cells q ; S, testa ; N, perlsperm ; B, endosperm con- 
sisting of aleurone layer al, and starch-parenchyma st. X 160. 
(After Winton, Conn. Agr. Exp. Sta.) 

epidermis, but occasionally traces of the mesocarp are evident. 
3. Cross-Cells (q). Whether this layer corresponds with the cross- 
cells of the tube-cells of other grasses, I have been unable to decide. 



MICROSCOPIC STRUCTURE OP WEED SEEDS 



519 



The tissue is made up of irregular spongy-parenchyma cells, 
usually transversely elongated with large, round or elongated inter- 
cellular spaces. 

The Testa (S). — Consists of one layer of elongated brown cells 
10-20A wide. 

Perisperm (N). — This layer is enormously developed. As may be 
seen in cross section, the cells are 40^ thick, but the walls are so 
swollen as to almost entirely obliterate the oavity. After soaking 
for some time in 1 per cent soda solution they are evident in sur- 
face view. 

Endosperm. — 1. The Aleurone Layer (al) is not of especial in- 
terest. 2. The Starch-Parenchyma (st) is remarkable for the thick- 
ness of the cell walls (often 10/* thick) and the elliptical starch 
grains 3-20/* in diameter. With proper illumination each grain 
may be seen to have an elliptical hilum. 
ep 




Fig. 397. Chess. 



Elements of fruit in surface view. Significance of letters same 
as in Fig. 396. 
(After "Winton, Conn. Agr. Exp. Sta.) 



Wild Barley or Squirrel-tail Grass {Hordeum juhatum L.). 

The grain is adherent to the palet. The epidermis consists of 
thick-walled, tangentially elongated cells, most of which are longer 
than broad. In part the cells are developed into short conical 
trichomes. The underlying cells are thick-walled with prominent 
pore canals. The remainder of the adhering palet consists of thin- 
walled cells much larger than broad. The pericarp as well as the 



520 



WEED FLORA OF IOWA 



testa is but slightly developed. In some cases the underlying 
parenchyma cells are not clearly defined. The blackish pigment is 
found in the internal part of the palet; some also occurs in peri- 
carps and the aleurone layer. The pericarp consists of one or 
two rows of rather thin-walled, tangentially elongated cells. The 
testa is reduced to a single layer of cells longer than broad. The 
nucellus is nearly absent except in the groove. It consists of a 
single row of thin-walled, colorless, compressed cells. In the groove 
several rows of cells occur. The aleurone in the specimens studied 
is made up of a single row of cells. The cells of the starch layer 
are larger than those of the aleurone. 

Darnel (LoUum temulenhim L.). 

Dr. A. L. Winton describes its microscopic structure as follows : 
The Flowering Glume is 6-8 mm. long, equaling or exceeding 
the caryopsis. It is obscurely five-nerved, lobed at the end, and 
bears an upwardly barbed awn often 15 mm. long. Like the glumes 
of barley, oats, and other cereals, it consists of four coats, some of 
which, however, are lacking on the margins and at the end. 1. The 
Outer Epidermis differs greatly in structure in different parts of 
the glume. At the margins (as is clearly shown in Fig. 1 by 
Moeller*), it consists of straight-walled, elongated cells inter- 
spersed here and there with short lance-shaped hairs. On the 
greater part of the surface, however, the cells, as in barley and 
some other cereals, are of three kinds : first, cells of wavy outline. 




FiQ. 398. Darnel (.Lolium temulentum) . Margin of flowering glume showing 

lance-sbaped hairs. X 300. 

(After Winton, Conn. Agr. Exp. Sta.) 



Microscopic structure op weed seeds 521 

into which the straig'ht-walled cells at the margin pass; second, 
circular cells corresponding to the conical hair-cell of barley ; third, 
exceedingly short, more or less crescent-shaped cells. Near the 
margins and on the veins, where they alternate with stomata, the 
cells of wavy outline are elongated; but in other parts they are 
very short, often being broader than long. Although thick-walled, 
the walls are transparent, whereas the middle lamella is con- 
spicuous, giving the impression of thin-walled cells. Pores are few 
and inconspicuous. Near the margin the circular cells are small 
and are usually accompanied by creseent-shaped cells which often 
exceed them in size. On the greater part of the glume, however, 
the circular cells are much larger, often being 70^ in diameter. 
Numerous pores are conspicuous, both in the radial and tangential 
waUs. Often one, sometimes two, crescent-shaped cells accompany 
a circular cell. Characteristic of this coat are the short, wavy 




Fig. 399. Darnel. Middle portion of flowering glume. X 160. 
(After Winton, Conn. Agr. Exp. Sta.) 

celjs and the numerous circular cells, the latter frequently exceed- 
ing in area the former. 2. Hypoderm. The fibers in this layer 
are much the same as in cereals. Fibers of similar structure also 
make up the ground-tissue of the aAvn. 3. Spongy -Parenchyma. 
The elements are more or less rectangular in shape, like those of 
the corresponding layer of barley, and are readily distinguished 
from the star-shaped elements of oats. 4. Inner Epidermis. This 
layer is made up of thin-walled cells and stomata, and is of no 
diagnostic importance. 



522 



WEED FLORA OF IOWA 



Palet. — The two-keeled palet is about the same size as the flower- 
ing glume, but is of a thinner texture, owing to the absence of a 
well developed hypoderm layer. The Outer Epidermis is much the 
same as that of the flowering glume, except that it is barbed on 
the keels with rigid thomlike hairs 150/* or less ia length, as is 
shown in Fig. 3 by Moeller. 




Fio. 400. Darnel. Keel of palet showing outer epidermis with hair h, and 

hypoderm fibers f. X 160. 

(After Winton, Conn. Agr. Exp. Sta.) 



The Pericarp (P). — Consists of four coats, of which only two, the 
epidermis and cross-cells, are fully developed. 1. Epidermis (ep). 
Cross sections of the mature seed show that this layer consists of 
collapsed, moderately thick-walled cells, which are best studied 
after heating with potash. Seen in surface view, the cells at the 
apex of the seed are nearly isodiametric, but at other parts are 
elongated. The walls are indistinctly beaded. 2. The Mesocwrp (m) 
is not developed on all parts of the seed, but is conspicuous on the 
angles. The cells vary greatly in shape and size, some being ir- 
regularly isodiametric, others transversely elongated, resembling the 
cells of the next layer. 3. Cross-Cells (q). Especially striking are 
the cells of this layer, which resemble the cross-ceUs of barley. As 
has been noted by Moeller, the radial walls appear indistinctly 
beaded, but this is evident only under favorable conditions. 
4. Tube-Cells, spongy-parenchyma, and various intermediate forms, 
make up the interrupted inner layer of the pericarp. 

Testa (S). — The cells are for the most part elongated and are 
often diagonally arranged with reference to the axis of the fruit. In 



MICROSCOPIC STRUCTURE OF WEED SEEDS 



523 




Pia. 401. Darnel. Transverse section of fruit. F, pericarp consisting of 
epidermis ep, mesocarp m, cross-cells q, and tube-cells sch ; S, testa con- 
sisting of outer layer a. and inner layer 1 ; N, perisperm ; f, fungus layer ; 
E, endosperm consisting of aleurone layer al, and starch-parenchyma st. 
X 160. 

(After Winton, Conn. Agr. Exp. Sta.) 

transverse sections this coat often separates from tte pericarp on 
the one hand and the perisperm on the other. Examined in water, 
only one cell layer (the inner) is evident; but successive treat- 
ments with 5 per cent potash, dilute acetic acid and chlorzinc 
iodine, bring out two layers. 1. The Outer Layer (a) is made up 
of thin-walled cells with euticularized outer walls. Treated as 
above described, the cuticle is colored yeUow-brown, the radial and 
inner walls, blue. 2. The Inner Layer (1) is not only thicker than 
the outer, but the cells are thicker-walled and, in addition, swell 
greatly with potash. These swollen walls are stained deep blue by 
chlorzinc iodine, thus differentiating them from the yellow-brown 
cuticle on the inner wall. 

Perisperm (N).^ — Characteristic. of this seed is the nueellar-coat, 
consisting usually of two cell layers. In cross section these cells 
are rectangular with swollen walls; in surface view, as may be 
seen after soaking for a long time in dilute potash, they are ir- 
regularly polygonal or more or less elongated. 

Fungus Layer (F) . — In most specimens a layer of fungus-threads 
20'' thick is present between the perisperm and the aleurone layer. 
So commonly is this fungus present in darnel grown in Europe, 
that it is of no little value in identifying the grain; but it remains 
to be determined whether in California, where the plant is a pest 



524 



WEED FLORA OF IOWA 



in wheat fields, the fungus is also a common accompaniment. After 
treatment with potash this layer is stained bright yellow by zinc 
chloride of iodine. 

Endosperm. — 1. The Aleurone Cells (al) vary from less than 20 
to 40'' in diameter. 2. Starch-Parenchyma (st). The thin-walled 
cells contain small polygonal grains 3 to Ta* in diameter. The in- 
dividual starch grains are not distinguishable from the grains of 
rice and oats, and like the latter, often occur in aggregates of 
various sizes. 




Fig. 402. Daniel. 



Elements of fruit In surface view. Significance of letters 

same as in Fig. 401. X 160. 
(After Winton, Conn. Agr. Exp. Sta.) 



URTICACEAB, NETTLE FAMILY. 

Hemp {Cannabis sativa L.). 

The smooth crustaeeous achene consists of an outer epidermal 
layer of thick-walled cells with wavy outline, the thickness of the 
radial walls varying somewhat. This is followed by a layer of 
loosely arranged parenchyma cells, and a layer of cells with brown 
contents. A layer of small cells spoken of as the dwarf cells by 
Winton, may also be made out in some sections. The palisade 
layer consists of thick-walled cells with pore canals, the walls 
having a wavy outline. The cell cavity is very much reduced. 
The testa is very thin and consists of thin-walled elongated paren- 
chyma cells, the second layer of spongy parenchyma. The com- 



MICROSCOPIC STRUCTURE OF WEED SEEDS 



525 



pressed nucellus follows. The endosperm consists mostly of a 
single layer of cells, the embryo of small epidermal cells and the 
elongated palisade parenchyma on the upper face of the cotyledon ; 
cells of embryo and endosperm contain fat and protein. 

Nettle {Vrtica gracilis Ait.). 

The pericarp of the small achenes consists of an outer epidermal 
layer of rather large cells with exterior walls thickened, and 
underneath several layers of loosely arranged parenchyma cells. 
The testa and nucellus are compressed ; cells of the embryo squarish^, 
containing fat and protein grains. 




Fig. 403. Microscopic structure of the seeds of the Nettle family. (Urtioaceae) , 
I. Hemp (Cannabis sativa). II. Common nettle (.Vrtica gracilis). 

ep=epidermis, thick-walled short cells, underneath followed by a pigment layer, 
thinner-walled parenchyma cells and a. layer of thick-walled cells. pal= 
palisade cells. p=parenchyma cells with the pigment. t=testa. n= 
nucellus. em=embryo. 

(Drawings by L. H. Pammel and Charlotte M. King.) 

POLYGONACEAE,* BUCKWHEAT FAMILY. 

Miss E. Sirrine finds, "In the seed coats of the family, the 
palisade portion constitutes the outer part of the achenium ; this is 
followed in most cases by the testa consisting of several layers of 
cells varying, however, in some cases ; they are quite regular in 
form and in some instances are of a dark color. In the mature 
palisade cell, the cavity is present; this varies greatly in the dif- 
ferent genera; in some cases occupying nearly the entire cell, in 
others small and irregular." 

•A study of the microscopic structure of the achenes is largely based on Miss 
Emma Sirrine's work and upon that of Dr. Winton. 



626 



WEED FLORA OF IOWA 



Sorrel or Sour Clover {Bumex acetosa L.). 

This species has very small palisade cells, rectangular in shape 
and with a small cell cavity which occupies only a small portion 
of the lower end of the palisade cell. No canals or irregularities 
of cell cavity. The cell is light in color while canal is darker. 
The sub-palisade portion is composed of small round cells of a 
variable number. The endosperm is composed of irregularly ar- 
ranged cells. Measurements: whole seed coats, 38.3/*; palisade 
cells, 23''; sub-palisade, 13.2/*. 




Fig. 404. Microscopic structure of the seed of some Polygonaceous weeds. 

I. Buckwheat (Fagopyrum esculentum) . II. Curled Dock {Bwmex crispua). 

III. (Wild Buckwheat or Bindweed (.Polygonum convolvulus). IV. Smarts 

weed (Polygonum persicarta). V. Sorrel (Bym,ex acetosa). VI. Knotweed 

(Polygonum ereotum). VII. Smartweed (Polygonum hydropiper) . 

e=epldermls. sd=sclerotlc layer. t=testa. al=aleurone layer. p=pareiichyma 

cells, 
(Drawings by L. H. Fammel.) 



MICROSCOPIC STRUCTURE OF WEED SEEDS 527 

Curled Dock {Bumex crispus L.). 

The brownish aehenes of this species consist of an epidermal 
layer of elongated cells with thick stratified walls, outer wall 
colorless and a thick cuticle. The underlying parenchyma cells 
of three rows are smaller, with thick, brownish walls; cells contain 
tannin. The testa consists of two layers of cells, one large, thin- 
walled with brownish walls, the other compressed. The endosperm 
cells are large, thin-walled, and contain simple starch grains. 

Lady's Thumb or Smartweed {Polygonum persicaria L.). 

In this species the palisade cells are long, narrow and truncate. 
The cell cavity extends the whole length of cell at the upper end, 
with prominent branching pore -canals. The sub-palisade portion 
consists of four layers of small roundish cells, a small chainlike 
layer also between the sub-palisade and endosperm. The endosperm 
consists of large irregular cells. Measurements: 138. 6^*; palisade 
cells, 108.9/*; sub-palisade, 29.7a'. 

Knotweed {Polygonum erecium L.). 

In this species the "palisade cells" are much broader than in 
the other species here described. The cells have irregular papillate 
projections as in P. dumetorv/m var. scandens. The cell cavity is 
narrow with long canals extending from it ; cavity branches divide 
near the end of the cell. In P. erecium the whole cell is of a light 
brown color while the cavity is colorless. The sub-palisade portion 
consists of two layers of isodiametric cells. The endosperm has 
long, narrow, regular cells. Measurements: whole seed coat, 82. 5/*; 
palisade cell, 60/*; sub-palisade, 22.5/f; papillate projections, S.Sa*. 

Smartweed {Polygonum hydropiper L.). 

In this species the palisade cells are long and narrow, very 
irregular and truncate at end. The cell cavity is very narrow 
and extends nearly the whole length of the cell. The cavity has 
sinuate canals which extend out from sides of the cavity. The cell 
is colored light brown while the cavity is deeper in color. The 
palisade cells resemble very much those of P. virginianum. The 
sub-palisade cells, however, are much smaller with more numerous 
indistinct layers, there being at least six layers well defined. The 
endosperm cells also are small and quite irregular. Measurements : 
whole seed coat, 132/*; palisade cells, 92.4/*; sub-palisade, 39.6/*. 



528 WEED FLORA OF IOWA 

Wild Buckwheat or Bindweed (Polygonum cowvolvulus h.). 

Dr. A. Li. Winton describes its microscopic structure as follows : 
Pericarp (f ) . — The black huUs or shells of the grain should be 
studied in cross section and in surface preparations, the latter 
being freed from the black coloring matter by warming on the slide 
with caustic alkali, or better by boiling for half an hour with 
1.25% sodium hydrate solution as in the determination of crude 
fiber. 1. Epicarp (epi). Cross sections show that the cells are 
about 0.10 mm. in radial diameter on the sides of the aeh«nes and 
are still longer at the angles. The inner wall is thin, but the outer 



Pig. 405. Black Bindweed. (.Polygonum convolvulus). Transverse section of the 
fruit. C, calyx ; Epi, epicarp ; Mes. mesocarp ; B, flbro-vascular bundle ; S, 
testa; B, endosperm; Em, embryo. X 16. 

(After Winton, Conn. Agr. Exp. Sta.) 

wall and the outer portions of the curiously wrinkled radial walls 
are strongly thickened. Proceeding from the inner wall outward, 
the radial walls increase in thickness until the much-branched cell 
cavity is almost obliterated. On the surface are numerous warts 
from 0.015 to 0.03 mm. in diameter, into each of which a narrow 
branch of the cell cavity passes. Surface preparations of the 
pericarp with the outer surface uppermost clearly show that the 
warts are arranged in irregular longitudinal rows, also that the 
epicarp cells at the surface are sinuous in outline, but gradually 
approach a circular form farther inward. As may be seen in 
preparations of the pericarp with the inner surface uppermost, 
the contour of the inner cell walls of the epicarp is, like the 
outer wall, sinuous in outline. 2. Hypoderm (hy) . Beneath the 
epicarp is a layer of slightly elongated parenchyma cells somewhat 
larger than the cells of the mesocarp. 3. Mesocarp (p.) At the 
angles of the fruit this layer is somewhat thicker than on the 
sides. The cells of the ground tissue are thin-waUed and 
isodiametrie, those of the inner layers being more or less obliterated 



MICROSCOPIC STRUCTURE OF WEED SEEDS 



629 




epi hy p eiid ae 4 ie al 



Fig. 406. Black Bindweed. Transverse section of the fruit. C, calyx consist- 
ing of the outer epidermis aep, the mesophyll m and the inner epidermis 
iep : F, pericarp consisting of the epicarp ei with cuticular warts w, the 
mesocarp p and the endocarp end ; S, testa consisting of the outer 
epidermis ae, the cross-cells q and the inner epidermis ie ; B, endosperm 
consisting of the aleurone-cells al and the starch-cells b. X 160. 
(After Winton, Conn. Agr. Exp. Sta.) 



in the ripe fruit. Six primary, sparingly branched vascular 
bundles pass longitudinally through the ground tissue of the 
mesocarp, one in each angle and one in each of the faces. 
4. Endocarp (end). Like the inner mesocarp, the cells are usu- 
ally obliterated in the mature seed and are seldom evident either 
in cross section or in surface view. 

Testa (S). — Three coats, analogous to those of buckwheat, but 
differing in. form, make up the testa. 1. Epidermis (ae). As in 
buckwheat, the epidermal cells are wavy in outline; but in bind- 
weed they are strongly elongated, whereas in buckwheat they are 
nearly isodiametric. 2. Cross-Cells (q). Most of the cells of 
34 



530 



WEED FLORA OF IOWA 



this layer are elongated, resembling the tube-cells of cereals; but 
short cells of more irregular shape also occur, particularly near 
the base and apex. These are more or less separated from each 
other, but in no part do they form a spongy parenchyma with 
circular intercellular spaces like that of buckwheat. 3. Inner 
Epidermis (ie). This coat consists of thin-walled, elongated ele- 
ments. 




Pig. 407A Fig. 407B 

Fig. 407. Black Bindweed. A. Eploarp in surface view. X 160. 
B. Tangential section of the epicarp. 
(After Winton, Conn. Agr. Exp. Sta.) 



Endosperm (B). — None of the elements are distinguishable from 
those of buckwheat, either in form or size. 1. Aleurone Cells (al) 
are of variable size and irregular shape. 2. Starch-Cells {s). In 
the outer layers the cells are tangentially elongated; farther in- 
ward, they are radially elongated and of large size. The polygonal 
or rounded granules vary in diameter from 0.003 to 0.012 mm. 
Vogl has noted that after treating the starch aggregates of buck- 
wheat with caustic potash, there remains a network corresponding 
to the outline of the starch granules, the threads of which are of 
homogeneous structure without granules. This phenomenon I have 
also observed in the fruits of P. convolvulus and other species of 
Polygonum as well as in a number of species of Rumex, and it is 
probably characteristic of the entire family. The Embryo, con- 
sisting of an elongated radicle and two oblong cotyledons, may be 
conveniently isolated by soaking the seed in 1.25 per cent, caustia 
soda solution for some hours until the starch is removed. 



MICROSCOPIC STRUCTURE OP WEED SEEDS 531 



PI — 




Fig. 408. Black Bindweed. Seed in surface view. Signiflcance of letters same 

as in Fig. 406. 
(After Win ton, Conn. Agr. Exp. Sta.) 

Detection in Powder Form. — Characteristic of this fruit are 
the papillae on the outer epidermis of the calyx and the epicarp 
with sinuous cell walls and rows of warts. The outer epidermal 
cells of the testa are sinuous in outline, like those of buckwheat, 
but, unlike the latter, lare commonly elongated. Although the cross- 
cells are morphologically the same as the spongy parenchyma of 
buckwheat, they resemble more nearly in structure the tube-cells 
of the cereals. The starch granules are not characteristic and the 
network obtained after treatment with caustic alkali serves merely 
as an indication that the seed belongs to a Polygonaceous plant. 

Buckwheat (Fagopyrum esculentum Moench.). 

The achenium consists of elongated epidermal cells with thick- 
ened walls, underneath similarly elongated thick-walled sclerotic 
parenchyma cells with pore canals. This layer contains the pig- 
ment. The testa follows the pericarp and is differentiated into 
an epidermal layer of yellowish brown walls, followed by smaller 
thin-walled, parenchyma cells. The testa is much compressed ; the 
albumen consists of an outer aleurone layer of small cells followed 
by larger cells. The albumen cells contain compound starch 
grains. 



532 



WEED FLORA OF IOWA 




Fig, 409. Black Bindweed. Surface view of the pericarp from below. 
Significance of letters same as In Fig. 406. 
(After "Wlnton, Conn. Agr. Exp. Sta.) 



X 160. 



CHBNOPODIACEAE, GOOSEFOOT FAMILY. 

Groosefoot or Lamb's Quarters (Chenopodium album L.). 

Harz has given an account of the structure of Beta and Spinaciw. 
The structure of the seed of lamb 's quarters is somewhat different. 
The thin utricle consists of an epidermal layer of somewhat wavy 
cells and an indistinct layer underneath. The testa contains the 
brownish pigment. The cells are thick-walled ; the nucellus is com- 
pressed. The cells of the endosperm are large and contain an 
abundance of small starch grains. 

Russian Thistle (Salsola kali (L.) var. tenuifoUa G. "W. F. Meyer) . 

The seed is without endosperm; the embryo fills the seed, and 
is coiled in a conical spiral. The seed coat consists of two parts, 
a layer of three rows of elongated cells followed by a layer of 
three rows of irregular parenchyma cells. One side of the seed 
coat is wider than the other and these cells contain an abundance 
of calcium oxalate crystals. The cells of the outer layer of the 



MICROSCOPIC STRUCTURE OP WEED SEEDS 



533 



embryo are somewhat elongated ; the remainder are nearly as broad 
as long; these contain no starch but albuminoids and fat. 




Fig. 410. Microscopic structure of seeds of the Chenopod family. CChenopodia- 
ceae). I. Russian Thistle (.Salsola kali va,T, tenuifoUa). II. Lamh's Quar- 
ters (.Chenopodium, album'). 

ep=epidermis. p=parenchyma cells. t=testa. n=nucellus. en=endospenn. 
(Drawings by L. H. Pammel and Charlotte M. King.) 



NYCTAGINACEAE, FOUR-O'CLOCK FAMILY. 

Wild Four-o'clock or Umbrella Plant {Oxybaphus nyctagineus 

(Mx.) Sweet). 

The nutlike fruit of the wild four-o'clock or umbrella plant is 
somewhat hairy; the outer portion of the pericarp is made up of 
thick black-brownish cells from 6 to 9 rows. The epidermal cells 
are smaller, some of the eeUs elongated into one-ceUed thick- walled 
trichomes. Adjacent to the testa are bundles of thick-walled, 
sclerotic cells, the outer layer of cells of the testa consisting of 
mucilaginous cells with colorless walls. This is followed by a 
second layer of thin-walled parenchyma cells. The nucellus con- 
sists of an indefinite granular mass, followed by the endosperm, 
and the thin-walled cells of the embryo. 

CARYOPHYLLACEAE, PINK FAMILY. 

Soap wort or Bouncing Bet {Saponaria officinalis L.). 

The kidney-shaped, black, roughish seeds consist of tangentially 
elongated, thick, black, rough cells, the outer layer being brownish 
colored, while the cell cavity is red or blackish brown. The inner 
walls of the testa are thinner, the cells are elongated and the inner 
seed coat is much compressed. The nucellus is indistinguishable 
from the inner seed coat. This is followed by the endosperm. 



634 



WEED FLORA OF IOWA 




FiQ. 411. Wild Four-o'clock (Oxybaplma nyotagineus) , The sclerotic paren- 
chyma, parenchyma and epidermis belong to the pericarp. 
ep=epldermis. p=parenchyma, scl=sclerotic parenchyma. t=testa, t'=trl- 
chome. en=endosperm. r=rlbs. 
(Drawing by L. H. Pammel and Charlotte M. King.) 

consisting of an outer tangential layer with granular contents. 
The aleurone layer and remaining portion of the endosperm cells 
consist of large rather thin-walled cells with compound starch 
grains and protein. 



Slender Catchfly {SUene ontirrMna L.). 

The small kidney-shaped seeds are rough and brownish in color. 
The outer epidermal walls are thick, brownish black in color. The 
underlying parenchyma cells are tangentially elongated with near- 
ly colorless walls. This is followed by an indefinite layer con- 



MICROSCOPIC STRUCTURE OF WEED SEEDS 



535 



sisting of an inner seed coat and a nucellus. The endosperm con- 
sists of thin-walled parenchyma cells with granular contents con- 
sisting of starch grains eind protein. 




Fig. 412. Microscopic structure of some seeds of the Pink family (Cary- 

ophyllaceae) . 
I. Bouncing Bet (Saponaria officinalis). II. Catchfly (.Silene antirrhina) , III. 

Virginia Catchfly iSilene virginioa). 
ep=epidermis. p=parenchyma» n=nucellus. h=hypoderin cells. en=endo- 

sperm. 
(Drawings by L. H. Pammel.) 



The seeds of Virginia Catchfly {Silene virginica) are irregular. 
The outer walls are greatly thickened, irregular, the underlying 
parenchyma cells being slightly elongated. This layer is followed 
by the nucellus and the aleurone layer and remaining endosperm 
cells containing starch grains and protein material. 

Silene inflcda is described and figured by Harz*. 

*Samenkunde 2 :10-79. 



536 



WEED FLORA OF IOWA 



RANUNCULACEAE, CROWFOOT FAMILY. 

Common Buttercup {Banunculus abortimis L.)- 

The greenish achenes of the buttercup consist of three distinct 
layers. The outer epidermal is of elongated, thickish black cells. 
The cells containing the brown pigment are yellowish brown. 
The underlying layers of three or four rows of seeds are similar 
but larger and paler in color. This layer is followed by a thick- 
walled sclerotic layer containing three or four layers of thick- 
walled cells with pore canals. The testa consists of an outer layer 
of thin-walled parenchyma cells; the inner layer consisting of 
sclerotic parenchyma cells filled with pore canals. The endosperm 
cells are large or thin-walled and contain protein material. Harz 
has given an account of the structure of B. arvensis* 




Fig. 413. Microscopic structure of the seed of Buttercup (, Ranunculus aborti- 

vus). 

ep-epiaermis. p=parenchyma. scl=8cterotlc parenchyma, en=endospenn. 

(Drawing by X.. H. Pammel and Charlotte M. King.) 

PAPAVERACEAE, POPPY FAMILY. 

Common Poppy {Papaver somniferum L.). 

Prof. A. L. Winton describes the seeds of this plant as follows : 

Testa (S). — Cross sections are prepared after soaking the seed 

in water that may be cleared with chloral or alkali. After soaking 

the whole seed for about twenty-four hours in 1 per cent sodium 

hydrate solution, the first four layers readily separate from the 

♦Landw. Samelfunde 2 :10-64. 



MICROSCOPIC STRUCTURE OF WEED SEEDS 537 

fifth. Subsequent treatment with hydrochloric acid dissolves out 
the calcium oxalate, and staining with chlorzinc iodine or safranin 
renders the outer layers more distinct. 1. The Epidermal Cells 
(ep) are polygonal and of enormous size, corresponding to the net- 
work on the seed. As appears in cross section, the cells are col- 
lapsed except in the neighborhood of the radial walls. In surface 
view the radial walls are sinuous and thin, what are often con- 
sidered the thick dark walls of this layer being not the walls at aU, 
but the ribs formed by the thickening of the second and third 
layers. This conclusion is consistent with Meyer's and Hanausek's 
figures of cross sections, also with Meyer's drawings and Mach's 
photomicrographs of surface preparations. The statement of 
Tschireh and Oesterle that the epidermis consists of elongated cells 
situated over the ribs, with large polygonal cells between, has since 
been corrected by the authors themselves. Doubtless they mistook 
some of the cells of the second layer for epidermis. Hanausek's 
surface view, on the other hand, might convey the impression that 
the ribs were the cell walls, but his description and cross section 
clearly, show their true nature. 2. Crystal Layer (k). On the 




Fig. 414. Poppy Seed (Papaver somniferum). 'I'ransverse section, s, testa 
consisting of epidermis ep, crystal layer k, fiber layer f, cross-cells q and 
netted-cells n ; e, endosperm containing aleurone grains al. X 160. 
(After Winton, Conn. Agr. Exp. Sta.) 

ribs, the cells of this layer are more or less tajigentially elongated, 
but between the ribs are isodiametrie and polygonal, the elongated 
cells having longer radial walls than the others, thus contributing 
to the formation of the ribs. They contain fine, granular crystals 
of calcium oxalate. Meyer has demonstrated that the blue color 
of the poppy seed is due, not to a blue pigment, but to the inter- 
ference of light by the crystals over the brown cells in the back- 
ground, and is the same phenomenon that causes the apparent 
blue color of the sky and the iris of the eye. As soon as these 
crystals are dissolved in hydrochloric acid, the seed appears brown. 



538 



WEED FLORA OF IOWA 



3. Fiber Lanjer (f). The fibers of this layer are IS-iO/* broad 
and are parallel to the curved axis of the seed. Seen in cross 
section, this layer is thickest in the ribs, the walls throughout 
being distinctly thickened and stratified. In surface view they 
are rendered more distinct by chlorzinc iodine. ^ Cross-Cells (q). 
The fourth layer consists of moderately thick-walled, transversely 
elongated, pointed cells arranged side by side in rows. The walls 
are impregnated with brown material. 5. Netted-Cells (n) . Ow- 
ing to the netted-veined, colorless walls and the presence of deep 
brown contents, these cells are particularly striking. They are 
arranged transversely and often side by side in rows. The cell 
contents are insoluble in alkali and do not give the tannin re- 
action. Some authors designate the cells of this layer "Pigment 
cells," notwithstanding the fact that in the white poppy they do 
not contain pigment. Meyer, Tsehirch and Oesterle, Vogl, and 
Hanausek describe an inner layer of thin-waUed cells, but I am 
unable to find such a layer except in the vicinity of the hilum. 




Fio. 415. Poppy seed. Testa in surface view. Significance of letters same as 

in Fig 414. pig, pigment. X 160. 

(After Winton, Conn. Agr. Exp. Sta.) 



The Endosperm (E) contains aleurone grains up to 3/* in 
the outer layers and 7i^ in the inner layers, each grain containing 
several globoids and crystaloids. 

Embryo. — In the cotyledons there is only one layer of palisade- 
cells and these cells are only slightly elongated. The aleurone 
grains are like those of the endosperm. 



MICROSCOPIC STRUCTURE OF WEED SEEDS 539 

Prickly Poppy (Argemone intermedia Sweet). 

The blackisli pitted seeds are difficult to study. They consist 
of nearly colorless epidermal cells, with thick outer walls and 
cuticle. The cells of the underlying layer are thick-walled, waUs 
and contents blackish, difficult to make out on account of dense 




Fig. 416. Rocky Mountain Poppy {Argemone intermedia). 
ep=epldermis with thick outer walls. pi=pigment layer, n=nucellus, en=en- 

dosperm. 
(Drawing by L. H. Pammel and Charlotte M. King.) 

pigment. The nueellus is compressed, colorless. The endosperm 
of large cells contains oil in large amounts, and protein. The 
structure seems to differ in a marked degree from Papaver as' 
described by Harz and G. Kraus. 



CRUCIFERAE, MUSTARD FAMILY. 
Virginia Peppergrass {Lepidium virginiciim L.). 

The seed coats consist of three weU defined layers. The outer 
or epidermal cells are tabulated, somewhat compressed. The cuticle 
forms a continuous layer over these. On the addition of water the 
epidermal cells elongate and form a mucilaginous mass, showing 
stratified layers. These are not difficult to make out when the 
specimen is mounted in water. The cell cavity is very much re- 
duced; that portion of the cell wall in contact with the cell cavity 
is differentiated from the outer cell wall substance. Long con- 
tinued addition of water causes the cuticle to break and the exterior 
becomes very irregular. 

The second layer is colored brown, the cell walls are considerably 
thickened laterally and project upwardly in the shape of cones. 
A section made through the ends of these seeds shows that the 
second layer is considerably more developed and there are evidences 



540 WEED FLORA OF IOWA 

here of an indistinct layer between the first and second. The 
layer following this consists of thin-walled parenchyma cells, in 
some cases considerably elongated but in others short. 

The third layer is followed by the endosperm which consists of 
a layer of rather thick-walled parenchyma cells. These carry 
granular protein grains. This is followed by one or more layers 
of elongated cells, in which the cell cavity is very much reduced. 
These cells reach their highest development between the folds of 
the caulicle and cotyledon. 

The cells of the first layer of the embryo are smaller, quite uni- 
form in size and filled with protein grains and oil. 

Small Peppergrass {Lepidmm apetalum Willd.). 

The cuticle forms a continuous layer over the epidermal cells, 
which are larger than in L. virgmicwm. On the addition of water 
the cell wall rapidly elongates, emitting a copious mucilage. The 
cell cavity is very much reduced but longer than in L. virgmicum. 
It is surrounded by a denser, more or less differentiated part of 
the cell wall which is more yellow in color than the remainder of 
the cell wall. The second layer is of a yellow straw color and 
. consists of very minute cells with small cell cavities. 

The cell walls of the third layer are strongly thickened, brown, 
and serve the same purpose as in the other species. The endosperm 
consists of thick- walled parenchyma cells. 

In the first layer of cells, the cell walls are very much larger 
and packed with protein grains. The other layers of endosperm 
consist of small elongated thick-walled ceUs with a small cell cavity. 
These attain their greatest development between the caulicle and 
cotyledon. In the embryo, the cells of the first row are isodiametric 
filled with protein grains and oil. The outer cells are elongated 
larger, and also densely packed with the same material. 

Shepherd's Purse {Capsella iursa-pastoris (L.) Medic). 

The seed coats attain their maximum development in the region 
of the caulicle. Cuticle covers the epidermal cells, the latter 
tabular, compressed but in the addition of water elongating, be- , 
coming mucilaginous and showing stratification. 

The second and third layers are brown with thick cell walls. 
Fourth layer consists of endosperm, one layer of isodiametric cells 
filled with protein grains, followed by thick-walled cells reaching 



MICROSCOPIC; STRUCTURE OF WEED SEEDS 



541 




Fig. 417. Microscopic structure of seeds of Mustard family (Cruciferae). 

I. Hedge Mustard (Sisymhrium canescens). II. Small Peppergrass iLepidmm 

apetalum). To the right an enlarged epidermal cell with mucilaginous walls. 

ep=epidermis. p=parenchynia. em=embryo. 

(Drawing by L. H. Pammel.) 

their greatest development between the cotyledon and caulicle. 
First row of cells of embryo nearly isodiametrie, filled with oil 
and protein grains. Others somewhat larger contain the same 
substances. Cotyledons incumbent. Central part of caulicle sepa- 
rated from the rest. Cells of caulicle very much larger than cells 
of cotyledons. 

Black Mustard {Brassica nigra Koch.). 

The cuticle covers the epidermal cells as a continuous layer; 
when mounted in alcohol the outer layer is very much compressed 
and shows very slight stratification; the cell walls expand and 
after it has been moist for a considerable time the cuticle breaks. 
Stratification is very evident on the addition of water. The second 
layer consists of rather thin-walled parenchyma. The cells of 



542 



WEED FLORA OF IOWA 




Fig. 418. Microscopic structure of some Cruciferous seeds iCraoiferae). 
I. False Flax iCamelina sativa). II. Black Mustard (.Brassica nigra). III. 
Common Mustard (B. arvense). TV. Winter Cress (.Barbarea vulgaris}, 
V. Peppergrass (Lepidium virginicum) . VI. Tumbling Mustard (.Sisym- 
brium altiaaimum) . VII. Shepherd's Purse (.Capsella bursa-pastoris) . 
t=testa. p=parenchyma cells. n=nucellus. em=enibryo. 
I, II, III, and IV. Elongated palisade cells below the epidermal layer and 
parenchyma cells. To the right of I, epidermal cells after the addition 
of water. 

(Drawings by L. H. Pammel.) 



this layer differ greatly with, reference to their size, being scarcely 
at all developed in places, in others nearly as large as the cells 
of the outer layer. 



MICROSCOPIC STRUCTURE OP WEED SEEDS 543 

The third layer consists of thick-walled parenchyma cells, densely 
packed, radially elongated, sides presenting a cone-shaped appear- 
ance. Underneath this is a layer of thick-walled parenchyma cells 
which contain some coloring matter. The endosperm follows this 
layer. The first layer consists of thick-walled cells, densely packed 
with albuminous matter. The remaining cells vary in number, 
are much elongated, thick-walled with a small cavity; these cells 
extend down between the contiguous portions of the cotyledon or 
caulicle. 

The Embryo. — The cells of the first layer surrounding the 
cotyledon or caulicle are smaller, filled with fat and protein grains. 
The remaining cells are larger, also filled with fat and protein 
grains. The central part of the caulicle shows a differentiation of 
the embryonic vascular portion, consisting of small cells. 

Charlock or Common Mustard {Brassica wrvensis (L.) Ktze.). 

The outer layer of cells is compressed, tabular, with stratification 
not evident, and cuticle well developed, and forms a continuous 
layer over the outer cells; on the addition of water, the cell walls 
become mucilaginous, elongate, stratification becomes evident, the 
cuticle breaks, and an irregular surface is formed. The second 
layer is but slightly developed, made up of thin-walled parenchyma 
cells. The cells of the third layer are elongated and thickened 
laterally. These cells are much longer than in B. nigra land brown 
in color. The fourth layer consists of one to two rows of rather 
thin-walled cells carrying pigment. Endosperm consists of several 
rows of cells; first row nearly isodiametrie, filled with protein 
grains. The three or four layers of cells following are thick-walled 
with a smaU cell cavity. 

Embryo. — First layer of cells nearly isodiametrie, those follow- 
ing somewhat larger, filled with protein and fat grains. 

Hedge Mustard (Sisymbrium offlcinale Soop.). 

Cuticle covering the epidermal cells, the latter tabular, much 
compressed. On the addition of water the cell walls become 
mucilaginous with evident stratification. The cells of the second 
layer are brown and thin-walled, much compressed. On addition 
of choloral hydrate they expand. Third layer much darker than 
the second, thick-walled, followed by endosperm, cells elongated, 
filled with protein grains, followed by elongated thick-walled cells 



544 WEED FLORA OF IOWA 

with a small cavity. These reach their highest development between 
cotyledons and eauliele. First row of cells of the embryo nearly 
isodiametrie, filled with protein grains and oil. 

Tumbling Mustard (Sisymhrium altissimum L,). 

On the addition of water the cell wall of the outer seed coat 
becomes mucilaginous. Outer epidermal layer covered with cuticle, 
cells elongated, on the addition of water, walls become mucilaginous 
and show stratification. Cell walls of second layer thick, light 
brown, followed by endosperm of two layers of cells, first elongated, 
thick-walled. Cells of embryo as in S. officinale. 

Hairy Hedge Mustard {^Sisymbrvwm canescens Nutt.). 

The testa of the small brownish cells consists of an outer 
epidermal layer with thick walls. These cell walls become mucil- 
aginous on the addition of water. This is followed by a layer of 
several rows of brownish cells and a compressed layer, the nueellus. 
The cells of the outer row of the embryo are smaller than the 
underlying cells. 

Common Winter Cress or Yellow Rocket {Barbarea vulgaris R. Br.). 

First layer of outer seed coat not well developed, cells elongated 
in the direction of the seed. Cuticle covers the epidermal cells. 
On the addition of water a slight mucilaginous modification takes 
place. Second layer with thick lateral walls and quite large cell 
cavities, colored brown. Third layer of rather thick-walled 
parenchyma cells also colored brown, followed by endosperm as is 
usual in cruciferous seeds. 

False Flax {Camelma sativa (L.) Crantz.). 

Seed coats consisting of four layers. The outer epidermal cells 
not much longer than wide, on the addition of water become 
mucilaginous and well stratified. On the addition of chloral hydrate 
stratification is more evident. The cell walls are differentiated 
into several layers. The second layer is not always developed. 
Cells of third layer with thick walls and brown pigment, followed 
by a narrow layer of thick-walled brown cells. The first row of 
cells of endosperm, rather thick-walled, filled with protein grains, 
the other layers of unequal development, cells elongated, thick- 
walled; followed by cells of embryo; these contain protein grains 
and fat. 



MICROSCOPIC STRUCTURE OF WEED SEEDS 545 

ROSACEAE, ROSE FAMILY. 

White Avens {Oeum canadense Jacq.). 

A greater part of the so-called seed is made up of the pericarp 
consisting of a layer of small epidermal cells with trichomes. The 
underlying parenchyma cells are large with numerous intercellular 
spaces. The testa is thin, consisting of an outer pigment layer 
followed by several rows of thick-walled, colorless cells. 




Fig. 419. Microscopic structure of fruit of Avens (,Geum canadense). 

ep=epidermis. p=parenchyma. per=pericarp. t=tricliome. t"^=testa. 

(Drawing by L. H. Pammel and Charlotte M. King.) 



LEGUMINOSAE,* PULSE FAMILY. 

Eattlebox {Grotalaria sagittalis L.). 

The testa not strongly developed; endosperm 196/* in thickaess. 
From Nadelmann's studies it appears that in" Crotcdaria verrucosa 
the homy endosperm is well developed, being four and one-half 
times as wide as the testa. The aleurone layer contains fat and 
aleurone grains. The cells of the embryo contain protein and fat 
but no starch. 



•The descriptions here given are taken for the most part from a paper by 
Li. H. Pammel, Trans. Acad. Sci. St. Louis, 9. 

35 



546 



WEED FLORA OF IOWA 



Malpighian. — The cells are prismatic in surface view, 9.8/» 
across, with five to six canals. In cross sections they are 84^* long. 
The cuticle forms a continuous layer, with longitudinal canals pro- 
jecting into the cells; these extend down through the upper part 
of the cell wall and the cuticularized substance ; this layer is lighter 
in color than the rest of the cell wall, and separates from the re- 
mainder of the cell in the form of a band. The narrow light line 
occurs close under the cuticularized layer. The cell cavity is 
narrow and gradually tapers upward; it contains some protein 
matter. The cell waU consists of cellulose. 

Osteosclerid.— The walls are thickened. Cells wide in the lower 
part and narrowing upwards, with large intercellular spaces. Cells 
contain protein. 

Nutrient. — Consists of radially elongated cells, which are slightly 
compressed. Walls of medium thickness, slightly colored. 



I ■! ■Irti:i:i:i.;i^'i:i:i'' 




Fig. 420. Microscopic structure of the testa of Rattle-box iCrotalaria aagittalis'). 
Il=llght line.- m=malplghlan cells. n=nutrient layer. o^osteosclerld. 
(Drawing by L. H. Pammel.) 



Endosperm. — ^Not strongly developed. The cells of the aleurone 
layer large, containing protein. Two layers follow this, the cells 
very much compressed, and somewhat radially elongated, of thick- 
walled cells. All of the cells contain protein and fat. 

Embryo. — Cells of outer row smaller; those adjoining the en- 
dosperm thicker walled, the inner part with thinner walls. The re- 
maining cells of the embryo larger. All of the cells filled with 
protein. Starch is absent. 

Black Medlck {Medicago lupulina L.). 

Testa and endosperm well developed, 245/* in thickness on sides. 
More than half of this thickness consists of endosperm. 



MICROSCOPIC STRUCTURE OP WEED SEEDS 547 

Malpiffhian. — Cells 40-42/* in length. Cuticle slightly irregular; 
underneath the cuticle a light colored area with conical projec- 
tions, as in Melilotus, but somewhat more prominent. "With chlor- 
iodide of zinc this rapidly colors blue. It corresponds to the 
mucilaginous "membrana interna" of Mattirolo and Busealioni, 
and, as shown by Schips, is chemically differentiated from the 
cuticle and remainder of the cell wall. The conical layer is highly 
refractive. The light line occurs below the conical layer and colors 
blue soon aftpr the addition of chlor-iodide of zinc. The cell cavity 
is broadest kt the base, gradually tapering upward. A large 
chromatophore occurs at the base or near the middle of the cell 
cavity. In colored seed some pigment occurs in the cavity as well 
as considerable amounts in the walls. Small pore-canals occur in 
the upper part of the cell wall. The cell walls color blue more 
slowly with chlor-iodide. of zinc than the cuticularized layer. 

Osteosclerid.-^Cells broad at the base, with conspicuous longi- 
tudinal pores; intercellular spaces below the Malpighian cells tri- 
angular ; walls colored brownish ; cells containing pigment and 
tannin. 

Nutrient. — This layer is much compressed, and differentiated 
into two parts; cells elongated, rather thin-walled; those in the 
lower portion carry a great deal of pigment, and are much more 
compressed than the upper portion. 

Endosperm. — The endosperm is of unequal development, later- 
ally as much as 150/* in thickness. Harz gives the thickness as 
250/*.;; Cells of the aleurone layer rectangular, thick- walled, and 
filled with fat and protein grains. This layer is followed by re- 
serve cellulose. The primary wall persists when treated with weak 
solvents. The walls, except the primary, color blue with chlor- 
iodide of zinc. The inner portion of the endosperm consists of 
thick-walled, elongated cells. 

Embryo. — ^CeUs of the first row smaller than those below; ex- 
terior walls thickened more than the lateral; all of the cell walls 
consist of cellulose. Cells contain fat and protein grains; starch 
grains do not occur, though Harz says they are usually abundant. 
In several specimens examined starch was not found even when 
potassium hydrate or weak sulphuric acid was used with the iodine. 



64S 



WEED FLORA OP IOWA 




Fig. 421. Microscopic structures of seeds of some leguminous weeds. 
I. and V. Yellow Sweet Clover (MeZiJottts officinalis). II. White Sweet 

Clover (Melilotus alba). III. Blaclt Medick (.Medicaffo liipulviia). IV. 

Bur Clover (Medicago dentioulata). 
m=malplghlan cells. ll=light line of the same. o=osteosclerid. em=embryo 

t=testa. en=endosperm. p^parencliyma. n=nucellus. 
(Drawings by L. H. Pammel.) 



MICROSCOPIC STRUCTURE OF WEED SEEDS 549 

Bur Clover {Medicago denticulata Willd.). 

The seeds of this species agree with those of M. hipuUna. 

Malpighian cells 35-38'' long; the narrow light line occurs be- 
low the conical layer; the chromatophores are absent. 

Osteosclerids IG-ISm long; longitudinal striae well marked. 
Cross sections show beyond a doubt that these striae are canals. 
The nutrient layer is much compressed. 

Aleurone layer of endosperm as in M. lupuUna. The mucil- 
aginous reserve cellulose not so strongly developed as in the last 
species. Treatment with iodine gives no reaction for starch; nor 
do blue grains appear when treated with weak sulphuric acid and 
iodine, or potash and iodine. An abundance of fat and protein 
grains occurs in the cells. Walls of the reserve cellulose color 
light blue. Malpighian cells a darker blue. 

Sweet Clover {Meliloiv^ alia Lam.). 

Testa and endosperm vary in thickness, average 75^. Malpighian 
cells as long as the thickness of the endosperm and remainder of 
testa. 

Malpighian.— Cuticle wavy and well developed ; the cutieularized 
layer below with small, conical projections, those of two adjoining 
cells meeting at the middle lamella of the lateral walls, giving the 
layer the appearance of consisting of conelike projections. These 
cones are also connected with the small pore-canals. This cutieular- 
ized layer is highly refractive. The light line consists of a nar- 
row but distinct refractive zone below the conical layer. The 
refractive zone colors blue with chlor-iodide of zinc. The whole 
upper part is more or less refractive. The remainder of the cell 
wall contains pigment and is colored blue with chlor-iodide of 
zinc; the cutieularized layer as well as the conical layer colors 
blue. Small canals project into the walls, and in some cases extend 
beyond the light line. The chromatophores are irregularly dis- 
tributed in the cell cavity, some near the base, others in the center. 

Osteosclerid. — Cells with a broad base and a small triangular 
intercellular space above ; longitudinal pore-canals in the upper 
part of the cell, but these do not extend its entire length. 

Nutrient. — This layer is much compressed; consists of thin- 
walled cells, divided into two parts; cell walls of lower part 
thicker. Both layers contain pigment and tannin, the upper more 
than the lower. Cell walls consist of cellulose. 



550 WEED FLORA OF IOWA 

Endosperm. — The aleurone layer is quite distinct; the cells are 
rectangular; cell walls made up of cellulose. The walls of the re- 
mainder of the endosperm, except where it joins the embryo, are 
thick, consisting of mucilaginous reserve cellulose. Cells of the 
internal layer of the endosperm thick-walled, elongated, containing 
some protein grains and fat. 

Embryo. — Cells of the exterior walls of first row thickened; 
smaller than those below. All of the cells contain fat, protein 
grains, and small starch grains. Procambial vessels well developed. 

Yellow Sweet Clover {MeUlotus officincAis Lam.). 

Testa with endosperm varying from 260-300/* in thickness. The 
Malpighian ceUs of this species are longer than in M. alba, and 
also more abundantly supplied with pigment. The conical pro- 
jections are longer. The osteosclerids are longer and nearly as 
wide above as below. The longitudinal canals are as conspicuous 
and well developed as in that species. Cells of the nutrient layer, 
especially in the lower part, are abundantly supplied with pig- 
ment and some tannin. The walls of the aleurone cells are thick; 
the mucilaginous reserve cellulose and the thick-walled, elongated 
cells are not essentially different from the last species. It also 
agrees with it with respect to the embryo. 

Hairy Prairie Clover (^Dalea cdopecuroides Willd.) {Parosela 
dalea (L.) Britt.). 

Testa and endosperm from 150-265/* in thickness. Variation is 
mostly due to endosperm, which reaches its greatest development 
laterally. 

Malpighian. — Cells are 36.4a' in length. Cuticle prominent; 
cuticularized layer not conspicuous; narrow light line near the 
cuticle; pores prominent, extending into the walls beyond the 
light line. Cell cavity broad at the base, containing protein 
grains. 

Osteosclerid. — Cells thick-walled, lighter in color than the Mal- 
pighian layer. They contain pigment, tannin and protein. 

Nutrient. — This layer is compressed and the cells are elongated. 
Walls color blue with chlor-iodide of zinc. Brown pigment 
abundant in the vascular region. 

Endosperm,. — ^Aleurone cells nearly isodiametric, containing fat, 
and protein; most of the endosperm consisting of reserve cellulose 



MICROSCOPIC STRUCTURE OF WEED SEEDS 



651 




Fig. 422. Microscopic structure of leguminous seeds (.Leguminosae) . 
I. Silky Sophora CSophora sericea). II. Parosela (Dalea alopecuroides) . III. 

Common Vetch iVicia sativa). IV. Stemless Locoweed (,0'xytropls lam- 

herti). V.. Wild Llquoric.e (.GlycyrrMisa lepidota). 
m=malplghlan cells. ll=light line. em=embryo. o=osteosclerid. p=parenchy- 

ma. al=aleurone layer. en=endosperm. en=endosperni reserve cellulose 

cells. tr=tracheae. 

(Drawings by L. H. Pammel.) 



552 WEED FLORA OF IOWA 

with prominent pore-canals ; the internal layer consisting of 
elongated thick-walled cells, with cell cavity much reduced. 

Embryo. — ^Pirst row of cells of embryo smaller than underlying, 
with thickened outer walls. Cells below with small intercellular 
spaces. Reserve material consists of fat and protein grains; 
starch is absent. 

Stemless Loco Weed {Oxytropis lamberti Pursh.). 

Testa and endosperm 170-175m. This, the so-caUed loco weed, is 
said to cause disturbances in animals, but alkaloids have not been 
found in the seed or any other part of the plant. 

Malpigkian. — Cells 40-42/* long. Cuticle somewhat uneven; the 
narrow well marked cutieularized layer colors blue with chlor- 
iodide of zinc; the light line occurs below the cutieularized layer, 
and this also colors blue; the remainder of the cell wall takes on 
a darker blue color. Cells contain an abundance of pigment, 
tannin, and some plastic material. 

Osteosolerid. — Cell walls thickened, not prominently I-shaped, 
but with an elongated intercellular space. 

Nutrient. — ^Layer consists of thin-walled elongated cells from 
ten to twelve rows. Pigment more abundant in lower than in 
upper part. Walls color blue with chlor-iodide of zinc. 

Endosperm. — The aleurone layer consists of thick- walled cells; 
the underlying thick-walled cells of the reserve cellulose become 
mucilaginous on the addition of water. The internal part consists 
of thick-walled, elongated ceUs. The cells contain protein. 

Embryo. — Cells of the first row smaller, with thick exterior 
walls; cells below not so compact and with thinner walls. Cell 
walls color blue with chlor-iodide of zinc. Starch is absent but 
cells contain fat and protein. 

Bush Clover (Lespedeza capitata Mx.). 

Testa and endosperm 90-100/» thick. Light line occurs close 
under the cuticle. A large spherical chromatophore occurs in the 
pigmented Malphigian cells which is variable as to its position in the 
cell. The long pores extend to the middle of the cell. The os- 
teosclerids are short. The nutrient layer is compressed, containing 
much pigment. Endosperm as in L. stuvei; the aleurone cells are 
thick-walled, and the reserve cellulose is mucilaginous. Embryo 
as in the other species containing fat and protein but no starch. 



MICEOSCOPIC STRUCTURE OF WEED SEEDS 553 

Common Vetch {Vida sativa L.). 

This species has been studied by Harz, Tsehireh and Oesterle, 
Beck, and Sempolowski. Testa irregular, with small projections, 
126^ thick. Endosperm reduced to a single layer. The presence 
of endosperm has been indicated by the above writers. Beck 
speaks of an aleurone spot (Aleurone fleck) in the epidermal cells 
of the cotyledons of this and other species of the genus Vicia. 

Malpiffhicm. — Cells 72-75/* long, pointed at the upper end; 
cuticle very irregular because of the projections; cuticularized 
layer most prominent in the depressions; pores project into the 
walls below the light line, and partly connect with the cell cavity ; 
the upper part of the cell is not pigmented, or very little. The 
light line occurs just above the pigmented part of the cell. Cell 
cavity is large at the base, narrows upward, becoming much con- 
stricted below the light line, and above widens again. .Small 
lateral projections or pores extend into the wall at right angles to 
the cavity. A large ehromatophore, some pigment, and small 
granules occur in the cavity. The walls in lower part of cell are 
colored bluish brown. 

Osteosclerid. — Cells are thick-walled, 13-16.8^ long, longitudinally 
striated. Upper and lower cross-bars nearly equal ; the inter- 
cellular spaces elongated. Tsehireh and Oesterle state that this 
layer is not very strongly developed, but in specimens which I 
have examined it is well developed. These cells are more or less 
variable, as indicated by Harz, who states that they are from 
11-13/* long. 

Nutrient. — This layer is differentiated into two parts ; the upper 
consists of thin- walled, elongated cells with a yellowish pigment; 
the cells of the lower part are larger, thin-walled and elongated, 
containing a brown pigment. 

Nucellus. — This consists of a narrow zone of compressed cells. 

Endosperm. — Occurs in the form of thick-walled elongated cells 
with a narrow cell cavity. Usually only one or two rows of cells. 

Embryo. — The outer row of cells of the cotyledon is continuous. 
The exterior walls are thickened; cells below are more loosely ar- 
ranged; small intercellular spaces in the angles of the cells; the 
epidermal cells contain fat and protein, the others in addition an 
abundance of spherical or elliptical starch grains measuring 25 
x22.5j" to 50x25m. Palisade cells wanting. 



554 WEED FLORA OF IOWA 

Wild Liquorice (GlycyrrMza lepidota (Nutt.) Pursh.). 

Testa and endosperm 490-500/* thick. Endosperm variable in 
different parts of the seed, but usually well developed. 

Malpighian. — Cells TO-TS/* long. Cuticle somewhat irregtdar; 
the light colored cuticularized layer is followed by a narrow but 
sharply marked zone, the light line ; cell cavity is large at the base, 
gradually tapering upward. Pore-canals extend into wall beyond 
the light line. Cells contain pigment and some plastic material. 

Osteosderid. — The I-shaped cells are thick-walled, with small 
projections somewhat similar to those shown for Ervum lens by 
Mattirolo and Busealioni. The intercellular space is elongated. 
The cells attain their greatest development in the hilar region. 
All of the cells carry some pigment and plastic material. 

Nutrient.— This layer is much compressed and thin-walled; cells 
number from four to six rows. Pigment is most abundant in the 
lower part of the layer. 

\ .Endosperm,. — ^Aleurone layer consists of nearly isodiametric 
thiek-waUed cells. The mucilaginous reserve cellulose is variable 
in quantity. Cell walls differentiated into primary, secondary and 
tertiary. Internal part of the endosperm consists of thick-walled, 
elongated cells. AU of the cells contain protein grains.. 

Embryo. — Cells of the outer row smaller than those within; ex- 
terior walls thickened, those below more loosely arranged than the 
epidermal; more compact and with thicker walls than those of 
Astragalus mexicanus. Cells contain fat and protein grains but 
no starch. 

LINACBAE, FLAX FAMILT. 
Common Flax (Linum usitatissimum L.). 

The shining, brownish seeds consist of an outer epidermal layer 
of thick-walled cells; walls colorless and stratified; these become 
mucilaginous on the addition of water. The cell cavity is very 
small, the underlying layer consists of yellowish parenchyma cells. 
The third, called the fiber layer by Winton, consists of sclerotic 
parenchyma cells with pore-canals, the sclerotic parenchyma fol- 
lowed by a layer of colorless cross-cells with thin walls. The 
parenchyma cells of .the pigment layer follow; these cells are 
squarish, pigment yellowish brown. The endosperm follows the 



MICROSCOPIC STRUCTURE! OP WEED SEEDS 



666 




FiQ. 423. Microscopic structure of the seed of common Flax (.Linum uaUatii- 

simum). 
ep=epidermls. p=parenohyma, underneath thick-walled sclerenchyma cells and 

the pigment layer. pl=pigment layer. en=endosperm. 

(Drawing by L. H. Pammel and Charlotte M. King.) 



pigment layer and consists of 2-6 layers of cells, the walls being 
thicker than those of the embryo, and containing fat and aleurone 
grains. The epidermal cells of the embryo are squarish, the cells 
underneath on the upper face of the cotyledon are palisade-like. 
All of the cells contain fat and protein. 



GERANIACEAE, GERANIUM FAMILY. 

Carolina Cranesbill {Geranium carolinianum L.). 

The testa of the smooth small seeds consists of an outer epider- 
mal layer, the cell walls not greatly thickened; underlying it 
is a single row of elongated parenchyma cells followed by the Mal- 
phigian cells; the light line is narrow and occurs in the middle of 
the cell; this is followed by a layer of much larger cells with 
thick walls. The inner seed coat is much compressed and consists 
of several rows of small cells and a single row of large cells. The 
walls in both cases are not greatly thickened. The nucellus is 
much compressed. The cells of the endosperm are not much longer 
than broad. The cells of the outer row or the aleurone layer are 
much smaller than those of the second layer. 



556 



WEED FLORA OF IOWA 




Fie. 424. Microscopic structure of the seed of common Geranium (Geranium 

caro linianum ) . 
ep= epidermis. p=parenchyma, malpighian cells below. ll=llght line of mal- 
pighlan cells. pal=palisade cells. it=lnner testa. n=nucellus. en=en- 
dosperm. 

(Drawing by L. H. Pammel and Charlotte M. King.) 

BUPHORBICEAE,* SPURGE FAMILY. 

Flowering Spurge {Euphorbia corollata L.). 

The outer layer of the seed coat is mucilaginous; the walls of 
the cells are thickened and colorless; showing stratification upon 
addition of water; the cell contents are dark in color. The granu- 
lar layer beneath the mucilaginous cells is well developed ; the con- 
tents give a blue reaction to iodine. Underneath the granular 
layer is a row of slightly elongated thin-walled parenchyma cells; 
beneath these are the long palisade-like cells, in which are pores 
of less prominence than in E. marginata and others. Next lie two 
compressed layers of thin-walled parenchyma cells. 

Spotted Spurge (Euphorbia preslii Guss.). 

The outer layer of cells are darkened; these cells are not 
mucilaginous. The palisade-like cells are present, as in all the 
species. 

•The descriptions here given are from a paper by L. H. Pammel, Trans. 
Acad. Sci. St. Louis. 5:543. The literature will be found in this paper. 



MICROSCOPIC STRUCTURE OF WEED SEEDS 



557 



Prostrate Spurge {Euphorbia maculata L.). 

The walls of the outer cells are dark in color; these cells are 
but slightly mucilaginous. The granular layer is not pronounced. 
The palisade-like cells resemble those of the other species. 





Fio. 425. Microscopic structure of the seeds of the Spurge family (.Euphor- 

biaceae). 
I. Cypress Spurge (.Euphorbia cypariasias). II. Flowering Spurge (BupTior- 

bia coroUata). 
ep=epiaermis. In figure II cell-walls mucilaginous. pal=palisade cells. p= 

parenchyma cells. 
' (Drawing by L. H. Pammel.) 

Yellow Spurge {Euphorbia cyparissias L.). 

The seed shows the usual palisade-like cells with the overlying 
and underlying thin-walled parenchyma cells. 

MALVACEAE, MALLOW FAMILY. 

Velvet Weed, Butterprint {Abutilon theophrasti Medic.).* 

The outer layer a, of the first integument is transformed into a 
strongly refractive layer. The second layer is composed of radially 
elongated cells. The seed hairs arise from a single cell and are 
large and conspicuous. The hairs are spindle-shaped and thin- 
walled ; they occur mostly at the ends of the seed and are more or 
less pressed to it. There is little or no coloring matter in this in- 

*From Rolfs, P. H., Bot. Gaz. 1893 :33-39. 



558 WEED FLORA OF IOWA 

tegument excepting in the base of the hair cells. The palisade 
cells, c, are narrow for their length. The cell cavity is not promi- 
nent and the nodosity is inconspicuous. The light line is narrow 
and occurs near the outer end of the palisade layer. The sub- 
palisade portion, d, is made up of two layers of light brown cells. 
They are symmetrical and elongated tangentially. 

Measurements, seed coats, 147/*; outer integument, IS/*; palisade 
layer, 96/*; subpalisade, 38/*. 

Shoo-fly {Hibiscus trionum L.). 

P. H. Rolfs has made a study of H: miUtaris, the microscopic 
structure of which species closely resembles that of H. trionum. 
The dark grayish seeds are roughened with tubercular processes, 
which contain the "seed hairs." The seed hairs consist of cells 
somewhat longer than broad beginning with a broad base, ex- 
tending into a several-celled trichome, the terminal portion larger 
than remainder of cell. These hairs contain a yellow pigment. 
The MJalpighian cells occupy about one-half the thickness of the 
testa, the cuticle is well developed, the light line is near the upper 
portion of the cell. The cell cavity is spindle-shaped and near 
the middle of the cell. The remainder of the testa consists of a 
subpalisade portion of parenchyma cells carrying a brownish pig- 
ment; underneath it, larger thin-walled cells ; walls broymish, a 
compressed narrow, brownish layer, the nuceUus, n. This is fol- 
lowed by the squarish cells of the endosperm. 

Common Mallow {Malva sylvestris L.). 

The surface of M. sylvestris is rough in appearance. The second 
layer, 6, of the outer integument, a, has been compressed into a 
thin layer and seems to have no definite arrangement. The outer 
layer, a, has been elongated radially. In places, these elongated 
cells have divided forming a double layer of cells. There is no 
brown coloring matter in this integument nor is there any between 
the integuments. The palisade cells, c, are clear; the walls thick. 
The cell cavity occupies about one-third the length of the cells, 
the lower end reaching to the middle. The nodosity is promi- 
nent. Below the cavity the ceUs are clear, almost transparent. 
The subpalisade portion, d, is usually made up of two layers, at 
some places only one, of large dark brown cells. 



MICROSCOPIC STRUCTURE OP WEED SEEDS 



659 



Measurements, seed coats, 122/*; outer integument, 27/*; outer 
layer of same, 22/*; inner layer of same, 5/*; palisade layer, 70/'; 
subpalisade, 25/*. (P. H. Rolfs.) 







Fio. 426. Microscopic structure of the seeds of some Malvaceous weeds. 
I. Slioo-fly (SiftiscKS trionum). II. Indian Mallow or Butterprint (AtvXMon 

theophrasti) . III. Mallow (.Malva sylvestris). IV. Slda (.Sida spinoaa). 

V. Cheeses or common Mallow (.Malva rotundifolia) . 
ep=epidermal cells. m=malpighian cells. ll=light line. pi=pigment layer. p= 

parenchyma cells. pal=palisade or malpighian cells. n=nucellus. en=eii- 

dosperm. h=trichome. t=plant hair or trlchome surface view 
(Drawings by P. H. Rolfs.) 



Cheeses or Mallow {Maiva rotundifolia L.). 

The roughened, somewhat velvety, dark grayish seeds consist 
of an outer row of rather large, rather thick-walled cells, walls 
colorless. This layer is followed by the very long Malpighian 
cells, which are longer than the cells of the rest of the testa, light 
line near the upper part of the cell, lower portion of cell slightly 
yellowish. Cavity spindle-shaped near the middle. The dark 



560 WEED FLORA OF IOWA 

brownish pigment cells of two or three rows. Adjacent to th* 
pigment layer is the colorless compressed nucellus and the squarish 
endosperm cells. 

Sida {Sida spinosa It.). 

The brownish seeds are minutely roughened. The Malpighian 
cells occupy more than one-half of the thickness of the testa, the 
cuticle is well developed, the light line occurs near the upper end 
of the cells. The cell cavity is spindle-shaped near the lower end 
of the ceU. The subepidermal layer contains the brownish pig- 
ment, the walls of these cells are thickened; the parenchyma cells 
of the layer underneath are colorless, the walls are less thickened; 
a narrow pigment layer follows. The cells of the endosperm are 
thick-walled containing protein grains. 

ONAGRACEAE, EVENING PRIMROSE FAMILY. 

Evening Primrose {Oenothera biennis L.). 

The small, irregular, winged seeds are rough. The epidermal 
cells, ep, of the testa are small, thick-walled with minute pore 
canals ; the underlying parenchyma cells, p, are large, thick-waUed 
and with small pore canals ; these cells reach their greatest develop- 
ment where the wings occur. The remaining portion of the testa 
consists of four or five layers of cells more or less rectangular. 
The nucellus and the endosperm much compressed, outer epidermal 
cells of the embryo, em, thia-waUed, a little longer than wide. 




Pig. 427. Microscopic structure of the seed of Evening Primrose (.Oenothera 

iiennis). 
■ep=epldermis of thick-walled cells. p=thick-walled parenchyma underneath 
thinner-walled parenchyma. n=nucellus and below a few layers of cells of 
the endosperm. 

(Drawing by Charlotte M. King and L. H. Pammel.) 



MICROSCOPIC STRUCTURE OF WEED SEEDS 



561 



UMBELLIPERAE, PARSLEY FAMILY. 

Sweet Cicely {OsmorrMza longistylis (Torr.) D. C). 

The epidermal ceUs are longer than broad, the outer walls are 
thickened, five to six rows of thin-walled parenchyma cells occur 
underneath the epidermal layer ; the ribs contain the vascular ele- 
ments, thiek-waJled sclerenchyma cells; the testa consists of a 
layer of thin-walled parenchyma cells, p, followed by a layer tan- 
gentially elongated and another of large parenchyma cells, p^, and 
the compressed nucellus, n^ The endosperm consists of large thin- 
walled cells. 




Fig. 428. Microscopic structure of some Umbelliferous weeds. 
X Sweet Cicely (OsmorMsa longistylis). II. Cow Parsnip (Heracleum lana- 
tum'). III. W^lld Carrot (Daucus carota). Underneath, parenchyma cells, 
thick-walled sclerotic parenchyma, sectional view to the right. 
ii=nucellus. p=parenchyma. t=testa. en=endosperm. ep=epidermis. o=oll 
duct. 

(Drawings by D. H. Pammel.) 
36 



562 WEED FLORA OF IOWA 

Wild Carrot {Dcmcus carota L.)- 

The eremoearp consists of an outer epidermis of cells some- 
what longer than broad; the underlying cells are of similar struc- 
ture except the cells near the inner epidermis, which are much 
longer than wide;, a large oil duct occurs in each rib. The testa 
consists of a single layer of parenchyma cells and a few rows of 
compressed elements, probably the nucellus. The endosperm of 
thin-walled parenchyma cells contains protein. 

Cow Parsnip {Heracleum lanatum). 

An outer epidermis with outer walls thickened. The underlying 
parenehjnna cells similar, followed by a layer of thick-walled 
selerenchyma cells. The testa of single layer of ceUs. The en- 
dosperm cells contain protein. 

ASCLEPIADACEAE, MILKWEED FAMILY. 

Milkweed (Asclepias syriaca L.). 

The flattened reddish brown seeds consist of an epidermis of 
isodiametric cells; the outer walls wavy, and thickened; each cell 
with a projecting point, outer walls colorless, contents brownish; 
the epidermis is followed by 10-14 rows of thin-walled parenchyma 
cells containing a brownish pigment This layer is followed by 




em 



Fio. 429. Microscopic structure of the seed of Milkweed (.Asclepias syriaca). 

ep=epldermls. p=parenohynia. n=nucellus. em=embryo. 

(Drawing by L. H. Pammel and Charlotte M. King.) 



MICROSCOPIC STRUCTURE OF WEED SEEDS 



563 



the compressed perisperm, brownish yellow in color. The endo- 
sperm consists of thickish-walled, colorless parench3rma cells, the 
outer TOW smaller than the underlying, the inner layer of smaller 
elongated cells. The contents consist of protein and fat. The 
inner epidermal cells of the embryo are smaller than the endo- 
sperm cells; they contain protein and fat. 

CONVOLVULACEAB, CONVOLVULUS FAMILY. 

European Bindweed {Coiwolvuhis arvensis L.). 

The testa consists of an outer row of short or elongated cells p 
with thick walls and brownish contents. This is followed by a 
layer of small cells with colorless walls. Contents brownish. The 
Malphighian cells m are situated underneath. This is followed by 
a layer of parenchyma cells consisting of 8-12 rows of cells. The 
endosperm consists of thick-walled colorless cells. The walls in 
part mucilagiuous. 




Fig. 430. Microscopic structure of the seeds of Oonvolvulaoeae. 
I. Morning-glory (Convolvulus septum). II. Cultivated Morning-glory (.Ipomoea 
purpurea). III. Dodder (Cuscuta epithymum). IV. Bindweed iConvol- 
vulua arvensis). 
ep=epldennls. m^malplghian cells. ll=light line, p^parenchyma. n=nucellu3. 
en^endosperm. 

(Drawings by L. H. Pammel and Charlotte M. King.) 



564 WEED FLORA OP IOWA 

Wild Morning Glory {Convolvulus sepmm L.). 

The testa of the seed of the common morning glory consists of 
an outer layer of elongated cells containing the blackish pigment 
followed by the Malpighian cells with small cell cavity and promi- 
nent light line. The colorless parenchyma cells are thick-walled 
followed by a compressed indistinct layer, the compressed micellus 
and the endosperm cells. 

Cultivated Morning Glory {Ipomoea purpurea (L.) Roth.). 

The black-brownish seeds are rough. The testa consists of a 
superficial layer of cells with granular brownish contents. The 
Malpighian cells m occur underneath; the light line is near the 
upper part of the cell, cell cavity small. The cells of the paren- 
chyma layer are compressed. The cells of the endosperm are thick- 
walled and somewhat mucilaginous. 

Dodder {Cusciita epithymum Murr.). 

The small seeds are minutely roughened and velvety. The outer 
layer of the testa consists of large cells with yellowish contents, 
the following layer consists of thick-walled cubical or prismatic 
cells p, the colorless Malpighian cells m follow. They are elongated 
with a small cell cavity. The layer following consists of com- 
pressed cells, tangentially elongated. The endosperm layer con- 
sists of an outer aleurone layer of nearly square cells. The cells 
below are irregular. The endosperm cells contain compound or 
simple starch grains and protein. 

BORAGINACEAE, BORAGE FAMILY. 

Wild Comfrey {Cynoglossum virginianum L.), 

The rough fruits are covered with hooked appendages, the sides 
roughened with small colorless points; the epidermal layer is ir- 
regular and prominent, in some cells developed into short triehomes, 
whose walls are greatly thickened. The epidermal walls and con- 
tents are blackish, the underlying sclerotic parenchyma cells have 
thick walls and are blackish. The parenchyma cells of the testa 
are thinner walled and colorless, followed by the compressed layer 
of the nucellus n. The endosperm cells are longer than broad, 
colorless, contain protein and fat. 



MICROSCOPIC STRUCTURE OF WEED SEEDS 



665 




Fig. 431. Microscopic structure of some fruits of the Borage Family (.Boragin- 

aceae). 
I. Stickseed (Lappula echincUa) part of fruit or bur. II. Stlckseed (Lap- 
pula echinata). Enlarged view of epidermal cells showing irregularities in 
cell wall and cavity. III. Wild Comfrey (Cynoglossum virginianum) . 
ep=epidermal cells. n=nucellus. pl=pigment layer. en=endosperm. t=tri- 
chomes. 

(Drawings by L. H. Pammel and C. M. King.) 



Stickseed {Lappula echinata Gilibert).. 

Tke fruits are rough and provided with hooked appendages, 
the cells of the appendages are elongated, thick-walled, the walls 
colorless; the cells of the epidermis toward the exterior are very 
irregular with projecting rounded or sharp points, walls colorless. 
The epidermal cells are elongated with central cell cavity and 
prominent pore canals at right angles with the cell cavity, these 
having the appearance of a series of cells one above the other. 
The epidermal cells contain a brownish pigment, the underlying 
parenchyma cells are thinner walled and also contain a brownish 



666 



WEED FLORA OF IOWA 



pigment. The testa is thin, consisting of thin-walled parenchyma 
cells with granular contents. 



VERBENACEAE, .VERVAIN FAMILY. 

Hoary Vervain (Verbena stricta Vent.). 

Epidermal cells thick- walled ; outer cells colorless. Underneath 
this lie several layers of pigmented cells, slightly longer than broad. 
This layer is followed by rather thick-walled, colorless cells, witii 
small cell cavity; one or two rows toward the middle are thick- 
walled and smaller. Next follow the cells of the embryo. 




FiQ. 432. Mlscroscoplo structure of seed and fruit of Vervain iVerbena atrlcta'). 

ep=epldermls, thlok-walled. p=parenchyma layer, pl^pigment layer of small 

parenchyma cells. The two inner layers of cells of the testa. 

(Drawings by L. H. Pammel and Charlotte M. King.) 

LABIATAE, MINT FAMILY. 

Catnip {Nepeta cataria L.). 

The small dull brown seeds are finely roughened. The pericarp 
consists of an epidermal layer with thin cuticle, on the addition 
of water becoming mucilaginous. This layer is followed by under- 
lying parenchyma cells, then the Malpighian cells with conspicuous 
light line. The cells are colored yellowish brown ; underlying this. 



MICROSCOPIC STRUCTURE OP WEED SEEDS 



567 



the testa, consisting of a single layer of cells, thin-walled. The 
nucellus of whitish, elongated, rather thick-walled cells, the en- 
dosperm differentiated into aji outer layer of larger parenchyma 
and a compressed inner layer of thick-walled cells. The epidermal 
cells of the embryo nearly isodiametric, contain protein and fat. 
The epidermal cells of the upper epidermis nearly like the lower, 
palisade parenehymia underneath. 




Fig. 433. Microscopic structure of seeds of the Mint Family ( Lahiatae) . 

I. Catnip (Nepeta cataria). II. Giant Hyssop (Agastache scrophulariaefolia'). 

ep=epidermis, underneath, parenchyma cells in I and sclerotic parenchyma in 

II, the epidermal cells irregular showing some triohomes. scl=sclerotlc 

parenchyma. en=endosperm. m=malpighian cells. n=nucellus. ll=llght 

line. p=parenohyma. em=embryo. 

(Drawings by L. H. Pammel and C. M. King.) 

Giant Hyssop (Agastache scrophulariaefoUa (Willd.) Ktze.). 

The small pubescent nutlet consists of the epidermal cells of 
the pericarp with small unicellular thickened triohomes; cells con- 
tain a brownish pigment; the cells of the layer underneath are 
thick-walled, cell wall and cavity contain a brownish pigment. 
The Malpighian layer follows, the cells being longer than wide, 
the light line near the upper part of the cell. These cells are 
yellowish. The testa is compressed and consists of elongated cells, 
brownish in color. The endosperm varies in thickness, the cells 
are in some cases elongated, in others squarish, and contain fat 
and protein material. 



568 



WEED FLORA OF IOWA 



SOLANACBAE, NIGHTSHADE FAMILY. 

Horse Nettle {Solamim caroUnense L.). 

The testa consists of an outer row of cells whose walls are 
mucilaginous; the underlying cells are thick-walled with interven- 
ing air spaces broad below and narrow above. The cells of this 
layer contain the yellow pigment. The underlying parenchyma 
layer is compressed, composed of colorless cells which are longer 
than wide; the layer adjacent to the endosperm is compressed 
and not clearly defined. The cells of the inner portion of the 
endosperm are smaller and contain protein. Cells of embryo are 
small and contain protein. 




c — Y~X — ]D C—^CZ^ )Cf J 




PiQ. 434. Microscopic structure of the seeds of sorne Solanaceous weeds. 

I. Jimson Weed (Datura atrcumonium) . II. Black Nightshade (.Solarium ni- 
grum). III. Buffalo Bur (Solanum rostratum). TV. Horse Nettle (8ola- 
num carolinenae). V. Ground Cherry (Phyaalia pubeacena). 

ep=epidennis. en=endosperm. pal=pallsade cells. em=einhryo. p=parenchyina. p*= 
elongated parenchyma cells. 

(Drawings by L.. H. Pammel and C. M. King.) 



MICROSCOPIC STRUCTURE OF WEED SEEDS 569 

Buffalo Bur or Spiny Nightshade {SoUmum rostraium Dunal). 

The black seeds are irregular on the surface, which is mucil- 
aginous; the underlying layer consists of thijk-waJled cells with 
large cavities into which thickened processes extend; the third 
layer is also pigmented and consists of squarish cells or elongated, 
compressed elements. The endosperm is composed of thick-waUed 
cells, the outer nearly square, the others elongated. Starch ab- 
sent; protein present. The cells of the embryo are smaller, thin- 
walled and contain protein and fat. 

Black Nightshade {SomMJtm, nigrum L.). 

The surface of the yellowish seeds is slightly irregular. The 
superficial layers consist of mucilaginous, parenchyma cells, fol- 
lowed by large parenchyma cells with thickened folds. These cells 
are, however, variable as to structure and are sometimes short 
with folds not evident. The elongated, thick-walled portion of 
the testa contains the yellowish pigment. The cell cavity is tri- 
angular. The second layer of parenchyma cells is compressed. 

Jimson Weed {Datura stramonium L.). 

The blackish seeds are rough, surface irregular, cells and walls 
of epidermis ep thick; the underlying thinner-walled cells p are 
small, longer than broad, followed by an indistinct layer p\ whose 
walls are not clearly defined. The layer adjacent to the endosperm 
consists of somewhat larger cells also thin-walled. The endosperm 
cells e are large, containing protein. 

Ground Cherry {Physalis puhescens L.). 

The epidermal cells are thick-walled, the outer walls colorless. 
These cells contain the pigment. The parenchyma cells of the 
second layer are elongated; an indistinct compressed layer follows. 
The outer row of the endosperm cells are smaller, containing 
protein. 

A discussion of the seed coats of this family is to be found in Harz, Somen- 
liunde, 2 996-1025. 



570 



WEED FLORA OF IOWA 
SOROPHULARIACEAE, PIGWORT FAMILY. 

Mullein {Veriascum thapsus L.)- 



The minute, roughened seeds are irregular, 
are dark colored, longer than broad and thick 
mal layer is followed by one or more layers 
more numerous in the micropilar region; an 
pressed layer with large intercellular spaces 
sponding to the irregularities on the surface, 



The epidermal cells 
walled. The epider- 
of parenchyma cells, 
indistinct and corn- 
follows, these corre- 
smaUer intercellular 




Fio. 435. Microscopic structure of the seeds of the Flgwort family (Scropftul- 

ariaceae). 
I Moth Mullein (.Veriascum hlattaria). II. Common Mullein (.Verbaacum 

thapsua). 
ep=epidermis. p=parenchyma. al=aleurone layer. en=endosperm. em=em- 

bryo. 
(Drawings by L. H. Pammel and Charlotte M. King.) 

spaces occurring between the larger. The nucellus is compressed, 
showing remnants of cell walls. The endosperm consists of an 
outer aleurone layer, the walls with pore canals; this is followed 
by cells of the same character. The cells of the embryo are 
smaller. The testa of Veriascwm blattaria in an undeveloped seed 
consists of the epidermal cells with chlorophyll and the underlying 
much larger cells also with chlorophyll. 



MICROSCOPIC STRUCTURE OF WEED SEEDS 



571 



PLANT AGINACEAE, PLANTAIN FAMILY. 

Oommoii Plantain {Planting o major L.). 

The small, yellowish brown seeds consist of an epidermal layer 
of thick black-brownish seeds. The walls on the addition of water 
become mucilaginous and expand. The cell cavity is small. The 
epidermal layer is followed by several layers and small parenchyma 
cells. These cells are usually somewhat compressed and brownish 
in color. The pigment layer and endosperm consist of an outer 
layer of aleurone. cells smaller than the underlying cells. These 
cells contain protein grains and starch; the walls have small pore 
canals. 




Fig. 436. Microscopic structure of the seeds of Plantain family. 
I. Bracted Plantain iPlcmtago aristata). II. Common Plantain (.Plantago 

major). III. Buckhorn (.Plantago lanceolata) . 
1= epidermal cells showing stratification. o=cell cavity. ep=epldermls. pl=un- 
derlying parenchyma cells. 2=underlying parenchyma cells of the testa. 
em=embryo. n=nucellus. p=parenchyma cells. en=endosperm. 
(Drawings by. L. H. Pammel and C. M. King.) 



572 WEED FLORA OF IOWA 

Buckhom {Pla/ntago lanceolata L.). 

The smooth, brownish, elongated seeds consist of epidermal cells 
with a small cavity and thick walls ; the outer walls become mucil- 
aginous on the addition of water. The underlying cells are thin, 
blackish, elongated, followed by a brown pigment layer as in the 
last species. The aleurone cells and remaining endosperm cells 
are of about the same shape and size; the walls are provided with 
small pore canals. 

Bracted Plantain {Plantago aristata Mx.). 

The seeds of this are similar in structure to those of P. lance- 
olata. The walls of the epidermal cells are mucilaginous. The 
underlying parenchyma cells and the underlying pigment layer 
are followed by the endosperm and embryo. The cells of the 
nucellus are narrow, elongated, and thick-walled. The cells of 
the embryo are isodiametric and are thin-waUed. Several species of 
the genus have been studied by Harz*. Numerous earlier papers 
and references will be found in Pammel's article in Transactions 
St. Louis Academy of Science, 9 :91. 

RUBIACEAB, MADDER FAMILY. 

Bedstraw {Galium aparme L,). 

The dry fruit of the common bedstraw is provided with hooked 
prickles. The epidermal cells are somewhat elongated, brownish. 
The triehomes consist of single hooked cells with pitted walls. The 
underlying thin-walled parenchyma cells are elongated. Harz ob- 
served mucilaginous cells in this portion of the pericarp. The 
testa is very much reduced, consisting of several layers of thin- 
walled cells with granular contents. The endosperm consists of 
an aleurone layer, thick-walled cells followed by a thick-walled 
irregular layer of cells with pore canals. Contents consist of pro- 
tein grains. 

•Samenkunde 2 ; 983. 



MICROSCOPIC STRUCTURE OF WEED SEEDS 



573 




Fig. 437. Microscopic structure of fruit of Bedstraw (Galium aparine). 

ep=epidermis. t=testa. t' =trichome. en=€ndosperm. 

(Drawing by D. H. Pammel and Charlotte M. King.) 



CUCURBITACEAE, GOURD FAMILY. 



Wild Cueumber {Sicyos angulatus L.). 



The testa of the brownish seeds consists of elongated epidenmai 
cells with narrow cell cavities; walls thickened, with pore canals. 
The underlying portion consists of a layer of one or two rows of 
cells with thin walls, and protein contents; the remaining portion 
of the testa is composed of thin-walled cells with large inter- 
cellular spaces. The related species, Echinocystis lobata, contains 
a thick, pigment layer of brownish sclerotic parenchyma followed 
by a thinner layer of thick-walled cells with blackish brown pig- 
ment. In this species, as in Sicyos angulatus, frequently portions 
of the fruit adhere to the surface. The seed coats of this family 
have been described by Harz. 



574 



WEED FLORA OF IOWA 




Fig. 438. Microscopic structure of seeds of some cultivated weeds. 
I. Wild Cucumber or Wild Balsam Apple (.Eohinooyatis lobata). II. Bur 

Cucumber (8icyos angulatua). 
ep=epldermls. U=light Una. p=parenchyma. m=malplghian layer. sol=scler- 

otic cells. 
(Drawings by D. H. Pammel and 0. M. King.) 



COMPOSITAE, COMPOSITE FAMILY. 

Large Ragweed {Ambrosia trifida L.). 

The so-called "seed" consists of an involucre of rather thick- 
walled sclerotic parenchyma cells, occurring underneath the 
epidermis; some of these cells are radially elongated, others are 
spherical in cross section, showing numerous pore canals. The 
internal layer of the involucre is composed of nearly isodiametric, 
thick-walled, sclerotic cells. The testa consists of a layer of brown- 
ish colored cells followed by a layer containing black pigment. 
Next within lies a layer of thick-walled, small, nearly colorless 
cells, then the compressed layer of the nueellus, followed by the 
nearly square cells of the embryo. 



MICROSCOPIC STRUCTURE OF WEED SEEDS 575 

Common Sunflower {Helianthus annuus L.). 

The microscopic structure of the fruit and seed has been studied 
by Hanausek, Harz, Winton and Moeller. The obovoid achenes 
are more or less four-sided. The pericarp in some varieties is 
nearly black, in others it is striped with white and black. The 
pericarp consists of thin porous walls which are dark colored in 
the black seeded varieties, although in the varieties with striped 
seeds only a part of the cells are colored. Some of the cells are 
elongated, forming duplex hairs, which are attached to what 
Haniausek called the "foot cell." The underlying hypodermal 
cells of 4-6 rows of cells are thick-walled and porous, the cells ar- 
rajiged in rows. These contain the blackish pigment, pitchlike in 
character. The third . layer consists of thick-walled sclerotic 
parenchyma cells. These cells are more or less isodiametric. This 
layer contains the fibrovascular bundles which occur adjacent to 
the thin-walled parenchyma cells. Extending into the sclerotic 
parenchyma are radial rows of thinner-walled parenchyma cells. 
This layer is followed by large thin-walled parenchyma cells. The 
testa consists of thin-walled loose parenchyma cells. The outer or 
epidermal cells are roundish and have obscurely beaded walls; 
the spongy parenchyma follows and contains the fibrovascular 
bundles. The spongy parenchyma is followed by the rectangular 
cells of the inner epidermis. The endosperm consists of one or 
two rows of aleurone cells. The epidermal layer of the embryo 
consists of small, rather thin-walled cells of the cotyledons and 
underneath this on the upper surface are several rows of palisade 
cells. These cells contain irregular spherical aleurone grains larg- 
er than those in the epidermal cells. 

Crownbeard, (Verhesina helianthoides Mx.). 

The microscopic structure of the achene includes a series of small, 
rather thick-walled epidermal cells, followed by elongated or short, 
rather thick-walled parenchyma cells. The pigment layer is com- 
posed of thick- walled cells, whose walls contain a blackish pigment. 
The testa consists of two layers ; an outer of elongated, thick- walled 
cells and an inner layer of diorter cells also colorless. The cells 
of the embryo are much larger and contain protein grains. 

Boot-jack, Spanish Needle (Bidens discoidea (T. & G.) Britton). 

The pericarp consists of an outer epidermal layer underlaid by 
a similar layer of elongated, thick-walled cells; between which are 



576 



WEED FLORA OF IOWA 



thinner-walled parenchyma cells. The outer layer of the testa 
is composed of nearly isodiametric ceUs, followed by larger thick- 
walled parenchyma cells ; cells of the lower portion compressed. The 
endosperm is much reduced, of elongated cells; embryo with row 
of outer cells longer than broad. 




Fig. 439A Fig. 439 B 

Fig. 439. Sunflower (.Helianthus annuua). 

A. Cross section of outer layers of pericarp, o, epicarp with h, hairs ; K, 
hypoderm ; H, fiber bundles separated by m, parenchyma ; p, parenchyma 
with g, fibro-vascular bundles. X 160. 

B. Epicarp with h, twin hairs, in surface view. 

After Wlnton. 



Burdock {Arctium lappa L.). 

The brownish mottled fruits consist of a thick-walled pericarp, 
the outer epidermal layer of thick-walled cells, walls colorless or 
but slightly colored; the underlying layer of six or eight rows of 
thick-walled cells, not as thick, however, as the epidermal cells. 
The first layer carries the brownish or blackish brown pigment. 



MICROSCOPIC STRUCTURE OF WEED SEEDS 



577 









Fig. 439A. Mlscroscopic structure of some weeds of the Sunflower family 

(Com^osjtoe). 
I. Small Ragweed (.Ambrosia artemisiaefolia) . II. Verbesina (.Verbesina hel- 
ianthoides) . III. Spanish Needle (.Bidena discoidea). IV. Burdock 
(Arctium lappa). 
ep=epidermis. sol=sclerotic parenchyma. t=testa. n=nucellus. en=endosperm. 
em=embryo. pal=palisade cells. 

(Drawings by L. H. Pammel and Charlotte M. King.) 

The pigment layer is followed by elongated sclerotic parencliyma 
with a narrow cell cavity; cells with granular contents. The testa 
is thin, cells elongated, cell wall thickened sUghtly, tinged with 
yellow. The testa is followed by remnants of the nucellus. The 
parenchyma cells of embryo follow thfe nuceUus. 

Wood or Field Thistle {Cirsiwm discolor (Mnhl.) Spreng.). 

The microscopic structure of the yellowish gray seeds shows a 

clear relationship to Arctium; the outer epidermal layer of the 

pericarp consists of thiek-walled colorless cells, the walls bright 

and lustrous; the pigment layer underneath the walls, not nearly 

37 



578 



WEED FLORA OF IOWA 



as thick-walled as the epidermal, pigment yellowish. The elong- 
ated sclerotic parenchyma cells lare yellowish white or nearly color- 
less; this layer is followed by the parenchyma cells of the testa and 
remnants of the niiceUus. The parenchyma cells of the embryo 
with numerous small intercellular spaces contain proteta and fat. 
The fibrovascular bundles are located one at each end of the achene. 




Fig. 440. Microscopic structure of the seeds of Thistles (Ctrsium). 
I. and II. Common Wood Thistle (.Cirsium discolor'). III. Iowa Thistle (.Cir- 

sium ioense). 
ep=thlck-walled epidermal cells. pi=plgment layer. scl=sclerotlc palisade cells 
with narrow cell-cavlty. p=parenchyma cells of testa. t=testa. n=nucellus. 
em= embryo. fv=fihro-vascular bundles. 

(Drawings by L. H. Pammel and Charlotte M. King.) 



Iowa Thistle {Cirsium ioense (Pammel) Femald). 



The microscopic structure of the seeds is similar to that of pre- 
ceding, comprising a thick-walled epidermal layer with bright 
colored walls and underlying pigment layer, an elongated sclerotic 
parenchyma and the testa of small parenchyma cells. 



MICROSCOPIC STRUCTURE OF WEED SEEDS 579 

Chicory {Cichorivm intybus L.). 

The microscopic structure of the pericarp and seed of chicory 
has been given by Harz and Lavialle. The pericarp consists of 
epidermal cells whose outer walls are irregular and cuticularized. 
This is followed by a variable number of rows, usually 10-15, of 
sclerotic parenchyma, some of the cells of which as observed by 




er 



en 



Fig. 441. Microscopic structure of the seed of Chicory (Cidhorium imtj/Bus). 

ep=epidermis. sol=sclerotic parenchyma. per=pericarp. t=testa. al=aleu- 

rone layer, en = endosperm. 

(Drawing by Charlotte M. King and D. H. Fammel.) 

Kraus, contain crystals of calcium oxalate. Beneath are 6-8 rows 
of thin-walled, elongated parenchyma. The testa consists of a layer 
of large epidermal cells, followed by smaller thin-walled parenchy- 
ma, thte inner portion much compressed. The aleurone layer is 
of elongated cells containing aleurone grains. 



Dandelion {Taraxacwm, officinale Weber). 

Harz has given an account of the structure of the pericarp and 
seed. The epidermal cells are irregular, many of the cells pro- 
longed into one-celled trichomes, the ribs forming tubercular 
processes. The underlying portion containing the thinner-walled 
parenchyma and the sclerotic parenchyma cells of the ribs. This 
is followed by several rows of compressed, elongated, thin-walled 
parenchyma cells. The testa consists of the epidermal layer of 
elongated, spirally thickened walls, followed by a compressed layer 
of parenchyma cells. The endosperm of one or two rows of 
aleurone cells. 



580 




Fig. 442. Dandelion (.Taraxacum officinale). 



BIBLIOGRAPHY. 

ANATOMICAl, STUDY OF SEED COATS. 

GENERAL. 

Buscaloni, L. Contribuzione alio studio della membrana cellulare. 

MalpigMa 6 :3-40, 217-228 ; pi. 1-2. 7 :105-162 ; pi. 1-2. 8 :3-13 ; 

pi. 1-3. 1875. 
Dahmen, Max. Anatomisch-physiologiseh Untersuclitmg iiber d. 

Funiculus d. Samen. Brings. Jahrb. f . wiss. Bot. 23 :441-478 ; 

pi. 20-22. 
Pluckiger, F. A., and Hanbury, D. Pharmacographia: a history 

of the principal drugs of vegetable origin met with in Great 

Britain and British India. Ed. 2, 803. London, 1879. 
Frank, A. B. Ueber die anatomische Bedeutung und die Entste- 

hung der vegetabilischen Schleime. Pringsh. Jhrb. f. wiss. 

Bot. 5 :161 ; pi. 15-16. 1886. 



MICROSCOPIC STRUCTURE OF WEED SEEDS 581 

Grodt'rin, H. Etude histologique sur les teguments semineaux des 

angiosperms. Bull. Soc. des Sci. de Nancy. 5:109-219. 
Godfrin, J. Reeherehes sur ranaitomie comparee des cotyledons 

et de 1 'albumen. Ann. Sei. Nat. Bot. Soc. des Sci. de Nancy. 

5 :109-219 ; pi. 1-5. 1880. 
Gruignard, L. Rechercbes sur le developpemient de la graine et en 

particulier du tegument seminal. Jour, de Bot. 7 :1-14, 21-34, 

57-66, 97-106, 114-153, 205-214, 214-250, 282-296, 303-331. 
Hanausek, T. F. Die Nahrungs-und Genussmittel aus dem 

Pflanzenreiche. 485, 100 f. 
Harz, C. D. Landwirthschaftliehe Samenkunde. 1:552; /. 1-14. 

2 :553-1362 ; /. IS-SOL Berlin, 1885. 
Verholzungen die hoheren Pflanzen, speciell iiber 

das Vorkommen von Lignin in Samenschalen. Bot. Centrbl. 

24:21-31, 59-61. 1885. 
Hofmeister, "W. Ueber die zu Gallerte aufquellenden Zellem der 

Aussenflache von Samen und Perikarpien. Ber. d. Kon. Sachs 

Gesell. D. Wiss. Sitz. 18-37. Feb. 20, 1853. 
Jenkins, T. B. H., & Winton, A. F. American feeding stuffs. 

Bull. U. S. Dept. Agr., Off. Exp. Sta. 11:155. 1892. 
Joxe. A. Siir I'ouverture des fruits ind&hiseents a la germination. 

Ann. de Sci. Nat. IX. 15:257-375. 
Junowicz, R. Die Lichtlinie in den Prisemnzellen der Samen- 

schalen. Sitzb. d. k. Akad. d. Wissensch. Wien. 76 :336-352 ; 

2 pi. 
Mattirilo, 0. La linea lucida nelle cellule Malpigbiane degli in- 

tegumente seminali. Mem. della R. Accad. delle Sci. II, 37 :30 ; 

1 pi. 1885. 
Mattirilo, 0., and Buscalioni, L. Letture suUa funzione della linea 

lucida nelle cellule Malphigiane. Nota preventiva. . Atti R. 

Ace. delle Sci. di Torino. 25 :310-315. 1890. 
Moeller, Josef. Mikroskopie der Nahrungs-und Genuss-mittel aus 

dem Pflanzenreiche. 394; /. 308. Berlin, 1886. 
Pammel, L. H. Some methods in the study of mature seeds. 

Jour. Appl. Micro. 1 :37-39 ; 6 f. 1898. 
Sempolowski, A. Beitriige zur Kenntniss des Baues der Samen- 

schale. Inaug. Dis. Leipsig. 1874. 60; pi. 1-3. 
Ueber den Bau der schale landwirtschaftliche 

wichtiger Samen. Landw. Jahrb. 3:824-866; pi. 7-8. 
Winton, A. L. Anatomy of weed seeds. Rept. Conn. Agr. Exp. 

Sta. 1902 :345-358. 



582 WEED FLORA OF IOWA 

AMARANTAGEAE. 

Gravis, A., and Constantinesco, Mile. A. Contribution a ranatomie 
des Amarantacees. Arch. Inst. Bot. Univ. Liege. IV:1-146. 
Harz, C. D. See Landwirthschaftliche Samenkunde. 2:1101. 

ASCLEPIADACEAE. 

Harz, C. D. See Landwirthsehaitliclie Samenkunde. 2:963-966. 

BERBERIDAOEAE. 

Pannmel, L. H., Bumip, J. R., and Thomas, H. Some studies on 
the seeds and fruits of Berberidaceae. Proc. la. Acad. Sci. 
5:11-25. 

BORAGINAGEAi:. 
Harz, C. D. See Landwirthschaftliche Samenkunde. 2:870. 
CABYOFSYLLACEAE. 

Harz, C. D. See Landwirthschaftliche Samenkunde. 2 :1075-1089. 

Winton, A. L. Anatomy of Cockle seeds. Winton's Microscopy 

of vegetable products. 148 ; Cowherb, p. 151, Soapwort, p. 151. 

CHENOPODIACEAE. 

Harz, C. D. See Landwirthschaftliche Samenkunde. 2 :1092-1039. 
Pammel, L. H. Bull. la. Agrl. Exp. Sta. 26:20. 

C0MP08ITAE. 

Gerdts, C. L. Ban und Entwickelung der Kompositenfrucht mit 

besonderer Berucksichtigung der offizineUen arten. These 

Inaug. Leipzig, 1905. 
Goldflus, Mathilda. Sur la structure et les fonctions de 1 'assise 

epitheliale et des antipodes chez les Composees. Joum. de 

Bot. Morot. 1898-1899. 
Hanausek, T. F. Ueber das Perikarp und Perikarpsekret der 

Gattung Carthamus. Ber. d. deutsch. Bot. Gesellsch. 29 :13-18 ; 

pi. 1. 
Zur entwickelungsgeschichte des Perikarps von 

Helianthus annuus. Ber. d. deutsch Bot. Gesellsch. 20:449; 

pi. 21. 
Harz, C. D. See Landwirtschaftliche Samenkunde. 2:841-866. 
Lavialle, P. Ovaire des Composees Ann. d. Sci. Nat. IX, 15: 

(No. 2.) 65-149; 97 f. 
Nichols, Mary A. Aehenial hairs of Compositae. Bot. Gaz. 18 :378 ; 

pi. 35. 



MICROSCOPIC STRUCTURE OF WEED SEEDS 583 

Prister. Oelliefemde Compositemfruchte. Landw. Versuch. 

Stat. 43. 
Rosenthaler and Stadler. Bin Beitrag zur Anatomie von Cnicus 

ienedictiis. Arch d. Pharm. 246 :436. 
Schwere. Zur Bntwicklungsgesehichte der frucht von Taraxacum 

officinale. Fiona 82. 1896. 
Winton, A. L". Anatomy of the seed of the Sunflower {H. annuus). 

See "Winton 's Microscopy of vegetable products. 194-197. 

GONVOLVULAGEAE. 

Harz, C. D. See Landwirthsehaftliche Samenkunde. 2:751-767. 
Guttenberg, H. von. Ueber die anatomischen Unterscheidung der 

Samen einiger Cuseuta — ^Arten. Naturwiss. Zeitschs. Forst. 

u. Landw. 7:32-43. 1909. Abs. in Bot. Cenfer. 111:578. 

GBVGIFERAE. 

Burchiard, 0. Ueber der Bau der Samenschale einiger Brassica — 

und Simapis Arten. Journ. Fiir Landw. 42 :125 ; 44 :377. 
Cordemoy, J. de. Recherches anatomiques sur les genres Brassica 

et Sinapis. 190; 45 f. Paris, 1907. 
Fournier, Eug. Recherches anatomiques et taxonomiques sur la 

famille des Cruciferes et particulierement sur le genre Sisym- 
brium. 154; pi 1-2. Paris. 
Harz, C. D. See Landwirthsehaftliche Samenkunde. 2:914-916. 
Bammel, L, H. On the seeds and testa of some Cruciferae. Cont. 

Bot. Dept. la. Agr. Coll. 6 :25. Reprint from Am. Mo. Mie. 

Jour. 
Pieters, A. J., and Charles, V. K. The seed coats of certain species 

of the genus Brassica. Bull. U. S. Dept. Agr. 29 :19. 
Schroder. Untersuchung der Samen der Brassica — Arten und 

Varietaten. Landw. Vei;suchs — Station. 14. 1871. 
Uloth, W. Ueber Pflanzenschleime und seine Entstehung in der 

Samen epidermis von Pla/ntago maritima und Lepidmm 

sativum. Flora. 58 :173-200, 209-216 ; pi. 6. 
Winton, A. L. Anatomy of oil seeds among Cruciferae. Microscopy 

of vegetable products. 174-193. 

EVPHORBIAGEAE. 

Harz, C. D. See Landwirthsehaftliche Samenkunde. 2:825-841. 
Pammel, L. H. On the seed coats of the genus Euphorbia. Contr. 

Shaw School of Bot. 8 :543-568. Trans. St. Louis Acad. Sci. 

5 :543-568. 



584 WEED FLORA OF IOWA 

0-ENTIANACEAE. 

Guerin, . Developpement et structure anatomique du tegument 

seminal des Gentianees. Compt. Ren. Acad, des Sci. de Paris, 
vi: 136. 

GRAMINEAE. 

Bessey, C. E. Structure of the wheat grain. Bull. Neb. Agr. Exp. 

Sta. 32 
Hanausek, T. F. Vorlaufige Mittheilung iiber der von Vogl. in 

der Frucht von Lolium temulentum entdeckten Pilz. Ber. 

Deutsch. Bot. Ges. 16 :203. 1898. 
Harz, C. D. See Landwirthschaftliche Samenkunde. 2 :1145-1349. 
Hillman, F. H. The seeds of fescue grass and chess. Bull. U. S. 

Dept. Agr., Bur. PI. Ind. 25 -A. 

Holm, Theo. A study of some anatomical characters of N. A. 

Graminese. Bot. Gaz. 16 :166-171, 219-225, 275-281. 17 :358-363. 

20:362-365. 21:357-360. 22:403-406. 
Jumelle. Sur le constitution des fruit des Graminees. Compt. Rend. 

107:285. 1888. 
Krutizky. On some peculiarities in the structure of the caryopsis 

of wheat. Just's Bot. Jahresb. 21: (Abt. I) 571. 1893. 
Moeller, J. Die Mikroskopie der Cerealien. Pharm. CentraUi. 25 : 

507. 1884. 

Pammel, L. H. Comparative anatomy of the com caryopsis. Trans, 
la. Acad. Sci. 1897. 5. 

The histology of the caryopsis and endosperm of some 
grasses. Trans. St. Louis Acad. Sci. 1898 :199-220. 
Pammel, L. H., Weems, J. B., and Lamson Seribner, F. The 

Grasses of Iowa. Bui. la. Geol. Survey. 1 :525. 
Winton, A. L. The anatomy and microscopic identification of the 
fruits of darnel and chess. Rept. Conn. Agr. Exp. Sta. 1903. 
165-174. 

Anatomy of the seed of green foxtail. Rept. Conn. Agr. Exp. 
Sta. 1902. 352-358. 
Anatomy of seed of yellow foxtail. Ibid. 1902: 358. 
Ueber amerikanische Weizenausreuter. Ztschr. Unters. 
Nahr-Genussm. 6 :433. 

LABIATAE. 
Harz, C. D. See Landwirthschaftliche Samenkunde. 2 :866-870. 



MICROSCOPIC STRUCTURE OP WEED SEEDS 685 

LEGUMIN08AE. 

Beck, G. Die Samenkunde einiger Leguminosen. Sitzb. K. K. 

Akad. Zu. Wien. 1878. 79. 

Vergleieliende Anatomie d. Samen von Vicia und Ervum. 

Sitz. d. k. Akad. d. Vissench. Wien. 76 :335-352 ; 2 pi. 
Chalon, J. La graine des legumineuses. I. Cellule de la carapace. 

II. Albumen. Soe. des Arts, et des lettres du Hainaut. 1875. 

66; pi. 1-3. 
Haberlandt, G. Ueber die Entwieklungsgeschichte und dem Bau d. 

Samensehule bei der Gattung Phaseolus. Sitz. d. k. Akad. d. 

Wissensch. Wien. 75:33-47; 2 pi. 1877. 
Harz, C. D. See Landwirthschaftliehe Samenkunde. 2; 562-736. 
Mattirolo, O. Rieerche anatomo-fisiologische sui tegumenti seminali 

delle Papilianacee. Nota preventivia. Atti. R. Aecad. delle 

sei. di Toniro. 24. 1889. 
Rieerche anatomo-fisiologische sui tegumenti seminali 

delle Papilionacee. I. Anatomia. II. Stor ia di sviluppo del 

tegumenti seminali. III. Contribuzioni alio studio della fisiol-. 

ogia del seminali. IV. Bibliographia. Reale Acead. delle Sci. 

di. Torino II, 42:223-318, 359, 445; pi. 1-5. 1892. 
Nadelmann, Hugo. Ueber d. Sehleimendosperme d. Leguminosen. 

Prings. Jahrb. Wisenseh. Bot. 21 :609-691 ; pi. 16-78. 1890. 
Pammel, L. H. Anatomical character of seeds of Leguminosse. 

Trans. St. Louis Acad. Sci. 9:91-263; Tables A-G; pi. 7-35. 
The seed coats of Grotalaria sagitalis and Astragalus mollis- 

simus. Bienn. Bept. Ia. St. Agr. Coll. and Farm. 13 :17-24 ; 

pi. 52-53. 

On the structure of the testa of several leguminous seeds. 

Bull. Torr. Bot. Club. 13 :17-24 ; pi. 52-53. 
Schips, K. Ueber die Cuticula und die Auskleidung der Intercel- 

lularen in den Samenschalen der Papilionaeeen. Ber. Deutsche. 

Bot. Ges. 11:311. 1893. 
Schively, Adeline F. Contributions to the life history of AmpM- 

carpaea monoica. Cont. Bot. Lab. Univ. Penn. 1 :270-363 ; pi. 

19-36. 
Schleiden, M. J. Beitrage zur Entwickelungsgeschichte d. Bluthen- 

theile bei d. Leguminosen. Nov.-Oct. K. Leopold-Carol. Akad. 

Naturf. 19:59-84; pi. 9-11. 
Winton, A. L. Anatomy of the seeds of Yicia sativa. Winton's 

Microscopy of vegetable products. 251-252. 



586 WEED FLORA OF IOWA 

MALVACEAE. 

Harz, C. D. See Landwirthsehaftliche Samenkunde. 2 :736-750. 
Rolfs, P. H. The seed coats of Malvacese. Bot. Gaz. 17 :33-39. 

ONAORACEAE. 

Harz, C. D. See Liandwirthschaftliche Samenkunde. 2 :875-878. 

PHYTOLAGGAGEAE. 
Harz, C. D. See Landwirthsehaftliche Samenkunde. 2:1088-1031. 

PLAN TAOIN ACE AE. 

Harz, C. D. Sec Landwirthsehaftliche Samenkunde. 2 :982-987. 

Winton, A. L. Anatomy of plantain seeds. Microscopy of vegeta- 
ble products. 163. 

Uloth, W. Ueber Pflanzenschleime und seine Bntstehung in der 
Samenepidermis von Plcmtago maritima und Lepidum sativum. 
Flora. 58:193-200, 209-216; pi. 6. 1885. 

POLYGOnACEAE. 

Harz, C. D. See Landwirthsehaftliche Samenkunde. 2:1101-1113. 

Sirrine, Emma. Structure of the seed coats of Polygonaces. Proc. 
la. Acad. Sci. 2:128-134; pi. 7-9. 

Winton, A. L. Anatomy of seed of black bindweed. Rept. Conn. 
Agr. Exp. Sta. 1902:340-352. Winton 's Microscopy of vege- 
table products. 157-158. 

RAJslVi^GULAGEAE. 

Harz, C. D. See Landwirthsehaftliche Samenkunde. 2:1063-1074. 
Winton, A. L. Anatomy of Bawiinculus arvensis. Microscopy of 
vegetable products. 152-154. 

8APINDAGEAE. 

Guerin, M. P. Developpement de la graine et in particulier du 
tegument seminal de quelques Sapindacees. Jour, de Bot. 15; 
336-348. 

SCROPHVLARIACEAE. 

Bachmann, E. Die Entwicklungsgeschichte und der Bau der 

Samenschalen der Scrophularineen. 179. Halle, 1880. 
Harz, C. D. See Landwirthsehaftliche Samenkunde. 2:966-973. 

80LANANCEAE. 
Harz, C. D. See Landwirthsehaftliche Samenkunde. 2:997-1025. 



MICROSCOPIC STRUCTURE OF WEED SEEDS 587 

UMBELLIFERAE. 

Harz, C. D. See Landwirthsebaftlielie Samenkunde. 2:1030-1063. 
Winton, A. L. Anatomy of the seeds of wild carrot. Microscopy 
of vegetable products. 158-159. 

VRTICACEAE. 

Harz, C. D. See Landwirthschaftliche Samenkunde. 2:978-982. 
Winton, A. L. The anatomy of certain oil seeds with especial 

reference to the microscopic examination of cattle foods. Conn. 

Agr. Exp. Sta. 1903. 175-180. 

Microscopy of vegetable products. 212-217. 



CHAPTER IV. 

MORPHOLOGY OF LEAVES 
AND FLOWERS 

By 
J. N. MARTIN 



CHAPTER IV. 



LEAVES. 



INTRODUCTORY STATEMENT. 



Leaves are distinguishable into primary and secondary. The pri- 
mary leaves arise directly from the first cells produced by the 
division of the fertilized egg and in seed plants are called cotyle- 
dons. They are usually transient, and not rarely lare so distorted by 
acting as storage places for reserve food that they do not function 
as foliage leaves at all. The secondary leaves arise upon the sides 
of the stem and are the ordinary foliage leaves of the plant. They 
are very important organs in connection with the work of nutrition. 



PARTS OF A LEAF. 



In the typical foliage leaf there are three parts — the expanded 
portion which is called blade or lamina, the leaf stalk (petiole), 
and a pair of lappendages at the base of the petiole known as 
stipules. 




Fig. 443. Apple leaf; b, blade; p, petiole; s, stipules. 
(After Thomg.) ■ 



592 WEED FLORA OF IOWA 

In some cases, as in the Hare's-ear mustard, {Conringia orient- 
alis) and in the upper leaves of Canada thistle {Girsmm arvense) 
the petiole is absent .and the blade is directly attached to the stem. 
Such leaves are designated as sessile. 




Fig. 444. Sessile leaf of Thistle. 
(After Thomfi.) 

The stipules are small leaf-like structures which appear at the 
place where the leaf is attached to the stem. They are very often 
absent but are conspicuous in the cinquefoils, vetches and other 
members of the rose and pulse families. 

VEINING. 

The blade of the leaf is traversed by a frame work of fibro- 
vascular bundles known as veins. In the leaves of grasses, sedges, 
and rushes, the veins run more or less parallel from the base to 
the tip of the leaf. These leaves are the parallel-veined type. In 
the leaves of most of our common weeds, the veins are branched so 
as to form a network. These are the netted-veined type. 

Palmate and pinnate veimng. — ^Netted-veined leaves are palmately 
veined when the primary ribs radiate from the base of the petiole 
as in the great ragweed. If there is only one midrib from which 
smaller ribs extend both ways, as in dandelion, dock, goldenrod, 
etc., the veining is said to be pinnate (meaning featherlike) . 

LEAF ARRANGEMENT. 

Sometime.} as in dandelion and evening primrose, the stem does 
not appear above ground or is late in appearing and the leaves at 
the surface of the ground are called radical leaves in distinction 
to the stem or cauline leaves. 



MORPHOLOGY OF LEAVES AND FLOWERS 



593 




Pig. 4451 Kg. 445II 

Fig. 445. I. Vetch. (Lathyrus aphaca), showing opposite leaves; r, tendril; b, 

flower ; f, fruit. Stipules performing the function of leaves. 

II. Grass type of leaf ; L, leaf blade ; G, leaf sheath ; Lig, ligule. 

(After Thomfi.) 



Leaves are usually arranged so as to secure the best exposure to 
the light. In the milkweed there is a pair of leaves at each node 
and the two leaves are on opposite sides of the stem. Here the 
leaves are said to be opposite. 




Fig. 445. 



38 



The clinging stem of the Bindweed, showing the alternate leaves. 
(After ThomS.) 



594 



WEED FLORA OF IOWA 



In the asters, ironweed, goldenrods, lamb's quarter, etc., there 
is only one leaf at each node, and they are spoken of as alternate. 
In some cases several leaves appear at each node in a whorl. Such 
examples of whorled or verticillate leaves are found in the bed- 
straws and Joe Pye weed. 

BRANCHING. 

The outline of a blade is extremely various. When the general 
outline is completely filled out and the margin represents an even 
line, the leaf is said to be entire. Examples of such leaves are 
found in water pepper {Polygowum hydropiper) , mild water pepper 
(P. hydropiperoides) , Fennsylvajiia smartweed (P. pennsylvani- 
cutn), etc. 



Fio. 447. Leaf of the Privet plant showing entire margin. 

To designate the amount and character of the branching, the 
following terms are used: 




\ 



Fig. 448IV 



Fig. 4481 

Fig. 448. I. Triangular, Ipbed leaf of the Notch- weed. II. The renlform or 
kidney-shaped leaf of Ground Ivy, Illustrating wavy margin. III. Arrow- 
shaped leaf of Bindweed. IV. Spear-shaped leaf of Sorrel. 
(After Thome.) 



Fig. 448II Fig. 448III 

Triangular, Ipbed leaf of the Notch-weed. II. 



MORPHOLOGY OF LE3AVES AND FLOWERS 



595 



Wavy margin, when the margin forms a wavy line bending 
slightly inward and outward in succession, as in the bitter dock 
{Bumex obtusif alius). 




Pig. 4491 T_ Fig. 449 II Pig. 449 III Pig. 449 IV Pig. 449 V 

Fig. 449. I. Leaf of Daisy, spatulate in shape with a serrate margin. II. 
Spiny-pointed, serrulate leaflet of alfalfa. III. "Wavy-margined leaf of 
Pigweed^' (.Amarantfms) . VT. Ovate, dentate leaf of Snowball. V. Serrate 
leaf of 'Hen-bit. 

(After Thome.) 



Toothed or dentate, when the margin is cut into sharp teeth and 
the teeth point out, as in the lower leaves of the daisy fleabane 
{Erigeron annuus). 




Fig. 450. Cleft and plnnatifid leaves of Wild Lettuce. 
(After Thome.) 



596 



WEED FLORA OF IOWA 



Serrate, when the teeth point forward, as in the common sun- 
flower {Helicmthus awnuus). 

Serrulate, when the margin is finely serrate as in milk purslane 
(Euphorbia maoulata). 

Crenate, when the teeth are broad and rounded as in the common, 
mallow {Malva rotundifoUa) . 





<^^^ 




Fig. 



Fig. 451 1 
451. Compound leaves. 



Pig. 451 II Fig. 451 III 

I. Leaf of Clover with three leaflets. IL. 



Pedately divided leaf of Dragon Root. III. Pinnate leaf of Locust withi 
19 leaflets. 

(After Thomd.) 

Lohed, when the leaf is deeply cut, as in the great ragweed. The- 
projecting portions are then called lobes. When the incisions are- 
sharp the term cleft is often used; the leaf is pinnatifid when the 
incision extends almost to the midrib, as in the prickly lettuce 
{Lactuca scariola) ; it is pinnate when the incisions have extended?, 
to the midrib and each separated portion takes the character of a 
leaf. Bach of the smaller portions is a leaflet, and the kaf is now 
considered compound. The spotted eowbane (Cicuta macuUda), 
spring vetch {Vicia sativa) and cinquefoil (Potentilla monspelien- 
sis) are good examples. 



MORPHOLOGY OF LEAVES AND FLOWERS 



597 




Fig. 452 I 



Fig. 452 II 



Fig. 452. I. "Wedge-shaped leaflet of Horse Chestnut. 

the Wall Pellltory. 
(After Thomg.) 



II, Pointed leaf of 



All of the above marginal cliaracters may characterize the lobes 
of a simple leaf or the leaflets of a compound leaf. 



LEAF STRUCTURE. 



Before considering the work t)f the leaf it will be necessary to 
become acquainted with its structure. 

The leaf is covered with an epidermis which is composed of com- 
pact layers of cells, so modified as to protect the more delicate 
inner parts. The epidermis may be peeled off as a delicate trans- 
parent skin. A microscope shows that this transparent skin is 
inade up of many cells, so closely fitted together as to make a contin- 
uous sheet or covering. Many slitlike openiu'gs between two cres- 
cent-shaped cells {guard cells) appear quite evenly distributed in 
the epidermis. The opening and guard cells constitute the stoma 
(plural stomata) which really means mouth. These numerous 
openings are passage ways into the interior of the leaf and per- 
mit interchange of gases between outside aif and the air in the 
leaf interior. The guard cells can eb«ffige their shapa, and so vary, 
the size of the opening. In horizontal leaves the stomata are chiefly 
and sometimes exclusively on the lower surface, a fair average 
number being about 62,500 to the square inch. 



598 



WEED FLORA OF IOWA 




Fig. 453. I. A cross section of a leaf of Feppergrass (.Jjepidium) showing 
the upper epidermis (e), the lower epidermis (S), stoma (s), the cblor- 
enchyma (c) consisting of closely placed palisade cells (p) and more 
loosely placed spongy tissue (f), and a vascular or conductive tract (v) 
with bundle sheath (b), hadrome or xylem (h), and leptome or phloem (1). 

II. Surface view of stoma from Easter Lily ; g, the kidney-shaped guard cells en- 

closing the stomatal aperture (s) ; b, the subsidiary cells. 

III. Cross section of stoma ; g, guard cell ; s, central slit ; o, outer slit ; 1, 

inner vestibule ; c, stomatal cavity ; b, subsidiary cell. 

IV. Surface view of a grass stoma (Poa pratensia) showing the guard cells 
(g). with their dumb-bell-shaped Imnlna ; b, subsidiary cells with prominent 
nucellus (n). 

v. Median cross section and cross section through end of stoma of Poa annua; 

g, guard cell lumlna ; b, lutnina of subsidiary cells. 

VI. A cross section of a leaf of blue violet {Tiola oucullatay showing a single 

row of elongated palisade cells (p), and the loose spongy tissue (f). 

(Drawings after Cowles modified by Charlotte M. King.) 



A cross section of a leaf will show the interior filled with a mass 
of thin walled cells containing green bodies {chloroplasts) . This 
inner mass of thin walled cells is called the mesophyll and is the 
food making tissue of the leaf. In the leaves of most weeds the 
cells just under the upper epidermis are much elongated and stand 
at right angles to the epidermis. These elongated cells are known 
as the palisade-cells. Between the palisade-cells and lower epi- 
dermis is the spongy tissue made up of irregularly shaped cells, 
so loosely joined as to form a system of intercellular spaces which 
permit the circulation of gases through the interior of the leaf. 
In the lower epidermis are seen the stomata with the air cham- 
bers beneath. Scattered through the mesophyll are the cross sec- 
tions of veins and veinlets which form the frame work of the leaf 
and conduct materials to and from the green working cells. 



MORPHOLOGY OF LEAVES AND FLOWERS 



599 




B^G. 454. Section of leaf of Bromus mollis. Car, irnd nerve D leptome H 
hadrome ; B, bulliform cells ; Ste, stereome ; CB chlorophyll bearing par 
enchyma ; EC, epidermal cells ; Tri, triohone. 
(Sirrine and King.) 



FUNCTION OF LEAVES. 

Photosynthesis. This is the process by which sugar and starch 
are produced for the plant. It is really a process of food manufac- 
ture by which raw materials are made into plant food and is an 
exceedingly important one, for upon it depends the lives of all 
plants and animals. 

If an active leaf be submerged in water in the sunlight, bubbles 
will be seen continuously forming on the leaf surface and rising 
through the water. If light is excluded, the action will cease, and 
by increasing and decreasing the amount of light, it will be found 
that the process varies with the amount of light. An examination 
of this gas will show that it is oxygen. It has also been found that 
at the same time the oxygen is given off by the leaf, oarbon dioxide 
(COo) is taken in, and that the outgo of oxygen and intake of car- 
bon dioxide have a close relation. 



600 WEED FLORA OF IOWA 

The formula for sugar shows that it is composed of three ele- 
ments, carbon, hydrogen, and oxygen. These elements are furnished 
by the carbon dioxide (CO2) which is taken in from the air, and 
the water (HjO) which is taken from the ground by the roots and 
conducted to the leaf tissue by the vascular bundles of the plant. 
Although CO2 and H2O furnish the necessary elements for sugar 
and starch, these are only the raw materials and some agent or iac- 
tory is needed to cause these elements to combine and to combine 
in the right proportions. These factories are the ehloroplasts, which 
give the green color to the entire leaf. The green pigment (chloro- 
phyll) is the active agent of the chloroplast in the manufacture 
of sugar. The process by which these raw materials are combined 
is not well understood, and it seems that several simpler products 
are formed before sugar is produced. We know that CO2 plus 
HjO forms carbonic acid (OH. COOH). The carbonic acid is prob- 
ably reduced to formaldehyde (H. COH). If six molecules of for- 
maldehyde were properly combined we would have one of the sim- 
ple sugars (HeCeOgHg) or better written (CgHiaOg). Two mole- 
cules of the simpler sugars combined with one molecule of water 
eliminated will give cane sugar — CoHijOg plus CsHi206=Cane 
sugar C12H22O11 plus HjO. By a further synthesis starch is pro- 
duced. 

When formaldehyde is produced as described above, oxygen is 
eliminated and this forms the escaping bubbles from the submerged 
leaf. 

In this process of photosynthesis, the ehloroplasts constitute the 
factory, carbon dioxide and water furnish the raw materials, sugar 
and starch are the products, and sunlight is the necessary condition 
without which the machinery will not run. 

Respiration. Plant cells as well as animal cells have much work 
to do and in order to perform work, energy is needed. Plant cells 
transform material into cell walls, increase and repair protoplasm, 
divide and do many other things which require energy. This work 
never ceases as long as the plant lives. The external indication of 
it is the absorption of oxygen and the giving out of carbon dioxide. 
This exchange is spoken of as respiration. It will be noted at once 
that this is exactly the reverse of what takes place in photosynthe- 
sis. During the day both carbon dioxide and oxygen are being 
both absorbed and eliminated. Photosynthesis and respiration are 
independent processes and must not be confused. 



MORPHOLOGY OF LEAVES AND FLOWERS 601 

Transpiration. "We are familiar witb the fact tbart; the air is 
continually taking up water in the form of vapor. ,A dish filled 
with water and exposed to the air in the laboratory or out of doors 
will soon become dry. We hang wet clothes upon the line so that 
the ladr will take up the water which they contain. When we look 
into the physics of this process, we find that the water is really the 
active agent, and that it is continually changing into vapor and 
passing into the air. This process of changing into vapor we call 
evaporation, and its rate depends upon temperature, the amount 
of moisture already present in the air, and atmospheric pressure. 
This same process of evaporation goes on in the leaf, for the air 
surrounds the leaf and fills the intercellular spaces within. This 
continuous loss of moisture from the leaves is called tramspiration. 

As seen in photosynthesis, water must be present in the leaf cells 
in sufficient quantity or the process of food making will be hindered. 
Water is further needed for dissolving and transporting food ma- 
terials. It is evident that transpiration is continually diminishing 
this quantity of water which is so necessary and if the supply, which 
is furnished from the ground through the roots and stems, does not 
equal the loss, disaster will come to the plant. So far transpira- 
tion seems to be only a detriment to the plant. It is thought to be 
of use in that it increases the flow of the water from the soil and 
through the plant and thus increases the amount and better dis- 
tributes the salts secured from the soil. 

It is remarkable how well most weeds can thrive, when economic 
plants are suffering severely from trpjispiration. This may be due 
to protective modifications which cut down transpiration or to the 
ability to supply the loss through a more efficient root system. 

One of the harmful effects of weeds is the taking from the soil 
of the water which economic plants need. According to careful 
estimates a sunflower {Eelianthus annuus) six feet high transpires 
on the average about 1 quart per day. A grass plant has been found 
to give off its own weight of water every ' twenty-four hours in 
hot, dry summer weather. This would make about 61/2 tons per acre 
or more than one thousand gallons every twenty-four hours for 
ordinary grass fields, or rather about 200 gallons for a plot about 
the size of a city lot. From the above figures we can form some 
notion of the immense loss of water from the soil through weeds, and 
see how weeds can retard the growth of economic plants. 



602 



WEED FLORA OF IOWA 



LEAF PROTECTION. 

Such an important organ as the leaf, witli its delicate active tissue 
well displayed, is exposed to numerous dangers. Chief among these 
dangers are excessive transpiration and intense light. By regu- 
lating the opening in the stomata which are the chief passageways 



Fig. 455 I 



Fig. 455 II 




Fig. 455 V Fig. 455 IV Fig. 455 IH 

Fio. 455. Some protective structures of leaves and stems. I. One-celled hair 
of the Pelargonium. II. Multicellular hair of Geranium. III. Scale of 
Oleaster (Elaeagnua). IV. Prickle from common Hop. V. Stinging 
hair of Nettle. 

(After Thom6.) 



MORPHOLOGY OF LEAVES AND FLOWERS 



603 



for the escaping moisture, the leai is able to check transpiration. 
The various epidermal modificiations which are quite common among 
the weeds afford protection. In some cases this consists of a waxy 
layer on the outside of the epidermis as in some milkweeds and some 
species of wild lettuce. This layer of wax prevents the escape of 
moisture, and protects the chlorophyll-bearing tissue of the leaf 
from the intense light rays. 

Another very common protective structure upon the leaves is 
to be found in the great variety of hairs developed by the epidermis. 
In the mullein the hairs are so prominent that they form a felt- 
like covering. Among the cinquefoils and thistles, thp hairs are 
usually not branched as in the mullein and the covering is not so 
dense. 




Fig. 456. Urticating hairs and cutting leaves, a, urticating hair of Nettle; 
b, bristle of Bugloss ; c, barbed margin of a leaf of Sedge ; d, barbed margin 
of a leaf of Grass. 

All stages from those in which the hairs are very small, giving 
the leaf a downy appearance, up to the extreme case in the mullein, 
can be. found among the weeds. 



604 



WEED FLORA OF IOWA 
FLOWERS. 



A satisfactory definition of a flower, has not yet been agreed 
upon by botanists. For this reason it seems better to describe a 
flower rather than attempt to define it. 




Pig. 457. 



Complete flower ; cal, calyx ; cor, corolla ; p, pistil, and s, stamens. 
(Alter Thomfi.) 



A complete flower consdsts of four cycles or sets dS organs — sepals, 
petals, stamens ajid pistils. The sepals taken together constitute 
the calyx; the petals taken together constitute the coroUa. 

Since the cells of the stem most active in forming new organs lie 
in the tip, it seems most natural that the organs appearing last, 
would be at the stem tip and that the age of organs would increase 
as their distance from the stem tip. According to this scheme, the 
succession of floral sets would be sepals, petals, stamens and pistils. 
This is probably the order of succession in many flowers, but many 
exceptions have been found. In shepherd's purse (Capsella) the 
petals are last to appear, while in the dandelion and other com- 
posites the sepals are last to appear. 




Pig. 458. Diagrammatic cross section of a perfect flower. St, ovary showing 

two cells ; S, stamens ; B, corolla ; K, calyx. 

(After -ThomS.) 



MORPHOLOGY OF LEAVES AND FLOWERS 



605 



Since the work of the flower is to produce seed, and seed forming 
is due to the co-operation of the stamens and pistils, these are 
known as the essential organs of the flower. A flower is a perfect 
flower if it contains both of the essential organs. The simplest 




Fig. 459. 'Essential organs of the flower of the Black Mustard, a, two short 
stamens ; b, four long stamens. Pistil is enclosed by the stamens ; the 
filiform body is the filament of the stamen ; the enlarged portion of the 
stamen is called the anther. 

(After ThomS.) 



flower would have one stamen or one pistil and no corolla or calyx. 
Imperfect flowers are designated as staminate when they contain 
stamens, but no pistils; pistillate when they contain pistils but no 
stamens. The term "bisexual" is applied to the flower which con- 
tains both stamens and pistils. This is the most common type of 
flower. 





Fig. 460. Irregular flower of a leguminous plant, dissected so as to show the 

difference in shape and size of petals. 

(After Thomfi.) 

Plants, such as ragweed and corn, which have pistillate and 
staminate flowers (i. e., pistils and stamens in separate flowers but 
both kinds of flowers on the same plant) are monoecious (one house- 
hold) . Such plants as the red campion {Lychnis dioica) , mulberry, 
willows and poplars, which bear the pistillate flowers on one plant 
and staminate on .another are dioecious (two households). A plant 



606 



WEED FLORA OF IOWA 




Fig. 461. II. Stamlnate flower of the Hazel showing the stamens and bracts. 
III. Pistillate flower showing pistils and enclosing tracts. IV. Style and 
two stigmas. Catkin at middle of stem containing the stamlnate flowers; 
female flower at top of stem. The Hazel is a monoecious plant. 
(After Thomfi.) 

which bears some perfect flowers and some staminate or pistillate 
only, is polygamous. 




Fm. 462. Longitudinal section through the hypogynous flower of the Pink, show- 
ing the attachment of floral parts. 
(After Thomfi.) 



MORPHOLOGY OF LEAVES AND FLOWERS 



607 




riG. 463. I and III. Staminate and pistillate catkins of the Willow. II and IV. 
Staminate and pistillate flowers. V. Cross section of ovary showing the 
one cell, two placentae and ovules. VI and VII show opening of pod 
and character of the seed. Since the male and female catkins are borne 
on different trees, this plant is dioecious. 

(After Thomg.) 



608 



Kg. 464 I 



WEED FLORA OF IOWA 

Fig. 464 II Fig. 464 III 



Wg. 464 IV 




Fig. 464. Flowers with petals Joined (gamopetalous). I. Globularia. II. 

Jasmine. III. Borage, rv. Ground Ivy. 

(After Thome.) 




Fig. 465. Gamosepalous and gamopetalous flower of Jamestown or Jimson Weed. 

(After Thome.) 



MORPHOLOGY OF LEAVES AND FLOWERS 609 
FLORAL ENVELOPES AND THEIR CHARACTERS. 

The sepals and petals constitute tlie two floral envelopes. The 
envelopes, taken together, are sometimes called the perianth. This 
is especially true in the lily family where the two envelopes do 
not differ much in shape and color. Floral envelopes are not es- 
sential and one or both may be absent. If only one is absent, it is 
the coroUa, and the flower is apetalous. In the grasses and sedges 
there is no true perianth but the essential organs are enclosed by 
chaff-like bracts and glumes. 





Pig. 466 I 



Fig. 466 II 



Fig, 



II. 



466. I. Flower of oats showing the gfass type of floral envelopes. G, 
empty glume ; Pe, lemna bearing an awn A ; pi, palea ; F. S., sterile flower. 
Between lemna and palea are pistil and stamens. 

Flower with lemna removed, showing palea and the small bracts (lodloules) 
at the base of the pistil and stamens. 
(After Thome.) 



Stamens. — The stamens surround the pistils and their number is 
various. They may be opposite the petals or alternate with them. 
In the mustards and buttercups the stamens are inserted on the 
receptacle. "When they are inserted on the corolla as in the morning- 
glory, they are epipetalous. Stamens are usually distinct or free 
from each other. "When they are united by their filaments into one 
set, as in the mallow family, lupines and lobelia, they are moniai- 
delphous (one brotherhood). If united into two sets as in clover, 
they are diadelphous (two brotherhoods). More sets would be 
designated by tri-, tetra-, etc. 
39 



610 



WEED FLORA OF IOWA 





mm 


Vvfiw 




F 




1 


^ 


h 



Fig. 467 I Fig. 467 II Fig. 467 III Fig. 467 IV 
Fig. 467. I. Flower of Ground Ivy with statnens differing in length. II. Mallow 
with monadelphous stamens. III. Orange with polydelphous stamens. IV. 
Clover with diadelphous stamens. 

(After Thomfi.) 

Relation of the attachment of floral envelopes and stamens to the 
pistil. — An examination of the floral sets in shepherd's purse {Gwp- 
sella) or mustard {Brassica alba) will show that sepals, petals and 
stamens are inserted on the receptacle below the ovary. This flower 
is hypogynous (i. e., parts under the pistil). When the petals and 
stamens are joined to the calyx, the flower is perigynous (i. e., parts 
around the pistil). In such flowers as the evening primrose and 
those of the composites, the calyx is adherent to the ovary and the 
corolla seems to arise from the top of the ovary. Such a flower 
is said to be epigynous (parts on the pistil). 




Fig. 468. Perigynous flower of the Rose. 
(After Thomfi.) 

Arrangement of flowers (inflorescence) . — ^Flower arrangement 
is of three classes; namely, indeterminate, when the flowers arise 
laterally and successively as the floral axis elongates; determinate, 
when the flowers arise from the terminal buds and thus check the 
elongation of the floral axis; and mixed, when these two are com- 
bined. 



MORPHOLOGY OF LEAVES AND FLOWERS 



611 




Fig. 469. Strap-shaped and tubular flowers from the head of Squaw Weed 
iSenecio). The corolla and calyx appear to arise from the top of the 
ovary. Such a, flower is epigynous and the free portion of the calyx Is 
called pappus. 

(After Thom«.) 

Flowers may arise singly, as in silverweed (PotentUla anserina), 
and are then designated as solitary. If in the axils of ordinary 
leaves, they are axillary and solitary. 

A raceme is that indeterminate inflorescence in which the flowers 
are stalked and arranged along the sides of a floral axis. The 
shepherd's purse has the raceme type of inflorescence. New flowers 
are continuously arising at the top as the floral axis elongates. 




Fig. 470. Solitary, funnel-shaped flower of field Bindweed. 
(After Thomfi.) 

If the inflorescence is of the raceme type with the exception that 
the flowers have no stalks, as in the plantain, we have the spike. 



612 



WEED FLORA OP IOWA 





Fig. 471 1 



Pig. 471 II 





Pig. 471 III Pig. 471 IV 

Fig. 471. Types of inflorescence. X. Raceme of Currant. II. Umbel-like 
inflorescence of Cherry. III. Head of Clover. IV. Umbel of Parsley. 



If. the lowest pedicels or flower stalks are elongated (or the upper 
ones remain short) so that the cluster is convex or nearly flat on 
top, we have the corymb type of inflorescence. 

In the wild carrot, common yarrow, and parsley family in gen- 
eral, the axis of the corymb is so much shortened that all pedicels 
seem to start from the same point and resemble the rays of an in- 
verted umbrella. This is the umbel. 

In the clover {TrifoUum procumhens) the flower axis is short 
and the pedicels of the flowers are either short or absent. This 
causes the flowers to be crowded into a roundish cluster which is 
called a head. 



MORPHOLOGY OF LEAVES AND FLOWERS 



613 




Fia. 472. Close head of a composite. 
(After Ibomi.) 




Fia. 473. Close head of the Dandelion. 
(After ThomS.) 



614 



WEED FLORA OF IOWA 



The flower axis is so much shortened in the dandelion, sunflower 
and composites in general, that it may be a concave, flat, or conical 
surface. The flowers are crowded upon this surface, and the en- 
tire group is surrounded by one or more rows of leaf-like bracts 
which form the involucre. This is the close head or composite 
type of inflorescence. 




\ 



Pig. 474. Milkweed with flowers in umbels. 



In many eases, as in field sorrel and in five-finger {Potentilla 
norvegica), the oldest flower of the floral axis is terminal and all 
later flowers must arise from axils below. This is the determinate 
type of inflorescence and this type of flower cluster is called a cyme. 



MORPHOLOGY OF LEAVES AND FLOWERS 



615 




Kg. 475 I Fig. 475 II Fig. 475 III 

Fig. 475. Flower of Milkweed, showing the peculiar hooded and horned stamens. 
I. Flower. II. Stamen. III. Pistil with adhering pollen masses. IV. 
Pollen masses or pollinia. 

(After Thom«.) 



THE DEVELOPMENT OF A STAMEN AND ITS FUNCTION IN SEED 

PRODUCTION. 

Every one knows that the pollen produced by the stamens has 
an important part to play in seed production. It is for this rea- 
son that the stamen is considered one of the essential organs of 
the flower. 

There is so little variation in the general dfevelopment of stamens 
in the higher seed plants that the history of a stamen from any 
weed will suffice for all. 

A mature stamen consists of a stalklike portion, the filament, 
and the pollen-bearing portion, the anther, which is borne on top 
of the filament. The filament may be variously modified or even 
wanting. 




Fig. 476. Cross sectiop of anther showing pollen sacs. A. pm, pollen mother 

cells ; t, food cells. B. Pollen grains mature and being shed. 

(From Coulter, after Baillon & Luerssen.) 

An anther appears distinctly four lobed. If a cross section of a 
young anther be made, four distinct regions will be found, one in 
each lobe or a pair on each side of the axis. These four distinct 



616 



WEED FLORA OF IOWA 



regions are conspicuous because the cells contained are larger and 
have a denser content. Each of these cells will produce four pollen 
grains and for this reason are called pollen mother cells. 

Surrounding each group of pollen mother cells is usually one 
layer of cells whose content is quite dense. These are sacrificed 
as food material for the pollen mother cells and are designated as 
tapetal cells. 

After the pollen grains are formed, they He loose in these cavities. 
Each cavity is considered as a case or angium and since a pollen 
grain is a spore, this case is called a sporangium. 

The partition between each pair of sporangia usually breaks 
down, and two spore-containing cavities are formed. These are 
generally called pollen sacs. The pollen sacs are now ready to 
open or dehisce as the process is called. This is due to especially 
modified cells, which produce such strains through the variation 
of moisture, that usually longitudinal slits or terminal pores are 
produced. 




FiQ. 477. Thrift, ov, ovary ; s, style ; st, papillary stigmas. 
(After Thoni6.) 



The pollen is now either by wind, insects, or water carried to 
the stigma of the pistil where it begins the performance of its 
important function. This process of transference is pollination. 
An examination of a pollen grain at the time of pollination will 
usually show that it has two nuclei; one of these has to do with 
the production of a tube which traverses the tissues of the pistil 
and furnishes a passage way to the embryo sac which contains the 



MORPHOLOGY OF LEAVES AND FLOWERS 617 

cells to be fertilized. The other nucleus of the pollen grain pro- 
duces two small nuclei which are called sperms. These sperms 
pass down the pollen tube to the embryo sac and fertilize the egg 
and endosperm nucleus. 

THE PISTIL AND ITS FUNCTION IN SEED PRODUCTION. 

A flower may have one or more pistils which occupy the center 
of the flower. They are the last to appear, siace the order of 
development is usually sepals, petals, stamens, and pistil. 




Fig. 478. Iris with petal-like stigmas. 
(After Thomfi.) 

A complete pistil consists of three parts — ^the expanded base 
which bears the seed and is called ovary (or "egg-case") ; the ex- 
panded portion at the top, or the stigma ; the portion that connects 
the ovary and stigma, the style. 

The style is not an essential part of the pistil and may be absent 
without disturbing the function of the pistil. 

The stigma has on its surface many minute papillae which re- 
tain the' pollen 'and excrete a sweetish, sticky fluid which serves 
as a nourishment and stimulant for the pollen grain. 



618 



WEED FLORA OF IOWA 




FiQ. 479. Corn-poppy with a shield-shaped stigma capping the ovary. 
(After Thomfi.) 



If we cut a cross section of the ovary of the May apple, we find 
within, a cavity beapng on one side a projection to which are at- 
tached the small, somewhat globular bodies or ovules. This cavity 



Fio. 480. Pistil of Thistle. 
(After Thome.) 



within the ovule is usually called a cell by manuals, but a better 
term is loeulus, since the term "cell" is universally used to desig- 
nate the unit of tissues. The thickened portion to which the ovules 
are attached is the placenta. 

The pistil of the May apple is a simple pistil and according to 
the older views concerning the pistil, it is a carpel. The older 
view was, that the carpel is a modified leaf. If one will imagine 
a leaf folded and the margins joined so as to enclose a loeulus and 
then the outer part modified so as to form a style and stigma, the 
(!onception of a carpel will be clear. An examination of the pistil 
of oxalis will reveal five styles and stigmas, and one ovary with 



MORPHOLOGY OF LIJAYBS AND FLOWERS 619 




Fio. 481. Cross section of the ovary of Gesneria showing one cell and two 

parietal placentae. 
(After Thome.) 



five locTili. This indicates that the pistil of oSalis consists of five 
carpels whose ovaries have united to form one with five locnli. 
This uniting may even extend to the styles and stigmas. A pistil 
that is made up of more than one carpel is compound. 




Fig. 482. I. Cross section of the compound pistil of Snapdragon, showing the 
two cells and the axillary placentae. II. Longitudinal section of an ovary 
with a, free central placenta. 

(After Thomfi.) 



Ovule. — The ovule is the most essential part of the pistil because 
it is the forerunner of the seed. The ovule consists of a central 
portion, the nucellus, which is enclosed by one or two jackets which 
are called the integuments. The integuments do not entirely close 
at the outer end of the nucellus and this small opening left is the 
micropyle through which the pollen tube usually passes. In the 
interior of the nucellus is a region which resembles a large cavity 
since it contains no cell walls. This is the embryo sac. At about 
the time the flower opens the embryo sac contains seven cells. The 
two which have an important future history are the egg and en- 
dosperm cells. 



620 



WEED FLORA OF IOWA 




Fio. 483. Diagrammatic representation of fertilization of an ovule. 1, inner 
coating of ovule ; o, outer coating of ovule ; p, pollen tube proceeding from 
one of the pollen grains on the stigma ; c, the place where the two coats 
of the ovule bend. (The kind of ovule here shown is inverted, its opening 
m being at the bottom, and the stalk f adhering along one side of the 
ovule. ) a to e, embryo sac, full of protoplasm ; a, so-called antipodal 
cells of embryo sac ; n, central nucleus of the embryo sac ; e, nucleated 
cells, one of which, the egg cell, receives the male nucleus of the pollen 
tube ; f, funiculus or stalk of ovule ; m, micropyle or opening into the 
ovule. 

(After Luerssen.) 



The egg is in the end of the sac nearest the micropyle, in the 
most convenient position for the entering pollen tube. The en- 
dosperm cell is near the center of the embryo sac. The embryo 
sac is now mature and awaits the entrance of the pollen tube. 

Fertilization. — The pollen tube traverses the tissues of the 
stigma and style and finds its way to the micropyle. It passes 
through the micropyle, penetrates the tissues of the nueellus, and 
pierces the membrane of the embryo sac. The two sperms, which 
have had a rather long journey through the pollen tube, now enter 
the embryo sac. One finds its way to the egg and soon fuses with 
the egg nucleus. The other fuses with the nucleus of the endosperm 



MORPHOLOGY OF LEAVES AND FLOWERS 



.621 





Fig. 484 



Fig. 485 



Fig. 484. Embryo sac of Buttercup (.RanuncuVus multifldus). Near the center 
Is the large endosperm nucleus. The egg is the Inner one of the three cells 
at the upper end of the sac and lies between the inner ends of the two 
synergids. The three antlpodals are shown closely crowded at the lower 
end of sac. 

(After Coulter.) 

Fig. 485. Fertilization in the Fleabane (.Erigeron) ; pt, pollen tube with two 

densely staining bodies (x) ; a, male cell fusing with egg; b, male cell 
fusing with endosperm nucleus. 

(After Land.) I 

cell. This process in wMeh the sperms or male nuclei fuse with 
the nuclei of the ^g and endosperm cell is fertilization, and both 
fusions are designated as double fertilization. 



THE DEVELOPMENT OF THE EMBRYO AND SEED. 

When the fertilized ^g^ germinates, a filament of cells, the 
suspensor, is usually found. At the end of the suspensor the 
embryo is developed which, when mature, is more or less sur- 
rounded by nourishing endosperm which has resulted from the 
growth and division of the endosperm nuclei. 



622 



WEED FX,OEA OF IOWA 




Fig. 486. Development of the ovule and embryo of the Shepherd's Purse 
(.Oapaella). A, young ovule, showing origin of two Integuments at base 
of nucellus, n. B, outer integument growing beyond the inner, and the 
ovule beginning to bend over ; es, embryo sac. C, diagram of a later 
stage with mature embryo sac. D, development of the suspensor s. E, 
early division of the terminal cell (embryo cell). F, later stage, showing 
the differentiation of an outer cell layer In the embryo, which is to be- 
come the epidermis. G, the two cotyledons c and the root region r now 
clearly defined. H, lengthwise section of an ovule, showing the position 
■of an embryo in an embryo sac ; em, embryo ; s, suspensor ; e, endosperm ; 
11, inner integument ; oi, outer integument ; m, mioropyle. 
(A, B. C, adapted after Campbell. Ginn & Co.) 



MORPHOLOGY OF LEAVES AND FLOWERS 



623 



The two groups of higher seed plants, or Angiosperms, differ 
widely in the structure of the embryo. In the group including the 
grasses, rushes, sedges and such plants as wild onion (Allmm 
canadense) the globular embryo soon develops into an axis with 
the root tip at one end and one cotyledon at the other. The stem 
tip arises from the side of the axis as a lateral member. This 
group of plants is designated as Monocotyledons (one cotyledon). 





Fig. 487 I Fig. 487 II Fig. 488 

Fig. 487. I. Fruit of Squaw-weed (.Senecio). II. Fruit of Dandelion. Each 
is crowned with pappus which aids in distribution. 
(After Thom«.) 

FiQ. 488. The fruit of the Winter Cherry (PKysalis) with a portion of the 

Inflated calyx removed to show the enclosed berry. 

(After Thome.) 

In the other group, to which a large number of the weeds be- 
longs the axis of the embryo develops a root tip at one end, a stem 
tip at the other, and a pair of cotyledons, one on each side of the 
stem tip. Since two, is the prevailing number of cotyledons, the 
term Dicotyledons is applied to this group. 






Fig. 489 Fig. 490 

Fio. 489. I. Fruit (pod) of Plantain with upper portion of pod breaking 
and falling off to allow seeds to escape. II. Pod of Poppy opening by 
a lid. 

(After Thomfi.) 

PiQ. 490. Fruit of Mallow which separates into as many one-seeded carpels 

as there are styles. 
(After Thomd.) 



624 



WEED FLORA OF IOWA 



Seed. — The seed is the matured ovule. It contains the young 
plant or embryo which is the essential part of the seed since it is 
through the later development of this young plant that new in- 
dividuals are produced. Accompanying this maturing of the ovule, 
various other changes take place which give distinguishing features 
to different seeds. Frequently the endosperm grows so extensively 
as to absorb and replace the cells of the nucellus and thus oomea 
to occupy all the space within the coats of the integuments, as in 
the morning-glory, onion, etc. The embryo may remain compara- 
tively smaU as iu the morning-glory or onion, or it may in turn 
absorb and replace all the cells of the endosperm and so come to 
occupy the space within the integuments, as in the bean and clover. 
Sometimes some of the nucellus and endosperm remain. The in- 
teguments also undergo various changes during the formation of 
the seed, often becoming hard or papery or provided with hairs, 
hooks or spinies, or becoming smooth or pitted. 






Fig. 491 1 



Pig. 491 H 



Fig. 492 



Fig. 491. I. Immature pistils of Geranium. II. Mature pistil and carpels 

with their long styles are separating from the elongated axis. 

(After Thorn*.) 

Fig. 492. Burry fruit of Jamestown or Jimson Weed (.Datura) showing method 

of dehiscing. 
(After Thomfi.) 



Fruit. — ^A fruit is a ripened ovary alone or a ripened ovary plus 
closely related parts such as. calyx, involucre, and receptacle. In 
the beggar-ticks (Bidens) the ovary becomes tough and invests the 



MORPHOLOGY OP LEAVES AND FLOWERS 625 

seed, while the awns which represent the calyx become barbed and 
aid in distribution. In the buttercups the ovary invests the seed 
while the style forms a hook. The involucre in the clotbur and 
ragweed remains around the pistils and becomes more or less spiny. 
In the nightshade {Solanum nigrum) the ovary becomes fleshy and 
the fruit is called a berry. 



40 



CHAPTER V. 

SCATTERING OF WEEDS 

ADA HAYDEN 



CHAPTER V. 



SCATTERING OF WEEDS. 

There is much to be observed as to how particular plants spread 
from one location to another, but from the hosts of observations 
that have been made the following means are recognized as agents 
of conveyance to the disseminules of plants to suitable habitats. 
Physical forces: 

Wind 

Water 

Snow and wind 
Animals : 

Man, furred animals and birds 
Mechanical adaptations: 

Explosive devices 

Hygroscopic movement 

Burial 
In comparing the amount of seed produced by a plant with the 
number of plants maturing from that seed, it is evident that rela- 
tively few plajits reach locations favorable to existence. Wind 
transported fruits may be recognized by their appendages in the 
form of wings, comas of hair and bristly parachutes. Water 
carried fruits are characterized by lightness, inflated coverings and 
corky buoys. Seeds disseminated by animals are characterized by 
hooked and clawed appendages or spines which become attached to 
pelts or fabrics or have succulent portions which are edible. Scat- 
tering by mechanical devices is illustrated by the forcibly splitting 
pod, the twisted pod, the spearlike fruited grasses whose twisted 
awns aid in entering the earth and the cleistogamous flowered plant 
which buries its seeds in the earth. 

Birds destroy large quantities of weed seeds. Mr. H. W. Hen- 
shaw* states that a ring-necked pheasant's crop from Washington 
contained 8,000 seeds of chiekweed and a dandelion head. Birds 
of the sparrow family, according to the same authority, feed largely 
on the seeds of weeds. The tree sparrow consumes one-fourth ounce 
of weed seeds per day. The tree sparrows on this basis annually 
consume 875 tons of weed seeds in Iowa. These birds save the 
farmers of the United States on this basis $89,260,000 annually. 

•Henry W. Henshaw. Fifty Common Birds of the Farm and Orcliard. Farm- 
ers' Bull. IT. S. Dept. Agr. No. 513. 



630 



WEED FLORA OF IOWA 






Fig. 493A 



Fig. 493B 



Fig. 4930 



Fig. 493. A. Seed of common Field Sorrel (.Oxalis corniculata) with two cap- 
sules from which the seeds are shot out. B and C. Common Dock (.Rumex 
crlspust. Fruit scattered by the water. The wings surrounding the fruit and 
tubercle make the fruit admirably adapted to floating on the water. Sec- 
tion of the fruit showing wings and tubercle shown In C. 
(Drawings by Ada Hay den.) 



Parts of the fruit which serve as disseminating mechamisms. — 
The stimulus of fertilization not only gives rise to the development 
of a seed but causes parts of the seed or seed-case to develop in 
many instances into a special contrivance for its dissemination. A 
fruit, botanically speaking, is a ripened ovary, including any 
closely attached parts, for example: the milkweed pod filled with 
seeds bearing tufts of hairs; the dandelion fruit with its parachute- 
like pappus. 

Parts which serve as dissemination mechanisms : 
Ovary wall. 

a. Fleshy, often attractively colored — cherry, horse 
nettle, black nightshade. 
Bursting — ^touch-me-not. 
Inflated — sedge. 
Corky tubercles — dock. 
Winged — ^maple . 



b. 
c. 
d. 
e. 

Calyx, 
a. 
b. 



Capillary hairs — dandelion. 
Spined — ^buflfalo bur. 



SCATTERING OF WEEDS 



'631 




Fig. 494B 

FiQ. 494. Scattering of seed by wind. A. The Iowa Tumble Weed (Amaranthua 
graecieans). The weeds piled up against the fence; the Russian Thistle and 
other Weeds are scattered in a similar way. B. Achene of Red-seeded 
Dandelion. 
(A, after Bergen's Botany — Glnn & Co. ; B, drawing by Ada Hayden.) 



Seed coat or its appendages. 

a. Coma of hairs — milkweed. 

b. Mucilaginous — peppergrass. 

c. Contractile seed coat — oxalis. 
Receptacle. 

a. Fleshy — rose. 
Bracts-!— basswood. 
Involucre. 

a. Spiny — ^burdock, cocklebur;, 



632 WEED FLORA OF IOWA 

The dissemination of weeds is not unlike that of other plants. 
Weeds are commonly recognized as plants out of place, plants 
which are detrimental to the growth of crops or otherwise in- 
jurious. "Wihile ash or maple seeds are not usually placed in this 
category ; if, in their seedling sba-ge they monopolize a piece of soil, 
for example a lawn newly planted with grass, absorbing the nutri- 
ment and crowding the plants desired in this location, these in- 
vaders have earned for themselves the title "weed." The epithet 





Pig. 495A P!g. 495B 

Fig. 495. Seeds and fruit scattered by the wind. A. Basswood (.Tilia ameri- 
cana), a light bract to which is attached a stalk bearing the fruits. B. 
Milkweed XAsclepias syriaca) pod and seeds. 

(Drawings by Ada Hayden.) 

"weed" brings to mind the obnoxious characters of the plants so 
designated, yet weeds have just as respectable lineage as the palm, 
oUve, lily or laurel, and in their systematic relationships they 
show by their structure that they are members of the first families 
of the plant kingdom. Thus the notable rose family, which serves 
the world with the apple, the plum, the cherry, the quince, the 
peach and the pear, claims among its numbers the aggressive little 
cinquefoil {Potentilla fruticosa), an invader of pastures and tilled 
lands, the thorny prairie rose {Rosa pratincola) and the prickly 
black raspberry {Buhus occidentalis) , which without invitation en- 
trench themselves upon the territory and contend with the agri- 
culturist as to what shall occupy the soil. Families such as the 



SCATTERING OF WEEDS 



633 



goosefoot (Chenopodiaceae) and the buckwheat (Polygonaceae) 
are recognized as cohorts of marauders thronging the highways, 
forging into fields, contesting with crops and contributing little 
beauty and few representatives of economic value. The great cos- 
mopolitan sunflower family {Gompositae) contributes numerous 
species of economic reputation as well as a goodly number of widely 
recognized but combated species. 

A large number of plants may be identified with their families 
by their type of fruit structure only. Families which have little 
variation in fruit structure have few agents of dissemination, while 
families with considerable variation have usually several agents, 
as in the sunflower family in which the calyx is represented by 
bristles forming a parachute in the dandelion, lettuce or the 






Fig. 496A Fig. 496B 

Fig. 496. Fruit scattered by the wind and animals. A. To the right 
scattered by the wind: a, achene of Goldenrod (SoUdago rigida) ; b, Blue 
Flowered Lettuce (Lacfuca floridana), the bristly hairs called the pappus. 
To the left scattered by animals : a, an achene, commonly called a seed, of 
_^ Bootjack or Beggar-ticks (.Bidens frondosa) ; b, Spanish Needle (Bidems 
hipinnata) . 

B. Anemone iAnemone cylindrica) . 
(Drawings by Charlotte M. King, la. Agr. Exp. Sta.) 

Canada thistle, or terminating in teeth as in Bidens or becoming 
a spiny involucre as in the cocklebur and the burdock. Some 
representatives of this family, for example the ragweed, have no 
special means of transportation and the seeds fall in great quan- 
tities near the mother plant where they germinate in large num- 
bers if not distributed by wind-driven snow or by chance inclusion 
with agricultural seeds. . The seeds of the milkweed family 



634 



WEED FLORA OF IOWA 





Fig. 497A Pig. 497B 

Pio. 497. Seeds and fruits scattered by the wind. A. Seeds of Catalpa (.Catalpa 
speciosa) with winged appendages. B. Key fruits of Soft Maple (.Acer 
saccharinum) are carried by the wind and in falling drop into the mud 
or soft grass of the lawn. 

(Drawings by Ada Hayden.) 



{Asclepiadaceae) are provided with tufts of hair which serve to 
float the seeds in the air as they escape from the pods. The oxalis 
family {Oxalidaceae) have seeds whose outer seed coat separates 
from the seeds shooting them from the bursting pods. The gera- 
nium family (Geraniaceae) have contractile pods which shoot 
the seeds several feet from the plants. The* mustard family 
{Cruciferae) have pods which burst but do not scatter the seeds 
far. Many species of this group have seeds with mucilaginous 
coats which, when in contact with damp surfaces, adhere to them. 
Peppergrass is a well known example. This family has also some 



SCATTERING OF WEEDS 



635 




Kg. 498A ■ Pig. 498B Kg. 4980 

Fig. 498., Weeds scattered by animals. A. Buffalo Bur (Solatium rostratum,). 
B. Pitchforks (.Bidens frondosa), the downwardly barbed points admirably 
suited for animal dissemination. C. Carrot (Daucus carota). 
(Drawings by Ada Hayden.) 




■''Uiiiui, 



FIO. 499. A. 




Fig. 499A Pig. 499B Pig. 4990 

Cow With attached Burdock. B. Burdock enlarged. C. 
frey iOynoglossum) enlarged. 



Com- 



(A, after Bailey, MacmlUan & Co. ; B, after Dewey, U. S. Dept. Agr.) 



636 



WEED FLORA OF IOWA 





Fig. 500A Pig. 500B 

Fig. 500. A. Weed seeds eaten by birds, a. Wild buckwheat (.Polygonum con- 
volvulus) ; b and d. Amaranth or Pigrweed ; c, Chickweed ; e, Spotted 
Spurge ; f , Ragweed ; g. Foxtail ; h. Dandelion. 

B. Seeds of sedges carried by water. 
(A, after Dewey, U. S. Dept. of Agr. ; B, drawing by Ada Hayden.) 

tumble weeds among which are several mustards like tumbling 
mustard. The seeds of the sedge family (Cyperaceae) are com- 
monly surrounded by inflated sacs or bear tubercles which enable 
them to be carried by water. Grasses (Gramineae) show consider- 
able variation in means of dissemination. Some grasses, for ex- 
ample Stipa, have sharp fruits with twisted awns a prominent 
factor. While dissemination is a prominent factor in the distribu- 
tion of plants, the factor of adaptation to habitat is no less im- 
portant for if a plant cannot adapt itself to the conditions in the 
habitat where the seed falls the transportation is of no avail so far 
as its development is concerned. Canada thistle produces some 
seed in northern Iowa, where habitat conditions are inore favorable 
than in southern Iowa. 



SCATTERING OP WEEDS 



637 




Fig. 501. Birds scatter the seeds of the Wild Black CJierry (Prunus serotma). 
1, flowering branch ; 2, fruit ; 3, fruiting branch ; 4, cross section of fruit ; 
5, flower; 6, branch with buds. 

(After Cheney in Green's Forestry of Minn.) 



From an ecological point of \dew weeds are plants which adapt 
themselves readily to ordinary agricultural conditions and since 
most crops are grown under mesophytic conditions, most weeds 
are mesophytes which adapt themselves to definite habitat con- 
ditions such as cultivated field or uncultivated field and are readily 
transferred with agricultural seeds, hence the association of certain 
weeds exclusively with certain crops, for example, among the com- 
mon clover field weeds are buckhorn, wild carrot and plantain. 
These are not found in corn fields where eocklebiar, horse nettle, 
morning-glory and sandbur flourish. Many of the most obnoxious 



638 



WEED FLORA OF IOWA 




Pig. 501A I 

Fig. 501-A. I. Chlcadee carrying fruit. II. 

by birds. 



Fig. 501A II 
Berries of Horse Nettle ; carried 



^, 4 




FiQ. 502; Mixture of weed seeds commonly foimd in low ^ade Alsike Clover 
seed : a, Alsike Clover ; b, White Clover ; c, Ked Clover ; d. Yellow Trefoil ; 
e, Canada Thistle ; f, Dock ; g, Sorrel ; h, Buckhorn ; 1, Rat Tail Plantain ; 
k, Lamb's Quarters ; 1, Shepherd's Purse ; m, Mayweed ; n. Scentless 
Camomile ; o, White Campion ; p. Night-flowering Catchfly ; q. Ox-eye Daisy ; 
I', Small-fruited False Flax ; s, Cinquefoil ; t, two kinds of Peppergrass ; 
u, Catnip ; v, Timothy ; x, Chickweed ; y, Canada Blue Grass ; z, Clover 
Dodder ; 1, Mouse Bar ; 2, Knotgrass ; 3, Tumbling Amaranth ; 4, Hough 
Amaranth; 5, Heal-all; 6, Lady's Thumb (enlarged). 
(HUlman, U. S. Dept Agr.) 



SCATTERING OF WEEDS 




Fig. 503. Seeds of Poas with impurities. 1, Kentucky Blue Grass rubbed and 
unrubbed; 2, Wood Meadow Grass CPoa nemoralis) ; 3, Ergot, a, fungus; 
4, Texas Blue Grass (P. arachnifera) ; 5, Canadian Blue Grass (Poo 
compressa) ; 6, Rough Stalked Meadow Grass iPoa trivialis) ; 7, Silky Bent 
Grass (Apera spica-venti) ; 8, Wood Hair Grass (.Deschampaia flexuosa) ; 
9, spine of Canada Thistle; 10, Canada Thistle; 11, caryopsis of Stink 
Grass (.Eragrostis major). 

(U. S. Dept. Agr.) 



640 WEED FLORA OF IOWA 

weeds have not prominent dissemination mechanisms but are trans- 
ferred with agricultural seeds, as carrot, buckhom, dodder, sheep 
sorrel, yellow trefoil, quack grass and pigeon grass. The separation 
of in^pure seed from agricultural seed necessitates the re^eognition 
by their morphological characters of obnoxious seeds. 

An economic consideration of dissemination of weed seeds and 
their control involves (1) familiarity with the morphology of the 
fruit and seed; (2) the limitation of the habitat in which the weed 
is able to thrive; (3) recognition of the avenues and agents of dis- 
tribution. 



CHAPTER VI. 

ROOTS AND ROOT-STOCKS OF 
WEEDS. 

J. C. CUNNINGHAM 



41 



CHAPTER VI. 



ROOTS AND BOOT-STOCKS. 

The study of root systems is aocompanied with more or less dif- 
ficulty and expense, and this, no doubt, accounts for the small 
amount of work done along this line. 

Two methods have been employed to obtain the complete root 
system of growing plants. That used by Ten Eyek is perhaps the 
most satisfactory, although tedious and expensive. It consists of 
excavating about a plant and enclosing the whole mass of earth 
containing the roots in a cage of wire netting. Steel rods are 
thrust through the cage horizontally to prevent the roots from 
breaking. The soil is then carefully washed away leaving the roots 
very nearly in their natural position. 

The other method, employed by a Russian investigator, Rot- 
minstror, has given quite satisfactory results. The plants are 
grown in soil made up of top- and subsoil. This is placed, the sub- 
soil below and the topsoil above, in boxes 1 in. wide, 20 to 40 in. 
deep and 20 to 40 in. long. These boxes are placed in the ground 
level with the surface. The plants are then grown in these boxes 
and removed when desired, the soil carefully washed away and 
the entire plant transferred to paper. 





f 


(^ 


^ 


/ . 


w 


^^*^ 


; 








r^^^~'^^k 


/i 


' 


r>^ 


ggf 




-^^J^-. 


,^-^^^ 


m 




^ 

^~»l 




'\ ' -.1^ j/>'^ 



FlG. 504. Root-stocks or rhizomes of Quack Grass (.Agropyron repens). These 

root-stocks are sometimes more than four feet long. 

(Photographed by Stevens.) 



644 



WEED FLORA OF IOWA 



The pictures shown here are of plant roots obtained by the 
first method, the wire cages being omitted. 

The roots of weedy plants vary widely in form, structure, and 
in longevity. Their function is three- and sometimes fourfold: 
First, to absorb water and dissolved mineral matter; second, to 
ajiehor the plant in the soil; third, to act as a storehouse for re- 
serve food, and fourth, may serve to propagate the plant. 




FiQ. 505. Eoots of VThite Sweet Clover (Melilotus alba). Plants with several 

strong branching roots. 

(Photographed by Stevens.) 

ROOT FORMS. 

Boot forms may be divided into four general types: First, the 
primary; in this case a single, usually enlarged central root is de- 
.veloped. From it grow the smaller lateral roots. The burdock 
(Arctium lappa), is of this class. Second, multiple primary, 
in which the embryonic root almost immediately breaks up into 



ROOTS AND ROOT-STOCKS OF WEEDS 



645 



many usually enlarged and fleshy roots. Sweet clover {Melilotus 
alba), Fig. 505, offers a good example of this type. Third, tuberous 
or those that develop an enlarged portion at the end of la some- 
what smaller one. Fourth, fibrous in which a mass of small roots 
develop usually just below the stem as in most of the grasses and in 
the plantains. 

Besides the forms already mentioned we find various types of 
aerial roots, or those that develop on the plant above ground. The 
aerial roots of the ivy become finger-like and cling to objects to 
assist the plant in climbing ; those of the mistletoe and the dodder 
become parasitic by pushing their aerial roots into the tissues of 
the host plant and drawing nourishment from it. 

In performing the four functions mentioned above the roots of a 
single plant may occupy considerable area. Dr. Pammel has pre- 
pared the following table showing the depth and spread of the 
root system of a number of our noxious weeds. 



Weed 



Depth 


Spread 


2- 8 in. 


24 


sq. in. 


3-13 " 


30 


" ** 


1- 6 " 


10 


" " 


3- 5 " 


30 


(( (( 


3-5 " 


40 


K .. 


2- 3 " 


4 


" " 


3- 6 " 


20 


(( t( 


6 " 


70 


" " 


2- 4 " 


36 


tt »i 


5-7 " 


144 


a «( 


8 " 


50 


" " 


40 " 


150 


1( (i 


1-4 " 


58 


<( 11 


1-4 " 


45 


" " 


1- 4 " 


90 


(( ti 


1- 2 " 


24 


ti u 


*- 24 " 


6 


a u 


4-10 " 


425 


n (( 


4 " 


48 in. long 


7-14 " 


144 


sq. ft. 


7-14 " 


144 


sq. in. 


2-8 " 


60 


((. (( 


8- 9 " 


60 


" 


5-8 " 


42 


(( It 



Buckhorn 

Plantain 

Wild hemp 

Evening primrose 

Beggar ticks 

Dog fennel 

Nigger head 

Goldenrod 

White vervain 

Canadian lettuce 

Field thistle 

Burdock 

Black nightshade 

Pennsylvania smartweed 

Lady's thumb 

Yellow oxalis 

Prickly lettuce 

Cocklebur 

Greater ragweed 

Rough pigweed 

Horseweed 

Tumbleweed 

Small ragweed 

Spanish dagger 



The amount of reserve food stored within weed roots depends 
to a considerable extent upon the length of time they continue to 
live. 



646 



WEED FLORA OF IOWA 




Fig. 506. Roots of Common Mllltweed (Asclepias syriaca). These roots are 
sometimes more than 14 feet long. Buds are numerously produced on the 
root. More than 100 were found on the roots of this plant. 
(Photographed by Colbum.) 



ROOTS AND ROOT-STOCKS OF WEEDS 



647 



Roots may be, classified according to their length of life, and this 
is, perhaps, the most practical knowledge to possess concerning 
weeds. Without this knowledge no intelligent or successful method 
of eradication can be adopted. 
. First we have the annuals or those which complete their growth 
ajid mature their seed in one year. These plants produce an 
enormous amount of seed, sometimes as high as 50,000 to a single 
plant. The root system is simple, although it may extend to a con- 
sidei*able distance horizontally. Such plants are easily destroyed 
by cultivation unless they root from the joint as in the case of the 
crab grass {Digit aria sanguinalis). 




Fig. 5.0 Z. 



Roots of Curled Dock (.Bumeas crispus). 
(Photographed by Stevens.) 



Second are the winter annuals. These plants may begin, their 
growth in the spring, in which case they become annuals. Many 
of the seeds, however, germinate in the fall and throw up a rosette 



648 



WEED FLORA OF IOWA 



of leaves and thus pass the winter stage. In the spring stems 
are thrown up frora these leaves and seed is produced. Our com- 
mon shepherd's purse {Caxpsella bursa-pastoris) is an example. 

The third class is the biennials or those which expend their energy 
the first season in forming a root system, usually fleshy, and the 
second season in maturing seed. We have numerous examples 
among the garden crops, such as the beet, turnip, carrot, etc., while 
among the weedy plants we have the burdock {Arctium lappa), 
the sweet clover, figure 505, the wild parsnip and others. If 
these plants are prevented from forming seed the second year they 
perish. 



, ! /■ 1 i j\J 


) 




\\^gK«yij 


I' 





^Kj^m 


V 


ml^mi^ 


\ 


SpMj^ 




il 




4,"" 


^^•T -' 


■t-^''^ 


nr~ / 


vS, y T~'-"' 




A r^ \ 






-^ 



Fig. 508. Roots of Buokhorn (Plantago lanceolata). This perennial weed is 

easily destroyed by cultivation. 

(Photographed by Colbum.) 



In the fourth class belong the perennials which live year after 
year and for this reason become our most noxious weeds. When 
the roots once become well established it is very difficult to eradicate 
them, as is shown by the lawns, fields and pastures which are in- 
fested with such weeds as dandelions, quack grass, Canada thistle. 



ROOTS AND ROOT-STOCKS OP WEEDS 



649 




Fig. 509. Fibrous roots of Buckhom. 
(Photographed by Gardner.) 



docks and wild morning-glory. These plants do not, as a rule, 
produce large quantities of seed but depend upon the roots or 
stems as a means of propagation. Thus if a field infested with 
quack grass or morniug-glory is plowed or disked the roots or 
rhizomes are broken up and each piece may produce a new plant. 

Some roots which do not spread extensively through the soil but 
form new plants from offshoots from the crown, such as the docks 
and wild gourds, form heavier roots from year to year for the fol- 
lowing reason: The root growth is most active at the apex of the 
main roots. This resumption of growth starves many of the older 
roots, as we find few lateral on these older portions, and it thus 
extends the root system. 

In the annuals there is little need for a large amount of reserve 
food within the roots for the elaborated food is used up largely as 
it is manufactured. The life of the plant ceases when seed is 
produced. In the biennials, however, large quantities of reservo 



650 



WEED FLORA OF IOWA 




Fig. 510. Biennial root of Young Bull Tiiistle (.Cirsium Icmceolatum) after one 

year's growtli.' 
(Photographed by Charlotte M. King.) 

food are stored in the roots. The same is true of the perennials 
although to a less marked degree than of the biennials. 

By studying the root system in the late fall w.e may determine 
roughly whether the weed is an annual, a biennial or a perennial. 
That is to say, dead small fibrous or primary roots and seed produc- 
tion indicate an annual ; large fleshy roots and no seed production 
a biennial ; reserve food within the roots beside seed production a 
perennial. 

PROPAGATION OF WEEDS BY ROOTS AND STEMS. 
Prof. Hitchcock says that weeds may be propagated by seed and 
buds or by vegetative sprouts. The layman is inclined to call all 
parts of the plant below ground root. It may be, however, a stem 
called a root-stock or rhizome. Microscopical examination is often 
ii^pessaryto determine which is root and which is stem. 



ROOTS AND ROOT-STOCKS OF WEEDS 



651 




Underground 



rhizomes of common 
sepium). 
(Photographed by Stevens.) 



Morning-glory ( Convolvulus 



Roots. 

Adventitious buds are produced at indefinite points along the 
roots and from them stems and plants develop. A number of our 
noxious weeds are propagated by these running or creeping roots, 
such as: milkweed (Asclepias cornuti), bindweed (Convolvulus 
arvensis), sheep sorrel {Bumex acetosella), Indian hemp {Apocy- 
num cammabinum) , perennial rag'wteed {Amhrosia psilostacJiifa) , 
pasture thistle [Cirsium undulatum). 

The weeds mentioned above are comparatively shallow rooted. 
A few weeds are propagated by buds which come from deep vertical 
roots. Among them we find the following : horse nettle {Solarium 
carolinense), ground cherry (Physalis sp.), Canada thistle {Girsiwn 
arvense). 

Undebgeotjnd Stems ob Rhizomes. 

These underground stems are usually found at a short distance 
beneath the surface. Along these stems are found nodes with leaf 
scales at definite intervals. From these nodes roots develop which 
penetrate the soil and leafy stems which develop above ground. 
Some of the weeds so propagated are as follows: quack grass 



652 



WEED FLORA OF IOWA 




Fig. 512. Roots of Sour Dock (.Bumeac crispus). 
(Photographed by Stevens.) 

{Agropyron repens), morning-glory {Convolvulus sepium), smart- 
weed {Polygonum muhlenbergii), poison ivy {Rhus toxicoden- 
dron), nettle {TJrtica gracilis), wild rose {Rosa arkansana). 




Fig. 513. Rhizome of Solomon's Seal; a, leaf bud; b, old stem; c, d, old stem 

scars. 
(After Thom6.) 



ROOTS AND ROOT-STOCKS OP WEEDS 



653 




FIELD BINDWEE.D 

( ConvolviilU.5 ar.vensis / I 



Fig. 514. European Morning-glory or Bindweed iConvolvulus arvensis). In gar- 
dens and fields. 
(After Clark and Fletcher.) 



654 WEED FLORA OF IOWA 

Ceowns oe Shoet Offshoots. 

A long list of weeds produce heavy crowns near the .surface of 
the soil. Stems spring from these crowns year after year. Parts 
of the crown may become separated from the parent plant and 
thus form an independent plant. Among the weeds so propagated 
we find the dandelion {Taraxacum, officinale), white vervain {Ver- 
bena urticaefolia) , plantain {Plantago lanceolata), catnip {Nepeta 
oat aria), curled dock {Bumex crispus), smooth dock {B%mex 
altissimus) , rib grass {Plantago lanceolata) , ox-eye daisy ( Chrysan- 
themum leucanthemum) , 



CHAPTER VII. 

NUMBER AND KINDS OF WEEDS 
ON DIFFERENT SOILS. 



CHAPTER VII. 



NUMBER AND KINDS OF WEEDS IN DIFFERENT FIELDS. 

During the season of 1912 Mr. Robert H. Birlingmair counted 
the weeds appearing on various fields under different conditions, 
for this purpose four feet each way being measured off and the 
different weeds noted. The results were as follows: 

FIELD 1.* 



Weed 



Date 





Mar. 29 


Apr. 6 


Apr. 18 


Apr. 20 


Apr. 27 


May 4 


Peppergrass** 


24 
6 
3 


14 
3 
1 


8 





1 




Dandelion _ _ 




Tall flveflnffer 


2 






1 


Small raeweed 


1 


31 
3 


10 


Blue grass 


20 

10 

1 




51 


24 


Bracted vervain 




Mustard 












Daisv fleabane 


8 


1 








!Pi ETWGftd 




1 






Snotted SDUiffe 








282 
4 

4 
2 


460 


Horseweed 










6 


Pennsylvania 
smartweed - 










1248 


(rround cherrv 










2 


Green foxtail 










84 








4 


















2 

















*On com land that was in blue grass sod last year. 
•*A winter annual. 

FIELD 2.* 



Weed 



Date 





Mar. 29 


Apr. 6 


Apr. 13 


Apr. 20 


Apr. 27 


May 4 


Yellow foxtail 












10 


Daisv fleabane 














Horseweed"* 


143 


65 


'"32" 


1 


34 


72 


Vervain 




Plantain - - 






11 






Pennsylvania 
smartweed . 








1 

















•On timothy meadow. 
••Winter annual. 

42 



65S 



WEED FLORA OF IOWA 
FIELD 3.* 



Weed 



Date 





Mar. 29 


Apr. 6 


Apr. 13 


Apr. 20 


Apr. 27 


May 4 


Small raeweed 






1 


1 

2 






Peimsylvania 
smartweed 








1 


Green foxtail 








1 

















•On corn land that had been fall plowed. Field worked up and sowed to 
small srraln just before April 27. 



FIELD 4.* 



Weed 



Date 





Mar. 29 


Apr. 6 


Apr. 13 


Apr. 20 


Apr. 27 


May 4 


Small ragweed 






10 


3 


8 
1 

99 




Lamb's quarters 






3 


Pemisylvania 
smartweed __ 






21 


78 


77 


Yellow foxtail 






215 

















•On land sowed to winter wheat. 



FIELD 5.* 



Weed 



Date 





Mar. 29 


Apr. 6 


Apr. 13 


Apr. 20 


Apr. 27 


May 4 


Yellow foxtail 












599 


Green cfoxtail 












718 


Daisy fleabane 




1 










Braeted vervain 




3 
3 








Peppergrass 








3 
4 

40 




Blue grass 








Pennsylvania 
smartweed _.. 










71 


Spurge 










47 

















•On old com land. Stalks harrowed down just previous to April 20. 



NUMBER AND KINDS OF WEEDS ON DIFFERENT SOILS 659 
FIELD 6.* 



Weed 



Date 





Mar. 29 


Apr. 6 


Apr. 13 


Apr. 20 


Apr. 27 


May 4 


Small ragweed 






1 


33 




Yellow foxtail __ 






475 


Green foxtail 










40 


Iiamb's quarters 






_ __ 




3 


Pennsylvania 
smartweed 




11 


54 






Blue grass 




1 




Doorvard knotweed 








3 


Horseweed 










3 


Spurge 










39 


Hedge iQUstard 










71 

















*On fall plowed oats stubble. 



FIELD 1* 



Weed 



Date 





Mar. 29 


Apr. 6 


Apr. 13 


Apr. 20 


Apr. 27 


May 4 


Dandelion 


5 


11 










Veronica _ 


-— 








Lamb's quarters _ _ 








i 

6 






Small ragweed 






9 






Yellow foxtail _ 










16 


Shepherd's purse 


75 

+5 

2 

2 


5 

+4 

7 


1 
1 

7 








or peppergrass 








Blue grass 


2 






Hoary vervain 






Pennsylvania 
smartweed _ 






1 






Lady's sorrel - 


+3 



















*On unplowed oats stubble. Field plowed previous to April 27. +Marks 
winter annuals. 



600 



WEED FLORA OF IOWA 
FIELD 8.* 



Weed 



Date 





Mar. 29 


Apr. 6 


Apr. 13 


Apr. 20 


Apr. 27 


May 4 


Small ragweed 




33 


169 
46 

++37 
10 


8 

++4 
49 






Mexican dropseed 




++16 


++18 


Lamb's quarters 






Morning glory 






++6 


++7 


Spurge 








Yellow foxtail 












Green foxtail 








398 
49 





1785 


Pennsylvania 
smartweed 


15 
23 


38 


65 




Mustard 






Horseweed _ 




++26 

n 


9 


10 • 


11 


Scribner's panic grass 








Tansy mustard __ 












Nyctelea 






3 






Yellow dock 










+158 


Large spotted spurge- 












129 


Old witch grass 












2 


Wild four-o'clock 












+2 


Self-heal- 












2 

















•In sheltered place on the south side of the railroad grade. Weeds were 
not all counted on April 27th, but there were hundreds of small ragweeds and 
smartwefids, and probably more than a. thousand green foxtail plants. 

-f-f Winter annual. 

-I- Perennial. 

These tables reveal some interesting facts. The first weeds to 
appear in March were the winter annuals, like peppergrass and 
shepherd's purse, certain perennial weeds, and in one case horse- 
weed {Erigeron canadensis) in a timothy meadow. Two weeks 
later smartweed {Polygonum) was abundant. Spurge {Euphor- 
bia), an annual, was abundant in the latter part of April and 
early May. Foxtails in some eases surpassed all other weeds in 
abundance early in May. The smartweeds {Polygonum) and 
spurges increased enormously. These weeds were entirely removed 
from the plots. Fall plowing and clean cultivation certainly in- 
dicate a smaller number of weeds. 

Long, who measured off a square yard of ground in* Great 
Britain, roughly grouping its plant life therein into species, found 
on this square yard 1,050 seedlings or 5,082,000 per acre. There 
were 654 buttercup seedlings, 107 of annual meadow grass, 60 of 
dock, 26 of goosefoot, 25 of groundsel, 15 of shepherd's purse, 14 of 

•Trans, of Hlshland Agri. Soc. Scotland V. 23: 52. 



NUMBER AND KINDS OF WEEDS ON DIFFERENT SOILS 661 




'^mM)^^-Mmm^mM. ' 



Fig. 515. A weedy cornfield, mostly Foxtail and Smartweeds. 
(Photographed by Colburn.) 



annual sow thistle, and 10 of ehickweed, besides 139 of other 
species. He states that Korsmo 's investigation revealed the pres- 
ence of an even larger number of seeds having the power of ger- 
mination, the seeds per square yard to a depth of 9.8 inches being 
as follows: Fallow field, 8,682 weed seeds (over 42,000,000 per 
acre) ; field for spring grain bearing the same crop for four suc- 
cessive years, 28,213 weed seeds (over 136,000,000 per acre) ; fallow 
field, 1,474 weed seeds (over 7,000,000 per acre). 

Mr. Lfong gives the following species of weeds found in Great 
Britain within an area 100 feet square: 



6662 



WEED FLORA OF IOWA 




Fig. 516. Shepherd's Purse, a common winter annual. 
(After Vasey, U. S. Dept. Agr.) 



NUMBER AND KINDS OF WEEDS ON DIFFERENT SOILS 663 




Fig. 517. A cornfield from which Quaclc Grass was removed by hoeing and 
cultivation. In adjacent checit it formed a sod. The checis was given the 
ordinary methods of cultivation. 

(Photographed by Colburn.) 



*Convolvulus arvensis (Euro-, 

pean bindweed) 
^Polygonum convolvulus (Black 

bindweed) 

* Polygonum aviculare (Knot- 

grass) 
*Bumex sp. (Dock) 
*Tussilago farfara (Coltsfoot) 

* Mentha arvensis (Pepper- 

mint) 
*8inapis arvensis (Common 

mustard) 
*8onchus arvensis (Field sow 

thistle) 



*Stellaria media (Chiekweed) 

Papaver sp. (Poppy) 

* Ranunculus arvensis (Com 

crowfoot) 
*Viola sp. (Violet) 
Potentilla anserina ( Silver 

weed) 
Aethusa cynapium (Fool's 

parsley) 
ScandAx pecten-veneris (Ven- 
us' comb) 
Senecio vulgaris (Groundsel) 
*Galium aparine (Cleavers) 
Yicia sativa (Vetch) 



664 WEED FLORA OF IOWA 

^Matricaria inodora (Wild *Agrostis sp. (Bent grass) 

chamomile) Agropyron repens (Quack 
Plcmtago major (Common grass) 

plantain) Poq, annua (Low spear grass) 

Lychnis alba (White cam- *'Ver(mica sp. (Speedwell) 
pion) Myosotis sp. (Forget-me-not) 

*Euphorbia exigua (Spurge) Alchemilla arvensis (Parsley- 
*Alopecunis agrestis (Foxtail piert) 

grass) 

Most of these species are troublesome weeds, and it may be added 
that those marked with * were abundant. 

For an Iowa cultivated field' on. June 2, 1903, the following 
weeds were found in one square rod. 

Name of weed. No. per sq. rod. 



Smartweed (Polygonum pennsylvanicitm) , 

Hedge mustard {Sisymbrium officinale) 

Black beggar-ticks {Bidens frondosa) 

Prickly lettuce (Lactuca scariola var. integrata) . 

Pigweed ( Ghenopodium album) 

Horseweed (Erigeron canadensis) , 

Dandelion ( Taraxacum, officinale) 

Foxtail (Setaria) , 



40,324 

3,060 

476 

204 

340 

7,412 

68 

136,000 



"WEEDS AND CONTINUOUS CROPPING. 

Everyone has observed that continuous cropping increases the 
number of weeds; not only is this true for many parts of Iowa but 
it is equally true for the older sections of the United States and of 
Europe. A. D. Hall who reported on the crops grown in grain 
land at Eothannstad* said: 

After continuous cropping for forty-seven years said weeds of all 
descriptions occupy considerably more space after continuous crop- 
ping than before. The relative proportion they bear to the grasses 
and clover has increased from year to year. Such weeds as bamet, 
hawkbit and black knapweed became abundant. 

Mr. Long gives the fallowing list of worst weeds made by four 
expert Scotch agriculturists : 

AraMe Lamd. — Charlock, runch, ehickweed, spurrey, docks, 
thistle, groundsel, coltsfoot, day nettle, red-shank, annual meadow 
grass, bulbous oat grass (pearl grass), couch grass, fine bent grass 
or black couch, and wild oats. 

•Jour. Roy Agr. Soc. 64 :-83. 



NUMBER AND KINDS OP WEEDS ON DIFFERENT SOILS 665 




Fig. 518. 



Green Foxtail (Setaria viridis). Common in gardens and fields. 
( Piiotographed by Colburn.) 



Grass Lcmd. — Buttercups, self-heal, docks, ragwort, daisy, thistles, 
ribwort, plantain, creeping soft grass, common bent grass, York- 
shire fog or woolly soft grass, moss. 

There are, however, many other weeds which are' given by him 
which are serious pests to the agriculturist of that country. Of the 
weeds of the arable land he lists buttercups, poppies, fumitory, 
charlock (Brassica arvensis) , Tuneh {Eaphanusraphanistruin),she'p- 
herd's purse, corn cockle, spurrey, silver weed, cleavers, thistle 
(Canada thistle), sow thistle, coltsfoot, groundsel, bindweeds {PoVy- 
gowwm convolwiiis) , {Convolvulus arvensis), dodder, buckhom, 
plantain, broom rape, corn or field mint, hemp and dead nettle,, 
smartweed, or red-shank {Plygonwm persicaria) , knotweed, docks, 
goosefoot, quack grass, fine bent grass, pearl grass {Arrenatherum 
avenaceum), slender foxtail {Alopecurus agrestis), wild oats and 



666 



WEED FLORA OF IOWA 




Fig. 519. Needle Grass (Stipa spartea). In pastures. 
(Photographed by Charlotte M. King.) 




Fig. 520. Purple Cone Flower (.Brauneria purpurea). In a prairie pasture. 
(Photographed by Pammel.) 



NUMBER AND KINDS OF WEEDS ON DIFFERENT SOILS 667 



horsetail. Of grass land weeds there are listed {Golchicum autum- 
nale), buttercups, leguminous weeds, g'orse (Ulex) broom, rest har- 
row {Ononis spinosa), dyer's green weed {Genista tinctoria), wild 
carrot, burdock, knapweed {Gentaurea nigra), thistles {Girsiwm 
arvense, C. acaule, G. Icmceolatum, G. palustris), cotton thistle 
{Onopordum acanthium), daisy {Bellis perennis) , ox-eye daisy, rag- 
wort {Senecio JMohaea) , plantains, yellow rattle, self -heal {Pru- 
nella vulgwis), docks, sorrel {Bumex acetosa, B. acetosella), sting- 
ing nettle {Urtica dioica) ; grasses: bent grass {Agrostis alba) tus- 
sock grass {Aira caespitosa), Yorkshire fog {Holcus lanatus), 
creeping soft grass {H. mollis), quaking grass {Briza media), bar- 
ley grass {Hordeum, pratense), and the bracken {Pteris aqidUna), 
horsetail, and mosses. 




Fig. 521. Common Porcupine or Needle Grass iSUpa spartea), A weed native 
to gravel soil, soon succumbs to cropping, a,, single spikelet ; b, . fruit with 
sharp pointed callus. 

(Lamson-Scribner, U. S. Dept. Agr. ) 



CHAPTER VIII. 

INJURIOUSNESS OF WEEDS 



CHAPTER VIII. 



INJURIOUSNBSS OF WEEDS. 

Weeds are injurious to man in the following ways : 

1. They crowd out the growing crop. 

2. They consume the moisture necessary for a crop. 

3. They consume the mineral or other food elements essential 
to a crop. 

4. They pull down the crop. 

5. They are injurious because the seeds are difficult to remove. 

6. They are injurious because they harbor insects. 

7. They are injurious because they harbor parasitic fungi. 

8. They prevent the proper cultivation of the soil. 

9. They may cause conditions which breed disease. 

10. They may poison the soil. 

11. They stop drains. 

12. They poison animals and man. 

1. WEEDS CROWD OUT GROWING CROPS. 

When weeds are abundant they crowd out growing crops. Every 
plant requires a certain amount of space to bring forth a bountiful 
crop. Two plants cannot grow together in the same place ; sooner 
or later, one plant will crowd out the other. If the weed is a more 
vigorous grower, like the greater ragweed, it will prevent the oat 
plant from maturing a crop. It prevents the proper amount of 
light coming to the plant, and so the food necessary for a crop can- 
not be made. 

2. WEEDS CONSUME THE MOISTURE. 

To produce a crop all weeds need moisture, which should go to a 
more desirable crop. They transpire water just as cultivated plants 
do. Long, in "Common Weeds of the Farm and Garden," says: 

Weeds also absorb from the soil land "transpire," or pass off into 
the atmosphere, large quantities of moisture which would be of 
great service to the growing crop. For example, a maize plant has 
been observed to transpire in the 16 weeks between May 22d and 
September 4th as much as 36 times its own weight. A large oak 



672 



WEED FLORA OP IOWA 




Fig. 522. Ragweeds (Ambrosia triflda) consume an enormous amount of mois- 
ture. 



INJURIOUSNESS OF WEEDS 673 

*. 
tree is also stated to transpire 10 to 20 gallons of water in a day ; 
while barley, beans, and clover were found to transpire, during 
five months of their growth, over 200 times their dry weight of 
water. Experiments conducted at the agricultural experiment sta- 
tion of Cornell university showed that during the growth of a 60- 
bushel crop of maize the plants pumped from the soil, and tran- 
spired into the air through the leaves, upwards of 900 tons of 
water. A 25-bushel crop of wheat similarly disposed of 500 tons of 
water. "Weeds also transpire, and if the ground be covered with 
weeds it is certain that much of the moisture which would be of 
value to the crop will be lost in the manner indicated. Weeds are 
especially harmful in this way in a hot summer, and the loss is 
most felt by the cultivated crop on light sandy soils. 

3. WEEDS CONSUME MINERAL AND FOOD ELEMENTS. 

A weed needs not only the carbon dioxide of the air to make 
food, but the nitrogenous and mineral elements of the soil to make 
plant food, all of which should go to the crop. Long gives the fol- 
lowing in his book, "Common Weeds of the Farm and Garden": 

Some analyses made at Konigsberg, and lately reported by Profes- 
sor Stutzer and L. Seidler, show that the amounts of nitrogen, phos- 
phoric acid, potash, and lime which are removed are deserving of 
serious consideration. A number of weeds without their roots were 
collected from oat fields, the soil of which was fairly heavy and 
poor in humus. In the case of the Wild Radish or White Char- 
lock the plants had already formed many seed-pqds, but the other 
weeds were in full bloom. The table following shows the percentage 
of ingredients in the dry matter. These figures indicate in a gen- 
eral way the amount of the chief plant foods required by weeds. The 
nitrogren in the Persiearia nearly equaled 20 per cent, and that in 
the Sow Thistle nearly 15 per cent of albuminoids in the dry mat- 
ter. Phosphoric acid was chiefly taken up by Spurrey and Persi- 
earia; potash by the Sow Thistle and Spurrey; and lime by Per- 
siearia, Yarrow, and Cornflower. 



48 



674 WEED FLORA OP IOWA 

PEBCENTAGE CONTENTS OF DKT MATTER. 





a 

1 


a 
a 


o 
I» 


0.88 


4.77 


1.94 


2.16 


0.78 


1.94 


3.13 


1.07 


1.08 


4.21 


1.52 


1.91 


0.78 


1.30 


1.81 


0.71 


1.16 


3.12 


4.93 


2.53 


0.93 


3.15 


3.84 


1.17 


0.93 


3.08 


2.86 


1.59 



Sow thistle {Bonchus oler- 

aceus) 

Cornflower {Centaurea cy- 

' anus) 

Spurrey (.Bpergula arverir. 

sis) 

Wild Radish (Raphanus 

raphanistrum) 

Persicaria or red-shank 

(Polygonum persicaria) . ' 
Yarrojtf (Achillea millefol- 

ium) 

Average of .six weeds 



2.39 

2.30 

2.36 

1.85 

3.12 

2.30 
2.38 



14.95 
8.12 

10.12 
5.22 

10.58 

9.61 
9.76 



4. WEEDS PULL DOWN THE CROPS. 

' "Weeds like morning-glory, bindweed, wild buckwheat, and others, 
pull down a cultivated plant and then prevent the formation of a 
good. crop. 

5. WEEDS ARE INJURIOUS BECAUSE IT IS DIFFICULT TO RE- 
MOVE THE SEEDS. 

It is difficult in many eases to remove weed seeds from seed of 
various kinds. Buckhorn can be removed with difficulty from 
clover seed ; peppergrass with difficulty from timothy seed ; greater 
ragweed from wheat ; wild oats from oats ; quack grass from brome 
grass; cockle from wheat. These impurities often greatly reduce 
the quality of the grain or seed. 

6. WEEDS HARBOR INSECTS. 
Long gives the following insects found on weeds: 




Morning-glory pulls down the corn and other crops. 
(After Vasey, II. S. Dept. of Agriculture.) 



676 



WEED FLORA OF IOWA 




/cT 



Fig. 524. Impurities found in Red Clover: 1, Bull Thistle; 2, Canada Thistle; 
3, Green Foxtail iSetaria viridia) ; i, common Plantain (.Plantago nigelH) ; 
5, Peppergrass (also found in Timothy) ; 6, Chicory; 7, Pigeon Grass 
CSetaria glauca) ; 8, Crabgrass (Digitaria sanguinaUa) ; 9, Old Witch Grass; 
10, Timothy; 11, Wild Carrot; 12, Pigweed (.Amaranthus retroflexus) ; 13, 
Smartweed {Polygonum persicaria) ; 14, Lamb's quarters; 15, Dropseed 
Grass (Muhleniergia) . 

(Drawings by Charlotte M. King.) 



Weed "host." 



Insect. 



Charlock (Sinapis 
similar Crucifers 



arvensis) and 



Goosefoot (Chenopodium album) 
Thistles (Girsium sp) 
Sow Thistle iSonchus) 
Dandelion (.Taraxdcuw,) and appar- 
ently Docks (Rumex) 



Turnip Flea Beetle or "Fly" (Pftyl- 
lotreta (.Haltica) nemorum) 

Cabbage and Turnip Gall Weevil 
(Ceutorhynchus sulcicoUis) 



■ Mangold Fly (.Pegomyia betae) 



stem Belworm {TylencJms devaa- 
tatrix) (apt an insect) 



INJURIOUSNESS OF WEEDS 677 

Charlock and other Cruclfers "I Diamond-Back Moth (Plutelfa mac- 

Prickly saltwort (.Salsola kali) j uUpennia) 

''ISo.lTn f^.£S ™^"^} ^^^-^ ^'^ '^'^^^ '^--^^« 

Hops, Yorkshire Fog, Poa annua, 
Daisy, Shepherd's Purse, Spurrey, 
Buttercup, Cornflower, Sow This- 
tle, Black Bindweed (Polygonum 
Convolvulus) and Plantain 

Nightshades Henbane. Hed^e, Mus-1 ^^^^^^^^ ^^^^^^ (Doryphora aecem- 
tard. Thistles, Goosefoot, and t i^eata) 
many other plants J ■"■>'""■"■/ 

Shepherd's Purse, Winter Cress, \ Cabbage Root Fly (Phoriia trot- 
Hedge Mustard J sieae) 

Various Grasses }• Frit Fly (.Osdnis frit) 

Docks, Goosefoot, and some other 1„ .■,,,. ^. ..» 

y^gg^a r Bean Aphis {Aphis rumicis) 

\ Ghost or Otter Moth (Bepialus 
Docks, Thistles, Burdock r lupuli) 

7. WEEDS ARE INJURIOUS BECAUSE THEY HARBOR PARA- 
SITIC FUNGI. 

Long and Percival, in ''Common Weeds of the Farm and Gar- 
den," have the following table of fungus diseases that affect var 
rious weeds : 



Weed "host." Disease. 

1 Finger-and-toe of turnips {Plasmodia- 
Charlock and other Crucifers I phora irassicae Wor.) 

J Peronospora parasitica De Bary 

(White Root-rot (Rosellinia necatrix 
Prill.) 
Sclerotium Disease {Sclerotinia scleroti- 
orum Mass.) 

Wild Barley {Hordeum mur- "1 Blindness in Barley and Oats (Helmintho- 
inum) J- sporium gramineum Erikss.) 

Shepherd's Purse and other"! White Rust of Cabbages (Oystopus can- 
Crucifers j didus Lev.) 

Many species } ^^°^^^^ Root-rot (Rhigoetonda iHolacea 

Agrostis canina L., and other"! Reed-mace Fungus {Epichloe typhina 
grasses j" Tul.) 



678 

Barberry- 
Sedges (Car ex) 
Goosefoot 



WEED FLORA OF IOWA 

[ Rust of wheat (Puccima grammis Pers.) 

} Gooseberry-leaf Cluster -cup (Puccinia 
pringsheimiana Kleb. ) 

I Peronospora effusa Rab., on spinach. 

Docks, Sorrel, and many"! Rosellinia radiciperda Mass. A white 
others J Root-rot in New Zealand. 

1 Chrysanthemum Rust (Puccinia hieracii 
Hawkweed (Hieraciwm) > Mart.) 

Groundsel, Ragwort, and"! Pine Cluster-cups (Peridermium pini 
other species of Seneclo j Wallr.) 



Many wild grasses 



\ Ergot of rye (Claviceps purpurea Tul.) 




Pio. B25. Leaf rust of Wild Barley (Puccinia rubigo-vera) also occurs on 

wheat. 
(Drawing by Charlotte M. King.) 

These fungus diseases are particularly noticeable in a number 
of plants of the mustard family. The Cystopus cnndidus common 
upon cabbages in Europe is very common on a large number of 
cruciferous plants, like mu.«tard, peppergrass. charlock, etc. At 
times it is very common upon the radish. A related fungus, downy 
mildew, of the mustard {Peronospora parasitica) is common and 
troublesome at times on some cultivated members of the mustard 
family. It is particularly common upon peppergrass and shep- 



INJURIOUSNESS OP WEEDS 



679 




Fig. 526. Rusts of cereals also occur on weedy grasses, like Squlrreltall Grass, 
Wild Oats, etc. Pucciriia graminis : A, "winter" or teleutospore ; t, ger- 
minating, B, germ-tube (promj/ceKjim) with lateral sporidSa sp. C, 
epidermis of under surface of leaf of barberry showing crescent shaped 
cells of stoma and the germinating sporidium sp at i penetrating the 
epidermis. D, uredo spore germinating after being in water fourteen hours. 
E, Pucoinia ruhigo-vera, the upper cell has germinated. C. D. E, magnified 
390 times, the other somewhat more. (After DeBary.) P, Pucoinia gram- 
inis, Pers. ; both cells have germinated ; a, a sporidium germinating, magni- 
fied 600 times. (After BoUey.) G, Puccinia coronata Cda. ; teleutospores 
of rust on leaves of oats, magnified about 600 times. (After BoUey.) 



680 



WEED FLORA OF IOWA 




Fig. 527. Barley Blight (.Helmintliosporium gramineum') on Wild Barley, 
and b, hypha; c, conldium. 
(Drawing by Charlotte M. King.) 



herd's purse. One of the very destructive diseases is the cluh-root 
of cabbage {Plasmodiophora Irassicae) which is common upon cab- 
bages in the eastern states, having now reached Illinois. This has 
been found on a large number of weeds of the mustard family, 
like mustard and charlock. A list of these was given by Dr. B. D. 
Halsted some years ago. Another most troublesome fungus dis- 
ease is rust of wheat {Puccinia graminis) which is abundant upon 
quack grass, red top and other grasses. This rust frequently 
spreads upon these weeds and then to our cultivated cereals. Some 
of the related rusts like Puccinia ruhigo-vera are common upon the 
leaves of squirrel-tail grass. A great many of the wild weedy 
grasses, like wild rye and quack grass, contain ergot {Claviceps 
purpv/rea). This is responsible in most cases for the conveying 
of this disease to cultivated cereals. We have a long list of root 
diseases found upon various weeds, like the scab of potato (Oospora 
scabies, Ozonium omnivora), etc. Certain species of Sderotinia, 
one of which occurs upon sunflower, are transmitted from these 
weeds to cultivated plants. 



INJURIOUSNESS OF WEEDS 



681 




Fig. 528. "White Rust (.AWugo Candida). 1. Inflorescence of Shepherd's Purse 
with fungus. 2. Mycelium with haustoria (h) x 390. 3. Conidiophores 
and conidia (spores) in chains x 400. i and 5. Formation of zoospores in 
conidia x 400. 6. Germinating zoospore. 7. Oogonium (o) and anther- 
Idium (a) attached, mycelium shown below. 8. Oospore with thick wall. , 
9. Germinating oospore forming a zoosporangium. 10. Zoospore 7-10 x 400. 
(After DeBary.) 

8. WEEDS PREVENT THE PROPER CULTIVATION OF SOIL. 

Weeds of certain types, particularly the perennial weeds, often 
make it extremely difficult to cultivate a soil. This is especially 
true of weeds like quack grass, which when present in the soil 
make it difficult not only to cultivate, but to plow and harrow, and 
also make the operation quite expensive. 

9. WEEDS MAY CAUSE CONDITIONS WHICH BREED DISEASES. 

Dr. Evans says that tall weeds contribute to the breeding places 
of mosquitos, and he thinks that in this way the mosquitos will 
lead to malaria. It is a well-known fact that the pollen from 
weeds like ragweed and goldenrod cause hay fever and for this 
reason these weeds should always be removed. 



10. WEEDS MAY POISON THE SOIL. 

There has long been a popular impression that weeds excrete 
poisonous substances which render the soil unfit for a succeeding 
crop. In regions where cockleburs are common, it is quite difficult 
to get a good stand of clover. Mr. E. B. Watson found that 



682 



WEED FLORA OF IOWA 





Fig. 580 

Fig. S29. Powdery Mildew of grasses (.Brysiphe graminisy. This Is common on 
Wild Barley, occurs also on Wheat, a, mycelium and erect conidiorhores ; 
b, c, conidla. 

Fig. 530. Cocklebur (Xanthium canadenae). There Is a widespread belief that 
Cocklebur and other weeds may excrete a substance which is Injurious to 
other crops. 



clover would not do as well in soil of this character, nor did the 
clover seed germinate as well, as in check soils. However, this 
subject has been investigated but little. Then there is the larger 
question of the actual antagonism between roots in occupied soils 
that should be occupied by the roots of agricultural plants. 

11. WEEDS STOP DRAINS. 

Drain tiles are frequently filled with a growth of the roots of 
weeds, causing stoppage and often much expense in removing the 
difficulty. 



INJURIOUSNESS OF WEEDS 



683 



12. POISONOUS WEEDS. 
There are many weeds which are injurious to man and to ani- 
mals because they are poisonous. One of the best known illustra- 
tions is the cowbane, one of the most deadly poisonous plants in the 
state; then there are jimson weed, also poisonous; and poison ivy, 
which is poisonous to the touch. 

A large number of weeds, while not strongly poisonous, are in- 
jurious ; some taint cow 's milk ; some are injurious because of spines 
and prickles and thorns. This subject has been treated in full in a 
large book by the writer, "A Manual of Poisonous Plants." Too 
little attention has been paid by the school teachers of the state to 
the subject of poisonous plants. 




Fig 531. Poison Ivy. Leaves poisonous to many people when they come In 
contact with the plant. 



CHAPTER IX. 

WEED MIGRATION 



CHAPTER IX. 



WEED MIGRATION. 

Geographical botany is that phase of botany which concerns itself 
with the distribution of plants over the earth 's surface. The study 
involves questions of geology, climatology, plant physiology, geog- 
raphy, paleobotany, ethnology, history, agriculture, horticulture 
and commerce. J. Burtt Davy says: "The facies of the world's 
flora is rapidly changing, and tends to become more uniform, within 
certain limits, under the influence of agriculture !and commerce." 
Before the advent of man the chief factors in weed immigration 
were the wind, water, snow, animals of various kinds, e. g., birds, 
mammals, reptiles, insects and gravity. Primitive man must have 
been an important factor in the distribution of plants. Many 
plants were no doubt widely scattered by the Indian. Some, like 
the persimmon, plum, pawpaw, maize; etc., were cultivated; but 
many weeds also were scattered by the Indian, finding a congenial 
environment near the wigwams. Commerce and the quest for new 
lands distributed many species far and wide. Lists of weedy plants 
of every civilized country, as indicated by Fernald, Davy, Gray 
and other botanists, show that a large percentage are foreigners. 
With the rapidity of modern transportation and with communica- 
tion with every part of the world, weed seeds have naturally been 
carried with the commercial products. Without exception, wherever 
agriculture has advanced in Iowa, I believe weeds have followed 
cultivation, generally making their appearance along the water 
courses where our agriculture was fostered earlier than in the in- 
terior of the state. For instance, such weeds as Jimson weed, 
Indian mallow, burdock, mayweed or dog fennel, cheeses, mullein, 
dock, black nightshade, smartweed, bull thistle, pigweed, lamb's 
quarters, and purslane, have been known in Iowa ior more than 
sixty years. Some of these were abundant species in cities and on 
farms along the Mississippi long before central and northwestern 
Iowa became settled. There are regions in northwestern Iowa 
where some of the above weeds are still unknown. The mayweed, 
velvet weed and mullein were only infrequent weeds in central 
Iowa twenty-five years ago, though becoming more frequent from 



688 



WEED FLORA OF IOWA 



year to year. Commerce indeed has taken an important part in 
the migration of weeds. Wild carrot, chicory, black medick, quack 
grass, Canada thistle, shoo-fly and dodder are becoming more and 
more abundant in the fields of Iowa. Many weeds, moreover, first 
make their appearance iu the vicinity of cultivated fields. In 
nearly every case wild parsnip, tansy, shoo-fly, bouncing betty and 
butter and eggs show the influence of cultivation. 




Pig. 531A V 



Fig. 531A VI 



Fig. 531-A. Seeds scattered with commercial seed. I. Quacl£ Grass (.Agropyron 
repens). II. Com Flower (.Centmirea cyanua) ; scattered with flower seed, 
a frequent escape from cultivation. III. Corn cockle (.Agroatemma 
githago) ; scattered with wheat, frequent in wheat fields. IV. Chicory 
(.Cichorium intybus) ; seed frequently foimd In alfalfa seed. It has been 
widely scattered In this way. V. Peppergrass (.Lepidium apetalum) ; wide- 
ly scattered with timothy seed. VI. Parsnip (,Pastinaca sativa) ; a fre- 
quent escape from cultivation. 

(I and V, drawings, Charlotte M. King; II and IV, drawings, Ada Hay den; 
III and VI, Hillman.) 



Every phytogeographer is confronted with the problem of placing 
weeds of the given area in their relation to other floras. Let us 
take as an illustration a virgin Iowa prairie covered with a close 
mat of such plants as the blue stems {Andropogon scoparius and 
A. furcatus), vetch {Viciat amiericama), meadow rue (Thalictrum 



WEED MIGRATION 



689 




Fig. 532. Blue Stem (.Andropogon scoparius). A plant common to the 
prairies of Iowa, a, spikelet ; b, c, first and second glumes ; d, third 
glume ; f, lodicules stamens and pistil. 

(Lamson-Sorlbner, U. S. Dept. Agr.) 



purpurascens) , hlack-eyed. Susan {Budbechm hirta), Scribner's 
panic (Panicum scribnerianum) , Philadelphia lily {Liliium phila- 
delphicum) , lobelia {Lobelia spicata), sorrel {Oxalis violacea), 
closed gentian {Gentiana andrewsii), goldenrods {SoUdago mis- 
souriensis and 8. rigi^a), aster {Aster laems, A. azureus) and a 
host of other associates. Compare with this an area in the Wis- 
consin drift where such plants as blue vervain {Verbena stricta), 
coreopsis {Coreopsis palmafa), side oats {BoiUeloua curtipendula) , 
needle-grass {Stipa spartea), perennial ragweed {Ambrosia psilo-. 
stachya), sunflower {Selianihus ocddentaUs), white aster {Aster 
44 



690 



WEED FLORA OF IOWA 
















Wig. 532-A. Prostrate Pigweed [Amarantlms 'bUtoides.) 
(Photographed by Hart.) 



multiflorus) , fragrant goldenrod {Solidago odora), and many others 
occupy the ground. What becomes of the flora when the sod and 
its flora have borne their own peculiar vegetation ? Comparatively 
few of the original inhabitants thereof remain as a part of the flora. 
The weeds most likely to appear here are such as have been partially 
adjusted to the open conditions. In such places it was not un- 
common in the early days to find that such weeds as the common 
Iowa tumble weed {Anuiranthus graecizans) , tickle-grass {Pamcum 
capillare), creeping verbena {Verbena iracteosa), milk spurge or 
milk purslane ( Euphorbia maculata and E. geyeri), evening prim- 
rose {Oenothera biennis), horSeweed {Erigeron canadensis), blue 
vervain {Verbena stricta), persisted for a few years, perhaps with a 
few other perennial weeds like flowering spurge {Euphorbia corol- 
lata) , Helianthus occidentaiis and Desmodium canescens, especially 



WEED MIGRATION 



691 



in a few places where tillage was not good; but in nearly every 
case these perennial weeds disappeared from the cultivated fields 
which thereupon became occupied by a large number of native 
annual weeds like the greater ragweed {Ambrosia trifida), Spanish 
needle {Bidens frondosa, B. discoidea) and smartweed {Polygonum 
sp.), a few hardy perennial weeds like milkweed {Asclepias 
syriaca), morning-glory {Convolvulus sepium), artichoke {Helian- 
thus tuberosus) and meadow sunflower {Ilelianthus grosseserratus) . 
Such annual or winter annual weeds as scjuirrel-tail grass {Hordeum 
jubatum), peppergrass {Lepid/ktm apetalum) began to compete 
with a host of European and other exntie wppds like lamb's quarters 
( Chenopodmm album), persiearia {Polygonum persicaria) , purslane 
{Portulaca oleracea), foxtail {Setaria glauca, 8. viridis) and, later, 
crab grass {Digitaria sanguinalis and D. humifusa). In grain 




FlQ. 533. Greater Ragweed (.Ambrosia ti'ft'm. 'I'l is weed rai'idlv occupief- 

cultivated ground. 
(Vasey, U. S. Dept. Agr.) 



692 WEED FLORA OF IOWA 

fields or flax fields appeared the usual crop of weeds that are car- 
ried with grain, like com cockle, chess, cow-herb, mustard, penny- 
cress and darnel. Then came the weeds which were introduced 
with clover seed as buckhom, dodder, evening catchfly, chicory, 
wild carrot, etc. 




Fig. 534. Small Peppergrass (.LepiOium, apetalum). Rapidly occupies the vir- 
gin soil. 
(Drawing by Charlotte M. King.) 

As our agriculture shifted from a wheat country to one domi- 
nating in com, the weed flora changed slightly. Corn cockle, chess 
and vetch {Yicia sativa), so common everywhere in a small grain 
country, disappeared over a large section of Iowa. They are again 
appearing where wheat is grown. Charlock, a relic of flax culture, 
remained to be distributed largely with oats seed. 



WEED MIGRATION 693 

The fact, however, remains that a goodly number of our Iowa 
weeds are indigenous to this state. Many of these were planta 
capable of enduring sunshine and so did not have to readjust them- 
selves to new conditions. So we have received not only from Iowa 
but from the country to the west, as Nebraska and the Dakotas, 
such plants as the squirrel-tail grass, buffalo bur, winged pigweed, 
common sunflower {Helicmthus amnuus), and stinkweed {Cleome 
serrulcsta) . 

The same thing has occurred in states to the west where many 
indigenous weeds are vying with the European weeds. To the 
north in Canada a pigweed {Monolepis nuttalUana) has become ex- 
tremely common, while such weeds as foxtail are troublesome to a 
limited extent only. The holy grass, a curiosity in many parts of 
Iowa, is a troublesome perennial weed of Manitoba. 

It would seem to me that it is not a question of self-fertilization 
or plasticity but one of tolerance of weeds for sunshine and ready 
means of dissemination either by natural agencies or by man. 

Kabsch, in a discussion of this problem, notes that precisely the 
same things have occurred in various parts of the world where the 
forests have been cleared. In Bolivia, Pteris, Anemia, SoMrurus, 
Lilicoya were followed later by small shrubs of the Eupcutoriaceae 
and Malvaceae. In Brazil, Pteris caudata and Tristegis glutinosa 
make their appearance after the forest fire. In Teneriffe, in 1815, 
Pteris, in 1820, Erica ariorea, and in 1830 Laurus camiriensis cov- 
ered the ground. Kabsch notes how suddenly the vegetation of 
a forest changes in Europe when sunshine is admitted after a 
forest fire or after the clearing of the forest. Plants like vetchling 
{O'robus), four-leaved grass {Paris quadrifoUa), Arum, lovers of 
the shade, soon succumb, and in their places fireweed {EpHobium 
angustifoliwm) , bedstraw {Galium), thistle {Girsium), wild mar- 
joram {Origarmm) , foxglove {Digitalis), and others appear to be 
followed later by roses, brambles, hazel nut, birches, and grasses 
like reed bent grass {Calamagrostis epigeios), meadow grass {Poa), 
sweet vernal grass {Anthoxanthum odoratum), and bear moss 
{Polytrichum commune). Later shade-loving plants have a chance 
to grow. 

In the Pacific northwest the fireweed {Epiloiium angustifolium) 
and common brake {Pteris aquilina) occupy the ground after a 
forest fire. Velvet grass {Holcus) and groundsel {Senecio) are 
followed by Spiraeas and the California blackberries (Ew&ms 
vrsmus and B. wutkanus) which in turn are succeeded by young 



694 



WEED FLORA OF IOWA 




Fig. 535. Common Brake (.Pteris aquiUna). A troublesome weed following 
flres in the northwest, also under similar conditions in some parts of 
northeastern Iowa. 

(Drawing by Charlotte M. King.) 



forests of Douglas fir. In places, the red cherry {Prunus emar- 
ginata) may occupy the soil for a long time. Cusick states that 
the "elkweed" of eastern Oregon, more commonly called fireweed, 
the only herbaceous plant to follow the fires, is followed in a year 
or so by the lodge pole pine {Pinvs murrayana) and Oregon fir 
{Psevdotsuga taxifolia). In western Oregon it takes more time; 
the ground is covered with a thick growth of blackberry plants. 
In the Rocky mountains the conditions are somewhat different. 
The first year after a fire very few plants will grow; but among 
the first, mention may be made of fireweed (Epilohium angusti- 
folium), thistle {Cirsium drummondii and the variety acaulescens, 
C. eriocephalum and foliosum), groundsel (Senecio ccmus), (and in 
moist places 8. triangularis), painted cup (Gastilleja integra), wild 



WEED MIGRATION 



695 



heliotrope {Phacelia sericea), stone crop {Sedum stenopetalum) , 
arnica {Arnica cordifolia) . During the first year the vegetation is 
frequently widely scattered, much depending on the source of the 
seed. The lodge pole pine may not reappear on the burnt area 
for a long time. Here again much depends on the distance from 
which the seed has to come. 

An Iowa forest, burned over, is covered by bull thistle {Cirsium 
lanceolatum) , fireweed {Erechtites hieracifolia) , horseweed {Erige- 
ron canadensis), whiteweed {Erigeron annuus), followed later by 
small perennials, as blue grass, goldenrods, asters and sunflowers; 
then hazel, coral berry, hawthorns, elms, poplars, maples and oaks. 

J. Burtt Davy* in an interesting account of alien plants spon- 
taneous in the Transvaal enumerates 141 species alien to that part 
of Africa; of these 15 are now so cosmopolitan that their original 
home is not known. Two were unidentified. .The origin of these 




Fig. 5'36. 



Lamb's Quarters (Chenopodium albuw,). 
Native to Europe. 



A common foreign weed. 



•Rep. S. Afr. Ass. Adv. Sci. 1901 ; 252-299. 



696 WEED FLORA OP IOWA 

alien immigrants he gives as follows: Mediterranean region, 33 
species ; tropical America and warm temperate regions, 13 ; tropical 
Africa, 16; Australia, 1; temperate Nortli America, 1; temperate 
South. America, 1; uncertain origin, 16. It is interesting to note 
that the following Iowa species are abundant and troublesome in 
the Transvaal (the exceptions being capitalized) : mayweed 
(Anthends cotula), black mustard (Beassica nigra), hemp {Can- 
nabis sativa), shepherd's purse (Capseli/A buesa-pastobis) , goose- 
foot (Ghenopodium album), wormseed {Chenopodiwm ambro- 
sioides), nut grass (Cyperus escvlentus), jimson weed (Datura 
stramonium), wire grass {Eleusine indica), fleabane (Erigeron 
canadensis), shoo-fly {Hibiscus trionum), common morning-glory 
(Ipomoea pubpueea) , load flax (Linabia vtiuiAEis) , darnel {Lalium 
temulentum), lady's sorrel {Oxalis oorniculata) , ribgrass {Plantago 
la/nceolata) , common plantain {Plantago major), black bindweed 
(PoLTGONTjM CONVOLVULUS) , larger fcttotwced {Polygormm erectum), 
purslane {Portulaca oleracea), jointed charlock {Baphanus rapha- 
nistrum), sheep sorrel {Bumex a^etoselhi) , yellow dock (Rumex 
CEisPus), smooth tobacco {Nicotiama glauca), cow-herb (Saponaeia 
vaccabia), bristly foxtail {Seta/ria verticillata) , black nightshade 
{Solamim, nigrum), dandelion {Taraxacum officinale), chickweed 
{Stellaria media), sow thistle (Sonchus ouebageos) , goat's beard 
(Teagopogon poeeipolius) , vetch (Vicia sativa). In addition to 
the above plants, Davy lists quite a number which are common in 
the states to the south of Iowa and in California. Such plants as 
castor-oil bean {Biciwws communis), zinnia {Zinnia pauciflorus), 
marigold {Tagetes erecta), cosmos {Cosmos bipinnatus), cockscomb 
{Celosia cristata), four-o'clock {Miraibilis jalapa), evening primrose 
{Oenothera gramdiflora) , Xylopleurum tetrapterum, Mexican poppy 
{Argemon'e mexicana) are commonly cultivated in Iowa. Some, like 
Argem,one, Oenothera and Cosmos, occasionally escape in Iowa. In 
a classification of these weeds, Davy places the alien plants under 
the following heads : I. Colonists (species not yet showing signs 
of spreading) ; shepherd's purse {Capsella bursa-pastoris) , eat's-ear 
{Hypochaeris radicata), (one of the most common weeds on the 
Pacific coast and spreading in New England, not reported from 
Iowa), black bindweed {Polygonum convolvulus) (common every- 
where in Iowa), toad-flax {Lvnaria vulgaris) (common in the 
north). II. Adventive (occasional, but spreading); mayweed 
{Anth&ms cotula), Mexican poppy {Argemone mexicana). Cosmos 
bipinnatus, morning-glory {Ipomoea purpurea), darnel {Lolium 



WEED MIGRATION 



697 




mmm^^^-^ 



Fig. 537. Caster Oil plant. Cultivated as an ornamental plant in Iowa, but u 

troublesome weed in South Africa. 

(After Faguet.) 



temulentum) , plantain {Plantago major), ribgrass {Plantoffo 
lanceolata), sheep sorrel {Bumex acetosella), curled dock (Bumex 
crispus), black nightsbade (Solanum nigrum), dandelion {Taraxa- 
cwm offiemale), cow-herb (Saponmia vaccaria), vetch {Vicia sch 
tiva). III. Common; spiny amaranth {Amaranthus spinosus), 
goosefoot {Chenopodium album), hemp (Cannabis indica), nut 
grass (Oypertis esculentus), shoo-fly {Hibiscus trionum), lady's 
sorrel (Oxalis cormc"ulatd) , purslane {Portulaca oleracea), castor- 
oil bean (Biciwus communis), and caltrop {Tribulus terrestris). 
IV. Abundant; (the most common species) purple amaranth 
(AwMranthus paniculatus) , sticktight (Bidens pilosa), jimson weed 
(Datura stramonium), purple thorn apple (Datura tatula), wire 



698 



WEED FLORA OF IOWA 



grass {Eleusine indica), Sida rhombifolia, spiny clotbur {XantMum 
spinosum), zinnia {Zinnia pauciflora). 




Fig. 538. Spiny Clotbur. An abundant and troublesome weed In South Africa, 

occasionally a weed in southeastern Iowa. 

(After Thurber.) 



As an example of the spread of American weeds in Europe sev- 
eral weeds may be cited. The small ragweed {Ambrosia artemisiae- 
f olia) , -which is common throughout the United States, has accord- 
ing to Laubert, been widely spread with American grown clover 
seed*, though known in isolated places in Germany for forty years. 
It is now on the increase, perhaps because of the recent clover 
importation, yet its spread is somewhat limited because it blooms 
late. The plants are often only pistillate. In Steglitz, Germany, 
it was associated with black bindweed {Polygonum convolvulus), 
fleabane {Erigeron canadense), wall barley {Hordeum murinum), 
ribgrass {Plantago lanceolata) , common plantain {Plantago major), 
wild carrot {Daucus carota), yarrow {Achillea millefolium) and 
tumble weed {Corispermum hyssopifolium) . 

•Landw. Jahrbucher. 35: 735-737. 



WEED MIGRATION 



699 





m^ ^^' 






^A^^^\M 






L A^s 






^ '^ J^A-x W 






^'" 


- ■ ■ <■: ■ '.'"> 



Fig. 538A. Caltrop (Tribulus terristris). 

(Photographed by Colburn.) 



Scherer and others record the occurrence of Solanum rostratum 
in Germany (1883) and in France. 

In Pflanzenleben, Kabsch says, "There are many illustrations of 
plant iromigrations and spreading of plants in Europe, but so far 
as I know they have never occupied the soil to the same degree in 
Europe as in America. Most of our weeds of fields, like the cereals 
among which they grow, are of foreign origin, as star thistle 
{Centaurea cyanus), corn cockle {Agrostemma githago), charlock 
{Baphanus raphcmistrum) , Myagrum, etc." There are many other 
weeds of grain fields that are of similar origin that are not men- 
tioned by Kabsch. Among them are the common mustard {Brassica 
arvensis), common vetch {Vicia sativa), darnel {Lolium temulen- 
tum), Eussian thistle {Salsola kali var. \enuifolia), pennycress 



700 



WEED FLORA OP IOWA 




Fia. 539. Com Cookie (.Agrostemma glthago). An Immigrant from western 

Asia. 
(After U. S. Dept. of Agr.) 



(Thlaspi arvense), false flax {Camelina sativa), Berteroa {Berteroa 
incana and B. mv,tabilis). These weeds were undoubtedly spread 
with the cultivation of grain. Many, though by no means all, were 
brought to Europe with wheat during the early cultivation of grain 
in Europe. The crusaders undoubtedly were responsible for the 
spread of these small grain weeds in Europe. Other plants, of 
which the horseradish is an illustration, were no doubt brought into 
west Europe as cultivated plants. 

It may not be out of place to give the expression of some of the 
phytogeographical writers on the subject. 



WEED MIGRATION" 



701 





Fig. 540A 
A. Charlock (.Brassica arvensis). 



Fig. 540B 



Fig. 540. A. Charlock (.Brassica arvensis). B. Black Mustard (B. nigra). 
Immigrants from western Asia brought to the United States by way of 
Europe ; early colonists. 

(Dewey, TJ. S. Dept. of Agr.) 

Warming and Vahl, in Oecology of Plants, speaking of the pam- 
pas in South America and the European plants found there, say : 

The pampas occupy the vast, rockless, alluvial. South American 
plains that stretch from the Atlantic coast to the Andes, and from 
Patagonia to the forests of Paraguay and Brazil. The boundless, 
level or somewhat undulating, uniform, treeless surface is clothed 
with perennial grasses and herbs, like "a shoreless sea of grasses 
on whose horizon the eye finds no resting point, save where the 
sun rises and sinks". The genera represented are Melica, Stipa, 
Aristida, Andropogon, Pappophorum, Pardcum, and Paspalum. 
Between' the grasses grow numbers of herbs belonging to various 
families; these include Verbena, Portidaca, Apocynaceae, Com- 
positae, Eryngium, and others. Curiously enough, there are very 
numerous European species, which have succeeded in exterminating 
the inland vegetation for miles and include not only such thistle- 
like Compositae as Cynara carduncuhis, Silybum marianum and 
Lappa, but also Loliwm perenne, Hordeum murinum, H. secalinwm, 



702 WEED FLORA OP IOWA 

Medicago denticulata, and Foeniculum capillaceum. In the flora 
of Buenos Ayres, according to Otto Kunze, at least three-quarters 
of the species^ are introduced, and largely Mediterranean in source. 

Roland M. Harper says: 

Every botanist who attempts to classify the vegetation of a 
populous region, such as the northeastern United States, is con- 
fronted at the outset with the problem of distinguishing the natural 
or undisturbed habitats from those which have been modified by 
civilization. Of course all our vegetation has felt the influence 
of civilization more or less, but it seems possible to draw a fairly 
sharp line between those habitats whose flora is essentially the same 
now as it was in prehistoric times and those where it has been 
so much altered that it is impossible to reconstruct the primeval 
conditions. 

In general it seems to be true — and the task of the phyto- 
geographer would be almost hopeless if it were otherwise — ^that 
external influences of slight amount or of short duration produce 
no permanent changes in vegetation. As an example of the first 
kind, when the pine trees are removed from 'an area of southern 
pine-barrens the amount of sunlight reaching the ground is in- 
creased probably not more than ten per cent, and this seems to 
make no perceptible difference to the herbaceous vegetation. But 
if the ground is then plowed up and cultivated, the original vege- 
tation disappears,, most of it never to return. 

In the second place if a deciduous forest is destroyed by lumber- 
men or swept by fire it presents a very different appearance for a 
time, but if left undisturbed it will regain its former appearance 
and flora, or very nearly so, as soon as the trees have time to 
grow up again. But if the cutting or burning is repeated every 
few years the ground will gradually become covered with herbs 
and short-lived shrubs, among which it is difficult for trees to 
regain a foothold. 

M. L. Femald has said along the same line : 

The clearing of the forest lands and the letting in of the direct 
sunlight is the inevitable forerunner of the farm and the village, 
but it is as inevitably the death warrant of hundreds of native 
plants. As is now well understood, a majority of our woodland 
species have a root structure which allows them to grow only in 
the moist, spongy humus of the forest or the swamp, conditions 
as many o£ us know from practical experience, almost impossible 
of artificial attainment. Try as we will, most if not all of us 
have failed to imitate with sufficient skill permanently to satisfy 
the plant the exact conditions which please the stemless lady's 
slipper (Cypripedium acaule), the trailing arbutus (Epigaea), the 
various species of Pyrola, the yellow wild foxgloves ( Gerardia) , the 
painted-cups {Gastilleja), or the fringed gentian; though in their 
undisturbed haunts these plants bloom regularly and reproduce 
freely. 



WEED MIGRATION 703 

In their own wild homes, likewise, these and scores of other 
species are almost as sensitive to change as when forced by man 
into an unappreciated state of culture. The simple cutting of the 
forest is to most of these plants disastrous, though such of them 
as are very hardy will often linger until fire has swept the cleared 
land and burned out the tinder-like humus. After the fire comes 
a complete change of vegetation, and, during the interval before 
the stumps are finally removed and the land turned by the plow, 
the clearing too often becomes a tangle of fire cherry {Prunus 
permsylvanica) , aspens (PoptUus tremuloides and P. grandidenlata) 
and other quick-growing trees and shrubs with a liberal mixture 
of ' blackberry and raspberry bushes, fireweeds {EpUoiium and 
Erechtites), rattlesnake-weeds {Prenanthes) , and other coarse 
plants which love the open and the direct sunshine. When the 
final planting of the farm crop comes, however, these sturdy plants 
of the burned land are quickly disposed of and rarely if ever do 
they make themselves troublesome in the cultivated field. 

E. W. Claypole, in speaking of the migration of weeds to 
America, says: 

Underneath the great wave of human emigration from the so- 
called Old to the so-called New World, underneath the noisy, busy 
surface tide that has swept westward from the shores of Europe 
to those of America during the last two hundred years, there has 
existed another and a less conspicuous wave, another and a less 
prominent tide of emigration. Westward in its direction, like the 
former, it has silently accomplished results that seldom strike 
the superficial eye, but yet are scarcely less in magnitude than 
those which have followed the advent of the white man to the 
shores of America. 

I allude to that slow and noiseless immigration of European 
plants which has been going on for many years, and which prob- 
ably commenced when the first European vessel touched our shores. 
Side by side with the displacement of the red man by the white 
man has gone on the displacement of the red man's vegetable com- 
panions by plants which accompanied the white man from his trans- 
Atlantie home. Not more completely have the children of the 
pilgrim fathers made themselves at home on the banks of the 
Charles and the Neponset, not more completely have the successors 
of Champlain and Jacques Cartier established themselves along 
the St. Lawrence, not more completely have the descendants of 
the aristocratic colonists of Maryland and Virginia appropriated 
the shores of the Chesapeake, than have the homely weeds of Eng- 
land and France made themselves at home in the New World; 
established themselves on its soil, appropriated its fields, its gar- 
dens and its waysides. Nor have the older states alone been seized 
by those European invaders. The stream has flowed beyond them, 
and as no village or hamlet in the west is without its population 



704 WEED FLORA OF IOWA 

of European descent, so too it is never without its plant population 
of European weeds. 

Dr. Asa Gray, who discussed the subject of weeds from a phi- 
losophical standpoint, said: 

In the United States, and perhaps in most parts of the world, 
a large majority of the weeds are introduced plants, brought into 
the country directly or indirectly by man. Some, such as dande- 
lion, yarrow, and probably the common plantain and the common 
purslane, are importations as weeds, although the species naturally 
occupy some part of the country. 

"Why weeds are so pertinacious and aggressive is too large and 
loose a question; for any herb whatever when successfully ag- 
gressive becomes a weed ; and the reasons of predominance may be 
almost as diverse as the weeds themselves. But we may inquire 
whether weeds have any common characteristic which may give them 
advantage, and why the greater part of the weeds of the United 
States, and probably of similar temperate countries, should be 
foreigners. 

As to the second question, this is strikingly the ease throughout 
the Atlantic side of temperate North America, in which the weeds 
have mainly come from Europe ; but it is not so, or hardly so, west 
of the Mississippi in the region of prairies and plains. So that the 
answer we are accustomed to give must be to a great extent the 
true one, namely, that, as the district here in which weeds from 
the Old World prevail was naturally forest-clad there were few 
of its native herbs which, if they could bear the exposure at all, 
were capable of competition on cleared land with emigrants from 
the Old World. It may be said that these same European weeds 
here prepotent had survived and adapted themselves to the change 
from forest to cleared land in Europe, and therefore our forest- 
bred herbs might have done the same thing here. But in the 
first place the change must have been far more sudden here than 
in Europe; and in the next place we suppose that most of the 
herbs in question never were indigenous to the originally forest- 
covered regions of the Old World; but rather, as western and 
northern Europe became agricultural and pastoral, these plants 
came with the husbandmen and the flocks, or followed them, from 
the woodless or sparsely wooded regions farther east where they 
originated. This, however, will not hold for some of them, such as 
dandelion, yarrow, and ox-eye daisy. It may be said that our 
weeds might have come to a considerable extent from the border- 
ing, more open districts on the west and south. But there was 
little opportunity imtil recently, as the settlement of the country 
began on the eastern border; yet a certain number of our weeds 
appear to have been thus derived; for instance, Molhigo verticil- 
lata, Erigeron canadense, Xcmthium, Ambrosia art&mdsiaefolia, 
Verhena hastata, V. urticifoUa, etc., Veronica peregrina, Solanum 



WEED MIGRATION 



705 




rig. 541A Fig. 541B 

Fig. 541. A and B. Small Ragweed (.Ambrosia artemisiaefolia). An immigrant 

from the southern part of the United States. 

(Vasey, IT. S. Dept. of Agr.) 



carolinense, various species of Amarantus and Euphorbia, Pamcum 
capillare, etc. Of late, and in consequence of increased communi- 
cation with the Mississippi region and beyond — especially by rail- 
roads — other plants are coming into the eastern states as weeds, 
step by step, by somewhat rapid strides; such as Dysodia ehrysan- 
themoides, Matricaria discoidea, and Artemisia biennis. Fifty 
years ago Budbeckia hirta, which flourished from the AUeghanies 
westward, was unknown farther east. Now, in tlwenty years, it has 
become an abundant and conspicuous weed in grass fields through- 
out the eastern states, having been accidentally disseminated with 
red clover seed from the western stiates. 

There are also native American weeds, doubtless indigenous to 
the region, such as Asolepias corwwti, Antennaria margaritacea and 
A. plantaginifolia, and in enriched soils Phytolacca decandra, which 
45 



706 



WEED FLORA OF IOWA 




Fio. 542. Tickle Grass (Panicum capillare). A common grass, probably orig- 
inally found in clearings, has rapidly spread to cultivated ground. 
(Lamson-Scribner, U. S. Dept. of Agr.) 

have apparently become strongly aggressive under changed condi- 
tions. These are some of the instances which may show that pre- 
dominance is not in consequence of change of country and intro- 
duction to new soil. 

In the interesting paper of Claypole the author argues that the 
abundance of European weeds in North America is because Euro- 
pean plants are more plastic than American plants. He says: But 

a weed possessing a plastic nature — one capable of being moulded 
by and to its new surroundings — ere long adapts itself, if the 
change is not too great or sudden, to its new situation, takes a new 
lease of life, and continues in the strictest sense a yreed.. 

Is it not possible that some such cause as this may lie underneath 
the facts we detailed in the earlier part of this paper? The true and 
full explanation of the transfer of European species to America 



WEED MIGRATION 707 

should at the same time explain the absence of American species 
from Europe. But the partial causes already alluded to fail to do 
this. There is a residual effect for which they do not account. 
May it not be true that the plants of the European flora possess 
more of this plasticity, are less unyielding in their constitution, can 
adapt themselves more readily to new surroundings, and thus secure 
their continuance in the New World 1 And may it not be the lack 
of this plasticity in the American flora which incapacitates it for 
securing a foothold and obtaining a living in the different condi- 
tions of the New World? Under the care of the gardener they 
grow and embellish the gardens and conservatories of Europe, but 
without this care they speedily fail and die. 

Dr. Gray in a very friendly criticism of this paper remarked 
that, ' ' So far as we know, the greater plasticity of European as com- 
pared with American plants is purely hypothetical. More plastic, 
would mean of greater variability, which, if true, might be deter- 
mined by observation. Because Europe once had more species or 
types in common with North America than it now has, it does not 
seem to follow that the former has 'a younger plant-life,' or that 
its existing plants are more recent than those of the American flora. 
And as already intimated, so refined an hypothesis is hardly neces- 
sary for the probable explanation of the predominance of Old World 
weeds in the Atlantic United States." 

It is interesting to note the large number of plants which are con- 
tinually being added to the flora of Europe. Bitter in his paper on 
the adventive flora of Bremen notes that out of the 2,492 plants 
listed by Gfareke in his flora of Germany, 230 are adventive ; Hock, 
who published a paper on the plants of North Germany, lists 54 
as weedy and ruderal. 

The region embraced in North Germany probably contains as 
many exotic weeds as Iowa. For our purpose let us compare foreign 
weeds of Iowa with the native plants. Hitchcock, in his catalogue 
of this plants of Ames and vicinity, lists 740 plants, of which 86 are 
introduced and of these about one-third have not become permia- 
nently established. 

Dr. Charles Mohr in his paper on Plant Life in Alabama, states 
that "fully one-sixth of the plants enumerated in the catalogue of 
the Alabama flora as growing without cultivation are immigrants 
from other regions, and but few of them are native in the more dis- 
tant parts of the continent north of Mexico. They are mostly from 
the warmer temperate, subtropical, and tropical regions of the Old 
World. Those of widest distribution and which have gained the 



708 WEED FLORA OF IOWA 

firmest foothold are wanderers following civilized man in his con- 
quest of the wilderness. Originally children of the open plain, ex- 
posed to the extremes of heat, cold, drought, and excessive rain, these 
plants necessarily acquire the widest elasticity in adapting them- 
selves to new surroundings and possess the greatest power of re- 
sisting adverse conditions. ' ' 

THE DIRECTION OF WEED MIGRATION. 

Mr. L. H. Dewey, who made a study of 200 North American 
weeds and their migration, says: "A study of the origin of weeds 
now in this country will impress one with the largeness of the num- 
ber that have been introduced from Europe in comparison with the 
number of native species or of species received from other direc- 
tions." In the list of 200 weeds of the United States published in 
the Year Book for 1895, 108 species are of foreign origin, while 92 
are native. Of the 108 introduced species, 64 are native in Europe 
and 30 are ascribed to the Old World in general, only 2 Asiatic 
species in the list having established themselves as weeds in this 
country without being first distributed in Europe. Africa and 
Australia are not represented among our weeds, while Central and 
South America have contributed only 12 or 15 important species, 
most of which are confined to the Gulf states. A list of the pleints 
of Michigan published in 1892 contains 1,604 indigenous species, of 
which 22 are recognized as injurious weeds, and 142 species intro- 
duced from Europe, of which 57 have become troublesome weeds. 

A list of Kansas weeds enumerating 209 species contains 129 na- 
tive species, 42 introduced from Europe, and 38 from all other 
sources. Eighteen species native in the states east of the Mississippi 
river have been introduced into Kansas in opposition to the pre- 
vailing winds and the direction of the drainage, while only 3 species 
are mentioned which have come from the Rocky Mountain region 
with both of these natural forces in their favor. 

In an article on the weeds of California 110 species are mentioned 
as troublesome in that state. Of these, 53 are native, 43 are intro- 
duced from Europe, 5 are from the eastern United States, 3 from 
Central and South America, and only 2 from Asia. Even in the 
states bordering the Gulf of Mexico the number of weeds introduced 
from Europe in cultivated land equals or exceeds those from Mexico 
and South America. Canada thistle, bur clover, and skunkweed 
have been taken from California to Australia, where they quickly 
become naturalized and are now rapidly spreading. 

The weeds which have followed civilization in America are, 
shepherd's purse, dandelion, sow thistle, stinging nettle, mallow, 
plantain, chickweed, St. John's-wort, yarrow, toadflax and purs- 
lane. Mana^eh Cutler, in 1783, reported 66 species, among them 
buttercup, chicory and daisy. Dr. Bigelow, in Florula Bostoniensis, 



WEED MIGRATION 



709 




Pig. 543. Jimson Weed (Datura stramonium). An immigrant from India, 

reached United States by way of Europe. 

(After Cliesnut, U. S. Dept. of Agr.) 



1814, records 83 introduced species and in the edition of 1840, lists 
140 species. Dr. Fernald says : ' ' Gradually this list has increased 
until we are forced to number among the wild plants of New 
England more than 600 species which have been introduced through 
human agency since the first cutting of the forests." The causes 
for the appearance of these weeds into New England, the west, 
Pacific coast and elsewhere must be ascribed to the sowing of 
seed that contained the weed seeds. Wheat always contained the 
seed of cockle, mustard, vetch, etc., consequently we find that 
these weeds are found wherever cereals are cultivated. Many 
plants were, however, planted for medicinal purposes, among 
which were peppermint, black henbane, tansy, chamomile, caraway, 
poison hemlock, and a long list of other plants utilized by the Mor- 
mons which have become weedy wherever these people have settled. 
Even in Iowa we find that such plants as tansy, elecampane, jimson 



710 



WEED FLORA OF IOWA 



weed, European raorning-glory, shoo-fly, and others have been 
spread from cultivation and have become weeds. In regard to the 
introduction of plants, Dr. Femald has stated the ease very well 
in the following paragraph : 

A review of the history and spread of this vagrant class of 
plants presents many aspects which are well worth consideration. 
John Josselyn, in 1672, stated that several species of European 
weeds had "sprung up since the English planted and kept cattle 
in New England", thus implying that these plants had come un- 
bidden or at least were not purposely brought to this country. 
He records no less than 40 European weeds introduced in this 
manner. According to a time-honored tradition, based perhaps on 
fact, the first weed to spring up in the track of the pioneer is 
plantain, and on this account it has been called by some primitive 
races "White-man's Foot", a name of more than fanciful appli- 
cation; for without question the plantain and many other roadside 
species are spread directly by the foot of man. For some years 
strange and outlandish weeds have been appearing along the river 
below Waterbury, Connecticut. These plants, upon careful study, 
prove to be vagrant species from geographically remote portions 
of the world, and their presence along the Naugatuck river has 




FiQ, 544. Poison Hemlock (.Conium maculatum). Common in Salt Lake Basin. 
(After Chesnut, TJ. S. Dept. Agr.) 



WEED MIGRATION 



711 



been a mystery. Eventually, however, the whole matter was 
cleared when the source of these plants was traced to a factory 
which utilized old rubber shoes. These shoes were collected from 
every available source, and, before being melted for their rubber 
were stripped of the cloth linings which were thrown upon a rubbish 
heap. These linings naturally contained seeds of innumerable 
plants from the roadsides of every land, and the rains and spring 
freshets of the Naugatuck valley gave them every opportunity to 
scatter and to start life anew in Connecticut soil. In this or simila'* 
ways many of the plants mentioned by John Josselyn, Manasseh 
Cutler, and Jacob Bigelow undoubtedly reached our shores; and 
these emigrants are being reinforced by almost every person who 
comes to us from foreign lands. 

Many weeds start in the proximity of woolen mills. Among 
these are, teasel, buffalo bur, various borages, erodium, etc. Others 
are introduced with agricultural seeds. In recent years there 




Fig. 545. Chicory (Cichorimn intuius). An immigrant from Europe, a, flower- 
ing branch ; b, single head ; c, single flower ; d and e aohene ; e, cross 
section. 

(U. S. Dept. of Agr.) 



712 



WEED FLORA OF IOWA 



have been introduced into Iowa such weeds as wild carrot {Daucus 
ca/rota) , Silene noctiflora, S. dichotoma, Gichorium intylms, Conium 
maculaiwm, Centcmrea solstitialis, Cirsium arvense, C. pratense, 
Cuscuta arvensis, G. epithymum, Eruca sativa, and others, largely 
with clover and alfalfa seed. Still another and frequent source 
of the introduction of weeds is through the cultivation of orna- 
mental plants which become weedy as : shoo-fly {Hibiscus trionwm) 
during recent years, the bouncing bet (Saponaria officinalis L.), 
toad flax (Linaria vulgaris), Euphorbia cypairissias, live forever 
{Sedum telephium) , snow-on-the-mountain (Euphorbia marginata) 
in many localities, pickerel weed {Eichornia crassipes) in Florida, 
water chestnut {Trapa natans) in central New England. The or- 
ange hawkweed (Hieracium aurantiacum) , and others of this class 
are excellent illustrations of how ornamental plants become weedy. 
In some cases plants cultivated for food have become weedy, as 
in Iowa, the horse radish; in California, the beet (San Francisco 
Bay region) ; and in Utah and California, the spinach. 




Fio. 546. Snow-on-the-Mountain (Euphorbia marginata). A western weed now 
common in some places in the east. 
(After Chesnut, U. S. Dept. Agr.) 



WEED MIGRATION 



713 



New introductions have come not only into western Europe 
from the United States, but from eastern Europe, Asia, and from 
the tropical world. The Berteroa incana, a recent introduction 
into Iowa, has been reported in Germany by Scherer. The spiny 
knapweed {Centaur ea solstitial^) , a recent Iowa introduction, has 
been reported from Germany by Lehmann, Bitter and Alpers. The 
Galinsoga parviflora, an introduction from South America into 
the United States, has been reported from northern France and 
southern Germany by Kieffer. The storksbill {ErocHum mos- 
chatum), the butterprint {Ahutilmi theaphrasti) , the spiny clotbur 
{XantMum spinasum) and the shoo-fly {Hibiscus trionum), are 
common plants of the tropical regions everywhere; these have ex- 
tended far northward. In recent years they have been reported in 
north Germany by Bitter. He has likewise reported as recent in- 
troductions the yellow sweet clover {Melilotus officinalis), Matri- 




FiG. 547. Velvet Weed or Butterprint (.Adutilon theophrasti) . A tropical weed 

now common in the north and spreading to Europe. 

(U. S. Dept. of Agr.) 



714 WEED F1.0RA OF IOWA 

caria discoidea of Asia, Mexican fireweed ( Kochia scoparia), brome 
grass {Bromus tectorum) in the vicinity of Bremen; all being in- 
digenous to eastern Europe and western Asia. 

Dr. Femald states that of the species of plants growing in the 
British Isles, at an altitude of 3,000 feet in the mountain country, 
where the primitive vegetation is but little disturbed, 68% are also 
native to the mountainous regions of New England, but of the 
species that occur everywhere at low altitudes and in thickly set- 
tled and closely farmed districts only 23% are native to New Eng- 
land while more than 50% have become established in New England 
as weeds; and that barely 1% of the plants of temperate Europe 
have been imported from America, but every year adds to the new 
weeds introduced into Europe. 

Dr. Gray, in that interesting paper on the Pertinacity of "Weeds, 
refers to the book by Mr. Hensiow on the Self-Fertilization of 
Plants, in which the latter comes to the conclusion that weeds are 
intrusive and dominating plants of great emigrating capabilities, 
and have a longer ancestral life history than their more or less 
aggressive relatives. Furthermore, this dominance may be at- 
tributed to self-fertilization. In the list of weeds that Dr. Gray 
mentions in this paper as the most abundant in eastern North 
America and the southern United States, the rule evidently does 
not hold that this dominance is due to self-fertilization; in fact 
some of the most dominant of these plants are pollinated by in- 
sects. For the sake of convenience I shall here use a list prepared 
by Dr. Gray in 1879, adding to it weeds that are more or less pre- 
dominant in the state of Iowa at the present time ; the Iowa weeds 
are printed in small capitals. There is a slight rearrangement, 
according to present interpretation of taxonomists. 

Gramineae. 

DiGiTARiA HUMiFUSA, Smooth cpab grass. 

D. SANGUiNALis, Crab grass. 

Panicum capillaee, Old-witch grass. 

P. DiCHOTOMiPLORUM, Sprouting crab grass. 

EcHiN-QCHLOA CEUSGALLi, Barnyard grass. 

Setaria glauca, Pigeon grass. 

S. viRiDis, Green foxtail. 

S. verticillata, Bristly foxtail. 

Cenchrijs teibuloides, Sandbur. 

Anthoxanthum odoratum, Sweet vernal grass. 



WEED MIGRATION 73 



MuHLENBERGiA MEXicANA, Mexican drop-seed. 

M. RACEMOSA, Marsh muhlenberg. 

M. ScHEEBEBi, Nimble "Will. 

Spokobolus vaginiflokus. Sheathed rush grass. 

S. NEGOiCTUS, Small rush grass. 

Alopecueus pratensis, Meadow foxtail. 

A. GENicuLATTJS, Marsh foxtail. 
PMeum pratense, Timothy. 
Ageostis ai/BA, Red top. 
AvENA fatua, "Wild oats. 
EiiEusiNE iNDiCA, Wire grass. 
Ebagrostis pilosa,' Southern spear grass. 

E. MEGASTACHTA, Candy grass. 
Dactylis glomerata, Orchard grass. 
Poa annua, Low spear grass. 

P. pratensis, Kentucky blue grass. 

P. trwialis, Rough-stalked meadow grass. 

P. cOMPRESSAj "Wire grass. 

Beomus secalinus. Chess. 

B. hoedeaceus. Soft chess. 

B. AEVENsis, Field brome grass. 
B. TECTORUM, Downy brome grass. 
Festuca pratensis. Meadow fescue. 

F. ovina. Sheep's fescue. 
Lolmm peremne, Common darnel. 
L. TEMUiiENTUM, Poison damel. 
Agropteon eepens. Quack grass. 
A. ca/ninum, Awned wheat grass. 
A. Smithh, "Western wheat grass. 
HoRDEUM jDBATUM, Squircl-tail grass. 
H. PusiLLUM, Little barley. 

Gyperaceae. 

Ctpeeus escuuentuSj Nut grass. 

Juncaceae. 
JuNCUS TENUIS, Slender rush. 

Liliaceae, 
Allium vineale, "Wild garlic. 

Vrticaceae. 
Cannabis sativa. Hemp. 
Uetica gracilis. Nettle. 



71 716 WEED FTLORA OF IOWA 

Polygonaceae. 

RuMEX CEisPus, Curled dock. 

R. Aunssiuvs, Pale dock. 

R. sANGtriNEUs, Bloody dock. 

R. ACETOSELLA, Sheep sorrel. 

Polygonum avicxjlaee, Knotweed. 

P. EEECTUM, Larger knotweed. 

P. LAPATHipoLiuM, Slender smartweed. 

P. MuHLENBERGii, Marsh smartweed. 

P. PENNSYiiVANiCTJM, Pennsylvania smartweed. 

P. ACRE, "Water smartweed. 

P. PERSicAEiA, Lady's thumb. 

P. CONVOLVULUS, Black bindweed. 

Chenopodiaceae. 

Chenopodium Botets, Jerusalem oak. 

C. ALBUM, Goosefoot. 

C. HYBEiDUM, Maple-leaved goosefoot. 

Ateiplex patula, Orach. 

Cycloma ateiplicifolium. Winged pigweed. 

KocHU. scoPAEiA, Mexican fireweed. 

Salsola kali vae. tenuipolia, Russian thistle. 

Amaranthaceae. 

Amaeanthus eeteoflexus, Green pigweed. 
A. GEAECiZANS, Tumble weed. 
A. BLiToiDES, Prostrate pigweed. 

ACNIDA TUBEECULATA V. PROSTEATA, Water hcilip 

Nyctaginaceae. 

OXYBAPHUS NYCTAGINEUS, Wild foUr-0 'clock. 

Oaryophyllaceae. 

Stellaeia MEDIA, Chicl?weed. 

Cerastium nutans, Mouse-ear chickweed. 

Ageostemma githago, corn cockle (wheat secticnt^' 

Lychnis alba. White campion. 

L. dioica, Red campion. 

Silene latifolia, Bladder campion. 

S. NOCTiFLOEA, Night-flowcring catchfly. 

S. ANTiEEHiNA, Sleepy catchfly. 



WEED MIGRATION 717 

Saponaeia officinalis, Bouncing Bet. 
S. VACCAEIA, soapwort (wheat sections). 

Portulacaceae. 
PoRTULACA OLEEACEA, Purslane. 

Ranunculaceae. 

Ranunculus aboetivus, Small-flowered crowfoot. 

B. bulbosus, Bulbous buttercup. 

B. acris, Tall buttercup. 

R. SEPTENTEioNALis, Swamp buttercup. 

Cruciferae. 

Beeteeoa incana, Alyssum. 

Thlaspi aevbnse, Frenehweed. 

Lepidium vieginigum, Large peppergrass. 

L. apetalum, Small peppergrass. 

Capsella bursa-pastoriSj Shepherd's purse. 

Camelina sativa. False flax. 

Neslia paniculatAj Ball mustard. 

Raphanus eaphanisteum, Jointed charlock (northeastern Iov\a). 

Beassica ae'tonsis, English charlock. 

B. NiGEA, Black mustard. 

SiSYMBEiuM officinale, Hedge mustard. 

S. ALTissiMUM, Tumbling mustard. 

Radicula nastuetium-aquaticum, "Water cress. 

R. AEMOEAciA, Horseradish. 

Baebaeea vxtlgaeiSj Winter cress. 

Capparidaceae. 

PoLANisiA GEAVEOLENs, Clammy weed. 
Cleome seeeulata, Stinkweed. 

Resedaceae. 
Beseda lutea. Dyer's rocket. 

Rosaceae. 

Geum canadensEj White avens. 
Rosa peatincola, Prairie rose. 



71 71 718 WEED FLORA OF IOWA 

Leguminosae. 

Cassia chamaecrista, Partridge pea. 

Genista tinctoria. Dyer's greenweed. 

Crotalaria sagittalis. Rattle-box. 

Trifolium arvense, Stone clover. 

T. PEOCUMBENS, Low Lop clover. 

T. procwmhens, Low hop clover. 

T. repens, White clover. 

Meulotus officinalis. Yellow sweet clover. 

M. AiiBAj White sweet clover. 

Medicagk) lupulina. Black medick. 

Dalea alopecuroides. Pink dalea. 

RoBiNiA PSEUDO-ACACIA, Falsc acacia. 

Gltotbrhiza liEPiDOTA, Liquorice. 

ViciA SATIVA, Vetch. 

V. villosa, Hairy vetch. 

Stbophostyles pauciflora, Wild bean. 

Oxalidaceae. 
OxAus CORNICULATA, Lady's sorrel. 

&eraniaceae. 
Geranium maculatum. Wild eranesbill. 

Euphorbiaceae. 

AcAiiTPHA viRGiNicA, Thrcc-seeded mercury. 
Euphorbia preslh, Large spotted spurge. 
E. MACuiATA, Spotted spurge. 
E. COROLLATA, Flowcring spurge. 
E. CTPARissiAS, Cypress spurge. 

Malvaceae. 

Abutilon theophrasti, Butterprint. 
SiDA SPINOSA, Prickly sida. 
Malva rotundifolia, Cheeses. 
Hibiscus trionum, Shoo-fly. 

Onagraceae. 

Oenothera biennis. Evening primrose. 
Gauea biennis. Biennial gaura. 



WEED MIGRATION 719 

UmbelUferae. 

Conium maculatum, Poison hemlock. 
Caeum carvi, Caraway. 
Pastinaca sativa. Wild parsnip. 
Daucus caeota. Wild carrot. 

Primulaceae. 
Anagallis arvensis, Pimpernel. 

Apocynaceae. 

Apocynum ANDEOSAEMiFOiiiuM, Spreading dogbane. 
A. cAnnabinum, Indian hemp. 

Asclepiadaceae. 

AscLEPiAs SPECiosA, Showy milkweed. 
A. STEiACA, Milkweed. 

Gonvolvulaceae. 

Convolvulus sepium. Wild morning-glory. 
C. AEVENSis, European bindweed. 
CusouTA EPiTHTMUM, Clover doddcr. 
C. AEVENSiSj Field dodder. 

HydrophyUaceae. 
Ellisia ntcteleAj Waterleaf. 

Boraginaceae. 

Ctnoglossum officinale, Hound's tongue. 
Lappula echinata, Stiekseed. 
Symphytum officinale, Comfrey. 
Echium vulgare, Blue weed. 

Terhenaceae. 

Veebena bracteosa, Bracted vervain. 
V. HASTATA, Blue vervain. 
V. STEiCTA, Hoary vervain. 

LaMatae. 

Nepeta cataeia. Catnip. 
N. HEDEEACBAj Grouud ivy. 
Lamium amplexicaule, Dead nettle. 



720 WEED FLORA OF IOWA 

Leonurus cardmca. Motherwort. 

Mentha piperit^a, Peppermint. 

M. spicata, Spearmint. 

Satureja nepeta, Tbyme. 

S. VULGARIS, Basil. 

Marrubium vulgare, Hoarliound. 

Galeopsis ietrahit. Hemp nettle. 

SoLANUM NIGRUM, Black nightshade. 

S. CAEOLiNENSE, Horse nettle. 

S. KOSTEATUM, Buffalo bur. 

Datura stramonium, Jimson weed. 

D. TATULA, Purple thorn apple. 
Verbascum thapsus, Mullein, 
y. hlaUaria-, Moth mullein. 
Linaria vulgaris. Butter and eggs. 
Veronica peeegrinAj Speedwell. 
Plantago major, Common plantain. 
P. RUGELn, Eugel's plantain. 

P. LANCEOLATA, Ribgrass. 

P. ARiSTATA, Bracted plantain. 

Compositae. 

Erigeron annuus, Daisy fleabane. 

E. canadensis, Fleabane. 
E. RAMOsus, Whiteweed. 

IvA xanthitolia. Marsh elder. 

Ambrosia artemisiaefolia. Smaller ragweed. 

A. TRiFiDA, Greater ragweed. 
Xanthium canadense, Cocklebur. 
Gnaphalium uliginosum, Cudweed. 
Imda helenium. Elecampane. 
Heliopsis scabra. Ox-eye. 
RuDBECKiA HiRTA, Cone-flower. 
Hemanthus annuus, Common sunflower. 
BiDENS PRONDOSA, Beggar-ticks. 

B. DiscoiDEA, Small beggar-ticks. 
Dyssodia papposa. Fetid marigold. 
Achillea millefolium. Yarrow. 
Anthemis cotula, Mayweed. 
Chrysanthemum leucanthemum. Ox-eye daisy. 
Tanacetum vuIjGare, Tansy. 



WEED MIGRATION 



721 



Artemisia bienniSj Wormwood. 
Erechtites hieracipoliAj Fireweed. 
Arctium lappa^ Burdock. 

CiRSIUM LANCEOLATUM, BuU thistle. 

C. ARVBNSE, Canada thistle. 
C. CANESCENS, WooUy thistle. 
CiCHORiUM INTYBUS, Chicory. 
Leontodon autumnalis, Hawkbit. 
Taraxacum oepicinale. Dandelion. 
T. ebythrospermum. Red-seeded dandelion. 
SoNCHus ASPEBj Spiny-leaved sow thistle. 
Lactuca scakiola, Prickly lettuce. 

L. SCARIOLA VAB. INTEGRATA. 

Lydgodesmia juncea, Lygodesmia. 
SoLiDAGO CANADENSIS, Goldcnrod. > 




Fig. 548. 



48 



Narrow Sneezeweed (Helenium tenuifoUum) . General aspect of plant 
and a single head enlarged. 
(After Chesnut, U. S. Dept. Agr.) 



722 



WEED FLORA OP IOWA 



Dr. Gray, in the above list mentioned 86 weeds which are more 
or less aggressive in the Atlantic United States. It would seem, 
however, that comparatively few of the aggressive weeds of the 
Gulf states are enumerated in the list. The more important gulf 
coast weeds are sneezeweed {Helenium tenuifoUum) , Louisiana ear- 
pet grass {Paspahim platycaule), Johnson grass {Sorghum hale- 
peTise), beard grass (Andropogon virginicum) , buffalo bur {Sola- 
rium rostratum), prickly sida {Sida spinosa), southern nut grass 
{Gyperus rotundus), wild pansy {Viola arvensis). Dr. Mohr gives 
the following list of weeds as the most conspicuous by their 
abundance all over the state of Alabama. 




Fio. 549. Johnson Grass (Sorghum halepense). An African weed. 
In the Gulf states, and reported from southwestern Iowa. 
(Lamson-Scrlbner, U. S. Dept. Agr.) 



Common 



WEED MIGRATION 723 

Leptochloa mucronata, Yard grass. 
Manisurus granularis, Manisurus. 
Cyperus rotundus, Southern nut grass. 
Amaranthus retroflexus, Green pigweed. 
Amaranthus hyiridus, Pigweed. 
Amaranthus spinosus, Spiny amaranth. 
Spergula arveiisis, Corn spurrey. 
Portidaca oleracea, Purslane. 
Cassia occidentalis, Senna. 
Cassia tora, Low senna. 
Sida rhombifolia, Rhombleaf sida. 
Sida spinosa, Prickly sida. 
Seneiiera pinnatifida, Peppergrass. 
Veronica peregrina, Neckweed. 
Veronica arvensis, Corn speedwell. 
Lamium amplexicaule, Dead nettle. 
Bichardia scabra, Mexican clover. 

Dr. W. A. and Mrs. Kellerman in a paper on the non-indigenous 
Flora of Ohio, state that out of 2,060 plants of the state 430 are 
not indigenous. Of the latter number 326 have come from Europe, 
30 from Asia, 2 from Africa, 46 from Southern and Western United 
States and 21 from tropical or South America. "When expressed 
in percentages the numbers are as follows: from Europe, 75.81%; 
from Asia, 6.99% ; from Africa, 0.47% ; from the United States, 
10.70% ; and from tropical and South America, 4.81%. 

Comparing the Old World species with those from parts of the 
American continent we find the numbers to be 358 and 67 re- 
spectively. Therefore 83.25% of the introduced species have come 
from the eastern hemisphere and 15.58% from America. 

Expressed in percentages of the total number of introduced 
species they are as follows: waifs, 11.86%; occasionally escaped, 
38.84% ; and thoroughly naturalized, 49.30%. 

The following list shows the families represented and the number 
of species in each. 

1. Amaa-anthaceae, Amaranth Family 5 

2. Aizoaceae, Carpet Weed Family 1 

3. Apocynaceae, Dogbane Family 2 

4. Berieridaceae, Barberry Family 1 

5. Bignoniaceae, Bignonia Family 2 

6. ■ Boraginaceae, Borage Family 11 



724 WEED FLORA OF IOWA 

7. Cactaceae, Cactus Family 1 

8. Campanulaceae, Bluebell Family 1 

9. Capparidaceae, Caper Family 1 

10. Gaprifoliaceae, Honeysuckle Family • 4 

11. Caryophyllaceae, Pink Family 23 

12. Chenopodmceae, Goosef oot Family 11 

13. Gompositae, Thistle Family 88 

14. Convolvulaceae, Morning-glory Family 8 

15. Grassulaceaf, Orpine Family 2 

16. Cruciferae, Mustard Family 27 

17. Gucurhitaceae, Gourd Family 6 

18. Gyperaceae, Sedge Family 1 

19. Dipsacaceae, Teasel Family 1 

20. Elatmaceae, Waterwort Family 1 

21. Euphorbiaceae, Spurge Family 7 

22. Fv/mariaceae, Fumitory Family 1 

23. Geraniaceae, Geranium Family 5 

24. Oramineae, Grass Family 46 

25. Hypericaceae, St. John's-wort Family 1 

26. Laiiatae, Mint Family 24 

27. Leguminosae, Pulse Family 19 

28. LiUaceae, Lily Family 7 

29. Linaceae, Flax Family 1 

30. Malvaceae, Mallow Family 9 

31. Marty maceae, Martynia Family 1 

32. Nyctagmaceae, Four-o'clock Family 2 

33. Oleaceae, Olive Family 2 

34. Oxalidaceae, Oxalis Family 1 

35. Onagraceae, Evening primrose Family 3 

36. Papaveraceae, Poppy Family 5 

37. Plantaginaceae, Plantain Family 4 

38. Polygonaceae, Smartweed Family 14 

39. Portulacaceae, Purslane Family 1 

40. Primulaceae, Primrose Family 2 

41. Ranwiculaceae, Crowfoot Family 9 

42. Resedaceae, Mignonette Family 3 

43. Bhamnaceae, Buckthorn Family 1 

44. Bosaceae, Rose Family 15 

45. Bubiaceae, Madder Family 3 

46. Salicaceae, Willow Family 8 

47. Saxifragaceae, Saxifrage Family 4 



WEED MIGRATION 725 

48. Scrophulariaceae, Figwort Family 14 

49. Simarubaceae, Quassia Family 1 

50. Solanaceae, Nightshade Family 9 

51. Unibelliferae, Parsley Family ; 12 

52. TJrticaceae, Nettle Family 5 

53. Valeriamaceae, Valerian Family 1 

54. Verbenaceae, Verbena Family 1 

55. Violaceae, Viola Family 1 

The weeds of the Pacific coast are somewhat different from those 
of the Atlantic coast. Eugene Hilgard, in a series of interesting 
articles in Garden and Forest, some years ago, S. B. Parish, J. 
Burtt Davy and other California botanists, have contributed notes 
on the introduction of these weeds of the coast. They enumerated 
the more important weeds, among which mention may be made of 
black mustard {Brassica nigra), catchfly {Silene gallica), storksbill 
{Erodium cicutarium), musk erodium (Erodium moschatum), 
small-flowered mallow {Malva horealis), black medick {Medicago 
lupulina), bur clover {M. denticulata), white sweet clover (Meli- 
lotus alba), and yellow sweet clover (M. officinalis), star thistle 
(Centaur ea cyamis), knapweed (C. solstitialis), brown knapweed 
(C. jacea), black knapweed (C nigra), wild carrot {Daucus car- 
ota), beet (Beta vulgaris), spinach {Spinacia oleracea), lady's 
thistle {Silybum marianum) , cotton thistle {Onopordon acanthium), 
dodder {Cuscuta epithymum). 

The writer recently noted the following weeds in the San Fran- 
cisco Bay region, Oakland, and Sacramento, many of our eastern 
weeds being common among them: Hedge mustard {Sisymbrmm 
officinale), Baphamus sativus, Marrubium vulgare, dock {Rumex 
crispus), cheeses (Malva rotundifolia) , mallow (If. crispa), bull 
thistle (Cirsium lanceolatum) , sow thistle {Sonchus oleraceus), 
eat's-ear {Hypochaeris radicata), knotweed {Polygonum erectu/m), 
black medick (Medicago licpulina), Brassica campestris, lamb's 
quarters (Chenopodium. album), chickweed {Stellaria media), Poa 
annua, Alfilaria {Erodium cicutaria), pineapple weed {Matricaria 
suaveolens), common groundsel {Senecio vulgaris), burdock {Arc- 
tium lappa) , Silybum marianum, Centaurea melitensis, prickly let- 
tuce {Lactuca scariola), mustard {Brassica campestris), also such 
native weeds as Amsinckia and Escholtzia. 



726 



WEED FLORA OF IOWA 




.♦- HO* 



mg. 549A 1 




Fig. M9A 11 






Fig. 549A III 

Fig. B49-A. Seeds of weeds scattered with agricultural seeds. I. Dodder In 
clover and alfalfa seed. II. Wliite Sweet Clover In alfalfa seed. Ill- 
Bitter Dock (.Rumex obtusifoUtis) in red clover seed. 



Many of these weeds have made their way into California by 
way of South America. Others are indigenous and widely scat- 
tered on the Paefiic coast. The Pacific northwest has in common 
with the rest of the Pacific coast many European weeds, but also 
many that are indigenous to the country. Many years ago Cusick 
called attention to the predominance of the Northern fireweed 
{Epiloivwm angustifolium) , which, after the removal of the forest 
and the burning of the slashings, comes Up in great abundance. 
The writer in another connection* discussed the weeds commonly 

•The Problem of Weeds in the West ; Proc. la. Acad. So. 15 : 34. 



WEED MIGRATION 



727 




Fig. 550. Curled Dock (Bumex crispus). A common European weed now 

occurring across the continent. 

(After Chesnut, U. S. Dept. Agr.) 



found in the northwest. A few of the abundant species may be 
mentioned. Russian thistle {Salsola kali var. tenuifolia) is abun- 
dant in the drier regioiis, especially east of the Cascades. In the 
Puget Sound country are found such common European weeds as 
Canada thistle {Cirsium arvense), bull thistle (C. lanceolatum) , 
batehelor's button {Centaurea cyanus), chicory {Cichorium iniy- 
bus), common mustard {Brassica arvensis), mullein (Verbascum 
thapsus) and also V. blattaria, and toadflax (Linaria vulgaris)'. 
It is not uncommon to find in clearings of the forest the small 
Kenilworth ivy (Linaria cymbalaria) , the common pansy {Viola 
tricolor), the petunia {Petunia grandiflora) , the dead nettles {La- 
mium amptexicaule and L. album), ox-eye daisy {Chrysanthemum 
leucanthemum) , hemp nettle {Galeqpsis tetrahit), foxglove {Digi- 
talis purpurea) , European bindweed {Convolvulus arvensis). The 



728 



WEED FLORA OF IOWA 



cats '-ear {Hypochaeris radicata) is one of the most common weeds 
in lawns. There is a common belief that it was introduced from 
Chile. 

In the Great Basin country, especially in Utah, a large number 
of the weeds are of European origin. Of the most common of 
these mention may be made of the brome grasses (Bromus brizae- 
fomds and B. tectorum), bouncing Betty (Saponaria vaccaria), 
black medick {Medicago lupvMna), dodders {Cuscuta arvensis and 
C. epithynmm),- -poison hemlock {Conium maculatum) , moth mul- 
lein {Veriascum Hattaria), mint {Mentha viridis), Russian thistle 
{Salsola kali \av. tenuifolia) , horehound {Marrubium vulgare) , 




Fig. 551. Awned Brome Grass (Bromus tectorum). Common In the Great 
Basin country and California, occasionally In Iowa. 



"WEED MIGRATION 



729 



prickly lettuce {Lactuca scariola) and storksbill {Erodmm cicni- 
tarium). There are also such native weeds as bee-plant {Cleome 
serrulata), wild liquorice (Glycyrrhiza lepidota), the squirrel-tail 
grasses {Eordeum jubatum and H. caespitosum) , prickly lettuce 
{Lactuca pulchella), pine-apple weed {Matricaria suaveolens) and 
prickly poppy (Argemone plmtyceras) . In the Rocky mountain re- 
gion, especially Colorado, many of the more recent introductions 
are from Europe. Among these are the sweet clovers (Melilotus 
alia and M. officinalis), black mediek {Medicago denticulata) , 
purslane {Partvlaca oleracea), dodder {Cuscuta arvensis and C. 




Fig. 551A I 





Fig. 551A III Pig. 551A IV 

Fig. 551-A. Seeds scattered with agricultural seeds. I. Barnyard Grass 
(EcMnochloa crusgalH). II. Medicago denticulata^ common in alfalfa 
seed. II. Horehound (.MarruMum vulgare), a, weed commonly scattered 
with alfalfa seed. Common in the Great Basin country. IV. Wild Buck- 
wheat or Bindweed (.Polygonum convolvulus), commonly scattered with 
grain seed. 

(All after Hillman.) 



epithymum), foxtail {Setaria viridis), storksbill {Erodmm cicu- 
tariii/m), Russian thistle {Salsola kali var. tenuifolia) , vegetable 
oyster {Tragopogon porrifolius) , goat's beard {T. pratensis) and 
lamb's quarters {Cheno'podium album). A large number of native 
plants have become weedy, such as marsh elder {Iva xanthifolia) , 



730 



WEED FLORA OF IOWA 



(Franseria discolor), the two annual sunflowers {Helianthus an- 
nuus, H. petiolaris) , small ragweed (Ambrosia artemisiaefoUa) , 
buffalo bur {Solanum rostratum) , Eocky Mountain bee plant 
(Cleome serrulata), gumweed {Grindelia squa/rrosa) and squirrel- 
tail grass (Hordeium jubatum). 





Pig. 551B I 



Fig. 551B 11 





Fig. 651B III 



rig..551B IV 



Fig. 551-B. Seeds of Immigrant weeds. I. Squirreltail {Hordev/m jubatum') ; 
widely scattered witli hay and stock trains from the western plains. II. 
Spinage iSpinacta oleracea) ; a common weed of the Great Basin country. 
Scattered from cultivated plants. III. Russian Thistle iSalaola kali var. 
tenuifoHa) ; brought to Dakota with flax seed and grain seed ; now scat- 
tered in Iowa with alfalfa seed. TV. Winged Pigweed (.Cycloma atri- 
plicifolmm'). 

(II, drawing, L. R. Collins ; the others after HiUman.) 



Cosmopolitan Weeds. — ^A great many weeds, originally, had a 
very wide distribution, although many of these so-eaJled weeds 
were probably introduced by man. In many eases it is almost 
impossible to tell how and whence they came to the places in 
which they occur. 

Who can trace the immigration of such weeds as common purs- 
lane, or charlock, or barnyard grass? In the first place, these 



WEED MIGRATION 



731 



plants immigrated when little was known about the species of 
plants. What was said about them by the early botanical writers 
was often very indefinite. In the second place, many of the early 
writers did not take pains to leave statistics concerning the intro- 
duction of the plants. The future records, however, will be more 
accurate as the adventive plants are being recorded by a host of 
botanical writers the world over. The notes in such floras as 
Britton's Manual, Robinson and Femald-Gray's Manual, Bentham 
and Hooker's Handbook of the British Flora, Garcke's Flora of 
Germany, Acloque's Flora of France, Moore's Handbook of the 
Flora of New South Wales, Arcangeli 's Flora of Italy, Baron Fer- 
dinand von Mueller's Systematic Census of Australian Plants, 
Grisebach's Flora of the British West Indies, Millspaugh's Flora 
of Yucatan, Hemsley's Botany of Central America, Urban 's papers 
on the Flora of the West Indies give more or less detailed infor- 
mation on introduced weeds. 




Fig. 552. Crabgrass (Diffitaria sanguinalis) . A cosmopolitan weed. 



The following weeds are more or less cosmopolitan: crab grass 
(Diffitaria sanguinalis), found in North and South America, Eu- 
rope, Asia, Africa, Australia and New Zealand; barnyard grass 
(Echinochloa criisgalli) , in Europe, Asia, Africa, North and South 
America and Australia; green foxtail {Setaria viridis), in Europe, 



732 



WEED FLORA OF IOWA 




Fig. 553. Foxtail Grass (Alopecurus ffeniculatus) . 

mopolitan grass. 
(U. S. Dept. of Agr.) 



Widely distributed. Cos- 



Asia, Africa, Australia, North and South America; pigeon grass 
(Setaria glcmca), in Europe, Asia, Africa, North and South Amer- 
ica; whorled millet {Setaria verticillata), in Europe, Asia, Africa, 
North and South Aitierica; Johnson grass {Sorghum hdlepense), 
in Europe, Asia, Australia and North America; foxtail grass 
{Alopecunis geniculatus) , in Asia, New Zealand, Australia, North 
America; hair grass {Agrostis hyemalis), in Australia, New 
Zealand, North America; Bermuda grass {Cynodon dactylon), a 
valuable forage plant, but, in cultivated fields, a weed, Europe, 
Asia, Africa, Australia, New Zealand, North and South America; 
southern spear grass {Eragrostis pilosa), Europe, Asia, Africa, 
Australia, New Zealand, North and South America ; crowfoot grass 



WEED MIGRATION 



733 



{Eleusine indica), Europe, Asia, Africa, Australia, New Zealand, 
North and South America; cheat {Bromus secalinus), Europe, 
Asia, North America, a weed; brome grass {Bromus tectorum), 
Europe, Asia, Africa, North America; soft chess {Bromus arven- 
sis), Europe, Asia, Africa, North America. It is singular that 
only one species of Bromus is given by Moore and Ferdinand von 
Mueller, the Bromus arenarius. Reed {Phragmites communis), 
though not regarded as a weed in the United States, is a cosmo- 
politan plant found in Europe, Asia, Africa, Australia, New 
Zealand, Papua, North America (Canada, United States and 
Mexico). 




Fio. 554. Tumbling Mustard (, Sisymbrium altissimum,') . Introduced with grain 

in the Dalcotas. 
(Dewey, U. S. Dept. Agr.) 

Cress (Bariarea vulgaris) occurs in Europe, Asia, Australia, 
New Zealand and North America. None of the most common 
North American weeds among the remaining members of the mus- 



734 WEED FLORA OF IOWA 

tard family occur in Australia or New Zealand, althougli shep- 
herd's purse {Gapsella hursa-pastoris) , common mustard {Brassica 
arvensis), the hedge mustards {Sisymbrium officinale and S. altis- 
simum) and peppergrass {Lepi<Mwm apetalum) are common in 
Europe and Asia. 

Of the pulse family the bird's-foot trefoil (Lotm cornicviatus) 
occurs in Europe, Asia, Africa and Australia; the indigo plant 
{InMgofera hirsuta) in Africa, Australia, Papua and Asia. The 
absence of black medick {Medicago lupulina) and hop clover {Tri- 
folimn agrwriwm,) from Australia is striking. 

Of the geranium family the common European, African and 
Asiatic species of storksbill {Erodium cicwta/rium) are absent in 
Australia and New Zealand and the little yellow flowered sorrel 
{Oxalis comiculata) is the only representative in New Zealand, 
Australia and Papua. This species also occurs in Europe, Asia, 
Africa and America. The only malvaeeous weeds in Australia 
common also to the United States are sida {Sida spinosa) and 
butter-print {Aiutilon theophrasti) , both of tropical origin. The 
former occurs in Europe, Asia, Africa, North and South America, 
Australia and Papua. The pigweed {Am,ar(mthus retroflexvs) of 
southern North America is common in Europe but has not reached 
Australia. None of our troublesome weedy species of dock, which 
are cosmopolitan, occurs in Australia. Of the smartweeds there 
are two species, the water pepper {Polygonum hydropiper) 
(Europe, Asia, North and South America) and slender smartweed 
(P. la/pathifolium) of Europe, Asia, North and South America. 
Silky cinquefoil {Potentilla anserina), of the rose family, is com- 
mon in the west and here and there in northern Iowa; it is found 
in Europe, Asia, Africa, Australia, New Zealand and North 
America. Feverfew {Agrim^wia striata) is found in Europe, 
Africa and North America. None of our Oenotheras is cosmo- 
politan; however the primrose willow {Jussiaea suffruticosa), & 
sub-tropical plant, is widely distributed in Asia, Africa, America 
and Papua. Very few of the Umbelliferae are cosmopolitan. 
Moore and Mueller record water parsnip {Sium latifolium) for 
New Zealand and Australia. 

The Mexican Ageratum conyzoides of the sunflower family, found 
in Africa, Asia, Europe, North and South America, is often weedy. 
The Spanish needle {Bidens bipinnata) is found in Asia, Europe, 
North and South America. The small number of plants of this 
family found in Australia and New Zealand is remarkable. None 



WEED MIGRATION 



735 



of our plantains is of common occurrence. There is no morning- 
glory. 

It may be of interest to compare the noxious weeds of Ger- 
many with those of the United States. Dr. A. Thaer of the Uni- 
versity of Giessen in 1881 published a small book on the agricul- 
tural weeds of that country listing the following: (Those printed 
in small capitals are also weedy in Iowa.) Com poppy (Papaver 
rhoeas), mustard (Beassica abvensis), charlock (Raphantjs 
eaphanisteum), Canada thistle (Ciesium abvense), corn cockle 
(Ageostemma githago), chickweed (Stellabia media), sheep sorrel 
{Bumex acetosella), vetch {Yida Mrswta), colt's-foot {Tussilago 
farfara), com chamomile (Anthemis arvensis), com marigold 




Fig. 555. Cypress Spurge (.Euphorbia cyparissias) . Common in Europe and 
waste places in Iowa. In many oases started in the vicinity of cemeteries. 
(After Strasburger, Noll, Schenek and Karsten.) 



{Chryscmthem-um segetum), groundsel {Senecio vernalis), corn- 
flower {Centaurea cyanus), sow thistle (Sonohus oleeacetjs), 
small bindweed (Convolvulus aevensis), clover dodder (Cuscuta 
bpithymum), broom rape {Oroianohe ramosa), garden orach 



736 WEED FLORA OF IOWA 

{Atriplex hortense), cock's comb (Bhina/nthus crista^galli major 
and ndiwr), smartweed (Polygonum persicabia), cypress spurge 
(Euphorbia cyparissias) , meadow saffron ( Colchicum autumnale), 
silky bent-grass (Agrostis spicchventi) , wild oats (Avbna patua), 
tfliess (Bromur segatjntjs), quack grass (Agropyeon rbpens), 
horse-tail (Equisetum arvense). 

L. Danger in his work on weeds and parasites of Germany, pub- 
lished in 1887, divides the weeds of Germany into two classes: 

A. Root weeds, B. Seed weeds. 

A. Boot weeds. — Quack grass {Agropyron repens), reed grass 
(Phragmites conumunis), bindweed (Convolvulus arvensis), deadly 
nightshade {Atropa ielladowna), goatweed {Aegopodium roda- 
graria), sheep sorrel {Bumex acetosella), sour dock {B. crispus), 
meadow saffron Colchicum cmtumnale), marsh marigold (Caltha 
paiustris), mint {Mentha arvensis), thistle {Cirsium arvense, C. 
alteraceum, C. accmle, C. heterophylhim, C. pahistre, C. lam- 
ceolatum), {Cardwus crispus, C. lanceolatus, C. natans), {Onopor- 
don acanthiwm), sow thistle {Sonchus arvensis, S. pahistre, 8. asper, 
S. oleraceus), colt's-foot {TussUago farfara, T. hybrida, T. peta- 
sites), yarrow {Achillea millefolium), {Leontodon autumnalis) 
dandelion {Taraxacum officinale), plantain {Plantago coron^pus, 
P. arena/ria, P. major, P. media, P. m^ritima, P. lanceolata) , horse- 
tails {Equisetum arvense, E. pahistre). 

B. Seed weeds. — Chess {Bromus secalinus), {Alopecurus 
agrestis), wild oats {Avctud fatua), {Agrostis spicorventi) , darnel 
{Lolium tem/ulentum), black nightshade {Solanum nigrum), black 
henbane {Hyoscyamus niger), Jimson weed {Datura stramonium), 
fool's parsley {Aethusa cynapium), hemlock {Conium maculatum), 
cowbane {Cicuta virosa), Venus' comb {Scandix pecten-veneris) , 
buckwheat {Fagopyrum esculentum), smartweed {Polygomim 
persicaria) , dooryard knotweed {Polygonum aviculare) , com cockle 
{Agrostemma githago), buttercups {Banunculus septentrionalis, 

B. flammula, B. arvensis), nettle {Lamium), charlock {Baphanus 
raphcmistrum) , foxglove {Digitalis purpurea), mustard {Brassica 
arvensis) , mayweed {Anthemis arvensis and A. cotvZa) , groundsel 
{Senecio vulgaris), horseweed {Erigeron canadensis), field mari- 
gold {Chrysanthemum segetum), Frenohweed {Galinsoga parvi- 
flora), spurge {Euphorbia cyparissias), orach {Atriplex hortense), 
nettles {Vrtica urens, U. dioica). 



WEED MIGRATION 737 



AMERICAN "WEEDS INTRODUCED INTO EUROPE. 

Every year more weeds are introduced into Europe from Amer- 
ica; however, it is very noticeable that the more abundant of these 
are from the warmer regions of America, rather than from the 
colder regions. A good many of these are weeds of the open 
country of North America. I have looked rather hastily through a 
few of the floras of Great Britain, Italy, Austria and Germany, in 
addition to a number of recent references on the adventive flora 
of Europe, from which these data have been compiled. 

Apple of Peru {Nicandra physaloides) Germany (Garcke). 

Aster (Aster ')i(H-i-helgii) Italy (Areangeli), Germany (Garcke), 
France (Acloque). 

Aster (Aster parviflorus) Germany (Garcke). 

Aster (Aster salicif alius) Germany (Garcke). 

Bug seed (Corispermum hyssopifolium) Germany (Garcke), 
Italy (Areangeli). 

Bur cucumber (Sicyos angulatus) Germany (Garcke), Italy 
(Areangeli) . 

Clotbur (Xanthiwrn spinosum) Italy (Areangeli), Germany 
(Garcke, Bitter, Kiefer), Austria (Neilreich), France (Acloque). 

CoUomia (CoUomia grandiflora) Germany (Garcke). 

Cone flower (BudbecMa Mrta) Germany (Garcke). 

Cone flower (Biodbeckia laciniata) Germany (Garcke, Bitter, 
Lehmann) . 

Cone flower (Lepachys pinnata) Germany (Bitter). 

Evening primrose (Oenothera sinuata) Germany (Bitter). 

Fleabane (Erigeron annuus) France (Acloque), Italy (Ar- 
eangeli) . 

Fleabane horseweed (Erigeron canadensis) France (Acloque), 
Austria (Neilreich), Germany (Garcke, Lehmann), England 
(Hooker), Italy (Areangeli). 

Galinsoga (Gaiinsoga parviflora) Italy (Areangeli), Germany 
(Garcke). 

Pigweed (Amaranthus retroflexus) Italy (Areangeli), Germany 
(Garcke, Alpers), France (Acloque), Austria (Neilreich). 

Goldenrod (Solidago canadensis) Germany (Garcke, Wegelin), 
Austria (Neilreich). 

Goldenrod (Solidago lanceolata) Germany (Garcke), England 
(Hooker). 
47 



738 



WEED FLORA OF IOWA 




Fig. 556. Goldenrod iSolidago rigida). Common In Iowa. 
(Photographed by Gardner.) 



Goldenrod (SoUdago serotina) Italy (Arcangeli), Germany 
(Gareke). 

Mexican tea {Chenopodium ambrosioides) Germany (Gareke, 
Alpers), Italy (Arcangeli).' 

Nightshade, buffalo bur {Solanum rostratum) Germany (Gareke, 
Alpers) . 

Nightshade, buffalo bur {Solanum heterodoxum) Germany 
(Gareke). 

Nightshade, Three-flowered {Solanum triflorum) Germany 
(Gareke, Alpers). 

Pellitory {Parietaria pennsylvanica) Germany (Gareke). 

Peppergrass {Lepidium virginicuni) Germany (Gareke), France 
(Tourlet). 

Phacelia, (P^aceZia tanacetifolia) Germany (Gareke). 

Pigweed, Tumbleweed {Amaranthus graecizans) Italy (Arcan- 
geli), Germany (Bitter). 

Pigweed {Amaranthus retroflexus) Italy (Arcangeli), Germany 
(Gareke, Alpers), France (Aeloque), Austria (Neilreich). 



WEED MIGRATION 



739 




FiQ. 55''- ^'"^^ *-'^'- Gt^'ass (Leersia orysoides). Common in low grounds, Iowa; 
I not, however, regarded as a weed. Common in Italy. ' 

(Lamson-Scribner, U, S. Dept. of Agr.) 



740 WEED FLORA OP IOWA 

Pigweed, winged {Cycloloma platyphyllum) Italy (Arcangeli). 

Plantain {Plant ago aristata) Germany (Bitter). 

Ragweed, small ■ {Ambrosia art emisii folia) Germany (Garcke, 
I^aubert). 

Eiee cut-grass {Leersia oryzoides) Italy (Arcangeli), Germany 
(Garcke, Buchenau), France (Acloque), Austria (Neilreich), 
England (Hooker). 

Sida {Sida spinosa) Germany (Alpers). 

Spanish needle {Bidens hipvnnata) Italy (Arcangeli), Germany 
(Garcke, Boute), France (Acloque). 

Spanish needle {Bidens frondosa) Italy (Arcangeli). 

Spanish needle {Bidens leucanthus) Germany (Garcke). 

Speargrass {Eragrostis pilasa) Italy (Arcangeli), Germany 
(Garcke), France (Acloque). 

Speedwell {Veronica peregrina) Italy (Arcangeli), Austria 
(Neilreich) . 

Sunflower, artichoke {Helianthus tuberosus) Italy (Arcangeli), 
Germany (Garcke). 

Sunflower, common {Helianthus annuus) Germany (Garcke), 
Austria (Neilreich). 

Tickle grass {Pamicum capillare) Germany (Alpers, Garcke), 
France, Italy (Arcangeli), Austria (Neilreich). 

Tickseed {Coreopsis tinctoria) Germany (Bitter). 

Waterweed {Elodea canadensis) Germany (Garcke, Scherer, 
Weshoff, Bitter), England (Hooker), France (Acloque). 

INDIGENOUS WEEDS COMMON TO THE NORTHERN HEMISPHERE. 

In all probability a few of the weeds here listed have been intro- 
duced, at any rate their origin is in doubt; some occur in Europe 
and North America only; those found in Asia are marked (As.). 

Achillea ynillefoliwrn (yarrow) (As.). 

Alopecurus geniculatus (marsh foxtail). 

Anagallis arvensis (pimpernel) (As.). 

Anaphalis margaritacea (everlasting). 

Atri/plex patula var. hastata (orach). 

Barba/rea vulgaris (yellow rocket). 

Bidens cernua (sticktight). 

Capsella bursa-pastoris (shepherd's purse). 

Gerastium arvense (mouse-ear chickweed). 

Convolvulus sepium (morning-glory) (As.). 



WEED MIGRATION 



741 




Fia. 558. Yarrow (.Achillea millet olium) . Common in the northern hemis- 
phere. 
(Drawing by Charlotte M. King.) 



Cyperus esculentus (northern nut grass) (As.). 

Epilobium angustifolium (fireweed) (As.) . 

Erigeron acris (fleabane). 

Erysimum cheiranthoides (treacle mustard). 

Galium, trifidum (bedstraw) (As.). 

Galium aparine (cleavers) (As.). 

Gnaphalium uliginosum (cudweed) . 

Hierochloe borealis (holy grass). 

Juncus tenuis (wire-grass). 

Lepidium apetalum (peppergrass) . 

Mentha arvensis (mint) (As.). 

Myosurus minimus (mouse-tail). 

Oxalis corniculata (field sorrel). 



742 



WEED FLORA OF IOWA 



Plamtago major (common plantain) (As.). 
Polygonum aviculare (dooryard knotweed) 
Polygonum, hydropiper (smartweed). 
Polygonum lapathifolium (smartweed). 
Potentilla amserma (silvery cinquefoil). 
Potentilla m^onspeliensis (five-finger) (As.). 



(As.). 




Fig. 559. 



Holy or Vanilla Grass (.Hierochloe borealis). Common In the nortliern 
hemisphere, mountain regions. In northern Iowa. 
(Lamson-Scribner, U. S. Dept. Agr.) 



Prunella vulgaris (self-heal). 
Radicula palustris (marsh cress) (As.). 
Banu/nculus cymbalaria (crowfoot). 
Ranuncjdus pennsylvanicus (crowfoot) (As.). 
Ranunculus repens (crowfoot). 
Bhinanthus crista-galli (yellow rattle"). 



WEED MIGRATION 743 

Senecio palustris ■ (ragwort) . 

Stachys palustris (woundwort) (As.)- 

Taraxacum officinale (dandelion). This species occurs every- 
where in the United States and Europe, even on the highest moun- 
tains. 




Fig. 560. Dandelion (Taraxacuvi officinale). Common in the northern hemis- 
phere, across the continent. 



INTRODUCTION OF SOME WEEDS INTO THE UNITED 
STATES AND INTO IOWA. 

CHENOPODIACEAE, GOOSEFOOT FAMILY. 

Russian Thistle (Salsola kali var. tenuifolia). 

This plant has long been known as a troublesome weed. Henf rey, 
in his work, "The Vegetation of Europe, its Condition and Causes," 
published in 1852, notes its abundance in Russia, east of the Volga. 



744 



WEED FLORA OF IOWA 



Linnaeiis, the Swedish botanist, seems to have known the plant as 
it occurred in eastern Europe. Prof. L. H. Dewey has given us a 
good account of the introduction of this weed in the United States.* 
It seems to have been first observed in Scotland, Bonhomme county, 
South Dakota, in 1873 or 1874, the seed having been brought in 
with flax seed. In 1877, it was reported from Yankton county; 
five years later in the counties to the north and west of Bonhomme. 
By 1888 it bad infested many of the counties east of Missouri river 
and two years later practically all of the counties of South Dakota 
and southern North Dakota. About the same time it invaded 




Fig. 561. Russian Thistle (Salsola kali var. tenuifolia) . Common in eastern 
Europe. Introduced into the Dakotas, 1873 or 1874. Now common In 
northern United States, particularly in the west 

(Drawing by Charlotte M. King.) 
•Bull. Div. of Bot., U. S. Dept. of Agr. 15 :12. 1894. 



WEED MIGRATION 745 

northwestern Iowa, northeastern Nebraska and western Minnesota. 
In 1898 it was reported from Colorado, Wisconsin, Illinois and 
other western states. In 1894 Pammel gave the following account 
of its distribution: 

Prof. Dewey's map indicates that the badly infested area extends 
from the east bank of the Missouri river at Bismarck to Jamestown 
and Moorehead in North Dakota ; south to- Sioux City, in Iowa ; it 
also occurs in many isolated places in Minnesota, Wisconsin, Iowa, 
and at Denver, Colorado. The localities at which he found it in 
Iowa- are Rock Eapids, Bmmetsburg, Spencer and west to the 
Missouri river. Council Bluffs, and on the Missouri river opposite 
Nebraska City. To these we must add Edna, Ames, Little Rock 
(Ball), Calumet (Louthan), Missouri Valley, Mason City, Eagle 
Grove, and in all probability it occurs along our great trunk lines 
across the state. Last season Mr. G. W. Carver found a small 
specimen of what undoubtedly was Russian thistle along the Chi- 
cago & Northwestern railroad; the place was revisited this year, 
and an abundance of the weed was found. A few days later 
Messrs. Robt. Combs and C. B. Weaver found several localities 
between Ames and Ontario, and Mr. Sheldon reported it in the 
Ames stock yards. As to its probable early appearance in Iowa 
we have reliable data. Prof. A. S. Hitchcock, an excellent ob- 
server and collector, reported it from Woodbury county in 1888, 
and Mr. R. I. Cratty, of Bmmetsburg, reported it from Emmet 
county in 1890 or 1891. It has also been sent to me from Ellsworth, 
in Nobles county, Minnesota, close to the Iowa line. Mr. G. W. 
CaiTver found great quantities of it near Chicago, at Turner Junc- 
tion, and J. J. McMahon from Peatone, Illinois. 

It occurred as early as 1890 in Wisconsin. The writer, in re- 
cently looking over a collection of specimens made in the vicinity 
of Prairie Du Chien, in 1890, found a specimen of Russian thistle. 
The species was growing in considerable quantity along the sandy 
embankment of the river and railroad, not far from the railway 
station. It is not unlikely that it spread eastward -along the Chi- 
cago, Milwaukee and St. Paul railroad for considerable distance. 

It now occurs in many Iowa counties, especially along railroads. 
It is one of the most abundant weeds in western Nebraska, Colo- 
rado, Utah, Montana and Idaho. It is more or less sporadic in its 
appearance ; some years more abundant than others. It was espe- 
cially common at many points in Iowa in 1910 and 1911. Its dis- 
tribution in Iowa as reported from time to time is as follows : Post- 
ville, 1894 (Orr) ; Mason City and Eagle Grove, 1894 (Pammel) ; 
Muscatine, 1894 (Reppert) ; Boone, 1895 (Carver) ; Ames, 1895 
(Rolfs) ; Hawarden, 1895 (Pammel) ; Missouri Valley, 1897 (Pam- 
mel) ; Ledges, 1898 (Pammel) ; Armstrong, 1901 (Cratty) ; Ogden, 



746 WEED FLORA OF IOWA 

1901 (Pammel) ; Sliiter, 1902 (Fawcett, Tener and Reinbott) ; Mar- 
shalltown, 1902 (Pammel) ; Aurelia, 1912 (Summers) ; Sidney, 1912 
(Graham). 

Winged Pigweed {Cycloloma platyphylhim Moquin.). 

Not indigenous in Iowa. Des Moines, 1887 (A; S. Hitchcock) ; 
Hamburg (A. S. Hitchcock) ; Muscatine, 1890; Ontario, 1892 
(Burgess) ; Des Moines, 1894 (Carver) ; Cedar Rapids, 1895 
(Palmer). 

City Goosefoot {Ghenopodium urbicum L.). 

Nevada, 1880 (A. S. Hitchcock) ; Iowa City, 1887 (A. S. Hitch- 
cock) ; Keokuk, 1887 (A. S. Hitchcock) ; Muscatine, 1890 (F. 
Reppert) ; Ames, 1891 (A. S. Hitchcock) ; Keokuk, 1891 (P. H. 
Rolfs). 

Oak-leaved Goosefoot (Chenopodium glaucum L.). 
Iowa City, 1889 (Hitchcock) ; Muscatine (P. Reppert). 

Jerusalem Oak {Ghenopodium iotrys L.). 
Ames, 1883; Iowa City, 1887 (A. S. Hitchcock). 

Mexican Tea {Ghenopodium ambrosioides L.). 
Keokuk (J. C. Arthur) ; Muscatine, 1890 (F. Reppert). 

Coast Elite {Ghenopodium rubrum). 
Keokuk, 1891 (P. H. Rolfs). 

Ovdifih- {Atriplex jjatula L. var. hastatum Gray). 

Iowa City, 1887 (A. S. Hitchcock) ; Keokuk, 1891 (P. H. Rolfs) ; 
Ames, 1896, where it has now become well established ; Boone, Ft. 
Dodge, 1912 (L. H. Pammel) ; Storm Lake, 1912 (L. H. Pammel). 
Var. littorale, Towa City, 3887, (A. S. Hitchcock). 

Silvery Orach {Atri/plex argenteum Nutt.). 
Ames, 1895 (G. W. Carver). 

Mexican Fireweed {KocMa scoparia (L.) Sehrad.). 

Mexicap £reweed is recorded as an adventive from Europe in the 
sixth edition of Gray's Manual of Botany, 1889, by Watson and 



WEED MIGRATION 747 

Coulter, with the statement "sparingly introduced^ in Vermont, 
Ontario, and Illinois. " It is not recorded in the fifth edition of the 
same work by Dr. Gray in 1867. In the Britton Manual, 1901, 
the distribution is given as Ontario, Vermont, and northern New 
York, adventive from Europe, native also of Asia. According to 
the Robinson and Fernald Edition of Gray's Manual (7th. Ed.), 
1908, it had become so common because of its cultivation and "lo- 
cally established as a weed" that the distribution was not given. 
The writer saw it in abundance as a weed in Denver and Ft. Collins, 
Colorado, and Salt Lake, in 1902, and in Chicago the same year. It 
has been spontaneous as a weed in Ames since the year 1900. It 
has been observed in Ames, Council Bluffs (1901), Sioux City 
(1902), Cedar Rapids (1905), LaCrosse, Wis.. (1904). The,.fol- 
lowing catalogue of plants lists the species : Rydberg, Colorado, 
at Fort CoUiiis. 

COMPOSITAE, SUNFLOWER FAMILY. 

Prickly Lettuce {Lactuca scariola). 

This species was abundant in Utah in 1898 and was. observed in 
many parts of California the same year, but was, however, far 
,less common in the east. It was first observed in central Iowa., 
Ames, in 1909 and now occurs in Ft. Dodge, Boone and Des Moines, 
and is rapidly spreading. It is common in dry places in the Rocky 
naountains ,aind on the Pacific coast. Robinson and Fernald state, 
"Roadsides, railway ballad, etc.. New England to Oregon, N. W., 
and Kentucky, chiefly westward, but even then less common than 
the following variety (var. integrata) ." It is common in northern 
and central Ohio, Indiana and Illinois (DeKalb, Fox, Aurora, 
Geneva, Chicago and Wheaton). 

Prickly Lettuce {Lactuca scariola var. integrata). 

Waste grounds, roadsides and fields from the Atlantic to the 
Pacific, especially northward. This is the form commonly referred 
to by botanists when speaking of the weed in the east. This variety 
was first reported by Dr. Gray, Specimens were collected by Mr. 
D. Murray in 1863 and 1864; some specimens were collected by 
M. S.Bebb at Rockford,- Illinois, in 1879, and about .the same time 
by Mr. Henry Eggert in St. Louis. In 1883 it was common in, thp 
vicinity of Madison but had not rea,ched La Crosse, Wia<?o.nsiii. 
In 1886 a few specimens were repocted in the vicinity lof lOijalaska 



748 WEED FLORA OP IOWA 

near La Crosse. It was abundant in Iowa in 1886, was reported 
from Eagle Grove in 1894 by Cratty, and by the same observer at 
lake Okoboji in 1901. The writer observed it abundantly in 
various places in Nebraska and eastern Colorado in 1894 and gave 
a more definite account of its distribution and spread in a paper 
in Proceedings Iowa Academy Sciences. In 1912 it was very 
abundant everywhere in Iowa. The seeds are easily scattered by 
the wind, which probably accounts for its wide distribution in a 
comparatively short time. 

Thistle {Cirsiunn paiustre). 

This European thistle is recorded as naturalized in woods, East 
Andover, New Hampshire, (Holt) by Robinson and Fernald in the 
7th edition of Gray's Manual, 1908, and was reported from Iowa 
in 1911 and again in 1912. 

Canada Thistle {Cirsium a>rvense). 

This well known weed is common everywhere in Europe and is 
perhaps a weed of the open. Linnaeus in his Flora Lapponica 
(1837) notes that it is the greatest pest of our fields. It is dis- 
tributed from the Atlantic to the Pacific across the northern states 
and in Canada.. In Iowa it is found more particularly in the 
north half of the state. The earliest floras of the state (Arthur, 
Bessey, and Parry) note its occurrence in Iowa. It has occurred 
in Ames for forty years. In 1889 it was noticed in many counties. 
Cratty reports the species from Emmet county in 1892. At this 
time it had been reported also from Howard, Adair, Chickasaw, 
Johnson and Poweshiek counties. In 1899 it was thoroughly es- 
tablished in a forest near Steamboat Rock in Hardin county. 
Plants from the early introduction seldom produced seed, but seed 
from the later introductions is not uncommon ; thus it has been 
matured in O'Brien county and in Cresco, 1892 (C. V. Johnson). 
It is spreading rapidly in northern Iowa, having become much 
more widely distributed in 1903 and 1906 with clover seed. 

It has been reported from Johnson county, 1874 (0. G. Bab- 
cock) ; Lawler, 1890 (P. H. Rolfs) ; Greenfield, 1891 (F. C. 
Stewart) ; Coming, 1895 (A. B. Shaw) ; Taylor, 1895 (J. B. 
Matthews) ; Maple River Junction, 1895 (L. Bemholtz) ; Farra^t, 
1895 (C. Collman); Marcus, 1896 (Willey) ; Winterset, 1896; 
Barnes City, 1896 (J. W. Jones) ; Nevada, 1898 (G. C. White) ; 
Steamboat Rock, 1899; Rockwell, 1901 (J. H. Boom); Badger, 



"WEED MIGRATION 



749 



1902 (Myrhe); Audubon, 10O5 (M. C. Griffith); Graettiuger, 
1906 (E. L. George) ; Clarion, 1909 (Melhus) ; also in Lorimer 
(Loehrie) ; Blairsburg (J. M. Hall) ; Oelwein (J. Thompson) ; 
Muscatine (F. Reppert) ; Reading (Dr. McGlanahan) ; Griswold 
(R. E. Pierce) ; Randall (C. & G. R. Christianson) ; Hartley (H. R. 
Poblenkamp) ; Garrison (J. Grayson) ; Roland (E. N. Waugh) ; 
Kossuth (S. A. Merrill) ; Cedar Palls (C. E. Daily) ; and Wool- 
stock (A. P. Reynold). 



Woolly Thistle {Cirsium canescens). 

This plant has been reported from several states north and west 
of the Mississippi. In Iowa it occurs chiefly in the northern half 
of the state, having been reported by A. S. Hitchcock in 1889, as 
growing near Sioux City. Later it was reported from Sioux City 
by Pammel, 1895; Armstrong (Cratty), 1897; Webster City 
(McCoy), 1901; Onawa (Fletcher), 1902; Le Mars, 1902 (Wm. 
Long) ; Charter Oak, 1903 (C. N. Weed) ; Pisgah (L. H. Raymond), 
1903; Rolfe (J. B. JoUiffe), 1908; Lu Verne (W. F. Blumer), 




FiQ. 562. Woolly Thistle (.Cirsium canescens). Originally along the Missouri 
and adjacent territory. Now spreading eastward. 1, head ; 5, single flower ; 
6, achenium ; 7, stamens and style ; a, stigma enlarged ; 8, pollen grain. 
(Drawings by Charlotte M. King.) 



750 WEED FLORA OP IOWA 

1911; Harlan, Shelby county, Buena Vista county, and Clay 
county, 1912 (Pammel) ; Sac county, 1912 (Lee) ; Storm Lake, 
1912 (Rehnstron) ; Dickens, 1912 (Evans) ; Smithland, 1912 (Bar- 
ber) ; Cartersville, 1912 (Connor). 

; Hawkweed (Hieracium floribunduin) . 

This weed, reported from Cutler, Maine, in 1902, now occurs in 
fields from New Bruns-wick to eastern Maine. 

Paint Brush {Hieracium mirantiacum) . 

Paint brush was cultivated as an ornamental plant in Maine in 
1875 and became frequent in the New England states and New 
York in the early eighties. It is now distributed from eastern 
Quebec to Pennsylvania and occasionally in Iowa. 

Cat's-ear {Hypochaeris radicata). 

According to Pernald this appeared in Penzance and Wareham, 
Massachusetts, in 1899; since then it has spread to other New 
England localities, as New Bedford and Dartsmouth. It had been, 
however, a very troublesome weed of lawns of the Pacific north- 
west for some time previously. It was abundant in Portland, 
Oregon, in 1906. 

Stinking Willie (Senecio jacobaea). 

Femald (1905) states that in the late 70 's a coarse yellow 
flowered plant {Senecio jacobaea) appeared as a waif on ballast 
at some points along Northumberland Strait in eastern New Bruns- 
wick. In 1884, it had begun to spread along the local railroads 
and now has reached Portland, Maine. The seventh edition of 
Gray's manual (1908) gives its distribution from Newfoundland 
to New Jersey. 

Barnaby's Thistle or Knapweed {Centaur ea solstitialis) . 

This weed was not reported in the sixth edition of Gray's 
manual (1889) nor in Britton's manual (1901). In the seventh 
edition of Gray's manual, Robinson and Pernald state, "Waste 
ground, eastern Massachusetts to Ontario and Iowa." It was re- 
ported from Iowa as early as 190.3, and since, a few times each 
year, in alfalfa fields as follows : Paton, 1903 (Lundell) ; Maple- 
ton, 1904 (Perrin) ; Moville, 1905 (Morton) ; Des Moines, 1907 



WEED MIGRATION 751 

(Wallace). J. Burtt Davy reported it from central California in 
the nineties. 

MaiTsh Elder {Iva xanthifolia) . 

Dr. Gray in the fifth and sixth editions of the manual gave its 
distribution, "Northwest "Wisconsin to Minnesota, Kansas and 
westward." Originally this must have been a local weed in "Wis- 
consin and eastern Minnesota. Upham in 1890 mentions it as one 
of the most aggressive weeds of Red river, especially in waste 
places. Parry includes it in his list of plants collected in the 
upper Mississippi valley in 1848. It is not improbable that this 
plant was brought to eastern Minnesota and "Wisconsin by the early 
voyagers, the Indian's or the white, settlers. It is a weed of the 
open and cultivated soil, especially near habitations. The early 
settlers in the Red river valley gave to it the name of "half breed 
weed" because so commonly ' found near the habitations of the 
half breeds who lived in that section of Minnesota, Manitoba and 
Dakota. There are early records of the weed, however. Hall 
mentions its occurrence near Athens, Illinois, in 1863. This was 
after Hall had returned from his trip to the Rocky mountains. He 
may have thrown away some of the seed, which germinated and 
produced plants. It was a common plant in the Rocky mountains, 
as reports of such botanists as Parry, Vasey, Hall, Fendler, M. E. 
Jones; Suksdorf, Cusick, Kelsey, Brandegee, Havard, Bigelow, 
(Camanehe Plains, 1853) -and others indicate its abundance. 
Though reported from Charles City by Arthur in 1871 it has not 
made much progress east of the Missouri river basin. Its dis- 
tribution and date of appearance may be seen from the following : 
Boone, 1890 (Pammel) ; Keokuk, 1890 (Rolfs) ; Woodbine, Vale, 
Eagle Grove, Mason City, and Carroll, 1894 (Pammel) ; Armstrong, 
1897 ( Cratty) ; Ogden and Slater, 1896 ; Hanlontown and Ames, 
1902 (Pammel) ; Decatur county, 1911 (Anderson). It was a fre- 
quent and abundant weed from Sioux City to Council Bluffs and 
probably south to Hamburg; reported at Independence, and, in 
1876, at Humboldt, by Harvey. It had been reported from Emmet 
county as early as 1875, having been introduced with cattle. It 
has not spread very rapidly at any of these interior points. It 
was reported in St. Paul in 1861 (T. J. Hale) and it was abundant 
along the highway on a bank near La Crescent, Minnesota, in 1884. 
It now occurs in Hokah, Brownsville, and other points along the 
river (1910). In the early nineties it appeared in Onalaska, Wis- 



752 



WEED FLORA OP IOWA 




Fio. 563. Marsh Elder (.Iva xanthiifoUa) . Common in the Red River Valley, 

spreading eastward. 



"WEED MIGRATION 753 

consin (Pammel) ; Menominee Valley, 1888 (Runge) ; Kewaunee 
county, 1889 ("Wheeler, Farwell) and in Seneca, New York. It is 
abundant throughout the country and common in the northwest to 
Washington. It is abundant in western Iowa and is rapidly 
spreading eastward, also becoming an aggressive weed from Ames 
north to the Minnesota line and westward. It was reported from 
Europe (Denmark, Ostenfeld) 1895. 

Perennial Sow Thistle {Sonchus arvensis). 

This thistle was reported by John Torrey in 1826 in the northern 
and middle states. Dr. Gray in 1848 in the first edition of the 
manual reported it from Massachusetts, Staten Island, and in New 
Jersey ; it did not occur in Pennsylvania, or at least was not men- 
tioned by Darlington. The 5th edition' of Gray's manual, 1867, 
gives its distribution "roadsides, etc.. New England, New York, 
becoming more abundant;" the 7th edition (1908) says "from 
Newfoundland to the Rocky mountains northward." Britton 
(1901) places it in the same general region and west to Salt Lake, 
Utah. The weed is not common in Iowa nor. in the surrounding 
states except northward in Minnesota and Dakota. It was re- 
ported from Grand Junction, Iowa, in 1898 by Tomson and from 
Ogden, Iowa, about 1900; the writer found it in Englewood, Il- 
linois, in 1886, and in northern Ohio in 1912. It has spread rapidly 
in recent years in Canada, North Dakota and Minnesota, as 
recorded in the agricultural press of the last two or three years. 

Galinsoga or Frenchweed {Galinsoga parviflora). 

Danger has given several accounts of the introduction of this 
weed into Europe. The term Frenchweed seems to have been 
commonly applied to this weed in Germany shortly after the French 
soldiers occupied Hanover. One authority states that it was 
brought from France with horse feed; it is said to have been in- 
troduced into Germany about 1812. One authority states that the 
weed was distributed from the Berlin Botanical Garden in the 
year 1812, at any rate it was very common in Hanover in the year 
1839 ; and has continued to spread. It may have spread from its 
first introduction near Paris to other, places of France about the 
year 1800, although there is no definite date as to when it made its 
appearance in the vicinity of Paris. This plant is native to Peru 
where it was discovered by Ruiz and Pavon about 1794, so 
48 



754 WEED FLORA OF IOWA 

it must have been introduced into Europe following their descrip- 
tion. In the United States the weed has become quite widely 
disseminated in recent years. The writer found it abundant in 
the vicinity of green-houses in the Missouri Botanical Garden in 
1886, subsequently in 1896 he found it in similar situations in 
Ames and about 1898 or 1899 in La Crosse, Wisconsin. The writer 
has observed it at other points but always first in the vicinity of 
green-houses. This would lead to the assumption that it probably 
has been disseminated with flower seed. 

Horseweed {Erigero-n canadensis). 

This widely distributed weed is common everywhere in North 
America and is said to have been introduced in the vicinity of 
Paris in 1635, although Leunis' Botany states "introduced in 
Europe in 1500." It is mentioned as one of the most common 
weeds of Germany and Switzerland by Ratzeburg (1859). Treatises 
by Gareke, Koch, Ratzeburg and Acloque mention it as a common 
weed. 

Spiny Ciotbur (Xanthium spmosum). 

According to Kabsch, this weed is said to have been introduced 
into Germany with wool brought from Hungary. Though it 
originated in tropical America it has become established as far 
north as Maine (Robinson and Pernald). Thurber in 1859 gave 
its distribution from Massachusetts to Georgia. In 1889, it reached 
Leavenworth, Kansas, and in the course of time will be found in 
Iowa. 

Hawkweed (Senecio vernalis). 

This weed was first mentioned by Rosenberg as occurring in 
Switzerland in 1882. It spread to Silesia; disappeared; was re- 
ported in West Prussia in 1824, in Breslau, 1835, Brandenburg, 
1850, Stettin in 1860, first as a mere waif, then spread to cultivated 
fields generally. 

Chicory (Cichorium intyhus). 

Chicory was introduced into Dorchester, Massachusetts, in 1775. 
Torrey records it for the northern and middle states in 1826. Gray 
in 1848 stated "naturalized in the Atlantic States;" the 6th edition 
of Gray's Manual stated that it occurs from New England to Iowa 
and Minnesota; the 7th edition adds Newfoundland and southward. 
It was common in Wisconsin in 1884 and was spreading; it oc- 



WEED MIGRATION 755 

curred in Colorado in 1896. Gray reports it for Santa Barbara, 
Galifornia, in 1880, and since then it has become fairly common in 
that state. It was reported from several localities by Crandall and 
Rydberg in Colorado in 1906; reported by "Webber in Nebraska. 
Mr. F. W. Paige states that this weed has been known in Ft. Dodge 
since 1887. In 1906 it was spreading in Pottawattamie, Story, Sac, 
Clay, and Kossuth counties, and has been reported from "Westgate 
(Bruce Fink), 1893; Boone (Geo. W. Carver and Pammel), 1895; 
Des Moines, 1895; Corning, 1895 (Ellen Bettomer) ; well estab- 
lished in Midway, 1896; Jordan, 1906 (Harriette Kellogg). 

Vegetable Oyster {Tragopogon pratensis It.). 

This was reported from Ames, in meadow, 1894; Iowa City, 
1889 ; Newton, 1889 (A. S. Hitchcock) . 

Fetid Marigold {Dyssodia papposa (Vent.) Hitchc). 

Ackley, 1878 (B. E. Canavan) ; Boone, 1890; Keokuk, 1891 
(P. H. Rolfs) ; Muscatine, 1891 (F, Reppert). This striking weed 
has been known for some time at Ames, and was said by Hitchcock 
to be frequent (Anth. Pteridophyta of Ames, p. S03). It is more 
or less sporadic in its appearance, being frequent in some years, 
in others not so common. It is, however, ,always abundant in 
western Iowa, which leads me to believe that the plant is not in- 
digenous to central Iowa, but introduced, although now occurring 
in timber and along river banks. 

Ox-eye Daisy {Chrysanthemum leucanthemum L.). 

For a long period of years occasional specimens of this weed 
have been found in the vicinity of the college, and it is an occa- 
sional introduction in meadows, but except in one place some four 
miles from Ames it shows no evidence of being naturalized. It has 
also been reported from Muscatine (Reppert) ; Atlantic (S. 0. 
Hamill) ; Ames, 1871 (C. E. Bessey) ; Ackley, 1878 (B. E. Cana- 
van) ; Sheldahl, 1885 (L. V. Harpel) ; Ames, 1891 (P. H. Rolfs) ; 
still occurs between Ames and Gilbert, 1911, ■ but is not spreading. 

Mr. J. H. Lees reports this plant as having been introduced into 
the vicinity of Cedar Falls as early as 1890 and as occurring near 
LeMars in 1912. 



756 WEED FLORA OP IOWA 

Gumweed {GrindeUa squarrosa Dunal). 

Indigenous to western Iowa, rapidly spreading in contiguous 
territory, and reported from Boone and Moingona, as abundant 
iii borders of woods along Chicago & North Western Eailway in 

1890 and still spreading in 1912; reported from Keokuk, 1891 
(P. H. Eolfs) ; Battle Creek, 1895 (E. G. Preston) ; Osgood, 1895 
(C. A. Wells) ; Carbonado, 1895 (John H. Smith) ; Smithland, 
1896 (J. M. Wrapp). 

Eclipta (ScHpte aifto. Hassk.). 
Keokuk, 1877 (Geo. B. Ehinger), 1891 (P. H. Eolfs). 

Sunflower {Eelicmtkus annuus L.). 

Occasional in Ames and other parts of central Iowa, but in 
western Iowa indigenous and very abundant, becoming frequent 
•as far as Carroll (Kelley) 1900; Denison and Boone. It was re- 
ported in Boone in 1871 (C. E. Bessey) ; Ames, 1882; Grinnell, 

1891 (M. E. Jones) ; Keokuk, 1894 (P. H. Eolfs) ; Muscatine, 1891 
(Eeppert) ; and Marshalltown, 1891 (F. C. Stewart). It is not 
abundant except in a few localities in central Iowa. It is an in- 
troduced plant with us. 

CONVOLVULACBAE, MORNING-GLORY FAMILY. 

Bindweed {Convolvuhis a/rvensis). 

This weed is of long standing in the United States. It is men- 
tioned by Torrey in his Compendium of ' ' The Flora of the North- 
ern and Middle States" in 1826, and Dr. Gray in his first edition 
of his manual in 1848 gives the distribution from Massachusetts 
to Pennsylvania. Darlington, in 1853, states: "This foreigner 
has gradually extended itself among us — and will probably give 
our farmers much trouble if they do not carefully guard against 
it." This certainly has been realized in many of the central and 
eastern states. The statement in the seventh edition of Gray's 
manual would indicate quite general distribution in the region 
embraced in this work. The fifth edition (1867) states, "fields 
near the coast; likely to become a troublesome weed." Britton 
gives its distribution from Nova Scotia to Kansas (1901) ; South 
Dakota, Parker (1903). It was abundant in St. Louis in 1886 
and was reported at various times in Iowa as a troublesome weed 



WEED MIGRATION 757 

before 1889. Since 1887 it has been well established in Ames; it 
was reported from Ladora, 1895 (John Hiltbrummer) ; Des Moines, 
1896 (C. N. Page) ; Westgate, 1902 (P. H. Hinager) ; Fort Dodge, 
1912 (F. W. Paige) ; and very likely occurs in other places! It 
was first introduced as a cultivated plant. This may become one 
of the most pestiferous of our perennial weeds. 

EUPHORBIACEAE, SPURGE FAMILY. 

Snow-on-the-Mountain {Euphorbia marginata Pursh.). 

Indigenous to western Iowa. Little Rock, Sioux City, Onawa, 
Council Bluffs and Hawarden. Naturalized east. Iowa City, 1887 
(A. S. Hitchcock) ; Hamburg, 1888 (A. S. Hitchcock) . Abundant 
at Denison, 1894; "Woodbine, 1894; Vale, abundant, 1894; Missouri 
Valley, Carroll, 1895, abundant (W. Newell). 

GRAMINEAE, GRASS FAMILY. 
Squirrel-tail Grass or Wild Barley {Hordeum juhatum L.). 

This plant was made known to science by Linnaeus, from speci- 
mens found in Canada. Dr. Asa Gray, in his Manual of Botany 
of Northern United States in 1856, gives its distribution as 
"marshes and moist sands of the sea shore and the northern lakes." 
In 1868, its distribution was not extended, but Watson and Coulter, 
who revised the manual (1890), add to the above "and westward." 
In the seventh edition of Gray's manual the distribution is given 
as "coast Labrador to New Jersey prairie and waste ground, 
Ontario to Illinois, Kansas, and westward." It evidently is very 
generally distributed throughout the United States. At Ames, 
specimens have been received from Wyoming, Colorado, Nevada, 
New Mexico, Idaho, Utah, Montana, Yellowstone Park, Illinois, Ne- 
braska, the Dakotas, Minnesota, Kansas and from Argentine. It 
has also been reported from California, Wisconsin, Arkansas, Mis- 
souri, Michigan, Indiana, Ohio, New York, New Jersey, Massa- 
chusetts, Maine, Canada (in many parts), Europe (Russia), and 
Siberia in Asia. A truly cosmopolitan weed. 

We are without exact data in regard to its early appearance in 
Iowa, though it was probably native in portions of western and 
northwestern Iowa, especially where the soil was somewhat broken 
up. From answers received it would seem that this grass has been 
known in parts of Iowa for over fifty years, but it is only during the 
last twenty-five years that it has made much headway. Though 



758 



WEBb FLORA OF IOWA 



7-* 
















' 


• 


"^""^ffiilMP 


P^P 


wbbbK/Kh 






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^H 


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Mi 




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1 






1 







Fig. 564. Wild Barley (.Bordeum jubatum). Originally common along the 
shores of the Great Lakes, and alkali regions of the west. 



possibly native, it is more than probable that this weedy grass has 
come into our state from the west as well as the east. It has be- 
come so thoroughly at home in many parts of Iowa that no one 
woul^ be able to say, except for the records we have, that it has 
not always been indigenous. 

Forty years ago this weed was mentioned by Dr. Bessey as oc- 
curring in Iowa, "found along railroads, perhaps introduced," 
being noticed at Ames especially. It undoubtedly occurred in 
other parts of the state, but could not have been abundant or its 
presence would have been noted. Early in. 1876 Dr. J. C. Arthur 
listed the plant from Iowa without locality. Prof. Halsted refers 
to the weed as common, but not excluding valuable plants. He 
considered it an introduced plant. One other botanist. Prof. A. S. 
Hitchcock, listed the plant from Ames, and remarks: "Waste 
places ; common. ' ' The plant was certainly abundant about Ames 
in 1889, when I came here, but it has not spread quite so alarmingly 
as prickly lettuce {Lactuca scariola L.). In July, 1895,- a circular 
was sent out to some correspondents in every county in. .the state 



' WEED MIGRATION 759 

inclosing a specimen and requesting information in regard to its 
introduction, weedy nature, diseases, etc. Replies were received 
from most of the correspondents. From this information it ap- 
pears that the -plant has been in parts of the state many years, 
and several correspondents reported it as indigenous. It has been 
in Cedar Rapids for 57 years; in Carroll county, 33 years; Mason 
City, 45 years ; Hawkeye, 40 years ; Hampton, 37 years ; Jefferson, 
40 years ; Mount Pleasant, 36 years ; Cresco, 35 years ; Newton, 35 
years; Unity, 35 years; Iowa City, 30 years; Shenandoah, 35 years; 
Neola, over 45 years; Fort Dodge, 50 years; Dedham, 35 years; 
Rossville, 45 years. It was not, however, generally distributed in 
the state. But it has shown wonderful aggressive powers and now 
occurs without doubt in every county in the state. 

It is more than likely that in Iowa, at least, the weed has spread 
from three sources: (1) Indigenous plants scattered in western 
and northwestern counties. (2) From the Great Lakes, where 
it is indigenous. (3) ■ From the western plains, where it no doubt 
was indigenous. 

LABIATAE, MINT FAMILY. 
Lance-leaved Sage (Salvia lanceaefoUa Poir.). 

Indigenous to western Iowa. Council Bluffs, Fremont county, 
Missouri Valley, Ames, 1890 (F. A. Sirrine) ; Muscatine, 1890 (F. 
Reppert) ; Des Moines, 1895, well established ; Harlan, 1912 (Pam- 
mel) . 

LEGUMINOSAE, PULSE FAMILY. 
Sweet Clover (Melilotus officinalis). 

Torrey, in 1826, gave the habitat of sweet clover as "wet mead- 
ows." Gray, in 1848, reports it for the east; it apparently had not 
reached Pennsylvania, since it is not recorded by Darlington. This 
plant was observed in the vicinity of St. Louis, Missouri, in 1887, 
and in Humboldt, Iowa, in 1892. In 1894 it was abundant in 
eastern Colorado, Fort Collins, Denver, and other localities, indi- 
cating naturalization for a considerable length of time. As yet 
it is not common in central Iowa, though it was abundant in Sioux 
City and Council Bluffs as early as 1895. It had already been re- 
ported from Iowa City by Hitchcock in 1889, and from Muscatine 
by Reppert in 1891. L. H. Pammel found it in Dakota City in 
1896, and R. I. Cratty reported it from Emmet county in 1903; it 
is rather abundant at present in Scott county. 



760 WEED FLORA OF IOWA 

White Sweet Clover (Melilotus alba Lam.). 

This plant is not named by Torrey in 1826, but in 1840 its dis- 
tribution was given by Torrey and Gray as "Rich soils, along rivers. 
New York and New England. Introduced." In Flora Cestrica, 
Darlington says that it appears in gardens and lots, having been 
naturalized from Europe. In 1853 he says that "this coarse hard 
stemmed plant has been partially cultivated by some amateur 
farmers ; but it is not likely to supersede the herbs now in general 
use as food for cattle." In the first edition of Gray's Manual its 
distribution is given as "adventitious from Europe." The same 
distribution is given in the sixth edition. In the seventh edition 
we read, "Roadsides, etc., common. (Nat. from Europe)." In 
Iowa, while it is found along the roadsides everywhere, the dates 
given with the following localities may indicate to some extent how 
it has spread: Vicinity of Ames, 1886; Iowa City, 1887 (A. S. 
Hitchcock) ; Emmet county, 1888 (Cratty) ; Ames, found frequent- 
ly, 1890 (J. F. Rolfs and P. C. Stewart) ; Muscatine, 1891 (Rep- 
pert) ; Turin and Onawa, 1894 (L. H. Pammel) ; Webster City and 
Postville, 1894; Alden, 1895 (Stevens) ; abundant in Moingona, 
Boone, Slater, Council Bluffs and Sioux City, 1895 (Pammel) ; Da- 
kota City, 1896 (Pammel) ; Kossuth county, 1897 (R. I. Cratty) ; 
Ogden, 1898; Carroll, 1898; Marshalltown and Des Moines, 1902 
(Pammel) . It was introduced into the vicinity of La Crosse, Wis- 
consin, as a forage plant in 1878 or 1879. 

Wild Liquorice (Glycyrrhiza lepidota Nutt.). 

This weed was reported from Grand Junction, 1872 (C. E. Bes- 
sey), and Harrison county, 1875 (Rev. Burgess); Ontario, 1886 
(Hitchcock) ; Ames, 1889 (Hitchcock) ; Greenfield, 1891 (F. C. 
Stewart) . Spreading near Greenfield, undoubtedly introduced, in- 
digenous to western and northwestern Iowa. It was spreading at 
Little Rock, 1893 (C. R. Ball) ; Hull, 1895 (W. Newell) ; Logan, 
1895; Council Bluffs, LeMars, 1896 (W. J. Newell) ; Lenox, 1896 
(J. L. H.). 

Stone Clover {Trifolium arvense L.). 

Collected by Professor Bessey in 1871, has not been found since. 

Hop Clover {Trifolium agrarium L.). 

Reported by Hitchock from Ames in 1886, has not been found 
since. 



WEED MIGRATION 761 

Low Hop Clover {Trifolium procumbens L.). 

Ames, 1882 (Hitchcock) ; Iowa City, 1884 (Hitchcock). It is now 
frequent in Ames ; also in northeastern Iowa, in Waukon, Decorah 
and Dubuque, also in Clayton county. 

Dakota Vetch {Hosackia purshiana Benth.). 

Indigenous to the loess of Iowa along Missouri river. Sioux City, 
naturalized. Boone, 1895 (G. W. Carver). 

Black medick {Medicago lupulina). 

Eeported by Dr. John Torrey in 1826 as occurring in fields, also 
by Dr. Gray in 1848 and Dr. Darlington in 1853. In the fifth 
edition of Gray's manual it was said to be "adventitious from Eu- 
rope in waste places." Britton, in 1901, states, "In fields and 
waste places, common only throughout our area. ' ' It was found in 
Kossuth county, Iowa, in 1898; at Ames, 1871 (C. E. Bessey) ; 
1898 (A. F. Sample and E. R. Hodson). Mr. F. W. Paige records 
having seen it in Fort Dodge about 1900. 

MALVACEAE, MALLOW FAMILY. 

Shoo-fly {Hibiscus trionum). 

Reported in the first edition of Gray's manual in 1848. It is 
also mentioned by Darlington in 1853 as occurring in gardens and 
lots. The fifth edition of Gray's manual states, "advanced from 
Europe." The seventh edition gives "a wide distribution, culti- 




PiG. 565. Shoo-fly (Hibiscus trionum). This weed was widely distributed as 

an ornamental plant. 
(Drawing by Charlotte M. King.) 



762 WEED FLORA OF IOWA 

vated and waste ground, rather local. ' ' This weed was common in 
Texas in 1888 and local in a good many counties in Iowa in 1909. 
In Iowa it has been reported as follows: Fayette, 1894 (Bruce 
Fink) ; Winterset, 1895 (G. W. Carver) ; Waterloo, 1904 (B. D. 
Roberts). 

Indian Mallow or Butterprint (AbvMlon theophrasti). 

This weed is not mentioned by Torrey, 1826, nor in the first 
edition of Gray's manual, 1848, but is recorded by Darlington in 
1853. This foreign weed is becoming rather troublesome in culti- 
vated grounds in Iowa. It was more or less common in the vicinity 
of LaCrosse in 1883 ; was abundant in Iowa in 1886. 

ONAGRACEAE, EVENING PRIMROSE FAMILY. 

Evening Primrose (Oenothera biennis). 

This American weed became a settler of Padua, Italy, in 1612. 
Since then it has spread to every country of Europe and is recog- 
nized as one of the most common weeds of the continent, although 
it does not have as good a means of dissemination as many other 
weeds, like the dandelion, thistle, bull thistle, etc. The small 
seeds of this plant may and perhaps frequently do cling to hoofs 
of animals and with mud may be carried by the feet of birds. 

PLANTAGINACEAE, PLANTAIN FAMILY. 

Buckhom (Plantago lanceolata). 

This weed seems to have been .pretty well established in the 
eastern states, when the first edition of Gray's manual was pub- 
lished in 1848, as it was reported as common. John Torrey, in a 
compendium of the Flora of the Northern and Middle States, pub- 
lished in 1826, describes the weed, indicating that it was evidently 
pretty well established. Darlington, in his Flora Cestriea, 1853, 
states, "this weed is extensively naturalized and more abundant 
than welcome in upland pastures." In the fifth edition of Gray's 
manual the distribution is given as "dry fields, common eastward," 
1867. The seventh edition indicates a wider distribution, and 
Britton in 1901 indicates a distribution from New Brunswick to 
northwest territory, Florida and Canada. It was observed in the 
vicinity of LaCrosse, Wisconsin, in 1892, and as early as 1874 in 
Ames (C. E. Peterson). F. W. Paige records it from Fort Dodge 



WEED MIGRATION 763 

in 1899. It is reported as quite common now in many counties of 
the state, being generally distributed with clover seed. It has also 
been reported in Ames, 1890 (F. A. Sirrine and L.. H. Pammel) ; 
1894 (G. W. Carver) ; Hartley, 1905 (W. B. Elliott) ; Audubon, 
1906 (A. H. Edwards) ; Ames, 1909 (M. Clapper) ; Fayette (Bruce 
Fink) ; Maynard (A. F. Crawford) . 

PHYTOLACCACEAE, POKEWEED FAMILY. 

Pokeweed {Phytolacca decandra L.). 

Grinnell, 1889 (A. S. Hitchcock) ; Muscatine, 1891 (F. Reppert) ; 
Ames, 1894 (L. H. Pammel). A waif; not established. 

POLYGONACEAE, BUCKWHEAT FAMILY. 
Patience Dock {Bumex patientia L.). 
Boone (G. W. Carver): Established. Escaped from cultivation. 

Prince's Feather {Polygonum orientale L.). 

Muscatine, 1890 (F. Reppert); Onawa, 1894; Clinton, 1897 
(Pammel) . 

PORTULACACEAE, PURSLANE FAMILY. 

Purslane {Portvlaca oleraced). 

Cultivated in Massachusetts in 1672 and since has spread to 
every part of the United States," appearing like an indigenous 
plant. It is likewise common in Germany, Holland, England, 
France and other European couiitries and in Australia. A cos- 
mopolitan weed. - ' 



764 



WEED FI.ORA OP IOWA 




Fio. 566. Purslane (Portulaca oleracea). At first cultivated in the United 

States for greens ; now appearing like an indigenous plant. 

(Vasey, U. S. Dept. Agr.) 



WEED MIGRATION 



765 



SOLANACEAE, POTATO FAMILY. 

Horse Nettle {Solanum carolinense) . 

This weed is a most troublesome species in southern Iowa. It 
was reported in the southeastern part of the state as early as 
1876 and has gradually moved northward until at present it 
is well scattered over the state. In Nebraska, Aughey had found 
it in 1875, and it was reported in Weeping Water by T. A. Will- 
iams in 1889 ; in Illinois it had been known for half a century near 
Peoria (Brendel) ; Port Byron, 1894 (Pammel) ; South Chicago 
(Higbee and Raddin) ; Delaware, Newcastle county, 1860 (Tat- 
nall) ; Pennsylvania, 1823 (Humphrey Marshall and Beck) ; West- 
chester, 1853 (Darlington) ; New Jersey, 1887 (Halsted and Brit- 
ton) ; New Tork, 1888; Buffalo, 1864 (Clinton); Cincinnati, 




Fig. 567. Horse Nettle (Solanum carolinense} . 
soutjiern states ; rapidly spreading northward, 
b, flower ; d, seeds ; c, seed enlarged. 

(After Dewey, U. S. Dept Agr.) 



Originally a weed of the 
1, general aspect of plant ; 



766 WEED FLORA OF IOWA 

Ohio, 1889 (James) ; central and southern Ohio, 1860 (Newberry) ; 
Grand Rapids, Michigan, 1886 (Crozier) ; Topeka, Kansas, 1883 
(Popenoe) ; Connecticut, Iowa, Illinois and, Michigan. Within 
fifty years this perennial weed has extended its range northward 
in Iowa over 150 miles. This has been possible because of its 
deep roots. Darlington, in his Flora Cestrica, states that it was 
introduced by the late Humphrey Marshall into his botanical gar- 
den at Marshalltown. 

It was reported from Nashville, Tennessee, in 1877 by Gattinger ; 
St. Louis, 1879, by Eggert, and abundant in western Missouri in 
1886 (S. M. Tracy) ; Rhode Island, 1887 (J. L. Bennett) ; Wiscon- 
sin, Watertown, 1887 (L. H. Pammel) ; Indiana, Dune Park, 1890 
(Higbee and Raddin, BoUey, Arthur) ; Illinois, 1891 (Brendel). 
In Iowa it was reported from Emmet county, 1875 (Cratty) ; south- 
eastern Iowa, 1876 ; Fremont county and Council Bluffs, 1883 (Ar- 
thur) ; Ames, 1886 (Halsted) ; Agency, 1888 (Mrs. Richman) ; Car- 
roll county, 1890 (T. T. Rutledge) ; Grand Junction, 1890 (Pam- 
mel) ; Polk City and Mt. Pleasant, 1891 (L. H. Pammel and J. H. 
Mills) ; Fontanelle, 1892 ; Denison, 1893 (J. Rollins) ; Coming, 1893 
(W. L. Abbey) ; Iowa City, 1893 (Fitzpatrick) ; Springdale, 1894; 
^Plattesville, 1894 (Studley) ; Postville, 1894 (Orr) ; Mt. Ayr, Guth- 
rie Center and Story county, 1894 (Sale, Ashton and Pammel) ; 
Des Moines, 1895 (Carver) ; Decatur county and Des Moines 
county, 1896 (Fitzpatrick) ; Webster City, 1897 (Garber) ; Shel- 
dahl, 1898 (Pammel) ; Yorkshire, 1899 (Stokes) ; Dallas Center, 
1902 (C. B. Royer) ; Mondamin, 1903 (A. Spooner) ; Cooper, 1903 
(Squires) ; Afton, 1904 (Geo. Williams) ; Audubon, 1905 (J. N. 
Eskech) ; Keota, 1905 (Klein) ; Lidderdale, 1907 (Mrs. Sander- 
son) ; Reinbeck, 1907 (Fred W;ilcox) ; La Porte, 1908 (R. S. 
Meath) ; Algona, 1912 (A. Hutchinson) ; Collins, 1912 (J. Leon- 
ard) ; Brandon, 1912 (Roster) ; Whitten, 1912 (Parrish) ; Ontario, 
1884 (Fletcher) ; Germany, Mulhausen, 1893 (Seherer Schorler) ; 
Denmark, 1895 (Ostenfeld). 

Buffalo Bur {Solanum rostratum). 

Has been reported frequently to me during the last few years. 
The number of specimens sent from Iowa correspondents during 
the season 1911 and 1912 was numerous, indicating a rapid spread 
in many different parts of the state. It has always been a native 
to the plains, finding a congenial home in the buffalo wallows. 
It was reported by Hartweg in 1837 as being seen north of the 



WEED MIGRATION 767 

city of Mexico; by Bexar in Texas in 1828, in Rock Creek by 
Fendler in 1847, and in El Paso in 1849; and by Geyer from 
Pierre, South Dakota, in 1839. Nearly all of the early collectors, 
as Rothroek, Parry, Fendler, Geyer, Hayden, Brandegee, Palmer, 
mention this weed. It is generally believed to have become rapidly 
diffused in Texas after 1865. 

Jimson "Weed {Datura stramonium). 

Found everywhere in Iowa and in many parts of the United 
States from the Atlantic to the Pacific. Common in eastern North 
America for more than seventy-five years. It is mentioned by 
Darlington, 1847, and Gray, 1848, states that it is a well known 
weed. The date of its appearance in Europe is not given by Ratze- 
burg, Kabseh notes that the thorn apple was introduced from India 
by gypsies. The plant is native to India where its poisonous prop- 
erties were long known. The 5th and 6th editions of Gray's 
Manual indicate a wide distribution in eastern North America. It 
was common in western Wisconsin in 1881. Cratty states that it 
was rare in Emmet county, Iowa, in 1881. 

UMBELLIFERAE, CARROT FAMILY. 
Wild Carrot (Daucus carota L.). 

This was reported by Dr. Torrey as occurring in fields in the 
northern and middle states in 1826. Dr. Gray records it as common 
in 1848; Darlington, in 1857, states that "this foreigner is ex- 
tensively naturalized and becoming more troublesome from the 
culpable negligence of our farmers. ' ' In his 5th edition. Dr. Gray, 
in 1867, states "advanced from Europe." In the 7th edition, 1908, 
Robinson and Fernald state "fields and waste places, a pernicious 
weed" indicating a general distribution. Britton, 1901, states 
"common throughout our area" and the writer knew this weed in 
western Wisconsin, in 1880. In some places it was pretty well 
naturalized. Occasional specimens were found by the writer in 
1889, in Iowa. It had previously been reported by Halsted and 
Arthur. It began to spread quite rapidly in 1904. F. W. Paige 
reports it from Ft. Dodge in 1909. It is now reported quite fre- 
quently from different places in the state. The following are a 
few of the localities: Greenfield, 1891 (P. C. Stewart) ^ Earlham, 
1903 (J. Long) ; Carrolton, 1904 (E. C. Schreiber) ; Zearing, 1904 
(E. E. Sparrow) ; Hawarden, 1905 (C. S. McCarty) ; Hartley, 
1905 (W. B. Elliott) ; Panora, 1906 (L. J. Hooper) ; Marshall 



768 



WEED FLORA OF IOWA 





Fig. 568. Carrot (.Daucua carota). Common in the east. Probably first spread 
from the cultivated carrot. 

county, 1906 (W. R. Moninger) ; "Whiting, 1907 (W. S. Whiting) 
Allerton, 1907 (J. H. Duncan) ; Lamoni, 1907 (T. L. Naftsger) 
Blaekhawk county, 1907 (Pammel) ; Ames, 1909 (J. R. Campbell) 
Polk county, 1910 (Pammel) ; Rippey, 1910 (Osborn) ; Dumont, 
1910 (Titus) ; Libertyville, 1911 (Armstrong) ; Bedford, 1911 
(Spacht); Glidden, 1912 (Walters); Kelley and Ledges, 1912 
(Pammel). 



Poison Hemlock (Conium maculatum) . 

This weed was reported by Dr. John Torrey in 1826 as occurring 
on roadsides. It is mentioned by Dr. Gray in 1848 as occurring in 
waste places. Britton in 1901 records it from Quebec to Michigan 
and Indiana, California, and Mexico. Robinson and Fernald in 
the 7th edition of Gray's Manual indicate "to Pennsylvania," the 
same distribution that Britton gives. It is not, however, common 



WEED MIGRATION 769 

in the Mississippi valley. It was reported from Pottawattamie 
county, Iowa, in 1909 and it was abundant in Salt Lake City, 
Utah, in 1908 where it evidently had been naturalized for some 
time. It was abundant in places in the Sacramento Valley in 1912 
indicating naturalization for some time. Brewer and Watson in 
Botany of California (1876) state "Sparingly naturalized." 



49 



CHAPTER X. 

MEDICINAL WEEDS OF IOWA 

HARRIBTTB S. KELLOGG 



CHAPTER X. 



MEDICINAL WEEDS OF IOWA. 

In the United States, the raising of drug plants has never re- 
ceived the commercial attention that has been devoted to this 
branch of agriculture abroad. As a result, we are importing 
regularly for the drug trade thousands of pounds of dried plants 
that might be raised in this country. Among them are many 
weeds, as, quack grass and mustard that, to us, are pests to be 
eradicated as quickly as possible. Not that it would be wise to 
devote good agricultural land to raising medicinal weeds but 'as 
by-products these are of value. The word "weed" is used ad- 
visedly; for, while many of our vegetable drugs come from plants 
which in this country are not weeds, it is undoubtedly true that 
many drug plants are noxious weeds in the country in which they 
were first applied medicinally. This is illustrated by such weeds 
as quack grass, the mustards, the docks, tansy, and dandelion, all 
of which are official in the U. S. P. 

As early as the days of Dioscorides the physician was the 
herbalist, and his knowledge of the active principles of plants was 
his stock in trade. Among semi-civilized and barbarous peoples 
the same thing is true today. 

While very many of the plants formerly considered medicinal, 
are at present discredited, a sufficient number remains to make 
raising drug plants a profitable industry. 

The literature of medical botany, if we include the "Herballs" 
is quite voluminous. In Germany, in 1787, Schoepf published the 
"Materia mediea americana, potissimum regni vegefcabilis" in 
which he listed three hundred and sixty medicinal plants which he 
had collected among the American Indians; but he stated that 
there were actually over seven hundred in use. Between 1817 and 
1821 Jacob Bigelow published three volumes of the "American 
Medical Botany; being a collection of the native medical plants 
of the U. S." in which he listed fifty plants, each illustrated by 
colored plates. William Barton, about the same time, published 
"Vegetable materia mediea of the U. S. ; or medical botany contain- 
ing a botanical, general, and medical history of medicinal plants 



774 WEED FLORA OF IOWA 

indigenous to the United States," in which fifty plants were de- 
scribed and illustrated. The high price of these books, however, 
necessarily limited their distribution. 

In Rafinesque's "MediVal Flora," published in 1828 and 1830, 
one hundred and five plants are named as being native North 
American plants. Among those listed are such weeds as mayweed, 
butterfly weed, wormseed, wild hemlock, cowbane, thorn-apple, 
fleabane, boneset, Joe-Pye weed and mullein. 

The most complete work of recent years is MiUspaugh's American 
Medicinal Plaiits in which he describes and illustrates with colored 
plates 180 medicinal plants native in the United States and recog- 
nized by homeopathic physicians as of therapeutic value. He also 
adds to each description, the active principles of the plant in ques- 
tion, the method of preparation and the physiological action of the 
drugs derived therefrom. In addition to the one hundred and 
eighty plants fully described, he mentions hundreds of others that 
are known to the profession but are not native to the United 
States, making in all so satisfactory a treatise that for many years 
it must remain our most reliable source of information in this line. 
In Dr. Pammel's Manual of Poisonous Plants, many medicinal 
weeds not of a poisonous nature are listed among the economie 
plants. 

The United States Department of Agriculture has issued a num- 
ber of bulletins containing references to medicinal weeds, which 
are listed in the bibliography at the end of the volume. 

Many plants not listed as official in the United States Phar- 
macopoeia have, nevertheless, value as commercial products. Such, 
for instance, is true of the wormseed plant which, although not 
recognized in our Pharmacopoeia, brings from 6 to 8 cents per 
pound in the drug market. 

Quack grass {Agropyron repens) is the only weed of the grass 
family that is official in the U. S. P. A fluid extract from the 
rhizome of this plant sold under the name of dog grass or triticum 
is a remedy in kidney and bladder troubles. 

The roots of various docks of the Iowa species are official. Bitter 
dock (Rumex ohtusifoliiis) and yellow dock {B. crispus) are rated 
at 2 to 8 cents per pound and form the basis of various blood 
purifiers. The leaves of sheep sorrel (E. acetosella) while not 
official, are of market value. 



MEDICINAL WEEDS OP IOWA 



775 




Fio. 569. Quack Grass (.Agropyron repens). The root-stock used lor bladder 

trouble, 
(Drawing by Charlotte M. King.) 

The entire herb of water pepper {Polygonum hydropiper) -when 
decanted with alcohol forms a valuable diuretic, but is not recog- 
nized in the Pharmacopoeia. 

The entire leafy part of the American wormseed {Chenopodium 
ambrosioides} is valued for its anthelmintic properties. Oil from 
the' fruit is official and sells for $1.50 per pound. 



776 WEED FLORA OF IOWA 

Of the Phytolaccaceas, pokeweed (Phytolacca decand/ra) has long 
been considered of medicinal value. The berries, collected when 
mature, are rated at 5 cents per pound; the roots at 2 to 5 cents; 
although not o£6.eial they are the basis of remedies for various 
diseases of the skin and blood, especially in allaying rheumatism. 

In the order Caryophyllaceqe is the corn-cockle (Agrostemma 
githago), the powdered seeds of which are the basis of a remedy 
used to cleanse the blood in certain skin diseasfis. 

Ghickweed {Stellaria media) formerly had some reputation as 
an alterative but is now used very seldom. 

Among the Criiciferae are several weeds that are recognized as 
medicinal. The most' important are the mustards, the seeds of 
which are ofSeial and sell at 3 to 6 cents per pound. Both the black 
mustard (Brassica nigra) and the white mustard (B. alba) are col- 
lected for this purpose and are used principally in making plasters 
and poultices but occasionally are administered in cases of dys- 
pepsia. They are emetic when given in large doses. 

The shepherd's purse {Capsella bursa-pastoris) is not ofiScial. 
At one time it was considered of value as a tonic, astringent, and 
antiscorbutic biit has fallen into disuse except when occasionally 
applied as an astringent in hemorrhages. 

Among the Malvaceae is a dooryard weed, common mallow {Malva 
rotundifolia) , the whole plant of which is sometimes applied locally 
as a poultice or iaternally as a demulcent. 

A decoction of the dried plant of the evening primrose (Oenoth- 
era biennis), a member of the Oimgraceae, is a remedy in cases of 
infantile eruptions, spasmodic asthma and bladder trouble. 

An introduced weed of the Leguminosae is noted; the yellow 
sweet clover (Melilotus officinalis), the seeds of which boiled with 
lard are sometimes, made into a salve which is applied to ulcers 
and open indolent sores, the remedy proving efficacious. 

Among the Umbelliferae are the caraway (Carum carvi), the root 
of which is sometimes ground into a poultice and the fruit and 
leaves of which are diuretic and stimulant; the poison hemlock 
(Conium maciilatum) , the root of which is deadly poisonous, al- 
though the unripe fruit, dried and preserved, is official, selling at 
8 cents per pound, and the leaves, though not official, are sometimes 
applied in cases of rheumatism, neuralgia or asthma to sooth the 
nerves; and the water hemlock (Gicuta maculata), sometimes sub- 
stituted for cowbane. 



MEDICINAL WEEDS OP IOWA 777 

Two of the Milkweeds {Asclepias incarnata and A. syriaca) are 
listed as medicinal, an extract from the root alone being used. 
This is a diaphoretic and was formerly applied in acute pulmonary 
and bronchial affections and in rheumatism. Although at present 
it has fallen somewhat into disrepute, it is sometimes given in cases 
of dropsy. 

A tincture from the whole plant of bindweed {Convolvulus 
arvensis), of the family Convolvulaceae, is sometimes used as a 
diuretic or gentle laxative. 

The leaves and root of one of the Boragi-rmceae, hound's tongue 
{Cynoglossum ojjicinale), are both medicinal, the latter being some- 
what narcotic. The leaves were at one time used as a styptic. 

Of the Yerhenaceae we find records of the use of the root and 
green parts of vervain {Verbena hastata) which were substituted 
occasionally for boneset in fevers and agues. They are emetic and 
expectorant. 

The Labiate, self-heal {Prunella vulgaris), is an astringent but 
by no means is the universal curative agent that its name would 
suggest. 

Catnip {Nepeta cataria) no longer official, nevertheless is rated 
at 2 to 8 cents per pound for leaves and flowering tops, the coarse 
stems being rejected. A decoction from these parts is a mild stimu- 
lant and tonic, being rather quieting in effect. 

Motherwort {Leonurus carMaoai) has similar properties. 

The family Solanaceae is very important medicinally, as it fur- 
nishes at least twenty drugs to the trade, of which the most im- 
portant is belladonna. Of the Iowa weeds Jimson {Datura stra- 
monium) is the best known. The leaves and seeds are official, the 
former being rated at 2^^ to 8 cents and the latter at 3 to 7 cents 
per pound. The leaves are applied in eases of asthma and the 
seeds in spasmodic diseases affecting the respiratory tract. Datura 
tustula is sometimes used in the same manner. 

The black nightshade {Solanum nigrum) is especially valuable as 
a resolvent but its use is no longer prevalent. In some parts of 
Iowa the bruised leaves are considered an unfailing remedy in cases 
of ivy poisoning. 

The root leaves and berries of horse nettle {S. carolinense) are 
mentioned by Alice Henkel as being medicinal though not official. 

Of the Scrophulariaceae, the cosmopolitan mullein weed {Ver- 
iascum thapsus) possesses considerable market value although it is 
not recognized by the U. S. P. as official. The dried leaves retail 



778 WEED FLORA OF IOWA 

at 21/^ to 5 cents and the flowers at 25 to 75 cents per pound. A 
tincture from these is a recognized remedy in coughs and catarrh. 
It quiets nervous irritation and relieves inflammation. 

The uses of the plantains (Plcmtago) are various. The fresh 
leaves are sometimes applied to wounds or chronic sores. The 
seeds steeped in milk form a remedy used in checking hemorrhages 
froni mucous surfaces and in dysentery. Almost every part of the 
plant at some time has been recorded as medicinal. The fibers from 
the leaves were thought to be an unfailing remedy for toothache, 
the fiber, however, being placed in the ear on the side of the tooth 
affected rather than about the tooth itself. Plantain is also an 
antidote to snake bites. A decoction of the root was sometimes ad- 
ministered in cases of intermittent fever. 

In short it would seem possible for one to have quite a complete 
medical dispensary in his own dooryard without care or expense. 

The family Compasitae undoubtedly contains a larger number of 
medicinal genera than any other plant family. 

A decoction made from the whole herb of yarrow {Achillea 
rmllefolmm) is a bladder medicine and is administered sometimes 
in cases of hemorrhage or ftatarrh. The ragweed {Ambrosia ar- 
tendsiaefolia) is used in similar eases. The mayweed (Anthemis 
cotvla) furnishes a bitter stimulant and tonic in aid of digestion. 
From the leaves may be made a fermentation which relieves pain 
and inflammation, sprains and bruises ; none of the last three named 
is official. 

The burdock {Arctiwm lappa), however, is recognized in the 
U. S. P. Its fresh root gathered in autumn retails at 3 to 8 cents 
and seeds at 5 to 10 cents per pound. These are both useful in 
preparations against blood and skin diseases. The leaves are some- 
times applied externally as cooling poultices. 

An infusion of the root of chicory {Cichorimm intyhus) is some- 
times offered to increase the appetite and to aid digestion. A decoc- 
tion from fireweed {Erechtites hieracifolia) is an alterative and is 
applied in cases of dysentery. The oil of horseweed {Erigeron 
ccmadense) is official, the herb being rated at 6 to 8 cents per pound. 
The plant has been known locally as "blood stanch" and, as the 
name implies, was used in arresting hemorrhages and bleeding from 
wounds. 

According to MUlspaugh this use of the plants is practiced today 
among the North American Indians. The oil only is official. The 
various local names of Eupatorium perfoliatum, boneset, feverwort, 



MEDICINAL WEED'S OP IOWA 



779 




Fig. 570. Burdock (Arctium lappa). Formerly used as blood purifier. 
(Vasey, U. S. Dept. Agr.) 



780 WEED FLORA OF IOWA 

or agueweed, indicate the uses of the plant. It is tonic, diaphoretic, 
emetic, or cathartic according to the size of the dose administered ; 
the root of the white snakeroot {E. wrticaefoUum) is also of com- 
mercial importance, being rated at 2 to 8 cents per pound. The 
Joe-Pye weed {E. purpureum) has uses somewhat similar to the 
preceding but is also a diuretic and is valuable in cases of jaundice, 
dropsy, rheumatism or gout. 

The leaves and flowering tops of the scaly grindelia {Grindelia 
squarrosa) are the basis of a remedy against asthma and are also 
sometimes made into a poultice to apply in cases of ivy poisoning. 
The sneezeweed {Helenium cmiunvnale) is a tonic and diaphoretic; 
the powdered flowers are sometimes snuffed to relieve affections of 
the nasal passages. The wild lettuce {Lactuca canadensis), once 
considered a substitute for opium, is an anodyne, a diaphoretic, 
and a diuretic, and is applied principally in nervous complaints. 
Tansy {Tanacetum vvigare) is official in the U. S. P., the leaves 
and flowering tops being rated at 3 to 6 cents per pound. It is a 
well known but poisonous vermifuge. 

The root of the dandelion {Taraxacum officinale), collected in 
autumn, is official, selling at 4 to 6 cents per pound. A decoction 
from this is a tonic in cases of dyspepsia and diseases of the liver. 
A hair tonic is also made from it. 

Undoubtedly this list could be greatly extended were it possible 
to obtain information in regard to all cases of home use of native 
drug plants. Unfortunately few written records are obtainable 
and one is obliged to depend largely on tradition handed down by 
word of mouth. 

There is undeniably an opening in Iowa for raising and market- 
ing medicinal plants and a few words in this line may not be out 
of place at this point. 

For the profitable marketing of drug plants it is necessary that 
the plants be suitably prepared, that is, that they be thoroughly 
cleaned and well cured. To be cleaned they must be freed from 
all foreign substances, whether dirt, sand, insects, or fragments of 
other j)lants ; when cured properly, they have been picked at the 
right season, and have been dried so as to retain so far as possible 
their characteristic color. If the leafy part is sought for the trade, 
the plant should be cut when in flower or before seeds have formed, 
then dried in gentle heat (not higher than 125° F.) so as to lose as 
little as possible of the volatile principle. In some plants, as cow- 
bane, the unripe frait, well dried and preserved, has value officially, 



MEDICINAL WEEDS OF IOWA 781 

Lut of mustard on the other hand, ripe seeds, only, are oificial. 
The dried leaves of the catnip have market value but no longer 
are recognized as official. The roots of the dandelion collected in 
the autumn are listed in the TJ. S. P. ; the rhizome of quack grass 
is marketable. In short, if one is to realize any financial profit 
from his fields of weeds, he must be able to recognize absolutely the 
weed in question, for poisonous herbs sometimes closely resemble 
innocuous weeds and a mistake in identification may result serious- 
ly ; he must also know what part of each plant is salable, when it 
must be collected, whether in the ripe or immature state, and in 
what form it is preferred by the trade. It is not an occupation to 
be followed by the careless or ignorant worker. Ignorance is no 
excuse for offering to the trade a deadly herb in mistake for its 
harmless relative. When the life of the patient is sacrificed as a 
result of such a mistake the old saying, that "if it kills it is poi- 
sonous, if it cures it is the right herb," will hardly suffice as an 
excuse. 

.For the careful gardener, however, who is willing to wait for his 
herbs to mature one year, two years, or, as with ginseng, seven 
years, the occupation of growing drug plants offers many induce- 
ments. 



CHAPTER XI. 

PHENOLOGY OF WEEDS 

CHARLOTTE M. KING 



CHAPTER XL 



PHENOLOGY OF WEEDS. 

Several species of weedy plants bloom very early in tlie spring, 
responding promptly to a comparatively limited amount of light 
and warmth; others come to bloom after the growing season is 
more advanced ; while a number blossom throughout the season, or 
from spring until fall. 

The time of bloom is, in each species, related to its definite 
physiological constant of warmth, sunshine and moisture. "Warm, 
sunshiny weather in the early part of the season will hasten the 
time of bloom, as cold, cloudy weather will retard it. There is a 
difference of about two weeks between the blooming date of plants 
of northern and southern parts of Iowa. 

The season of a plant's activity is related in part to the hardiness 
it has developed, and to the climatic conditions of the geographical 
region selected by it, as most favorable to its existence. 

It is vigor and tenacity as well as wide seed distribution which 
contribute to the troublesome character of the plants which we call 
weeds. 

It is indicated by the accompanying table, as known also by com- 
mon experience, that the rain, warmth and sunshine received at 
the arrival of midsummer produce greatest bloom of weedy plants 
for the season in both number and kinds ; and since weeds quickly 
mature, it is apparent that the harvest of weed seeds steadily in- 
creases from that time until fall. 

The crucifers are among our earlier blooming weeds, as the 
winter annuals, shepherd's purse and peppergrass; the legumes 
and umbellifers are at their full growth about midsummer; the 
plantains begin in May, the polygonums in June; whilst com- 
posites are usually blooming throughout the latter part of the 
season. 

Grasses distribute their blossoming-time* throughout the summer 
from May until October; vanilla grass and blue grass appear in 
May, orchard grass, quack grass, needle grass and timothy in June, 
crab grass, fescue grass, and rye grasses about July, Bouteloua in 
August, blue-stem and drop-seed grasses in September. 
50 



786 WEED FLORA OF IOWA 

Many plants, either annual or perennial, which have a recog- 
nized weedy character, have a prolonged period of bloom and seed- 
ing, thus maintaining a vigorous hold. 

Common cosmopolitan weeds, belonging to various orders, have 
often remarkable perennation, as in case of the dandelion, shep- 
herd's purse and chickweed; these weeds begin bloom in earliest 
spring and are also more resistant to frost than are other weeds. 

The period of time required for maturing fruit after blooming 
varies in different species; a comparatively short time is needed 
in ease of most weeds, especially the late blooming ones. 

The dormant period required for a seed before germination will 
take place differs with varieties, and with individual seeds of the 
same variety. In seeds requiring a period of rest, this delay may 
be a matter of days, weeks, or years; therefore there is a distribu- 
tion for seeds through time as well as through space. Many seeds 
germinate immediately if conditions are favorable. Many young 
plants must be lost by this autumnal vegetating, in case of seed- 
lings overtaken by frost before they can bear seeds or establish 
roots; but the hardy habit of the winter annual, the biennial and 
perennial, protects for the most part such young plants after fall 
germination. 

Quack grass has a crop of seedlings of the same season as the 
ripening of seed ; this is true also of wild cajTot, burdock, thistles, 
horse nettle and ribgrass, all of which being biennial or perennial 
persist throughout the winter. 

The freezing and thawing of winter facilitates germination of 
weed seeds in the spring; and very early one may note, in the loca^ 
tion of the parent of last season, as soon as the soil grows warm 
enough, many flourishing young colonies of seedlings, such as 
spurge, oxalis, pigweed and smartweed crowding each other for 
foothold. The culturist is greatly influenced by considerations of 
blooming-time, seed-time, and time of seed-germination in his ef- 
forts to control and to exterminate we^ds. 



PHENOLOGY OF WEEDS 
BLOOMING PERIOD OF COMMON WEEDS 



787 



Stellaria media A. Chickweed , 

Capsella /bursorpastoris A. Shepherd's purse 

MeAioago lupuUna A. Yellow trefoil 

Oxalts comiculata A. & P. Lady's sorrel 

Taraxacum officinale P. Dandelion 

Nepeta Jiederacea P. Ground ivy , 

Barbarea vulgaris B. Yellow rocket , 

Cynoglossum boreate B. Hound's tongue , 

Flantago lanceolata P. Buckhorn , 

Banunculus abortivus B. Small-flowered buttercup 

Ranunculus septentrionalis P. Buttercup , 

Bumew altiss,imu^ P. Smooth dock , 

Taraxacum erythrospermum P. Small-flowered dan- 
delion 

AMwm aanadense A. & P. Wild garlic 

Asolepias spedosa P. Showy milkweed 

Brassica arvensis A. Wild mustard 

Bromus tectorum A. Downy hrome grass 

Garum carvi B. Caraway 

Cerastium visicosum A. & P. Mouse-ear chickweed. 
Convolvulus arvensis P. European morning-glory. . 

Convolvulus sepium P. Wild morning-glory 

Batura tatula A. Purple thorn-apple 

Euphorbia marginata A. Snow-on-the-mountain 

Euphorbia preslii A. Spurge 

Glycyrrhiza lepidota P. Wild liquorice 

Hierochloe odorata P. Vanilla grass 

Hordeum pusillum A. Small squirrel-tail grass. . . . 

Lepidium apetalum A. Apetalous peppergrass 

LeipicKum virgimiioum A. Wild peppergrass 

Lithospernnum a/rvense A. Corn gromwell 

Lolium italicum B. or P. Italian rye-grass 

Malva rotundifoUa P. Common mallow 

Oxybaphus nyotagineus P. Wild fonr-o'clook 

Flantago major P. Door-yard plantain 

Flantago purshii A. Pursh's plantain 

Fotentilla anserina P. Silverweed 

Radicula palustris A. or B. Marsh cress 

Rhus toxicodendron P. Poison ivy 

Rudbeckia hirta B. Black-eyed Susan 

Rumex acetosella P. Sheep sorrel. 

Sisymbrium officinale A. Hedge mustard 

Bolamum cm-olinense P. Horse nettle 

Bolanum rostratum A. BuffaJo-bur 

Bonchus oleraceus A. Sow thistle 

Trifotium procumbens A. Hop clover 

Verbena braoteosa P. Bracted verbena 

Veronica peregri/na A. Speedwell 

Vida saliva A. Vetch , 

Achillea millefolium P. Yarrow 

A. Annual. 

B. Biennial. 
P. Perennial. 



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788 WEED FLORA OF IOWA 

BLOOMING PERIOD OF COMMON WEEDS— C!ontinued. 



Acalypha virginica A. Three-seeded mercury 

Amaranthus graecizans A. Tumbleweed 

Amaranthus blitoides A. Spreading pigweed... 

Anthemis cotulla A- Mayweed 

Apocynum oannaMnum P. Dogbane 

Asclepias synaca P. Milkweed 

Berteroa incana A. or P. Berteroa 

Brassiea nigra A. Blacli mustard 

BrOTTiMS secaliniis A. Cheat 

GanteUna sativa A. False flax 

Garex vulpinoi&ea P. Sedge 

Ghenapodium alium A. Lamib's quarter 

CictUa maculata P. Cowbane 

Girsium arvense P. Canada thistle 

Girsium undulatum B. Wavy-leaved thistle 

Grotalaria sagittalis A. Rattle-box 

Gycloloma atriplicifolium A. Winged pigweed 

Datura stramonium A. Jimson weed 

Daucus carota B. Wild carrot 

Erigeron annuus A. Fleabane 

Erigeron canadensis A. Horseweed 

Erigeron ramosus A. Branched fleabane 

Euphorhia maculata Spotted-leaved spurge 

Geum canadense P. Avens 

Helianthus petiolaris A. Petiolate sunflower... 

Hordeum ju'batum A. or B. Squirrel-tail 

Hypericum perforatum P. St. John's- wort 

LactUiCa canadensis A. or B. Wild lettuce 

Lactuca pulchella P. Blue lettuce 

Lappula virginiairw, A. Beggar's lice 

Leonurus cardiaca P. Mother-wort 

Lygodesmia juncea P. Lygodesmia 

Melanthium virginicum P. Bunch flower 

Melilotus alha B. White sweet clover 

Oenothera 'biennis B. Evening primrose 

Parietaria pennsylvanica A. Pellitory 

Fastinaca sativa P. Parsnip 

Plantago rugelii P. Rugel's plantain 

Polanisia trachysperma A. Polanisia 

Polygonum avioulare A. Dooryard knotgrass 

Por.ygonum hydropiperoides P. Mild water pepper 
Polygonum lapathifoUum A. Slender smartweed . . 

Eleusine indica A. Goose-grass 

Eragrostis megastachya A. Candy-grass 

Linaria vulgaris P. Toadflax 

Silene antirrhina A. Sleepy catchfly 

Thlaspi arvense A. Pennycress 

Urtica gracilis P. Nettle 

Gonringia orientalis A. Hare's-ear mustard 

Polygonum persicaria A. Lady's thumb. 

Portulaca oleracea A. Purslane 

Radicula armoracia P. Horseradish 

Raphanus sativvs A. or B. Radish 

Rumex crispus P. Curled dock 



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PHENOLOGY OF WEEDS 789 

BLOOMING PERIOD OF COMMON WEEDS-CoNTiNtTED. 



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Bumex oibtusifoUus P. Bitter dock 

Saponaria iMccaria A. Cow-herb 

Sida spinosa A. Prickly sida '. 

Sisymbrmm altissimwm A. or B. Tall hedge mustard . 

Btaehys palustris P. Woundwort 

Teucriv/m ccmadmse P. G-ermander 

Tribulus terrestr'is A. Caltifep 

Yerbascnim thapsus B. Mullein 

Vertena hastata P. Blue vervain 

Brorrms hordeaceus A. Soft chess 

Agrostemma githago A. Corn cockle 

Veriena striata P. Hoary vervain 

Atriplex patula A. Orach 

AcnMa tuherciblata A. Water hemp. 

Avena fatua A. Wild oats 

Amirosia artemisiifoTia A. Small ragweed 

Amhrosia trifida A. Large ragweed 

Arotium, fappa B. Burdock 

Bidens. cenvua A. Sticktight 

Bidens diseoidea A. Sticktight 

Bidems frondom A. Sticktight 

Gfienapodium Tiy'bridum, A. Maple-leaved goosefoot. . 

Giohorium intybus P. Chicory 

Cirsium discolor B. Field thistle 

Cirsium ioense B. Iowa Thistle 

Cirsium lanceoXatum B. Bull thistle 

Gleome serrutata A. Stinking clover 

Gusouta arvensis A. Field dodder 

Digitaria humifusa A. Smooth crab grass 

Dy&sodia pappo&a A. Fetid marigold 

Eragrostis pilosa A. Pilose eragrostis 

ErecMites hieracifoUa A. Fireweed 

Eupatorium urticmefoHum P. White snakeroot 

Gawa tiennis B. Gaura 

Oonolotus laevis P. Anele-nod 

HelicmtJius annuus A. (Wild) Sunflower 

Ipomoea hederacea A. Wild morning-glory 

Iva xantMfolia A. Poverty weed 

Kochia scoparia A. Kochia. 

Lotiv.m pererme P. Rye grass 

MeUlotus officinalis A. or B. Yellow sweet clover. . 

Mentha spicata P. Spearmint 

Phy salts sulgXabrata P. Smooth ish ground cherry. . 

Polygonum convolvulus A. Black bindweed 

Polygonum erectum A. Erect knotweed 

Polygonum hydropiper A. Water pepper 

Polygonum muhJerifiergii P. Tanweed 

Polygonum pennsylvanicum, A. Pennsylvania smart- 
weed 

Polygonum, ramasissimum A. Branching knotweed. . 

PotentiUa mofispeHensis B. or P. Five-finger 

Salsoia kali var. tenuAfolia A. Russian thistle 

Scrophulariu maryiandica P. Simpson's honey plaiit . 
Setaria glauca A. Yellow foxtail 



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-I- 



790 WEED FLORA OF IOWA 

BLOOMING PERIOD OF COMMON WEEDS— CONCIiUDED. 



Setaria vertioillata A. Wliorled foxtail 

Betaria viridis A. Green iCbxtail. 

Silene noctiflora A. Night-flowering- catcMy 

Solanum nigrum A. Night-shade. 

Sonchus arvensis P. Field thistle 

Saponaria officinalis P. Bouncing Bet 

Stipa spartea P. Needle grass. 

Strophostyles helvola A. Wild pea. , 

Syfnphoricarpos orbiculata P. Indian currant 

Tcmacetum vulgare P. Tansy , 

Lactuca scariola A. Prickly lettuce. ..'. 

Hibiscus trion/um A. Shoo-fly. 

Vr(ica dioica, P. Stinging nettle. , . . , 

Yernonia fasciculata P. Iron-weed. , 

Alutiloh theophrasti A. Velvet leaf. , 

Amaranthus retroflexus A. Tumbling pigweed. .. ., 

Aristida dicKotoma A. Poverty grass 

Artemisia Menhis B. Wormwood 

Artemisia ludoviciana P. Western mugwbrt , 

Aster multifloris A. Many-flowered aster , 

Aster sailicifoHus A. Willow-leaved aster , 

Bidens aristosa A. or B. Sticktight 

Oenchrus triiuloides A. Sandhur , 

Cfienopodium amirosioides A. Mexican tea 

Cirsium <aTtissimum B. Tall thistle. 

Cirsium [canescens B. Woolly thistle 

Cyperus esculentus P. Northern nut grass 

Dalea alopecuroides A. Foxtail dalea 

Digitaria sanguinalis A. Crab grass 

Echinochloa crusgalU A. Barnyard grass. 

Belianihus grosseserratus P. Wild prairie sunflower. 
HeUantJius maximiliani P. Maxmilian's sunflower. . 

Selenium antumnale P. Sneezeweed , 

MuKlenbergia m,exicana P. Mexican dropseed 

Muhlenbergia racemosa P. Dropseed grass 

SoUdago canadensis P. Canada goldenrod 

Solidago rigida P. Stiff goldenrod 

Solidago serotina P. Goldenrod 

Panicum capillare A. Hair grass '.'...! 

Sporolol-us neglectus A. Small rush grass 

Sporohulus vaginiflorus A. Sheathed rush grass. . . , 

Xanthium canadense A. Cocklebur 

Xanthium spinosum A. Spined cocklebur 

Helianthus tuberosus P. Artichoke 



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CHAPTER XII. 

WEED AND SEED LAWS 

L. H. PAMMEL 



CHAPTER XII. 



PURE SEED AND WEED LAWS. 

Many states of the United States have weed and seed laws and 
similar laws are on the statute books of the principal agricultural 
countries of the world. Long, who in ' ' Common Weeds of the 
Farm and Garden" has summarized the legislation, states, in Ap- 
pendix III, that the laws are quite stringent in Australia, and in 
the South African Colonies; that the only laws requiring the de- 
struction of weeds in the British Islands are in Ireland and the 
Isle of Man; that no laws or regulations are in force in Great 
Britain although there is an Adulteration and Seeds Act. 

Canada has a good general seed law; Manitoba has a noxious 
weed act passed in 1906 which included common wild mustard, 
Canada thistle, perennial sow thistle, wild oats, "stink-weed" or 
penny cress, and false flax. The law provides that owners and 
occupants of land shall be compelled to cut down, or destroy weeds, 
to prevent seeding. 

In Ontario the law provides that every occupier must cut down 
all Canada thistles, ox-eye daisies, wild oats, ragweed, burdock and 
all other noxious weeds to which the act may be extended by 
municipal law to prevent the ripening of seed, provided it does 
not destroy the growing grain. 

The law of the Northwest Territories is similar to that of 
Manitoba, excepting that inspectors are appointed who have the 
power to act in the case of the occupier's default. It is further 
provided that threshing machines shall be cleaned before being re- 
moved from one place to another. 

The law of Quebec includes daisies, wild endive, chicory, celan- 
dine and wild mustards as weeds. 

In Saskatchewan the Noxious Weed Ordinance schedules nine- 
teen species including six species of mustard and three of thistles. 
This province also provides for the appointment of weed inspectors. 

The province of Alberta, Act of 1907 amended in 1908, mentions 
22 noxious weeds. Inspectors are also appointed. The sale of 
seed containing 5 per 1,000 noxious weed seeds is forbidden and 
the germinating power of all weed seed must be destroyed before 



794 WEED FLORA OF IOWA 

cleanings, etc., can be removed from any premises. Threshing ma- 
chines must be thoroughly cleaned before being removed to another 
place. 

WEED LEGISLATION. 

Various states have legislated in regard to certain weeds as 
follows: Arizona on coekleburs and sunflowers; California on 
Canada thistles and any and all weeds that are spread by the 
wind; Connecticut on Canada thistle and wild carrot; Delaware, 
Canada thistle; Illinois, Canada thistle on highways, coekleburs 
and all weeds before maturity; Iowa, Canada thistle, cocklebur, 
burdock, curled dock, smooth dock, wild parsnip, quack grass, vel- 
vet weed, horse nettle, Russian thistle and shoo-fly ; Indiana, Can- 
ada thistle ; Kansas, on highways, coekleburs. Rocky Mountain sand- 
burs, burdocks, sunflower, and such other weeds as may be in- 
jurious to the best interests of the farming community ; Kentucky, 
Canada thistle; Maryland, Canada thistle; Michigan, to remove 
noxious weeds on highways, Canada thistle, milkweed {Asclepias 
syriaca) ; Minnesota, weeds in three groups: first group, wild mus- 
tard, wild oats, cocklebur, burdock, tumble mustard, second group, 
Canada thistle, ox-eye daisy and quack grass, third group, French 
weed; a section prohibits the spread of weeds from empty freight 
cars ; the following weeds must be destroyed on highways : Russian 
thistle, Canada thistle or other thistles, burdock, ox-eye daisy, wild 
mustard, snap dragon or toad flax, cocklebur, sow thistle, sour 
dock, yellow dock and other noxious weeds; Missouri, Canada 
thistle; Nebraska, Canada thistle; New Jersey, Canada thistle; 
New Tork, Canada thistle and other noxious weeds along canals; 
North Dakota, Canada thistle, cocklebur, mustard, wild oats, 
French weed, Russian thistle; Ohio, brush briers, thistles or other 
noxious weeds, Canada thistle, wild parsnip, sweet clover, wild 
carrots, teasel, burdock, coekleburs; Oregon, dagger cocklebur, 
Canada thistle; Pennsylvania, Canada thistle; South Dakota, 
Russian thistle, Canada thistle, and cocklebur ; Vermont, all thistles 
and noxious weeds ; Washington, Canada thistles ; in West Virginia, 
the county court may offer reasonable bounties or rewards for birds 
of prey or weeds; Wisconsin, Canada thistle, burdock, ox-eye 
daisy, toad flax, cocklebur, sow thistle, sour dock, and yellow dock, 
mustard, wild parsnip, sweet clover, and Russian thistle. 

Many states have passed supplementary legislation. Many other 
countries besides those mentioned here have rather stringent laws 



WEED AND SEED LAWS 795 

on the extermination of weeds. There are laws in Prance and 
Germany but most of the European countries appear to have no 
legislation on the destruction of weeds. 

Denmark .awards prizes to members of societies for weedless 
fields. In most countries and most states of the United States the 
laws are fla;grantly violated. In the Canadian Provinces, where 
weed commissioners are appointed, they seem to have remedied 
this defect. 

A few years ago these laws were compiled by Dewey.* The 
present Iowa law is as follows : 

IOWA. 
SENATE PILE NO. 136. 

AN ACT TO PBOVTDE FOE THE DESTRUCTION OF NOXIOUS" WEEDS AND 
OTHER WEEDS; UPON LANDS, HIGHWAYS AND OTHER PLACES; PRE- 
SCRIBING PENALTIES FOR THE VIOLATION THEREOF ; ASSESSING THE; 
COSTS AND EXPENSES OF THE DESTRUCTION OF THE SAME TO THE 
LANDS AND OWNERS THEREOF; AND PROVIDING FUNDS WITH -WHICH 
TO DESTROY THE SAME, AND REPEALING ALL OF CHAPTER NINETY- 
SIX (96) OF THE ACTS OF THE THIRTY-THIRD GENERAL ASSEMBLY^ 
RELATING TO WEEDS UPON LANDS AND HIGHWAYS. I 

Be it Enacted by the General Assembly of the State of Iowa : 

Section 1. It shall -be the duty of each owner, occupant, person, 
company or corporation in control of any lands within the state of 
Iowa, whether the same shall consist of improved or unimproved 
lands, town or city lots, lands used for highways, railway right of 
way or depot grounds, lands in which the public has an easement 
for road, street or other right of way, or lands used for any other 
purpose whatsoever, to cUt, burn, or otherwise entirely destroy all 
noxious weeds as defined in section two (2) hereof at such times in 
each year and in such manner as shall prevent the said weeds from 
blooming or coming to maturity, and to k,eep the said lands free 
from such growths of other weeds as shall render the streets or 
highways adjoining the same unsafe for public travel or shall in- 
terfere in any manner with the proper construction or repair of the 
said streets or highways, and shall cause to be cut, near the surface, 
all weeds on the streets or highways adjoining said lands between 
the fifteenth day of July and the fifteenth day of August of each 
year. But nothing herein shall prevent the land owner from har- 

•Bull. U. S. Dept. Agr. Div. Hot. 17:60. 



796 WEED FLORA OP IOWA 

vesting the grass grown upon the roads along his land in proper 
season. 

Sec. 2. The following weeds are hereby declared to be noxious 
weeds; namely, quack grass (Agropyron repens), Caniaida thistle 
{Cirsium wrvense), cocklebur (Xanthnim canadense), wild mustard 
(Brassica arvensis), sour or curled dock {Bumex crispus), smiooth 
dock (Bumex aUissimus), buckhom or ribbed plajitain. {Plantago 
lanceolata) , A^ild parsnip (PasUnaca sativa), horse nettle {Solwnwm 
carolinens&), velvet weed or button weed (Abutilon theophrasU) , 
burdock (Arctium lappa), shoo-fly (Hibiscus trionum), wild carrot 
(Dattcus carota) and Russian thistle (Salsola kaU L. var. -tenui- 
folia) . 

Sec. 3. If any such owner, occupant, person, company or corpor- 
ation in control of any such land shall fail or neglect to do the 
things necessary to prevent the said noxious weeds on any such land 
from blooming or coming to maturity, or shall permit weeds thereon 
contrary to the provisions of section one (1) hereof, or if it shall 
appear that there is danger that any such noxious weeds on, any 
such land may mature, then upon their own motion or upon com- 
plaint made to any member tliereof , it shall be the duty of the board 
of trustees of the township in which such land lies or to which such 
land may be adjacent and within the same county, or of the town 
council or board of commissioners if within the limits of an incor- 
porated town or city, to make investigation of such condition or 
complaint, and if it appears that there is danger that any such nox- 
ious weeds may mature or that weeds thereon render or are about 
to render the streets or highways adjoining the land unsafe for pub- 
lic travel or interfere or are about to interfere in any manner with 
the proper construction or repair of the said streets or highways, 
the said board of trustees, town council or commissioners, as the 
case may be, shall make an order fixing the time within which the 
weeds shall be prevented from maturing seed or the said weeds 
shall be destroyed, prescribing the manner of their destruction, and 
shall forthwith give notice in writing of the said order personally 
to the owner of the_ land upon which the same exist if service of 
such notice can be made within the township in which such land 
is situated, and if it can not be so served, then by mailing said no- 
tice by registered mail to the owner at his last known address, and 
also by giving a copy of the notice to the person, company or cor- 
poration in the apparent control or occupancy of the said land, 
whose duty it shall also be to mail said notice to the owner, and 



WEED AND SEED LAWS 797 

if the order so made is not substantially complied with by the time 
fixed in the order and after reasonable notice as herein provided, 
then it shall be the duty of the board of trustees, town council or 
commissioners, as the case may be, forthwith to cause said order to 
be fully performed, and the expense of the same, including the 
costs of serving said notice and the special meetings of the board 
of trustees, town council or commissioners, if any were required, 
shall be advanced out of the township road fund, or town or city 
general fund, as the case may be; or if the said fund shall be in- 
sufficient therefor, the town council, commissioners, or the board 
of trustees may borrow the money necessary to advance the same 
by issuing warrants of a like amount upon the road fund, or upon 
the town or city general fund, and at any meeting of the board 
they shall assess all of the same against the said land and the owner 
thereof by a special tax which shall be certified and collected to- 
gether with interest and penalty after due in the same manner as 
road taxes unpaid and shall be collected by the county treasurer 
and when collected shall be paid into the fund upon which said 
warrants were drawn. Before making said assessment, ten days' 
notice shall be given such owner of the time and place of meeting 
of the trustees, council or commissioners, which notice shall also 
contain a statement of the work done and the expense thereof with 
costs, and shall be given in the same manner as originally given to 
owners as hereinbefore provided. At said time and place such 
owner may appear with the same rights given by law before boards 
of review upon increase in assessments. 

Sec. 4. It shall be the duty of the board of trustees of each town- 
ship to consider the conditions of all lands and highways within the 
township and outside of incorporated towns and cities as to noxious 
weeds, and the town councils and commissions shall have the same 
duties with reference to lands within their respective towns or 
cities, and on complaint made to them or on their own motion, when- 
ever it may appear that any of such lands within their jurisdiction 
are infested with noxious weeds or other weeds, whether about to 
bloom and mature or not, they shall order their destruction before 
a date to be fixed in the said notice and prescribe the manner in 
which the destruction shall be accomplished, notice of which order 
shall be given as provided in section three (3) hereof, and if the 
said order shall not be complied with the board may proceed to 
cause the said order to be performed and shall certify the expense 
thereof and it shall be paid and assessed to the lands upon which 



798 WEED ST^ORA OF IOWA 

the same shall have been destroyed and to the owners or owner 
thereof and be collected in the same manner as is provided for the 
expense of proceeding under section three- (3) hereof. 

Sec. 5. It shall be the duty t>f all officers directly responsible for 
the care of public highways to make complaint to the proper town- 
ship trustees or town councils or commissions, as the case may be, 
whenever it shall appear that the provisions of section one (1) 
hereof may not be complied with in time to prevent the blooming 
and maturing of noxious weeds or the unlawful growth of weeds, 
whether in the streets or highways for which they are responsible 
or upon lands adjacent to the same. 

Sec. 6. All of the provisions of this section relating to the duty 
of the owner of the lands to prevent the blooming and maturing of 
noxious weeds thereon and to destroy such growths of other weeds 
thereon as may interfere' with the use of highways shall apply also 
to cities and tot^ns and the proper officers there as to all streets, 
highways and lands of any Mnd within their borders the fee of 
which shall rest in the public. ' 

Sec. 7. It shall be the duty of the township clerk between the 
first and fifteenth days of May of each year to post in two conspic- 
uous places, in each s6hool district of the township a notice calling 
attention to the weed law of the state of Iowa and giving a list of 
the noxious weeds contained therein and notifying the property 
owners to meet the requirements of the law. 

Sec. 8. It shall be the duty of the township clerk between the 
fifteenth and thirteenth days of October of each year to make a re- 
port to the board of supervisors of the county in which this town- 
ship is situated as to the presence and location of noxious weeds 
that have been reported or found within the township and the steps 
taken to bring about the destruction thereof, a copy of which report 
shall be forwarded to the board of supervisors to be kept on file 
and a copy of same to be forwarded by them to the secretary of the 
Iowa department of agriculture not later than the first day of De- 
cember following. 

Sec. 9. Any township trustee or road officer or other officer 
who neglects or fails to perform the duties incumbent upon him 
under the provisions of this act shall be guilty of a misdemeanor 
and shallbe punished by a fine not exceeding one hundred dollars 
($100.00). 

Sec. 10. Chapter ninety-six (96) of the acts of the Thirty-third' 
General Assembly is hereby repealed. 



WEED AND SEED LAWS 799 

Sec. 11. This act being deemed of immediate importance shall 
take effect and be in full force after its publication in the Register 
and Leader and the Des Moines Capital, newspapers published in 
Des Moines, Iowa.* 

Approved April 23, A. D. 1913, and became effective by publi- 
cation May 1, 1913. 

The law which was in force until repealed by the above act is as 
f oUows : 

Section 1. Land owners or tenants to destroy weeds — when. — 
It shall be the duty of every person, firm or corporation owning, 
occupying or controlling lands, town and city lots, land used as 
right of way, depot grounds or for other purposes to cut, bum or 
otherwise entirely destroy all weeds of the kinds mentioned in 
section two (2) hereof at such times in each year and in such 
manner as shall prevent the said weeds from blooming or coming 
to maturity. 

Section 2. Noxious weeds. — The following weeds are hereby 
declared to be noxious weeds, namely, quack grass {Agropyron 
repens), Canada thistle (Cirsium arvense), cocklebur {Xamrthium 
canadense), wild mustard {Brassica arvensis), sour or curled dock 
{Birniex crispus), smooth dock {Bumex altissinms) , buckhorn or 
ribbed plantain {Plarttago lamceolata) , and wild parsnip {Pastinaca 
sativa), horse nettle {Solanum oarolinense), and velvet weed or 
button weed {AbutUon theophrasti) and burdock {Arctium lappa). 

Section 3. Destruction on highways — neglect or refusal to de- 
stroy. — It shall be the duty of the township trustees or other 
officers responsible for the care of public highways in each town- 
ship or county in this state to destroy or cause to be destroyed all 
noxious weeds mentioned in section two (2) hereof or unnecessary 
brush on the highways in such a manner as to effectually prevent 
the production of their seeds or their propagation in any other 
manner, to warn out labor or to employ labor for this purpose in. 
the same manner as for repairs to the highways, and for neglect 
or failure to perform this work they shall be subjected to the 
penalties in this act. If any occupant of lands adjacent to the 
public highways neglect or refuse to destroy the noxious weeds 
upon his land, or shall fail to prevent the said noxious weeds from 
blooming or coming to maturity, when such weeds are likely to 
be the means of infesting the public highway, or upon complaint 
of ,any land owner to the township trustees that his lands have 
been or are likely to be infested by weeds from the lands of an- 



800 WEED FLORA OF 'IOWA 

other including railway right of way, the trustees shall make an 
investigation of such condition or complaint and if the same ap- 
pears to be well founded they shall make an order fixing the time 
within which the weeds shall be prevented from maturing seed, 
and an order that within one year such noxious weeds shall be 
permanently destroyed, and prescribing the manner of their de- 
struction and shall forthwith give notice to the occupant of the 
lands where the noxious weeds exist, and i£ he shall neglect to 
obey such order within the time so ordered the trustees may cause 
such noxious weeds to be prevented from maturing seeds or may 
cause such noxious weeds to be permanently destroyed and the 
cost of the work shall be recovered from the owner by a special 
tax to be certified by the township clerk in the same manner as 
other road tax not paid. 

Section 4. Boad funds may he expended. — The destruction of 
noxious weeds in the public highway and other public places is 
hereby made a part of the road work of the township trustees and 
the county supervisors and they shall have authority to expend 
road funds for the destruction of weeds. 

Section 5. Property tax. — The law as it appears in section 
fifteen hundred and twenty-eight (1528) of the supplement to the 
code, 1907, is hereby amended as follows, namely: By inserting 
after the comma in the eighth line thereof the following words: 
' ' and for the destruction of noxious weeds in public highways and 
other public places," and by striking out the word "four" in the 
tenth line of said section and inserting the word "six" in lieu 
thereof. 

Section 6. School of instruction. — Between November and the 
succeeding April of each year the county supervisors shall call a 
meeting of the township trustees and the road supervisors of the 
county to consider the best methods of road work and weed de- 
struction, and in the public interest may secure the services of 
experts to give instruction in road building and weed destruction. 
For such attendance the same compensation shall be allowed to 
the trustees and road supervisors and the county supervisors as 
is allowed by law for other services, to be paid as other expenses. 
The expenses of experts herein provided for may be paid from 
the county road fund. 

Section 7. Gutting of weeds on highways. — It shall be the duty 
of township trustees and other officers directly responsible for the 
care of public highways to cause to be cut near the surface all 



WEED' AND SEED LAWS 801 

weeds on the public highways in their respective districts at such 
times and in such mariner as to prevent seeds from maturing. 

Section 8. Penalty. — ^Any person, firm or corporation violating 
any of the provisions of this act, or any township trustees, in- 
spector or other officer who neglects or fails to perform the duties 
incumbent on him under the provisions of this act, shall be guilty 
of a misdemeanor and shall be punished by a fine not exceeding 
one hundred dollars ($100.00). 

Section 9. Repeal. — The law as it appears in sections fifteen 
hundred and sixty-two (1562) , fifteen hundred sixty-two-a (1562-a) 
and fifteen hundred sixty-three (1563) of the supplement to the 
code, 1907, and sections fifteen hundred and sixty-four (1564) and 
fifteen hundred and sixty-five (1565) and section five thousand 
and twenty-four (5024) of the code are hereby repealed. 

Approved April 21, A. D. 1909. 

Hon. C. E. Brenton and the writer framed a bill with the aid of 
Kobert Hunter, an attorney in Des Moines, which would meet all 
requirement. This provided for weed inspectors. The bill was in- 
troduced into the Senate by Mr. McCoU and in the house by Mr. 
Brady; however this bill failed to pass. As the subject is so im- 
portant and is likely to come up again at a future session of the 
Legislature, I insert the bill. 

A BILL 

FOE AN ACT TO AMEND CHAPTER NINETT-SIX (96) OF THE ACTS OF THE 
THIETT-THIRD (33) GENERAL ASSEMBLY, AND TO CREATE THE OFFICE 
OP COUNTY "WEED COMMISSIONER, AND TO PROVIDE FOR HIS APPOINT- 
MENT AND DUTIES. 

Be it Enacted hy tTie General Assembly of the State of Iowa: 

That Section One (1) of said chapter be amended by adding 
thereto the following: 

Section 1-a. The office of County "Weed Commissioner is hereby 
created. It shall be the duty of the County Board of Supervisors, 
at a regular or special meeting of the Board, not later than the 
first day of April in each year, to appoint a County "Weed Com- 
missioner whose term of office shall be from the first day of May 
after his appointment to the first day of November following. 

Section 1-b. The County "Weed Commissioner shall devote his 
entire time to the duties of his office, and shall receive as full com- 
pensation for his services a salary not exceeding seventy-five dol- 
51 



802 WEED FLORA OF IOWA 

lars ($75.00) per month and his actual and necessary traveling ex- 
penses incurred while performing his official duties, payable in like 
manner as the salaries of other county officers. 

Section 1-c. The Board shall furnish such weed commissioner 
an office at the county seat, and all stationery, blanks and supplies 
necessary in the performance of his official duties. 

That Section Two (2) of said chapter be amended by changing 
the period at the end of said section to a comma, and adding im- 
mediately thereafter the following: 

And shoo-fly (Hibiscus Trionum), and wild carrot (Daucus 
Carota) . 

That all of Section Three (3) of said chapter following the 
words "in this act," in the ninth line thereof, be stricken out and 
the following enacted in lieu thereof : 

Section 3-.a. It shall be the duty of the County Weed Commis- 
sioner during the first thirty (30) days of his term of office, to 
post in public places in each township of the county, at least fifteen 
(15) notices setting forth therein, in substance, the law of the 
State of Iowa in reference to noxious weeds and the destruction 
thereof; to inspect all lands, including highways and railway 
rights-of-way within the county, for noxious weeds, as defined in 
Section Two (2) hereof, and give to the owners or occupants of 
said land, and to the officers responsible for the care of the high- 
ways on which any such noxious weeds be found, information in 
reference to the presence of such weeds and the manner of destruc- 
tion thereof. 

Section 3-b. If any occupant or owner of land, or any owner 
or operator of a railway right-of-way, neglect or refuse to destroy 
the noxious weeds upon his land or right-of-way or shall fail to 
prevent the said noxious weeds from blooming or coming to ma- 
turity, when such weeds are likely to be the means of infesting the 
public highways, or the lands of adjoining owners, the County 
"Weed Commissioner shall cause such noxious weeds to be prevented 
from maturing seed, or shall cause such noxious weeds to be per- 
manently destroyed and the cost thereof, not exceeding (30) cents 
per hour for each man so employed, shall be recovered from the 
owner of the land, or owner or operator of such railway right-of- 
way by a special tax certified to the county auditor by the County 
Weed Commissioner to be paid by the owner or operator of the 
land or railway right-of-way as the case might be, and collected 
by the county treasurer the same as other taxes. 



"WEED AND SEED LAWS 803 

Section 3-c. ,. If any toTnisliip trustee or other officer, or officers, 
responsible for the care of the public highways in each township 
or county in this state, neglect or refuse to destroy any noxious 
weeds upon such highway, or shall fail to prevent the said noxious 
weeds from blooming or coming to maturity, when such weeds are 
likely to be the means of infesting the land adjoining such high- 
ways, the County "Weed Commissioner shall forthwith give written 
notice to such officer or officers, responsible for the care of such 
highways, to destroy such noxious weeds, and if such officer or 
officers shall neglect for ten (10) days after such notice to destroy 
such weeds, or to prevent the same from maturing seed, then such 
officer, or officers, shall be subject to the penalty provided in Sec- 
tion Eight (8) of this chapter. 

Section 3-d. The County "Weed Commissioner shall make a re- 
port of the work of his term to the Board of Supervisors, not later 
than the thirtieth (30th) day of October of the year for which he 
was appointed, such report to contain a statement in detail on the 
presence and location of Canada thistle, horse nettle and quack 
grass, and the board shall forward a copy of such statement to the 
Secretary of the Iowa Department of Agriculture not later than 
the first day of December following: 

Section 3-e. It shall be the duty of the Secretary of the Iowa 
Department of Agriculture to furnish to the Board of Supervisors 
of each county, the notices described in Section 3-a hereof, as well 
as all necessary blanks for reports to be made to said department, 
and to keep on file in his office all reports of such noxious weeds 
furnished him by County Boards of Supervisors, and include in 
his annual report a summary of the report furnished by such 
boards. 

This act being deemed of immediate importance shall take effect 
and be in force from and after its publication in the Eegister and 
Leader and the Dea Moines Capital, newspapers published in Des 
Moines, Iowa. 

ILLINOIS. 

In Illinois the criminal code statutes provide a penalty of not 
less than $10.00 nor more than $100.00 for bringing Canada thistle 
in packing material or in grain, grass or vegetable seed on any 
land in this state ; nor shall it be permitted to go to seed. The same 
law also applies to railroads. This includes other noxious weeds 
growing on the right-of-way of other land operated by railways, 
but the fine is placed at not less than $50.00 nor more than $200.00. 



804 WEED FLORA OF IOWA 

An Illinois statute provides for the appointment of a commis- 
sioner of Canada thistles by the board of town auditors in counties 
under township organization and by the county commissioner in 
counties not under township organization for each township or 
election precinct and by the city council of any city or by the 
president and trustees of any town or village as the case may be, 
the former to hold his term of office for three years. Compensation 
$2.00 per day. The commissioner shall diligently enquire concern- 
ing the introduction and existence of Canada thistles in his town- 
ship or precinct. He shall take care that they do not go to seed, 
or otherwise spread. The commissioner shall advise with the owner 
of the land concerning treatment. . The limit of money to be ex- 
pended by the commissioner shall not be more than $100 on any 
one infested tract. The commissioner shall make out a written re- 
port to the supervisor of the town or to the county commissioner. 
The report shall be read publicly at the annual town meeting, as 
to whether any thistles are growing; if growing, where; it shall 
contain a statement as to the treatment of the infested tract and 
shall make such other suggestions as may seem proper. He shall 
forward a copy to the secretary of the state Board of Agriculture. 

A land owner shall not deposit weeds or trash on the public 
road. The same chapter provides that the commissioners of high- 
ways in their respective towns shall enforce the law with reference 
to cocHebur, Canada thistle and Russian thistle. 

INDIANA. 

The Indiana law makes it a misdemeanor for any person or 
corporation, on property belonging to the person or corporation, 
to allow Canada thistles to grow until they become the length of 
6 inches from the surface of the ground to the tip of the stem. 
The law makes it a misdemeanor for persons having charge of high- 
ways to allow Canada thistle to grow to the length of 6 inches or 
to mature. It makes it the duty of the road supei^isor or of the 
president of the board of trustees, to notify the occupant of the 
land on which Canada thistle grows to cut said thistles below the 
surface of the ground within 5 days of notice. Penalty is attached 
for not complying with the notice. A penalty is also attached to 
non-performance of the duties of the supervisor, township trustee 
or mayor. 



WEED' AND SEED LAWS 805 

KANSAS. 

The state of Kansas has several statutes in regard to the destruc- 
tion of weeds : one on Canada thistle and Russian thistle ; another 
on Johnson grass. Chapter 17: 923, of the revised statutes, re- 
quires cities of the first class to enforce the cutting and destruc- 
tion of weeds on vacant lots, pieces of land, streets and alleys. 
A five days' written notice shall be given; if not removed the city 
may make a special assessment the same as for sidewalks. Chapter 
16 gives cities of the first class the power to pass an ordinance on 
the removal of rank grass and weeds. Chapter 41 makes it the 
duty of the owner of real estate to cut the weeds along said real 
estate before they go to seed. The Canada thistle and Russian 
thistle laws make it the duty of every corporation, owner of land, 
or the occupier of lands where these we^ds occur to remove the 
same at such times as the board and county commissioners may 
direct. When not removed, notice shall be published in one or 
more county papers not less than three weeks before the fixed time 
of destruction. The highway overseer of every township or county 
shall also cut or destroy all noxious weeds on the highway. The 
Johnson grass statute makes it unlawful to introduce into or sell 
or offer for sale within the state any seeds or roots of Johnson 
grass. It is made the duty of the county commissioner of each 
county within the state where Johnson grass occurs to prescribe 
the jurisdiction of each road overseer; each township to be in- 
eluded within the jurisdiction of some road-overseer. It is made 
the duty of the road overseer to prevent its spreading and if he 
receives written notice from any person in writing that the grass 
is seeding he shall investigate; if found to be the case he shall 
give 5 days' time in which to destroy it, if not destroyed he shall 
remove it and tax the costs against the land. If the owner of the 
land fails to notify tenant, on execution of lease, the owner shall 
be responsible for any damages. "Full tassel," as contained in 
law, shall mean seed. 

■ MINNESOTA. 

In regard to the suppression of noxious weeds in Minnesota the 
law is as follows: "Where the dean of the department of agri- 
culture of the university of Minnesota deems it necessary for the 
suppression of noxious weeds and for experimental purposes to 
sow timothy, clover, red top or other seeds on burned-over state 
lands, said department is hereby authorized*, to do so with seed 
purchased under this act." 



806 WEED FXiORA OP IOWA 

"Any county commissioner who knowingly allows or aids in 
allowing to any such applicant under this act any timothy, clover, 
red top or other seed, unless such applicant belongs to the class 
referred to, who is destitute of needed seeds, shall be guilty of a 
misdemeanor. ' ' 

MISSOURI. 

The revised statutes of Missouri make it the duty of the owner, 
lessee or other occupant of lands and every railroad company or 
corporation in the state to destroy Canada thistle and Scotch 
thistle, prevent the formation of seed, and prevent said thistles 
from spreading. A penalty of ten dollars is attached for every 
offence. Notice shall be given to the agent, overseer or other 
person having charge of the streets, roads or highways or places 
where such thistles occur. Cases of violation may be brought be- 
fore any justice of the peace of the county or city. Said fine when 
recovered shall be paid into the county school fund. Where such 
cutting is done on land by the overseer the cost is charged as a 
tax against the property and collected as other taxes. The law 
prohibits the throwing away of material with Canada thistle and 
Scotch thistle seed and provides for the burning of straw or grass 
packing containing thistle. 

NEBRASKA. 

In the state of Nebraska, there are two statutes concerning the 
destruction of weeds, one pertaining to the destroying of weeds 
in public roads, the main provisions in the law being as follows: 
It is the duty of land owners in the state to mow or otherwise 
destroy all weeds to the middle of all public roads running along 
their lands, at least once each year, namely, between the fifteenth 
day of July and the fifteenth of August. The overseer of roads 
has authority to cut the weeds when complaint is made; expenses 
connected therewith shall be sent to the county clerk who shall 
make an assessment against the land. The usual penalty is also 
provided. 

In a second statute there is provision for the city of Omaha for 
the destruction of weeds and worthless vegetation upon vacant 
lots or land in the city of Omaha. 

NORTH DAKOTA. 
The state of North Dakota has a law which seeks to prevent the 
spread of noxious weeds by threshing machines. This act provides 
that any owner, or teamster employed in hauling grain, either 



WEED' AND SEED LAWS 807 

threshed or unthreshed, shall Tipon completing any threshing en- 
gagement and before leaving the premises on which said work was 
done take all reasonable care to prevent the conveying and carry- 
ing away and scattering of noxious weeds which may have ac- 
cumulated in or on the machines. The law provides how this shall 
be done by operating the machine and sweeping. A printed copy 
of the law shall be kept posted on every machine operating in the 
state. A fine, or imprisonment, or both, is provided for violation 
of the law. I am told the law is not enforced. 

OHIO. 

The state of Ohio has several laws relative to the destruction of 
weeds, briers and brush. With reference to the destruction of 
these on toll, steam, and electric roads the law provides for the 
destruction of brush, briers, burs, Russian, Canada, or common 
thistle, wild lettuce, wild mustard, wild parsnip, ragweed, milk- 
weed, ironweed, and all other noxious weeds growing within the 
limits of any right of way whether in actual operation or not. If 
said weeds are not destroyed between the first and twentieth of 
June and between the first and twentieth of August and if neces- 
sary between the first and twentieth of September of each year, 
the trustees of the township through which such road passes shall 
cause it to be done and shall have right of action against such 
toll, steam, or electric road and one hundred per cent penalty; 
costs of action to be recovered before any justice of the peace of 
such county. The weed law as applied to the destruction of weeds 
on graveled or improved roads, turnpikes, county township roads, 
streets, etc., is essentially the same, putting the enforcement in the 
hands of pike superintendents and turnpike directors. The amount 
of money which can be collected is fixed at one dollar and a half 
per day to destroy these weeds. A street commissioner shall be 
paid for such services by the proper municipal authorities. The 
land owner or tenant is allowed to cut the noxious weeds along 
the highway abutting the property. The superintendent shall fix 
a reasonable compensation for the work. 

Another section provides that upon written information that 
Canada thistle, Russian thistle, wild lettuce or wild mustard is 
growing on land in a township and is about to spread or mature 
seeds between the first day of June and the fifteenth day of Oc- 
tober, the trustees of the township shall serve written notice upon 
the owner, lessee, agent or tenant that such weeds occur and that 



808 WEED FLORA OF IOWA 

they must be destroyed within five days after the service of such 
notice. These laws are not enforced in Ohio. 

SOUTH DAKOTA. 

The South Dakota law specifies that every person or corporation 
shall destroy, on all land which he or it may occupy, all weeds of 
the following kinds: Russian thistle, Canada thistle and cockle- 
bur. The enforcement of the law is in the hands of the board of 
supervisors. If the weeds are not destroyed a notice for three 
weeks shall be published in the papers. After such notice the 
weeds shall be destroyed. Owners must also destroy weeds on 
highways abutting their property. These weed laws are not en- 
forced. 

WISCONSIN. 

The state of Wisconsin has a law requiring that every person 
or corporation shall destroy, on land which he or it shall own, 
occupy, or control, all weeds known as Canada thistle (Cirsium 
arvense), ox-eye daisy {Chrysanthemum leuccmth&mwm) snap 
dragon {Linaria vulgaris), sow thistle (Sonchus arvensis), sour 
dock and yellow dock {Bumex crispus), mustard {Brassica <w- 
vensis), wild parsnip (Thaspium harhmode), burdock {Lappa 
offlcinaiis), Russian thistle {Salsola kali) and wild barley {Hor- 
deum jubatwm), at such times and in such manner as shall ef- 
fectually prevent them from bearing seed. The above weeds shall 
be destroyed to the middle of the highways by the commissioner of 
noxious weeds. The corporation or party shall be given notice 
and if weeds are not removed within 6 days a $5.00 fine is im- 
posed every day thereafter during which such neglect shall con- 
tinue. The weeds shall be specified ; also on what land they occur. 
The commissioner or commissioners of weeds shall be appointed 
by the chairman of each town board, the president of each village, 
or the mayor of each city. The commissioner of weeds shall hold 
the office for one year. He shall give notice if the weeds are not 
removed. Then the commissioner shall remove the same. The 
city of Milwaukee is exempt from these provisions. 

SEED LEGISLATION. 

Numerous states of the Union and various European countries 
as well as Canada and other British countries have legislated on 
the subject of seeds and seed adulteration. Two classes of laws 
are in vogue in the United States. One requires a guaranty of 



WEED' AND SEED LAWS 809 

the seed sold and may be called the Maine idea. The other gives 
standards of purity and vitality and is the Iowa idea. This law 
has been passed in many states, among them, "Wisconsin, "Wash- 
ington and Wyoming. The Iowa law is as follows : 

Section 1. Every lot in bulk, bag, pail, parcel or package of 
concentrated commercial feeding stuffs as defined in section three 
(3) of this act; and every parcel, package or lot of agricultural 
seeds as defined in section nine (9) of this act, and containing one 
potmd or more, offered or exposed for sale in the state of Iowa, 
for use within this state, shall have afSxed thereto, in a conspicuous 
place on the outside thereof, distinctly printed in the English 
language, in legible type not smaller than eight point heavy 
gothic caps, or plainly written, a statement certifying: 

In the case of agricultural seeds: 

First. The name of the seed. 

Second. Full name and address of the seedsman, importer, 
dealer or agent. 

Third. A statement of the purity of the seed contained, specify- 
ing the kind and percentage of the impurities as defined in sec- 
tions eleven (11) and twelve (12) hereof, provided that said seeds 
are below the standards fixed in this act. 

Fourth. Locality where said seed was grown, when known. 

Section 6. The state food and dairy commissioner shall cause 
to be made analyses of all agricultural seeds sold or offered for 
sale in this state. Said state food and dairy commissioner is here- 
by authorized, in person or by deputy, to take for analysis a sam- 
ple from any lot or package of agricultural seeds not exceeding 
four ounces ia weight ; but said sample shall be drawn or taken in 
the presence of the party or parties in interest, or their repre- 
sentative, and shall be taken from a parcel, lot or number of par- 
cels which shall not be less than five per cent of the whole, lot in- 
spected and shall be thoroughly mixed and divided into two sam- 
ples and placed in glass or metal vessels carefully sealed and a 
label placed on each, stating the name or brand of the agricultural 
seeds or material sampled, the name of the party from whose 
stock the sample is drawn, and the date and pla.ce of taking such 
sample, and said label shall be signed by the state food and dairy 
commissioner, or his authorized agent; or ^aid sample may be 
taken in the presence of two disinterested, witnesses; one of said 
duplicate samples shall be left on the premises of the, party whose, 
stock was sampled and the other retaiaed by the. state food an.d. 



810 WEED FLORA OF IOWA 

dairy commissioner, for analysis and comparison with the certified 
statements required by sections one (1) and four (4) of this act. 
The result of the analysis of the sample, together with additional 
information shall be published from time to time in bulletins issued 
by the state food and dairy commissioner upon approval of the 
executive council. 

Section 7. Any person purchasing any agricultural seeds in 
this state for his own use, may submit fair samples of said seeds 
to the state food and dairy commissioner, who, upon receipt of an 
analysis fee of fifty cents (50c) for each sample of agricultural 
seeds shall cause an analysis of the same to be made. 

Section 8. No person shall sell in ground form, wheat or rye 
screenings containing cockle or other poisonous or deleterious sub- 
stances. 

Section 9. The term, agricultural seeds, as used in this act, 
shall include the seeds of the red clover, white clover, alsike clo- 
ver, alfalfa, Kentucky blue grass, timothy, brome grass, orchard 
grass, red top, meadow fescue, oat grass, rye grass and other 
grasses and forage plants, flax, rape and other cereals. 

Section 10. No person shall sell, offer, or expose for sale, or 
distribution in this state, for the purpose of seeding, any of the 
agricultural seeds as defined in section nine (9) of this act, unless 
the said seeds are free from the seeds of the following weeds: 
Wild mustard, or charlock {Brassiccs sinapistrum) , quack grass 
{Agropyron repens), Canada thistle {Cmicus arvensis), wild oats 
(Avena fatua), clover and alfalfa dodder (Guscuta epithymum) , 
field dodder {Cuscuta arvensis), and corn cockle (Lychnis githago). 

Section 11. The seeds of the following weeds shall be consid- 
ered as impurities in the agricultural seeds as defined in section 
nine (9) of this act, sold, offered, or exposed for sale, within the 
state for the purpose of seeding: White cockle {Lychnis vesper- 
iina), night-flowering catchfly {Siiene noctiflom), curled dock, 
{Uumex crispnis), smooth dock {Buniex altissimus), sheep sorrel 
{Rumex acetosella) , yellow trefoil (Medicago lupulina), burr clover 
(Medicago denticxdata) , sweet clover (Melilotus alba and officinalis), 
black mustard {Brassica nigra), plantain, buckhorn {Plantago 
lanceolata). bracted plant^n {Plantago aristata), bindweed {Gon- 
volvnlus sepitim) , smooth crab grass {Panicum glabrum) , common 
cMckweed {Stellaria media). When such impurities or any of 
them are present in quantity exceeding la total of two per cent of 
the weight of said agricultural seeds, the approximate percentage of 



WEED' AND SEED LAWS 811 

each shall be plainly indicated in statement specified in section 
one (1) of this act. 

Section 12. Sand, dirt, chaff and foreign substances and seeds 
other than those specified in sections thirteen (13) and fourteen 
(14), or broken seed and seed not capable of germinating, sha,ll be 
considered impurities when present in agricultural seeds sold, of- 
fered, or exposed for sale, in this state, for the purpose of seeding, 
and when such impurities, or any of tbem, are present in quantity 
exceeding the standards of purity and viability authorized in sec- 
tion sixteen (16) of this act, the name and approximate percentage 
of each shall be plainly indicated in the statement specified in 
section one (1) of this act. 

Section 13. For the purposes of this act, seeds shall be deemed 
to be mixed or adulterated: 

First. When orchard grass {Dactylis glomerata) seed contains 
10 per cent or more by weight of meadow fescue {Festuca elatior 
pratensis) seed, or Italian rye grass {Lolvwm italicwm) seed, or 
Englisli rye grass {LoUum perenne) seed. 

Second. When blue grass or Kentucky blue grass {Poa pra- 
tensis) seed contains 5 per cent or more by weight of Caaadian 
blue grass {Poa compressa) seed, red top chaff, red top {AgrosHs 
alia) seed, or any other seed or foreign substance. 

Third. When red clover {TrifoUum pratense), mammoth red 
clover {TrifoUum pratense var.), or alfalfa {Medicago sativa), 
contains 5 per cent or more by weight of yellow trefoil {Medicago 
lupulina), or sweet clover {Melilottis alba and M. offlcmalis) seed 
or bur clover {Medicago dentioulata) seed. 

Fourth. When rape {Brassica rapa) contains 5 per cent or 
more of common mustard {Brassica sinapistrum) or black mustard 
(jB. nigra). 

Section 14. For the purposes of this act, seed shall be deemed 
to be misbranded: 

First. When meadow fescue {Festuca elatior pratensis), Erig- 
lish rye grass {Lolium pererme) or Italian rye grass {Lolium 
italicum) is labeled or sold under name of orchard grass {Dactylis 
glomerata) seed. 

Second. When Canadian blue grass {Poa compressa) seed, red 
top {Agrostis alia) seed, or any other seed not blue grass seed, is 
sold under the name of Kentucky blue grass or blue grass {Poa 
proitensis) seed. 

Third. When yellow trefoil {Medicago lupulina), bur clover 
{Medicago denticulata) or sweet clover {Melilotus alba) is sold 



812 



WEED FLORA OF IOWA 



under the name of clover, June clover, red clover, (TrifoUum 
pratense), mammoth red clover, medium red clover, small red 
clover, sapling clover, peavine clover (T. pratense var.). or alfalfa 
{Medicago sativm) seed. 

Section 15. The provisions concerning agricultural seeds con- 
tained in this act shall not apply to: 

First. Any person or persons growing or selling seeds for food 
purposes only, or having such seeds in possession for sale for such 
purposes. 

Second. Any person or persons growing or selling seeds direct 
to merchants to be cleaned or graded before being offered for sale 
for the purpose of seeding. This shall not, however, exempt the 
seller from the restrictions of section ten (10) of this act. 

Third. Seed that is held in storage for the purpose of being re- 
cleaned, and which has not been offered, exposed or held in pos- 
session of or for sale for the purpose of seeding. 

Fourth. Seed marked "not absolutely clean," and held or sold 
for export outside the state only. 

Fifth. The sale of seed that is grown, sold and delivered by 
any farmer on his own premises for seeding by the purchaser him- 
self, unless the purchaser of said seeds obtains from the seller at 
the time of the sale thereof a certificate that the said seed is sup- 
plied to the purchaser subject to the provisions of this act. 

Sixth. Mixtures of seeds for lawn or pasture purposes. This 
shall not, however, exempt the seller of such mixtures of seeds 
from the restrictions of sections ten (10) and eleven (11) of this 
act. 

Section 16. The following standards of purity (meaning free- 
dom from weed seeds or other seeds) and viability are hereby 
fixed: 

STANDARD OF PURITY AND VIABILITY OF AGRICULTURAL SEEDS. 



Name of Seed 




Per cent oi 

germinable 

seeds 



Alfalfa (Medicago sativa) 

Barley 

Blue grass, Canadian (Poa compressa) . 
Blue grass, Kentucky {Poa pratensis) . . . 

Brome, awnless (Bromus inermis) 

Clover, alsike (TrifoUum hyhridum) . . . 

Buckwheat 

Clover, crimson {TrifoUum incarnatum) 
Clover, red (TrifoUum pratense) 



SO 
90 
45 
45 
75 
75 
90 
85 
80 



WEED' AND SEED LAWS 



813 



STANDARD OF PURITY AND VIABILITY OF AGRICULTURAL 

SEEDS CbNTINUBD. 



Kame of Seed 




Per cent of 

germinable 

seeds 



Clover, white (Trifolium repens) 

Corn, field (Zea mays) 

Corn, sweet 

Fescue, meadow {Festuca prattensis) 

Flax (Linum usitatissimum) 

Millet, common {8etaria italica) 

Millet, hog (Panicum miliaceuw,) 

Millet, pearl (.Pennisetum, typhoideum) 

Oats (Avena sativa) 

Oat grass, tall (Arrhenattierum avenaceum) 

Orchard grass {Daotylis glomerata) 

Rape (Brassica rapa) 

Red top {Agrostis alba) 

Rye (Secale cereale) 

Rye grass, perennial (Lolium perenne) 

Rye grass, Italian {LoUum italicum) 

Sorghum (Andropogon sorghum) 

Sorghum, for fodder 

Timothy {Phleum pratense) 

Wheat ( Tritioum,) 



75 
94 
75 
85 
89 
85 
85 
65 
90 
70 
70 
90 
70 
90 
90 
80 
80 
60 
85, 
90 



Section 17. It is hereby made the duty of the state food and 
dairy commissioner to enforce the provisions of this act. The in- 
spectors, assistants and chemists appointed by the state food and 
dairy commissioner shall perform the same duties and have the 
same authority under this act as are prescribed by chapter one 
hundred and sixty-six (166), laws of the thirty-first general as- 
sembly, and the said state food and dairy commissioner may ap- 
point, with the approval of the executive council, such analysts and 
chemists as may be necessary to carry out the provisions of this 
act. 

Section 18. Whoever sells, offers or exposes for sale any of the 
seeds specified in sections thirteen (13) and fourteen (14) of this 
act which are mixed, adulterated or misbranded, or any agricul- 
tural seeds which do not comply with sections ten (10), eleven (11) 
and twelve (12) of this act, or who shall counterfeit or use a 
counterfeit of any of the tags prescribed by this act ; or who shall 
prevent or attempt to prevent any inspector in the discharge of 
his duty from collecting samples or who shall violate any of the 
provisions of this act shall be guilty of a misdemeanor, and upon 
conviction, shall be fined not more than one hundred dollars ($100) 
and costs of prosecution; provided, that no one shall be convicted 



814' WEED FLORA OF IOWA 

for violation of the provisions of section ten (10) of this act if 
he is able to show that the weed seeds named in section ten (10) 
are present in quantities not more than one in ten thousand, and 
that due diligence has been used to find and remove said seeds. 

Section 19. There is hereby appropriated, for the purpose of 
enforcing the provisions of this act, a sum not exceeding three 
thousand dollars ($3,000) annually. Such expense shall be paid 
by warrant of the state auditor upon bills filed by the state food 
and dairy commissioner with the executive council and approved 
by them. All fees collected under the provisions of this act shall 
be paid into the state treasury. 

The Michigan law permits the sale of cereal grasses, clover, and 
forage plants containing two per cent of quack grass, charlock, 
black mustard, Canada thistles, chicory, toad flax, buckhom, 
Rugel's plantain, night-flowering catchfly, and pennycress. The 
adulteration shall not be more than five per cent of any other 
distinguishable seed, sand, crushed rock or any other materials to 
be found mixed with agricultural seed. "When found to be wilfully 
adulterated or not as clean as it is commercially practicable to 
make it, the results should be published in a bulletin together with 
names of the persons selling the same. 

The Canadian act requires that no person shall sell or offer for 
sale, seed, cereals, grasses, clovers or forage plants unless they 
are free from any seeds of wild mustard, hare's-ear mustard, bull 
mustard, field pennycress, wild oats, bindweed, perennial sow 
thistle, ragweed, greater ragweed, purple cockle, cow cockle, orange 
hawkweed, and ergot. This law has done much to stimulate the 
sale of good seed. 

The enforcement of the Wisconsin law is placed in the hands of 
the Agricultural Experiment Station. 

The Maine law requiring a guaranty of seed sold in that state 
is working out well and has greatly improved the quality of seed 
sold in that state. 

The North Dakota law has the following forbidden weed seeds: 
couch or quack grass, Canada thistle, sow thistle, and dodder. 
Also the sale of agricultural or garden seeds containing more than 
a reasonable trace of the seeds of greater ragweed, cornfiower, 
marsh elder, Russian pigweed, dandelion, chicory, Russian thistle, 
plantain, buck plantain, bracted plantain, white cockle, cow cockle, 
curled dock, sorrel, sheep-sorrel, purslane, bindweed, wild buck- 
wheat, wild onion, wild oats, pigeon grass, holy grass, chess, mus- 



WEED' AND SEED LAWS 815 

tard, tumbling mustard, hare's-ear mustard, pennycress, pepper- 
grass, shepherd's purse, false-flax, bird's-foot, trefoil, yellow tre- 
foil, bur clover, sweet clover, ergot, or of the seeds of any other 
noxious weed is unlawful. The inspection of the law is in the 
hands of the botanists of the North Dakota Agricultural College. 
The law has greatly improved the quality of seeds sold in that 
state. The forbidden list of weed seeds is large and probably 
difficult to enforce. 

The only way to enforce any seed law is to have fields in which 
commercial seed is grown inspected by some competent botanist. 
The seed should not be sold unless the weed seeds can be removed. 



CHAPTER XIII. 

HISTORY AND BIBLIOGRAPHY 

L. H. PAMMEL HARR ETT . KELLOGG 

and 

CHARLOTTE M. KING 



52 



CHAPTER XIII. 



HISTORY AND BIBLIOGRAPHY. 

Perhaps the best known of the modem German treatises on the 
subject of weeds is that of Thaer of the University of Giessen on 
the Agricultural Weeds, in which some 27 species are described 
with colored figures, methods of extermination being given. Many 
of the weeds here described, as the sheep sorrel, corn cockle, 
Canada thistle, quack grass, and horse-tail, are common to North 
America. This work passed through several editions ; the first ap- 
pearing in 1881 and the last in 1905. 

L. Danger in 1887 published a treatise of 166 pages on the sub- 
ject of "Weed and Plant Parasites. This work discussed the more 
important weeds of Germany, frequently giving methods of ex- 
termination, and numerous notes on the origin of weeds, including 
also, under the head of Geographical Botany, a list of weeds found 
in different soils. The following soils are characterized: (1) Gra- 
velly soils containing 80 per cent of gravel; under this head he 
names such weeds as the horse weed {Erigeron ccmadends) and 
spurge {Euphorbia pephis). On the whole, however, the list is a 
short one. (2) Sandy soils, in which there is 80 per cent of sand 
of smaller diameter than in gravel soils. The weeds found here 
are awned brome grass {Bromus tectorum), sheep sorrel {Bumex 
acetosella), common evening primrose ( Oenothera biennis), com 
cockle (Agrostemma githago)^ horse weed (Erigeron canadensis), 
and spurge (Euphorbia cyparissias) . (3) Loamy soils with some 
sand, lacking lime. Some of the weeds found here are sow thistle 
(Sonchus arwnsis), Canada thistle (Girsium arvense), shepherd's 
purse (Capsella bursa-pastoris) , dandelion, (Taraxacum officinale), 
wild carrot (Daucus caroia) and chess (Bromus secaliMus). (4) 
Clay soils. This class contains only one of our common weeds, 
namely horse-tail (Equisetum arvense). (5) Marl soils, contain- 
ing from 5 to 50 per cent of carbonate of lime. The only weed 
given in this list that we have in Iowa is prickly lettuce (Lactuca 
scariala). (6) Limy soils, containing more than 50 per cent of 
calcium carbonate, are represented by some Cruciferae, and 
Legummosae. (7) Humus soils, the organic matter consisting of 



820 WEED FLORA OF IOWA 

about 50 per cent of humus; the humus mentioned must be in the 
nature of peat, as the list of plants mentioned all belong to the 
peat flora. (8) Alkali soils. The plants mentioned here are 
hardly characteristic in this state, only a few of the species being 
reported in old lake beds in northern Iowa. Some of the weeds 
mentioned by him are Triglochin maritima and Juncus balticus. 
This author also gives more or less extended accounts of the 
methods of extermination of these weeds in Germany. 

Sorauer and Frank discuss the weeds of Germany. Stebler and 
Schroeter discuss, in an extended way, in a work appearing in 
1891, the weeds of Switzerland, giving many colored illustrations 
and good descriptions. Numerous other papers also have ap- 
peared in German technical agricultural journals and in the 
transactions of societies. 

"William Darlington of West- Chester, Pennsylvania, was a 
pioneer along the line of writing a special treatise on the subject 
of weeds; for in 1847 he wrote a work on agricultural botany, an 
enumeration and description of "useful plants and weeds, which 
merit the notice or require the attention of American agricul- 
turalists." He says in the preface: 

The study of Botany, in its widest sense — comprising, as it does, 
the entire vegetable creation, — ^will ever have its select votaries in 
those who can appreciate its manifold charms, and find their re- 
ward in the pleasures incident to the pursuit; but when regarded 
in a more limited and practical point of view, it may fairly chal- 
lenge the attention even of the most inveterate Utilitarians 

In my humble opinion, no education can be deemed sufficient 
without some acquaintance with the rudiments, or first principles, 
of Botanical Science — some rational knowledge of the vast and 
multiform creation around us, known as the Vegetable Kingdom. 

If our American youths who are being educated with a 

view to Agricultural pursuits, were thoroughly instructed in the 
admirable Textbook, above referred to, (Botanical Textbook by 
Prof. A. Gray),^ — and were then required to make themselves 
botanically acquainted with that portion of the vegetable king- 
dom which annually demands their attention, on the farm, — ^the 
Profession would speedily assume a new and engaging aspect. 
The labors of the field would be blended with the contemplation of 
facts and phenomena of the deepest interest to inquiring minds, — 
and Agriculture — instead of being shunned, as an irksome drudg- 
ery — would be justly esteemed as one of the noblest employments 
of a free and intellectual people. 

In the revised second edition a weed is defined as follows: 
In popular language, any homely plant which is not noticeable 
for the beauty of its flowers, not entitled to respect by a reputa- 



HISTORY AND BIBLIOGRAPHY 821 

tion for medicinal or other useful qualities, is designated by the 
epithet weed. In an agricultural sense, the term is used with a 
more restricted meaning, and is applied to those intrusive and un- 
welcome individuals that will persist in growing where they are 
not wanted, — in short, the best definition that has yet been given 
of a weed is the old one, "a plant out of place." Most of the 
weeds troublesome in our agriculture are immigrants, either from 
the Old "World, or from the warmer portions of this continent. 
The number of plants indigenous to our country, that are entitled 
to rank as pernicious weeds, is comparatively small. As the 
aborigines disappear with the advance of the whites, so do the 
native plants generally yield their possession as cultivation ex- 
tends, and the majority of the plants to be met with along the 
lanes and streets of villages, and upon farms, are naturalized 
strangers, who appear to be quite at home, and are with difficulty 
to be persuaded or driven away. 

"Weeds are introduced upon a farm in a variety of ways. Many 
have their seeds sown with those of the crops; this is particularly 
the case where the seeds of the weeds and of the grain are so 
nearly alike in size that their separation is difficult. Proper care 
in procuring and preserving clean seed will often save much 
future trouble and vexation. The observing farmer will notice 
the means wMch nature has provided for the scattering of seeds, 
and he will find that the most pernicious weeds seem to have been 
especially furnished with contrivances to facilitate their dispersion. 
The Clot-bur, Beggar's Lice, and others, have barbs or hooks by 
which they adhere to clothing and the coats of animals, and are 
widely distributed by this agency. All of the thistles, and many 
others of the same family, have a tuft of fine silky hair attached 
to the seed, or more properly fruit, by which they are buoyed upon 
the air, and wafted from place to place. So numerous are the 
ways by which seeds are dispersed, that, however careful a farmer 
may be upon his own premises, a slovenly and neglectful neighbor 
may cause him infinite annoyance by furnishing his lands with 
an abundant supply. In some European countries a farmer may 
sue his neighbor for neglecting to destroy the weeds upon his 
lands, or may employ people to do it at the delinquent's expense. 

The vitality of seeds, particularly if buried in the earth below, 
the reach of the influences which cause germination, in some cases, 
endures through many years ; hence, an old field, after deep plow- 
ing, has often a fine crop of weeds from the seeds thus brought 
to the surface. Weeds that have been cut or pulled after they 
have flowered, should not be thrown into the barnyard or hog- 
stye, unless the farmer wishes to have the work to do over again 
with their progeny, as the seeds will be thoroughly distributed in 
the manuring of the land. In England they dry the pernicious 
weeds and burn them, not only destroying root and branch, but 
seed also. 



822 WEED FLORA OF IOWA 

He introduces the subject by giving an account of the structure 
of plants. Throughout this admirable treatise, under the head of 
observations, Dr. Darlington gives an account of the troublesome 
weeds. The book describes such weeds as Indian mallow, bladder 
ketmia, common mallow, quack grass, horse nettle, boot jack, 
cocklebur, ragweed, dead nettle, smartweeds and European morn- 
ing-glory. Strangely enough, however, the common morning- 
glory is not mentioned, nor is the field dodder or the clover dodder. 
This work passed through another edition revised by Dr. George 
Thurber, a botanist of some note who was editor for a time of the 
American Agriculturist and died in 1863. The second edition 
of the book, under the title of American Weeds and Useful Plants, 
appeared in 1859. This work filled a splendid place in American 
agricultural literature and did much to stimulate a study of the 
weeds which are injurious to agriculture. 

Mr. Thomas Shaw in 1893 published a small book in which he 
discussed the prevalence of weeds, the evils which arise from the 
presence of weeds, the possibility of destroying weeds, the agencies 
concerned in the distribution and propagation of noxious weeds, 
methods and principles generally applicable in the destruction of 
weeds and finally specific modes of eradicating certain trouble- 
some weeds, which should generally be adopted to keep a field free 
from weeds. He makes many excellent suggestions, among which 
are the following: 

(1) The persistent and careful study of the habits of growth 
of all the various sorts of weeds virith which one's farm is infested, 
so as to be able to deal with them in the most rational way possible. 

(2) The modification (when necessary) of the scheme of rota- 
tion that has been adopted, so that such crops as allow the seeds 
of the weeds which infest them to ripen, may for a time, be omitted 
from the rotation. 

(3) When certain methods of eradication have been fixed upon, 
the careful and wise adaptation of these methods to such condi- 
tions of soil and climate as are found in the locality concerned. 

(4) The exercise of due care when seeds are purchased, to see 
that they are perfectly pure, that is, perfectly free from the seeds 
of weeds; and also the exercise of due care with respect to such 
seeds as are grown at home to see that they, too, are perfectly free 
from weed seeds. 

(5) and (6) * * * 

(7) The growing of hoed crops upon the farm infested, to the 
largest extent that is practicable. 



HISTORY AND BIBLIOGRAPHY 823 

(8) The growing of clover and lucerne, so far as this can be 
done with profit. 

(9) The growing of soiling crops, to the extent that may be 
found practicable, both because of the fact that they can be cut 
almost at any time that is desirable, and also because of their 
' ' smothering ' ' properties. 

(10) The utilizing of sheep for the destruction of weeds in 
pastures. 

(11) The growing, as far as possible, at home, of the food re- 
quired by the live stock of the farm, instead of purchasing it else- 
where. 

(12) The keeping of the land of the farm constantly at work, 
so far as this possibly can be effected. 

(13) The stimulation of the soil to a constantly vigorous 
production by means of thorough working and a large use of 
manure. 

(14) The practice of autumn cultivation to the largest extent 
that is possible. 

(15) The exercise of the utmost possible precaution that no 
weed seeds ripen upon the farm, if by any means whatever their 
ripening can be prevented. 

(16) The giving of due heed to all the agencies by which weeds 
are distributed and propagated, so as always to be able to counter- 
act or defeat those agencies. 

(17) When once the work of eradication has been undertaken, 
the making of it as thorough as possible, and the accomplishment 
of it in the shortest possible time. 

(18) When once a state of cleanliness has been secured, the 
maintenance of it thereafter as perfectly as possible under all 
circumstances. 

In 1911 Orange Judd & Co. published a book on Weeds of the 
Farm and Garden, which was written by L. H. Pammel. This 
book contains, in addition to a number of half tone plates, figures 
of a great many weeds of North America, discusses their geographi- 
cal distribution and the best methods of extermination, and the 
most important noxious weeds with their distribution. The table 
of contents of the book is as follows : 

1. Weeds. Injury to Crops and Nature of. 2. Kinds of Weeds 
as to Duration. 3. Dispersal of Weed Seeds. 4. The Parmer's 
Interest in Good Seed, and How to Test Seed. 5. Weed Impurities 
in Agricultural Seeds. 6. Some Weed Laws and Seed-Control 



824 WEED FLORA OF IOWA 

Laws. 7. Weeds of Special Crops. 8. Poisonous Weeds. 9. Table 
of Noxious Weeds. 10. Migration of Weeds. 11. Extermination 
of Weeds. 12. Treatment for Special Weeds. 13. Morphology of 
Weeds. 14. Descriptions of Some Common Weeds. 15. Partial 
Bibliography, Consisting of Easily Accessible References, Ar- 
ranged by Harriette S. Kellogg. This lists the important papers 
on the subject. 

A little treatise, "A Talk on Weeds," an address given before 
the County Road School, Clinton County, 1910, gives an account 
of a few of the important weeds and notes for the teacher. A 
somewhat similar paper especially adapted for schools was pub- 
lished by Miss Caroline Forgrave of Dallas county. This little 
paper gives suggestions of what school children may do to study 
weeds. Both of these were written by Mr. Pammel. 

Bulletin 70 of the Iowa Agricultural Experiment Station, by 
the same writer, discusses a few of the more important Iowa weeds 
with an account of the dissemination of seeds and the pollination of 
a few plants; subsequently Mr. Pammel and Miss King putjlished 
an extensive bulletin on the treatment of weeds, especially with 
iron sulphate. 

Prof. H. L. BoUey also published an extensive treatise on "Weeds 
of North Dakota," particularly with reference to the treatment 
with iron sulphate. 

Attention may also be called to a little semi-occasional publica- 
tion by the American Steel and Wire Company on "Weeds," par- 
ticularly on treatment with iron sulphate. This little journal is 
well illustrated. Many of the nature study works like those of 
Hodge, Stevens, Birkett and Hall, GofE and Mayne, such as 
"Weeds," "Farm Friends and Farm Foes," as well as the Agri- 
cultural botany of John Percival, give short accounts of weeds. 

W. S. Blatchley, in the "Indiana Weed Book," 1912, describes 
one hundred and fifty common weedy plants ; including an account 
of their nature and habits, as well as suggestions for eradication. 
Of the weeds considered, it is interesting to note that seventy- 
seven are natives of Indiana, while seventy-three are introduced 
species. 

Of the more important treatises on weeds the recent bulletin by 
J. W. Beal, who was formerly botanist of the Michigan Agricul- 
tural College should be mentioned. This book of 167 pages de- 
scribes and figures the important weeds of Michigan. This is a 
most helpful treatise, and with the excellent figures one will be 



HISTORY AND BIBLIOGRAPHY 825 

able to recognize any of the common weeds of that state. Another 
special bulletin is the Ohio weed manual by Prof. Selby. This 
excellent manual describes and gives the distribution of Ohio 
weeds as well as hints on extermination of the common weeds of 
that state. The discussions on- weeds by Crozier, Dewey and other 
botanists of the United States Department of Agriculture, are 
most helpful as regards the more common weeds of eastern North 
America. 

The most recent extensive account of weeds in Canada is a 
book by Clark and Fletcher. This work describes many families 
of weeds, one or more species of each genus being illustrated with 
colored figures. In addition many weed seeds are described. Some 
of the headings are as follows : Losses Due to "Weeds, How Weeds 
Spread, Weed Seeds in the Soil, Commercial Seeds and Feeding 
Stuffs. This book will enable one to recognize the more or les.= 
common weeds found in Canada. It has passed through two edi- 
tions, the first having been published in 1906 and the second in 
1909. 

The most recent English publication is a book by H. C. Long 
and John Percival, "Common Weeds of the Farm and Garden." 
This book of 451 pages contains many half tone illustrations and 
figures of weeds that are common to the British Isles, treated under 
the following heads: Weeds of Rivers and Ditches also Drives, 
Worst Weeds, Weeds and the Improvement of Grass Land, Weeds 
of the Arable Land, What Weeds Are and How They Affect our 
Crops and Stock, Parasite Plants and Poisonous Plants, Principles 
of Seed Testing, besides a Bibliography of 5 pages referring to 
the more important papers published in Europe, England and 
Canada. In addition to this English publication there have been 
published by M. G. Smith "One Hundred Yorkshire Weeds," and 
"A Contribution to our Knowledge of the Influence of Manures on 
the Botanical Composition of the Herbage of Permanent Grass- 
Land." 

Many weeds have received special attention in the United 
States. Of these, perhaps the Russian thistle, some 20 years ago, 
received more attention for a few years than any other weed. The 
earliest account of this weed was made by J. N. Rose in 1891, fol- 
lowed by a more extensive bulletin on the same weed by Dewey in 
1893, and another paper by the same author in 1894. Papers were 
also published by Bessey of Nebraska, Goff of Wisconsin, Pammel 
and Wilson of Iowa, Hays of Minnesota, BoUey of North Dakota, 



826 WEED FTjORA OF IOWA 

Williams of South Dakota, Clinton of Illinois, Selby of Ohio, and 
Wooten of New Mexico; in addition press notices on the subject 
were published in agricultural journals during the years 1891- 
1895. Since then there have been comparatively few accounts, ex- 
cepting a few notes in 1911 and 1912 in the agricultural journals. 
The chemistry of the weed has also been discussed by G. E. Patrick 
of Iowa and by the Colorado Experiment Station. This weed was 
considered so important that a number of northern states passed 
laws looking for its extermination. A bill was introduced into 
Congress by Senator Hansbrough in which congressional aid was 
asked to exterminate it. 

The Canada thistle has been discussed by numerous writers both 
in Europe and in the United States. The spread of this weed is 
considered in another connection. We find, however, that mention 
of this weed is made by Linnaeus in his Flora Lapponica, by 
Ratzeburg in 1859, and by Darlington in 1853. More recently the 
weed has received attention from such botanists as H. L. BoUey of 
North Dakota, T. J. Burrill of Illinois, E. S. Goff of Wisconsin, 
Fletcher and Clark of Canada, L. F. Henderson of Idaho, L. H. 
Dewey of Washington, D. C, Prof. Howitt of Canada, and L. H. 
Pammel. There have been many press notices in the agricultural 
papers, particularly in the northern Mississippi Valley. Attention 
may be called to those in Wallace's Farmer, Iowa Homestead, 
Breeders' Gazette, Farmers' Review, Prairie Farmer and Success- 
ful Farming. 

Another weed that attracted much attention a few years ago 
was squirrel-tail grass or wild barley. This was discussed by C. S. 
Crandall of Colorado, Hillman of Nevada, Nelson of Wyoming, 
Wooten of New Mexico and Pammel of Iowa. 

Prickly lettuce has been discussed by Arthur of Indiana, Weed 
of Ohio, Dewey of Washington, D. C, Morrow of Illinois, Pammel 
of Iowa, and Fernald of Massachusetts. 

Buffalo bur has been discussed by Henry of Wisconsin, Halsted 
and Pammel of Iowa, Clinton of Illinois, Harvey of Maine, and in 
numerous press notices in the agricultural journals. 

Mustards of various kinds have been discussed by Dewey of 
Washington, D. C, Clark and Fletcher of Canada, Hitchcock of 
Kansas, Howitt of Canada and Pammel of Iowa. 

The perennial sow thistle has been discussed by the agricultural 
press of Canada and in special treatises by Howitt and Fletcher 



HISTORY AND BIBLIOGRAPHY 827 

and Clark of the Dominion of Canada and in numerous notices in 
the agricultural press of the northern United States. 

Broom rape has been discussed by Garman of Kentucky and by 
the United States Department of Agriculture. 

Much has been published on the subject of weed seeds. The 
more important contributions are the following:* 

European work. — The importance of this' work has long been 
recognized in Europe. The pioneer work in this line was carried 
on first in Germany, a station for testing commercial seeds having 
been organized in 1867 in connection with an academy located in 
Tharandt. Dr. Nobbe was its first director. Early in his work 
he saw the importance of making careful examination for the im- 
purities of various grass and clover seeds. In 1876 appeared his 
classical book, Handbuch der Samenkunde. In addition to this 
work he was the author of many other important papers on via- 
bility of seeds and other physiological seed problems. 

Among other important contributions along this line, we may 
mention the papers and work of Kraft, Luhn, and Harz. The work 
of Harz summarizes not only the facts pertaining to the anatomy 
of seeds but also to many other important topics; the literature 
bearing on the subject of seeds is also given. 

The work of Burchard on the adulteration of seed with special 
reference to their origin is particularly noteworthy. In his book 
he has published statistical records showing the origin of clover 
seed and the weed seeds found in the same from Middle Europe, 
Eastern Europe, Southern Europe and North and South America. 
He sometimes missed the important weed species that are found 
in our American clover seed, but on the whole it is true that the 
character of the weed seeds found in our clover and other seeds 
will enable one to tell where they were grown. 

Burchard, in his account published in a contribution from the 
Seed Control Station of Hamburg, states that a large number of 
seeds investigated by him had impurities. Of two hundred and 
eighty seeds tested, one hundred and sixty-seven belonged to the 
pulse family, seventy-nine to the grass family, twenty-three to 
forest seeds, and eleven were miscellaneous. He found the mini- 
mum purity of the clover seed was 54.2 per cent. The highest 
percentage of purity was found in timothy, 99.42. The lowest 
germinative energy was found in fescue grass, 0.17 per cent, and 

*The more important references here given upon the history of seed investi- 
gation are talcen from bulletins 88, 99 and 105, issued by the Iowa State Agri- 
cultural Experiment Station, which are more completely listed in the bibliography. 



828 WEED FLORA OF IOWA 

the highest in clover, 97.25 per cent. Of the sixty samples of red 
clover examined for dodder, twenty-eight were free. The most 
common species was clover dodder, although others were also found. 
One lot of alfalfa from South America contained the Chilian 
dodder. In this investigation as in others, he emphasizes the im- 
portance of determining the kinds of weeds found in the seed, 
thus: In Australian orchard grass the hairy brome grass was 
common, and in North American seed, orchard grass, timothy, blue 
grass and tickle grass. 

The work of Settegast treats extensively the subject of agricul- 
tural seeds and seed testing, especially with reference to vitality 
and seed production. 

Vandevelde's work treats of the morphology and physiology of 
germination and includes a splendid bibliography. 

Attention should be called to the excellent contributions of 
Wollny whose reports of his splendid work on seeds and the care 
of agricultural crops often give considerable detail on the ger- 
mination and viability of various agricultural seeds. 

Kienitz gives a detailed account of the methods to be followed 
in the study of germination of seeds. 

Fniwirth carried out a study on the color and specific gravity 
of clover seeds. He found that the dark violet seeds were heavier 
than the light colored ones of the same head, and perhaps had 
greater germinative energy. 

Samek carried on an experiment, testing seeds for a period of 
eleven years, showing the results of germination after the first and 
eleventh years. 

Hiltner in a somewhat recent paper discusses the limitations of 
seed testing and the importance of obtaining pure seed. 

H. von Guttenberg gives the description of five species of 
Cuscata and a key for their identification. Von Degen notes the 
germination of dodder under varying conditions. Kinzel has made . 
a study of the effect of freezing seed and its bearing upon agri- 
cultural weeds. Pieper discusses the method of testing the ger- 
mination of seeds and presents a new method of determining the 
germination of grass seed. Dorph-Petersen gives a summary of 
seed tests carried on by the Danish Seed Control Station, during 
which 9,024 samples of clover, grass, and other seeds were analyzed. 
The paper gives a list of weed seeds found and includes notes on 
germination and purity. F. G. Stebler, of the Zurich Seed Control 
Station, Switzerland, gives the results of tests made of 10,335 



HISTORY AND BIBLIOGRAPHY 829 

seeds examined in 1908, with reference to adulteration, purity, 
vitality, and the presence of Cuscuta. Vilke gives an account of 
the presence of weed seeds found in Swedish seeds. J. Paczoski 
notes the important weeds found in the Cherson Government. 
A. Malzew reports on the more important weeds found in Russia; 
black bindweed {Polygonum con/volvulus) and corn cockle {Agros- 
temma githago) were common in wheat; oats had, in addition, wild 
oats {Avena fatua, glabrata), and Neslia paniculata. In rye, the 
black bindweed {Polygonum convolvulus), lamb's quarters {Gheno- 
podium album), stickweed {Echinospermum lappula), and Neslia 
pamculata were found. Lesage made a study upon the effect of 
solutions of common salt and alcohol on the germination of garden 
cress. 0. Munerati and T. V. Zapparoli of Italy have made a 
study of weed seeds with hard coats. F. Johnson and R. Hensman 
discuss the source of the alien flora of Ireland through weed im- 
purities found in agricultural seed. A. J. Ewart made tests of 
various grass and garden seeds with reference to the vitality of 
seeds after a sea voyage. In a lengthy report on the prolonged 
vitality of seeds it was found that quite a per cent of seeds ger- 
minated after half a century. Rees made a study of hard seeds 
with reference to the cuticular layer. This layer repelled the water, 
and for this reason seeds retained their vitality. 

A recent paper by E. Lehmann on the temperature and light 
relations and the germination of seeds, gives both an exhaustive 
summary of the subject and a great deal of original matter. 

It is difiScult to say under what conditions seed will germinate. 
Older investigators regarded light as having no definite action on 
the germination of seeds. Crocker found that the structure of the 
seed coats retarded germination in the case of Xanthium. Shull, 
Crocker, and others found that oxygen hastened the process. In 
a recent paper by E. Lehmann, attention is called to the action of 
light and temperature on the germination of seeds, both of which 
influence this action. The seeds of Whitlavia grandiflora indicated 
that germination is retarded at higher temperatures but not at 
lower. He designates some seeds, suoh as EpHohiwin roseum, E. hir- 
sutum (Lehmann), and Vermvlca peregrina (Heinricher) as light 
germinating seeds. Dark germinating seeds are represented by 
Phlox drummondii. Lehmann found that 4 per cent germinate ia 
light and 31 per cent in darkness. Maturity also influences ger- 
mination of seed. When wheat is ripened at a lower temperature, 
it requires a longer optimum temperature for germination than seed 



830 WEED FLORA OF IOWA 

ripened at a higher temperature. The seeds of blue grass when 
planted soon after maturity did not germinate in darkness but 
under the influence of light 88 per cent germinated. In spring, 
however, the germination was equally good in darkness and light. 

Cieslar found that light influenced germination. It would seem 
from this and other investigations that structure, the oxygen, sub- 
stratum moisture, temperature, light, in short, the ecology and 
structure as well as physiology play an important part in germin- 
ation. 

There are many other contributions, but most of these papers 
will be found recorded in the literature cited by Vandevelde, Harz 
and Nobbe. 

Americcm work. — Connecticut. — ^The pioneer work in this coun- 
try was done by Profs. E. H. Jenkins and Warneke, of the Con- 
necticut Agricultural Experiment Station. 

Miss Mary G. Jagger and E. H. Jenkins report the results of 
analyses for 1908-1909-1910-1911, and note the character of the im- 
purities of seed found in the Connecticut market. 

North Carolina. — Gerald McCarthy, of the North Carolina Agri- 
cultural Experiment Station, published an elaborate paper on the 
subject in which he gave the details of an extensive investigation 
carried on in North Carolina on germination of seeds. 

Michigan. — Some excellent work was done by Prof. "W. J. Beal 
who reported results of germination of clover seeds furnished by 
seedsmen. From 'seeds grown on moist paper the results of the 
germination showed that large red clover had a germination of 
88 per cent, medium red clover 88 per cent, white clover 84 per 
cent and alsike clover 64 per cent. Prof. Beal called attention to 
the difference in germination of seeds when grown in sand and in 
blotting paper. From seeds grown in sand the following results 
were obtained: Medium clover had a germination of 76 per cent, 
white clover 92 per cent, red clover (two separate lots) 70 and 56 
per cent. 

A later report of Prof. Beal gives two tests of twelve years old 
clover seeds in both of which the germination was 35.8 per cent. 

Subsequent reports on the vitality of clover and other seeds were 
also made. 

Prof. Beal also reports tests on seeds sent by farmers. Fifty- 
eight samples ranged from 25 to 97 per cent, seventeen being above 
90 per cent. He early called attention to the presence of rib grass 
in clover seed. Recently he has published an exhaustive bulletin 
on the seeds of Michigan weeds with excellent figures made by 



HISTORY AND BIBLIOGRAPHY 831 

F. H. Hillman. Dr. E. Zeeuw has published the results on the 
comparative viability of seeds, fungi, and bacteria, when subjected 
to various chemical agents. Ernest Bessey gives the results of seed 
analysis for 1911 and 1912 from which it appears that buckhorn 
and plantain were frequent. The paper gives the number of weed 
seeds in a pound. 

Mr. Parsons in 1893 made some interesting tabulations in a 
summary of American seed vitality tests. In the results offered 
by him we find the following : Alsike 72.7 per cent, crimson clover 
59 per cent, red clover 84.8 per cent, mammoth clover 82.5 per 
cent, white clover 72.1 per cent, alfalfa 61.6 per cent. 

Pennsylvania. — ^Prof. Butz studied many hundreds of samples 
of seeds, chiefly with respect to their germinative power. In many 
cases the percentage of germination was very low. Thus we find 
recorded the following : Alfalfa 52 per cent, alsike clover 61 per 
cent, Japan clover 69 per cent and seradella 13 per cent. 

Ohio. — Mr. Devol early recognized and emphasized the im- 
portance of the experiment station in studying the viability of 
seeds. In tests conducted by him clover showed a germination of 
93 per cent. 

Later Selby and Hicks made a study of fifty-two samples of 
clover and alfalfa seeds sold in Ohio. They found not only that 
the seeds had a low vitality but that they contained considerable 
impurities. 

Nevada.^Several very important papers have been published 
by Mr. Hillman on clover seeds and their impurities. One of his 
earlier bulletins deals with the descriptions of weed seeds and their 
distribution, together with an incidental account of.the occurrence 
of these seeds in commerce. In a later publication he considers 
the weed seeds found as impurities in various types of seeds, in- 
cluding alfalfa, red clover, white clover, alsike clover, crimson 
clover, Japan clover, Bokhara clover, yellow trefoil and esparcette. 
In his investigations a large number of samples was examined. 
The paper therefore gives a fair estimate of the impurities gen- 
erally found in the various clover seeds offered for sale in this 
country. 

Kansas.- — Prof. Roberts and Mr. Freeman carried on an extensive 
investigation of alfalfa seed, showing adulteration, substitutes 
and impurities; and the methods of detecting the latter. They 
found some adulteration in alfalfa seed. The yellow trefoil 
{Medicago ' lupulina) was most frequent though there were occa- 



832 WEED FLORA OF IOWA 

sional instances in whieli burr clover (Medicago denticulata) and 
sweet clover {Melilatus alba) occurred. The most noxious weed 
seeds found were the docks and the English plantain. The average 
germination of alfalfa seed was 83 per cent. The subject is also 
briefly discussed by Ten Byck. 

Prof. Roberts and Mr. Freeman also made quite an exhaustive 
study of the grass seeds commonly sold in Kansas. The dodder 
may prove to be a destructive clover parasite in the United States. 
Mt. Brown, in a paper on legal and customary weights per bushel 
of seeds, has also brought together much important matter on the 
subject of the weight of commercial seeds. 

Maine. — ^Prof. Harvey and other members of the staff of the 
Maine Experiment Station investigated the vitality and the im- 
purity found in the agricultural seeds offered for sale in that 
state. The results of Prof. Harvey's investigations disclosed the 
advisability of having a law to regulate the sale of seeds. Such 
a law was passed by the state of Maine and the work of carrying 
on this law was placed in the hands of the director of the Station. 

The results of the tests and regulations concerning the seed 
testing for Maine were published by Charles D. "Woods, director 
of the Station. In a subsequent bulletin he discusses seed inspec- 
tion and lists 79 kinds of weed seed. With Hammond the require- 
ments of the law are given as well as results of seed testing. 

Minnesota. — ^W. L. Oswald, Bulletin 127 of the Minnesota Station 
gives the results of purity and germination tests for 1275 samples 
of commercial seed. 

North Carolina. — ^McCarthy in an early bulletin of the North 
Carolina Statipn reported on the analyses of seed in 1912. 0. I. 
Tillman reported on the analyses of commercial seed in accordance 
with the North. Carolina pure seed act. 

Kentucky. — Prof. Garman and others, of the Kentucky Experi- 
ment Station, have investigated the impurities in grass and other 
forage plants sold in Kentucky. It was found that thirty-six of 
the five hundred samples examined were adulterated; among these 
were red clover, blue grass, timothy and orchard grass. They con- 
cluded that the greatest fraud perpetrated is in the sale of certain 
varieties under an assumed name. In several publications Prof. 
Garman discussed the impurities and adulterations of grass seed 
sold in Kentucky and recommended that no field seeds should be 
sold in Kentucky containing more than 5 per cent weed seeds. 
He also gave a comprehensive account of seed testing apparatus 



HISTORY AND BIBLIOGRAPHY 833 

and the conditions under which germination tests are made, with 
special reference to work in Kentucky. 

Kentucky now has in consequence of this work an admirable 
law forbidding adulteration or misbranding of the clovers and 
timothy sold for seed in the state. Its effects have been most 
salutary and have been studied with profit by other common- 
wealths. 

Vermont. — ^Mr. L. W. Barton, under the direction of Profs. 
Jones and Orton of the Vermont Experiment Station, ma,de an 
examination of thirty-four samples of clover seed in Vermont. He 
reports the total percentage of impurities in red clover as being 
from .3 to 5.3, with an average of 1.8 per cent; alfalfa as having 
a maximum of 7.1 per cent and a minimum of .6 per cent. Sorrel 
was found in 60 per cent of the red clover samples and wild carrot 
in a few, the rib plantain occurred in 77 per cent, dodder in 5 
per cent, and Canada thistle in 5 per cent. Dodder did not occur 
in the alfalfa, but in 8 per cent of the samples Canada thistle 
was found. 

Massachusetts. — G. E. Stone reports on seed tests made in 1908 
and 1910. Smith, Chapman, and Stone describe fourteen weed 
seeds most commonly found in grass seed and cattle foods, with a 
brief account of the weeds of the state. 

Maryland. — E. I. Oswald made a series of experiments to deter- 
mine the vitality of seeds when placed in manure under different 
conditions. It was found that weed seeds when left for six months 
in manure had lost their vitality completely. When left there for 
one month under conditions usually followed by dairymen, the 
seeds of ribgrass, horse nettle, dock, and a few others were still 
firm. Mention of weed seeds is made in the treatise by J. B. S. 
Norton on Maryland weeds. The same author gives the result of 
seed analysis of various commercial seed. 

Nebraska.— E. M. Wilcox in a paper on dodder in alfalfa seed 
discusses the frequency of the impurities and means of eradicating 
the weed. 

New Hampshire. — ^F. W. Taylor in reports of seed tests for 1910 
and 1911 discusses the New Hampshire law giving results of purity 
and germination tests. 

New York. — F. C. Stewart under the head of alfalfa troubles 
discussed dodder in alfalfa seed and subsequently gave a method 
of screening dodder out of alfalfa seed. In 1910 G. T. French re- 
53 



834 WEED FLORA OP IOWA 

ported on an examination of several hundred samples of seed with 
special reference to the occurrence of dodder, Russian thistle, and 
Centaurea rep&ns; an earlier report by the same author reported 
on seed tests made at the station. Further discussion is found in 
the New York Agricultural Experiment Station Circular 8 :l-4, 
Dodder in Alfalfa, by F. C. Stewart and G. T. French. Mr. M. 
T. Munn in Bulletin 362 gives the seed tests made in 1912, giving 
results of examinations made for purity of commercial samples. 

North Dakota. — ^H. L. BoUey discussed the pure seed law of 
North Dakota and seed work ending December 31, 1909, with an 
account of weed seeds found. 

Wisconsin. — A. L. Stone in a circular of information discussed 
the seed inspection law of the state, adding some general informa- 
tion. "With G. T. Moore he also discussed the question of the eradi- 
cation of farm weeds which have been introduced by means of im- 
pure seed. 

Mr. George T. Harrington discussed the worst weeds in connec- 
tion with grass and clover seeds. D. L. Beach made a study of 
commercial feeds with reference to the germination of weed seeds 
found in these feeds. Feed subjected to steaming before feeding 
contained no germinable weed seeds. 

Texas. — ^According to 0. M. Ball alfalfa seed sold in. Texas con- 
tains the following chief impurities: Russian thistle, ribgrass, 
tumbleweed, pigweed, two kinds of dodder, green foxtail, curled 
dock, bur clover, and sweet clover. The vitality varied from 49.5 
to 96.5 per cent. A subsequent report also on alfalfa seed was 
made. 

Arizona. — Prof. Thomber made an examination of alfalfa seed 
sold in Arizona. This showed a high percentage of germination. 

Iowa. — The Iowa Agricultural Experiment Station has produced 
several publications relating to weed seeds. Ball discussed im- 
purities in grass seed; Pammel, Buchanan and King have pub- 
lished a bulletin eoveoring impurities of commercial seed. Two 
bulletins by L. IT. Pammel and Charlotte M. King, "Results 
of seed investigations for 1907" and "Results of seed investiga- 
tions for 1908 and 1909," give the results of analyses of seed sent 
by farmers to the Station. The results of the 1907 investigation 
indicated that the weed seeds were different in many cases from 
those reported in a previous publication; dropseed grass was 
common, occurring in 3.3 per cent of the samples; Canada thistle 
seed was also less frequent. The investigations for 1908-1909 in- 



HISTORY AND BIBLIOGRAPHY 835 

dicated that the seed sold in the state has improved, field tests-of 
germination were lower than laboratory tests. A method of deter- 
mining, the vitality is also given. The subject of delayed germina- 
tion is discussed by H. S. Fawcett, who found that a relationship 
exists, between the hardness of the seed coat and the dormant 
period. L. H. Pammel states that different conditions influence 
the germination of seeds, such as hard coats and freezing of seeds. 
The delayed vitality of weed seeds is discussed by L. H. I^ammel 
and Charlotte M. King. "Weed seeds after freezing germinate 
more readily when frozen. 

Work of the United States Government. — The National Govern- 
ment began a serious investigation of agricultural seeds and their 
impurities in 1893. Early articles on the subject appeared under 
the head of "Pure Seed Investigations." 

Mr. Hicks called attention to the abuses in the seed trade. The 
matters that were mentioned by him have evidently not been 
remedied since 1894. Since then the work of the Department has 
been immeasurably increased, especially by such contributions as 
have been made by Mr. Duvel on the vitality of buried seeds and 
the storage and germination of wild rice; and the paper by Mr. 
Pieters on "The Farmer's Interest in Good Seed." Among the 
notes on seed testing in 1897, Prof. Hicks and Mr. Sothoron Key 
published an account of the germination of several forage plants 
and flower garden seeds. 

A good table on the percentage of germination standards re- 
quired of seeds will be found in a paper by Mr. Pieters. These 
seed standards were also published in the Year Book of 1896. Later 
Mr. Pieters discussed the presence of clover dodder and other im- 
purities in clover seed. In a circular by Prof. Dewey of the same 
division the dodders found in clover were discussed. 

The quality of the seed, especially its germinative energy, de- 
pends somewhat on the manner in which seeds are kept. Two ar- 
ticles on this subject are of special interest in this connection, one 
by Pieters, "Agricultural Seeds, Where Grown and How to 
Handle," and an article by Pieters and Brown, "Kentucky Blue 
Grass Seed, Harvesting, Curing and Cleaning." 

The United States Department of Agriculture has published 
rules and described apparatus for seed testing. These were adopted 
by the standing committee on seed testing of the Association of 
American Agricultural Colleges and Experiment Stations. 



836 WEED FLORA OP IOWA 

In reports of more recent work, A. F. Woods found dodder seed 
frequent in alfalfa and red clover seed. The adulteration and mis- 
branding of alfalfa, red clover and grain seeds was discussed by 
W. A. Taylor and B. T. Galloway. F. H. Hillman in several papers 
on the impurities, adulteration, etc., of clover and forage plant 
seeds and vetches, presented admirable figures and good descrip- 
tions of weed seeds found as impurities, Westgate, McKee, Evans, 
and Vinall gave a brief account of impurities found in alfalfa seed 
and sweet clover. The subject of low grade clover seed was con- 
sidered by Edgar Brown and Miss Crosby. 

In a paper by Brown and Hillman, "The Seed of Red Clover 
and its Impurities," the more important impurities found in Eu- 
ropean and American grown clover seed are given. Attention is 
called to the introduction of bad seeds from Chile. In 1905 two 
hundred and seventy-five thousand pounds of Chilean red clover 
seeds were imported into the United States, and this clover seed 
contained Chilean clover dodder seed. 

Canadicm work. — In 1892 Prof. J. H. Panton called attention to 
the importance of making an investigation of seed purity and of 
carrying on a campaign for better and cleaner seed. He thought 
a large number of the weeds on the Ontario farms were introduced 
in clover seed. 

He found the number of weed seeds varied greatly, all the way 
from one to four thousand five hundred and forty per half ounce. 
Among the weed seeds he reported several that have become trouble- 
some in the Mississippi valley; these include ribgrass and chicory. 

Saunders in several reports of the Experiment Farms has dis- 
cussed the vitality of grass and clover seeds. In 1903 there were 
tested one hundred and eighty-six samples of clover. The highest 
percentage of germination was low, the lowest 17 and the average 
76.3. A large number of grass seeds were also tested. The work 
has been continued by Saunders and Grisdale (1910) relative to 
determining the climatic conditions favorable to high vitality of 
seeds. 

Since 1903 the Department of Agriculture of the Dominion of 
Canada has created a seed division with Mr. G. H. Clark in charge 
of the work in purity and vitality tests. 

A very notable publication on the subject of weeds and weed 
seeds has been contributed by Clark and Fletcher who have given 
colored illustrations of the more important impurities, found in 
clover and other seeds. 



HISTORY AND BIBLIOGRAPHY 837 

A. B. MeCready of the Ontario Agricultural College gives the 
results of germination tests of alfalfa and clover in which the 
superiority of bright, clean seed is shown. 

Australia. — A. J. Ewart made tests of various grass and garden 
seeds with reference to the vitality of seeds after a sea voyage. In 
a lengthy report on the prolonged vitality of seeds it was found 
that quite a per. cent of seeds germinated after half a century. 
Rees made a study of hard seeds with reference to the cuticular 
layer. This layer repelled the water and for the same reason seeds 
retain their vitality. 

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Cassidy, James, & 'Brine, D. Some Colorado grasses and their 
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Goessman, C. A. Analyses of weeds. Bull. Mass. Agr. Exp. Sta. 
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Jenkins, E. H., & "Winton, A. L. A compilation of analyses of 
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838 WEED nLrORA OP IOWA 

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840 WEED FLORA OF IOWA 

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842 WEED FLORA OF IOWA 

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Orange Hawkweed, or "Paint-brush." Bull. Vt. Agr. Exp. 

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Knowlton, C. H. Two introduced plants [Brassica hirsuta and 

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reiches. 3 Parts. 533. Jena, 1841-1845. 



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844 WEED FLORA OF IOWA 

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51 



850 WEED FLORA OP IOWA 

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852 WEED FLORA OF IOWA 

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62 :334-341. 
Waldron, L. R. Weeds. Sp. Bull. N. D. Agr. Exp. Sta. 2 :4. 
Weed, C. M. Farm friends and farm foes, xl :334. 1910. Chicago. 
Wilcox, E. M. Dodder v. alfalfa. Cir. Bur. Insect Pest and Plant 

Dis. Neb. Agr. Exp. Sta. Dir. Bot. 3:3. 
Wilcox, E. V. Carbon bisulphid for killing weeds. Pr. Bull. 

Hawaii Agr. Exp. Sta. 25:4. 
Killing weeds with arsenite of soda. Pr. Bull. Hawaii Agr. 

Exp. Sta. 30:15. 

Poisonous weeds and their eradication. Cy. Am. Agr. 3: 

119-122. 
Williams, T. A. Fungi damaging both useful plants and weeds. 

Bull. S. D. Agr. Exp. Sta. 29 :51-52. 
Willing, T. N. Noxious weed inspection. Rept. Dept. Agr. N. W. 

Ty. 1901: 56-64. 
Wilson, A. D. Some common weeds and their eradication. Bull. 

Minn. Agr. Exp. Sta. 95:195-237. 



HISTORY AND BIBLIOGRAPHY 853 

"Wilson, F. W. Johnson grass control. Rept. Ariz. Agr. Exp. Sta. 

1911: 549-550. 
Wittrock, V. B. Cuscuta europaea and its hosts. Svensk. Bot. 

Tidskr. 3:1-17. 
Woods, A. P. The wastes of the farm. Yrbk. U. S. Dept. Agr. 

1908: 195-216 (Weeds 207.). 
Woods, C. D., and Bartlett, J. M. On destroying wild mustard and 

wild radish. See Bull. Me. Agr. Exp. Sta. 167 :100, 101. 
Zinger, N. Ueber die im Lain als Unkraut auftretenden Camelina 

und Spergula Arten und ihre Abstammung. Travaux Musee 

bot. Ac. Imp. Soc. St. Petersburg. 6 :309. 1909. Abs. in Bot. 

Centrbl. 119 :298-300. 

MEDICINAL PLANTS. 

Barton, W. G. Vegetable materia mediea of the United States; 

or medical botany. 2 v. 516 p. 1817-1818. 
Bigelow, Jacob. American medical botany. A collection of the 

native medical plants of the United States. 3 v. 596 p. 
. Boston, 1817-1820. 
Blankenship, J. W. Native economic plants of Montana. Bull. 

Mont. Agr. Exp. Sta. 56:36. 
Chesnut, V. K. Plants used by the Indians of Mendocino Co., 

Cal. Cont. U. S. Nat. Herb. 7:295-408. 
Thirty poisonous plants of the United States. Far. Bull. 

U. S. Dept. Agr. 86 :32. 
Duggar, J. F. Melilotus. Cyc. Amer. Agric. 2:467-468. 
Evans, J. R. Medicinal plants of the Cherokees. Proc. Am. Phar. 

Assoc. (Abs.) 23:289-336. 
Gattinger, A. The medicinal plants of Tennessee. 128. Nash- 
ville, 1894. 
Gibbons, W. P. Medicinal plants of California. Proc. Am. Phar. 

Assoc. 19:297-308. 
Greenish, H. G. An introduction to the study of Materia Mediea, 

being a short account of the more important crude drugs of 

vegetable and animal origin. 571. London, 1899. 
Hayne, F. G. Darstellung und besehreibung der Arzneigewachse 

wie auch soleher pflanzen welche mit ihnen verwechselt warden 

konnen. 13 v. 1853-1856. Many colored plates. 
Henkel, Alice. American medicinal leaves and herbs. Bull. U. S. 

Dept. Agr. Bur. PI. Ind. 219 :56. 
American root drugs. Bull. U. S. Dept. Agr. Bur. PL Ind. 

107:80. 



854 WEED FLORA OF IOWA 

Weeds used in medicine. Far. Bull. U. S. Dept. Agr. 

188 :45. 
Wild medicinal plants of the United States. Bull. Bur. 

PI. Ind, 89:76, 
Henkel, Alice, & Klugh, G. F; The cultivation and handling of 

golden seal. Cir. U. S. Dept. Agr. Bur. PI. Ind. 6:19. 
'■ Golden seal. Bull. IT. S. Dept. Agr. Bur. PI. Ind. 51 :35-46. 

Hobn, Theo. Medicinal plants of the U. S. (A series of articles 

in Merck's Keport) 1910. 
Hyams, C. W. Medicinal plants which have been collected and 

used in North Carolina. Bull. N. C. Agr. Exp. Sta. 150: 

329-409. 
Johnson, L. A manual of -the medical botany of North America. 

,2.92. N«5W, York, 1884. 
Kellogg, Harriette S. Folk-lore in medicinal plants. Trans. la. 
. . St. Hort.Soc! 39:143-148. 

Klugh, G. F. Tansy.' Cy. Am. Agr. 2:465. (Cy. Amer. Hort.) 
Kramer, H. A textbook of botany and pharmacognosy. Ed. 4. 

888. Philadelphia, 1911. 
Millspaugh, 0. F. American medical plants. An illustrated and 

descriptive guide to the American plants used as homeopathic 

remedies, their history, preparation, chemistry and physiolog- 
ical effects. 2 v. 190. 180 pi. . 
PammQl, L. H. A manual of poisonous plants, chiefly of eastern 

North America, with brief notes on. economic and medicinal 

plants, and numerous illustrations. 977, 17 pi, 458 f. Cedar 

Rapids. 1911. (Many articles on medicinal plajits are listed 

in the bibliography.) 

Poisonous and medical plants of Missouri. Bull. Mo. Bd. 
' 'Of. Hort. 14:46. 
Peterson, Maude G. How to know wild fruits. A guide to plants 

when not in flower, by means of fruit and leaf. 340. 1905. 

Poreher, F. P. Resources of the southern fields and forests, 

. medical, economical and agricultural,, being also a medical 

botany of the IT. S. Rev. Ed. 1867. 
Rafinesque, C. S. Medical flora : or manual of the medical botany 

of the United States of North America. 2 v. 544. 48 pi. 
Sehoepf, J. D. Materia qiedica americana,. potissimum regni 

vegetabilis. 170. 1787. 
Special Crops. Contains directions for cultivating such plants as 

ginseng, etc. Edited by C. M. Goodspeed. Skaneateles, N. T. 



HISTORY AND BIBLIOGRAPHY 855 

True, R. H. Cultivation of drug plants in the United States. 
Trbk. U. S. Dept. Agr. 1903: 337-346. 

Medicinal, condimental and aromatic plants. Cy. Am. Agr. 
2 :458-467. 

Progress in drug plant cultivation. Yrbk. U. S. Dept. Agr. 
1905 : 532-540. . (Domestication of wild drug plants, 534-535 ; 
Utilization of weeds, 535-536.) 

Weschke, C. The enumeration of the medicinal plants of Minne- 
sota. Phar. Rund. 8:155-157. 

Young, T. B. American Wormseed {Chenopodium anthelndnti- 
cum)'. Cy. Am. Agr. 2:466. i 

WEED SEEDS. 

Ball, C. R. The purity and vitality of grass seed. BuU. la. Agr. 
Exp. Sta. 54:164-180. 

Ball, 0. M. AlfalEa seed testing. Bull. Tex. Agr. Exp. Sta. 81 :15. 

Beach, C. L. The viability of weed seeds in feeding stuffs. Bull. 
Vt. Agr. Exp.^Sta. 138:11-20; ! 

Beal, W. J. Seeds of Michigan Weeds. Bull. Mich. Agr. Exp. Sta. 
260:101-182. 
Testing Seeds. Rapt. Mich. Bd. Agr. 1877: 377-392. 
Vitality and growth of seeds buried in the soil. Proc. See. 
Prom. Agr. Sci. 10:15-16. 

The vitality of seeds.' Proc. Soc. Prom. Agr. Sci. 26 :89-93. 
The vitality of seeds buried in the soil. Agr. Sci. 8:284. 
Proc. Soc. Proip.; Agr. Sci. 6:14-15; 15:283. Rept. Mich. Bd; 
Agr. 1884: 332-334. 

The vitality of seeds twenty years in the soil. Proc. Soc. 
Prom. Agr. Sci. 20:86-87. 

Bessey, B. A. Seed analysis for 1911 and 1912. Bull. Mich. Agr. 
Exp. Sta. 270:71-98. 

Boynton, M. F. Observations upon the dissemination of seed^ Bot. 
Gaz. 20:502-503. 

Brown, Edgar. Legal and customary weight per bushel of seeds. 
Bull. U. S. Dept. Agr. 51 :27-34. 

Brown, E., & Hillman, F. H. Seeds of. red clover and its im- 
purities, -^^ar. Bull. U. S. Dept. Agr. 169:24. 

Burchard, 0.. Die Unkrautsamen der Klee-und Grassaaten. mit 
besonderer Beriicksiehtigung ihrer Herkunft. 100, 5 pi. Ber- 
lin, 1900. , , r'i 



856 WEED FLORA OF IOWA 

On object and methods of seed investigation and establish- 
ment of seed control stations. Exp. Sta. Rec. 4:793-801; 

882-900. 
Ueber die Herkunftsbestimmung amerikanischer Kleesaaten. 

Mittheilungen aus dem Bot. Laboratorium mit Samen-Prii- 

fungsanstalt im Hamburg. Die Landw. Versuchs. 43 :239-246. 

Abs. in Beih.zum. Bot. Centbl. 4:397. 
Butz, G. C. Germination experiments. Ann. Kept. Penn. St. 

Coll. Exp. Sta. 1887: 20-21; 1889: 163-165. Bull. Penn. Agr. 

Exp. Sta. 4:8-10. 
Carruthers, W. Dodder seeds in seed mixtures. Jour. Roy. Agr. 

Soc. 69 :311-313. Weeds in Clover seeds, id. 308-310. 
Chapman, G. H. The microscopical examination of cattle foods. 

Bull. Mass. Agr. Exp. Sta. 141:71. 52 f. 
Cieslar, Untersuchungen iiber den Einfluss des Lichtes auf die Kei- 

mung der Samen. Forschungen aus dem Gebiete der Agrikul- 

turphysik. 1883. 6:270-295. 
Crocker, Wm. Role of seed coats in delayed germination. Bot. 

Gaz. 42:265-291. 
De Loach, Gertrude B., Carrier, L., & Hutcheson, T. B. Impurities 

of grass and clover seeds sold in Virginia. Bull. Va. Agr. 

Exp. Sta. 184:3-18. 
Devol, "W. S. Vitality tests of seeds. Rept. Ohio Agr. Exp. Sta. 

1:113-116; 2:149-181; 3:186-203; 4:136-185; 5:234-258; 6:283- 

285. 
Dewey, L. H. Dodders infesting clover and alfalfa. Cir. U. S. 

Dept. Agr. Div. Bot. 14:7. 
Dorph-Peterson, K. On some investigations of the appearance and 

longevity of weed seeds. Tidskr. Landbr. Planteavl. 17: 

584-626. 
Duvel, J. W. T. The storage and germination of wild rice seed. 

Bull. U. S. Dept. Agr. Bur. PI. Ind. 90:34. 

The vitality and germination of seeds. Bull. 58 :96. 
Vitality of buried seeds. Bull. 83 :20 ; 3 pi. 
Ewart, A. J. On the longevity of seeds. Proc. Roy. Soc. Victoria. 

n. ser. 1908. 1: Abs. in Exp. Sta. Rec. 20:628. 
Faweett, H. S. The viability of weed seeds under different condi- 
tions of treatment, and a study of their dormant periods. Proc. 

la. Acad. Sci. 15 :25-45. 
Fruwirth, C. On color and specific gravity of clover seeds. Landw. 

Vers. Stat. 55 :439-452. Abs. in Exp. Sta. Rec. 13 :656. 



HISTORY AND BIBLIOGRAPHY 857 

Garman, H. On the adulterants and weed seeds found in Ken- 
tucky samples of blue grass, orchard grass, timothy, red clover, 
mammoth clover and alfalfa seeds. Bull. Ky. Agr. Exp. Sta. 
124:35. 

Garman, H., & Didlake, M. L. The inspection of seeds under the 
Kentucky pure seed law. Bull. Ky. Agr. Sta. 127 :129-169. 

Harrington, G. T. The grass and clover seed trade in Vermont in 
1907-1909. BuU. Vt. Agr. Exp. Sta. 146:205-240. 

Harvey, F. L. Examination of seeds for impurities. Kept. Me. 
Agr. Exp. Sta. 1891: 186-187. 

Germination experiments. Kept. Me. Agr. Exp. Sta. 
1887: 149-160; 1888: 136-147; 1889: 150-160; 1890: 107-112. 
Vitality of seeds. Note in Bot. Gaz. 12 :253. 
Weeds and seeds. Kept. Me. Agr. Exp. Sta. 1896 : 113-116. 

Harz, C. D. Landwirthschaftliche Samenkunde. 1:552; /. 1-14. 
2:553-1362; /. 15-201. Berlin, 1885. 

Hicks, G. H. Pure seed investigation. Kept. U. S. Dept. Agr. 
1894: 389-408. 

Hicks, G. H., & Key, Sothoron. Additional notes on seed testing. 
Yrbk. U. S. Dept. Agr. 1897 : 441-452. 

Hillman, F. H. The adulteration of forage plant seeds. Far. Bull. 
U. S. Dept. Agr. 382:23. 

Glover seeds and their impurities. Bull. Nev. Agr. Exp. Sta. 
47:88. 

Vetch seed and its adulterants. Far. Bull. U. S. Dept. Agr. 
515:23-27. 

Jenkins, E. H. Seed tests. Ann. Eept. Conn. Agr. Exp. Sta. 
1879: 121; 1880: 96-104; 1882: 93; 1883: 96-107. 

Jenkins, E. H., Card, F. W., Lazenby, W. R., Brown, B., & Shamel, 
A. B. Rules and apparatus for seed testing. Adopted by the 
standing committee on methods of seed testing of the Associa- 
tion of American Agricultural Colleges and Experiment Sta- 
tions. Cir. U. S. Dept. Agr. Offi. Exp. Sta. 34:24. 

Jenkins, E. H., & Warneke. Seed tests. Ann. Rept. Conn. Bd. 
Agr. 1878: 352. 

Johnson, T., & Hensman, R. Agricultural seeds and their weed 
impurities, a source of Ireland's alien flora. Sci. Proc. Roy. 
Dub. Soe. n. s. 12:446-462. 1910. Abs. in Exp. Sta. Ree. 
24:338. 

Jones, L. R., & Orton, "W. A. Impurities of Vermont clover seed. 
Rept. Vt. Agr. Exp. Sta. 11 :229-234. 



858 WEED FLORA OF IOWA 

Kienitz, M. Ueber Ausfiihrung von Keimproben. Forst. PI. 6. 

Abs. in Bot. Cent. 1 :52-53. 1880. 
Kinzel, W. Concerning the germination of dodder seed. Naturw. 

Ztschr. Han.- u. Forstw. 1903 : 104-110. 

On the germination of half-ripe dodder seed. Landw. Vers. 

Stat. 55 :255-256. Abs. in Exp. Sta. Ree. 13 :658. 
Kolkwitz, E. Ueber die Athmung ruhenden Samen. Ber. Deutsch. 

Bot. Gesells. 19:285-287. 1901. 
Korsmo, E. On the viability of weed seeds after passing through 

the digestive tract of farm animals. Tidskr. Norske. handbr. 

18 :223-230. 
Kuntze, R. E. Germination and vitality of seeds. Torrey Bot. 

Club. 1901. 
Lehmann, Ernst. Ueber die Beeinflussung der Keimung lichtemp- 

findlieher Samen durch die Temperatur. Zeits. f . Bot. 4 :465- 

529. 
Laschke, W. Einige vergleichende Untersuehungen iiber den Ein- 

fluss des Keimbettes, sowie des Liehtes auf die Keimung ver- 

sehiedener Samereien. Landw. Vers. 65 :295. 
McCarthy, Gerald. Seed-testing; its uses and methods. Bull. 

N. C. Agr. Exp. Sta. 108:349-415. 
Munerati, 0., & Zapparoli, T. V. On investigations on the ger- 
mination of seeds of some • weeds. Staz. Sper. Agr. Ital. 

44:40-50 (1911). 
Nobbe, F. Handbueh der Samenkunde. 631. Berlin. 1876. On 

viability of seeds, see Landw. Vers. Stat. 13 :233. 
Pammel, L. H., Buchanan, R E., & King, C. M. The vitality, 

adulteration and impurities of clover, alfalfa, and timothy 

seed in Iowa in 1906. Bull. la. Agr. Exp. Sta. 88:69. 
Pammel, L. H., and King, C. M. Delayed germination. Proe. la. 

Acad. Sci. 18:20-33. 

Results of seed investigations for 1907. Bull. la. Agr. Exp. 

Sta. 99:71-91. 
Results of seed investigation for 1908 and 1909. BuU. la. 

Agr. Exp. Sta. 115:156-177. 
Pammel, L. H., & Lummis, G. M. The germination of weed seeds. 

Proc. Soc. Prom. Agr. Sci. 1903 : 89-92. 
Panton, J. H. Impurities in clover seed. Bull. Ontario Agr. Coll. 

98 :8 ; 10 f. 
Weeds of Ontario. Rept. Ont. Agr. Coll. & Exp. Farm. 

19 :27-32. 



HISTORY AND BIBLIOGRAPHY 859 

Parsons, C. L. A summary of American seed tests. Agr. Sei. 

7 :541-545. 
Pieters, A. J. The farmer's interest in good seed. Far. Bull. U. S. 

Dept. Agr. 111:24. 
Red Clover seed. Cir. U. S. Dept. Agr. Div. Bot. 24 :5. 
Seed of red clover and its impurities. Far. Bull. U. S. Dept. 

Agr. 260:24. 
Testing seeds at home. Kept. U. S. Dept. Agr. 1895: 

175-184. 
Pieters, A. J., & Brown, E. Kentucky blue grass seed; harvest- 
ing, curing, and cleaning. Bull. U. S. Dept. Agr. Bur. PI. 

Ind. 19:19. 
Ridley, H. N. Dispersal of seeds by birds. Nat. Sci. 8 :186-199. 
Roberts, H. F., & Freeman, G. F. Alfalfa seed; its adulterants, 

substitutes and impurities, and their detection. Bull. Kan. 

Agr. Exp. Sta. 133 :53-lll ; 33 pi. 
Rolfs, P. H. Preliminary report on the examination of some seeds. 

Bull. la. Agr. Exp. Sta. 13 :75-84. 
Samek, J. On vitality of seeds. See Tirol. Landw- Blatter. 13. 

1894: 161-162. Abs. in Exp. Sta. Ree. 6:429-430. 
Settegast. Die landwirthschaftliehen Samereien und der Samen- 

bau. Leipsic, 1892. 
Selby, A. D., & Hicks, J. F. Clover and alfalfa seeds. Their 

purity, vitality, and manner of testing. Bull. Ohio Agr. Exp. 

Sta. 142:111-130; 4 pi. 
Smith, P. H., Chapman, G. H., and Stone, G. E. Notes on seeds, 

screenings, and weeds in Massachusetts. Rept. Mass. Agr. 

Exp. Sta. 1908. Pt. 1. 
Stewart, P. C. Impurities of clover seed. Bull. la. Agr. Exp. Sta. 

21:805-815. 
Stewart, F. C, & French, G. T. Dodder in alfalfa seed. Cir. N. Y. 

Agr. Exp. Sta. 8:4 (n. s.). 
Stewart, F. C, French, G. T., & Wilson. Troubles of alfalfa in 

New York. Bull. N. Y. Agr. Exp. Sta. 305 :333-416. 
Thornber, J. J. Practical suggestions for seed testing. Bull. Ariz. 

Agr. Exp. Sta. 54 :99-102. 
Vandevelde. Die Keimuug der zaadplanten Morphologic en 

Physiologic. Gent. 1896. 
Waldron, L. R. Buried weed seeds. Bull. N. D. Agr. Exp. Sta. 

62:439-446. 
"Wollny, E. Saat u. Pflege. der landwirthschaftliehen Kultur- 

pflanzen. Berlin, 1885. 



«60 WEED FLORA OF IOWA 

Woods, Chas. D. Testing seeds. Bull. Me. Agr. Exp. Sta. 36:8. 

WEED LAWS. 

BoUey, H. L. The seed control act. Special Seed Bull. N. D. Agr. 
Exp. Sta. 1:15. 

Burtt-Davy, J. B. Text of law in regard to burweed (XantMum 
spinoswm). See Par. Bull. Transvaal Dept. Agr. 54. 

Clark, G. H. Weed control and weed legislation. Cy. Am. Agr. 
4:533-536. 

Dewey, L. H. Legislation against weeds. Bull. U. S. Dept. Agr. 
Div. Bot. 17:60. 

Garman, H. and Didlake, M. L. The inspection of seeds under the 
Kentucky Pure Seed Law. Bull. Ky. Agr. Exp. Sta. 127: 
129-169. 

Laws of Iowa relating to Agriculture. Iowa Yearbook Agr. 
9 :944-958. 

Maine law in regard to seeds. An act to regulate the sale of Agri- 
cultural Seeds. Kept. Me. Agr. Exp. Sta. 1896 : 143-181. 

Taylor, F. W. Results of seed tests for 1911. (Includes text of 
seed law.) Bull. N. H. Agr. Exp. Sta. 156:14. 

Thistles, illustrated description of, etc., included within the pro- 
visions of the Thistle Act of 1890. Victoria Dept. Agr. 

Tillman, 0. I. Purity and germination of agricultural and vege- 
table seeds sold in North Carolina. , (Contains seed law.) 
Bull. N. C. Agr. Exp. Sta. 32:78; pis. 8. f. 2. 

GENERAL. 

Anderson, L. Weedy flavors in butter. Ann. Rep. Cal. Agr. Exp. 

Sta. 1902-3: 121-126. Exp. Sta. Rec. 15:813. 
Bailey, L. H. Some reflections upon weeds. Bull. Cor. Agr. Exp. 

Sta. 62:522-526. 
Bowen-Jones, J. Influence of weeds on crops. Jour. Roy. Agr. 

• Soc. Eng. 66 :122. 
Brenehley, W. E. The weeds of arable land in relation to the soil 
on which they grow. Ann. Bot. 25 :155-165 ; 26 :95-109. 

Weeds in relation to soils. Jour. Bd. Agr. (London) 
18 :18-24. 1911. 

Weeds; their peculiarities and distribution. Sei. Prog. 
Twentieth Cent. 1912: 413-437. 
Carruthers, W. Determination of weeds. Jour. Roy. Agr. Soc. 
Eng. 3 :738-742. Jour. Roy. Agr. Soc. 69 :313-315. 



HISTORY AND BIBLIOGRAPHY 861 

<Cates, J. S., & Cox, H. R. The weed factor in the cultivation of 

corn. Bull. U. S. Dept. Agr. Bur. PI. Ind. 257 :35. 
Dewey, L. H. "Caesar Weed" useful as a fiber plant. See Cyc. 

of Amer. Agri. 2 :285. 
"Weeds in cities and towns. Trbk. U. S. Dept. Agr. 1898: 

193-200. 
IHenfrey, Arthur. Outlines of the natural history of Europe. The 

vegetation of Europe, its conditions and causes. 387. 4 col. tab. 

1852. 
Halsted, B. D. Our worst weeds, a scale of points. Proc. Soc. 

Prom. Agr. Sci. 10:39-43. 
Holtz, P. L. Weeds. Nat. Study Rev. 6 :237-245. 1910. 
Tammel, L. H. A talk on weeds. (Address delivered before 

County Road School, Clinton County, Iowa, 1910 — with ap- 
pendix describing a few weeds.) 54. Ames, 1910. 
Weeds of the Farm and Garden. 281, IBl f. Orange Judd 

& Co., 1911. 
Tammel, L. H., & Fogel, E. D. The underground organs of a few 

weeds. Proc. la. Acad. Sci. 16 :31-40. 
Severance, G. Germination of wheat affected by Russian Thistle 

in the soil. See Pop. Bull. Wash. Agr. Exp. Sta. 15. Abs. in 

Exp. Sta. Rec. 21 :130. 
'Shull, C. A. The oxygen minimum and the germination of Xan- 

thium seeds. Bot. Gaz. 52 :453-477. 
"Stone, A. L. The weed situation. Rept. State Conserv. Com. Wis. 

1911: 60-67. 
Teindl, J. C. Die Unkrautpflanzen. Vienna, 1827. 
Toumey, J. W. Something about weeds. Bull. Ariz. Agr. Exp. 

Sta. 22:32. 
Tronmer. Bonitirung des Bodens. 1853. 
Vitek, E. Weed studies. Monatseh. Landw. 3:333-344. 1910. 

Abs. in Exp. Sta. Rec. 24:543. 
Waldron, L. R. Weed Studies. Bull. N. D. Agr. Exp. Sta. 

62 :449-457. 
Weaver, A. T. Farm management and weeds. Farm Weeds. 

1909 (Nov.) : 1. 
Williams, T. L. Some plants injurious to stock. Bull. S. D. Agr. 

Exp. Sta. 33:21-44. 
Wilson, A. D. Cost of weeds to the farmer. See Farm Weeds. 



862 WEED FLORA OF IOWA 

GLOSSAEY. 
BY HARRIETTE S. KELLOGG. 

Aceumbent. Lying against, as when the edges of the cotyledon 
lie against the cauliele or radicle. 

Achene. A dry, hard, 1-celled, 1-seeded, indehiseent fruit. 

Acuminate. Tapering somewhat gradually to a point. 

Acute. Ending in a sharp angle, not prolonged. 

Aerial roots. Those appearing on the stem above ground; may 
be brace roots as in corn, or clinging roots as in ivy. 

Albumen. Nutritive material in seeds accompanying the 
embryo. 

Aleurone grains. Protein grains replacing albumen in a few oily 
seeds, and starch in others. 

Aleurone layer. Outer layer of the endosperm next to the peri- 
sperm. 

Alternate (leaves). One at a node, not opposite; (flowers) parts 
of one whorl opposite to intervals of next. 

Anatropous. Inverted and straight. 

Angiosperms. Higher seed plants. 

Angium. Case for pollen grains. 

Annual. A plant that performs its life cycle from germination 
to matured seed in one season. 

Annual (Winter). A plant that germinates in the fall, grows 
until frost; but blooms and matures seed the following spring. 

Anther. The part of the stamen which contains the pollen. 

Apetalous. "Without petals. 
■ Apex. Is opposite to point of attachment. 

Appressed. Lying flat against. 

Arachnoid. Cobwebby; covered with tangled hairs, fewer and 
longer than when tomentose. 

Arrow-shaped. See Sagittate. 

Ascending. Rising obliquely or curving upward. 

Auricle. An ear-shaped appendage. 

Awn. An appendage composed of bristles. 

Axil. The upper angle formed between the leaf and stem. 

Axis. The central line of any organ or support of a group of 
organs. 

Axillary. In the axil. 

Barbed. With ridged points or short awns usually reflexed. 



HISTORY AND BIBLIOGRAPHY 863 

Base. The part of an organ nearest its point of support. 

Beard. Awns of grasses; a tuft of hairs, generally stiff and 
long. 

Biennial. Of two years duration; a plant germinating one 
season and maturing seed the next. 

Bract. A modified leaf subtending a flower or flower branch. 

Bracteate. Furnished with bracts. 

Bristle. A short stiff hair. 

Bulb. A leaf bud with fleshy scales; usually subterranean. 

Bulbiferous. Bulb-bearing. 

Callus. A hard protuberance or callosity. 

Calyx. The outer part of the perianth. 

Canescent. Hoary with gray or white pubescence. 

Capillary. Hair-like. 

Capitate. With a globose head. Collected in a head or dense 
cluster. 

Capsule. Any dry dehiscent fruit composed of more than one 
carpel. 

Carpel. A simple pistil or one element of a compound pistil. 

Caryopsis. A dry one-seeded indehiscent fruit with a thin, ad- 
herent pericarp as in many of the grasses. 

Caulicle. The first internode of the stem above the true root. 

Cauline. On the stem. 

Cellulose. Primary cell wall substance. A carbohydrate having 
the general formula (CgHmO,-,) n. 

Chaff. A small thin scale or bract becoming dry or membranous 
as in the glume of grasses or bracts on head of compositse. 

Chalaza. That part of the ovule where all the parts grow to- 
gether. 

Chlorophyll. Green coloring matter of plants. 

Chromataphore. The color-granule. 

Ciliate. Having hairs or bristles on margin. 

Circumseissile. Dividing bj' a transverse circular line as in 
capsule of purslalue. 

Clavate. Club-shaped ; gradually thickened away from the point 
of attachment. 

Cleft. Having narrow sinuses extending about half-way to 
base; as cleft leaf. 

Cleistogamous. Fertilized in bud; closed flowers. 

Climbing. Rising by laying hold of other objects without 
twining. 



864 "WEED FLORA OF IOWA 

Coma. A tuft of any sort. 

Compound. Composed of two or more similar, subordinate- 
parts united into one whole. 

Conduplicate. Folded upon itself lengthwise. 

Cordate. Heart-shaped with point upward. 

Coriaceous. Leathery. 

Corolla. Inner part of the perianth. 

Corymb. A convex, or flat-topped, indefinite inflorescence, like- 
a raceme with lower pedicels elongated. 

Cosmopolitan. "Widely distributed. 

Cotyledons. The first leaves of a plant as found in the embryo^ 

Creeping. Kunning along above ground or beneath the surface,, 
and rooting. 

Cremocarp. Fruit of Umbelliferffi. 

Crenate. Dentate with rounded teeth. 

Crested. Having a ridge or terminal appendage. 

Crystalloids. Protein bodies in the form of crystals. 

Cubn. The stem of grasses. 

Cuneate. Wedge-shaped. 

Cut. Having divisions deeper than when dentate. 

Cyme. A somewhat flat-topped, determinate inflorescence, re- 
sembling a corymb. 

Decumbent. Keclining but with end rising. 

Dehiscent. Opening in a regular manner by valves or slits to- 
discharge seeds. 

Dentate. Toothed, usually with teeth directed outward. 

Denticulate, Finely dentate. 

Determinate Inflorescence. Flowers arise from terminal bud' 
and check growth of axis. 

Diadelphous (stamens). Collected in two sets. 

Dicotyledonous. Plants producing two cotyledons. 

Diffuse. Spreading loosely and irregularly. 

Digitate. Compound with parts radiating from apex of supports 

Dioecious. Having stamens and pistils in separate flowers upon 
different plants. 

Divided. Having incisions extending to base or midrib. 

Dorsal. Pertaining to back or outer surface of organ. 

Downy. Having a dense covering of short weak hairs. 

Elliptical. Oblong and rounded at ends. 

Emarginate. Notched at end. 

Embryo. Rudimentary plantlet within the seed. 



HISTORY AND BIBLIOGRAPHY 865 

Endosperm. Albumen of seed in embryo-sac as distinguished 
from perisperm. 

Epicarp. Outer layer of pericarp. 

Epiderm. External layer of cells in any organ. 

Epigynous. Corolla seems to rise from top of ovary. 

Erect. Perpendicular, or nearly so, to the surface to which at- 
tachment is made. 

Exserted. Protruding beyond margin of envelope as stamens 
from corolla. 

Falcate. Scythe-shaped. 

Fertile. Capable of producing fruit. 

Pibrovascular Bundle. A bundle of stringlike, woody, fibro- 
vascular tissue, containing xylem and phloem. 

Fibrous. Composed of fibers. 

Filiform. Thread-shaped. 

Floccose. Covered with mats or flocks of soft woolly hairs. 

Foliate. Leaved, as trifoliate (three-leaved). 

Fruit. The mature ovary and its contents with any closely ad- 
hering part. 

Funicle. The stalk of a seed or ovule. 

Fusjforjn. Enlarged in the middle and tapering toward each 
eod. 

Gamopetalous. Having petals more or less united. 

Glabrous. Smooth. 

Gland. A secreting surface or structure. 

Glandular. Bearing glands or glandlike. 

Glaucous. Covered with a whitish bloom, as on cabbage. 

Globoids. Granules of calcium-magnesium-phosphate found in 
grains of aleurone. 

Globose. Spherical or nearly so. 

Glomerate. Compactly clustered in ^ head. 

Glume. One of the outer floral envelopes of grasses. 

Glutinous. Viscid, sticky. 

Hairy. Covered with hairs longer and coarser than when 
pubescent. 

Halberd-shaped. See hastate. 

Hastate. Describing leaves which have spreading lobes at the 



Heart-shaped. See cordate. 

Herb. A plant which contains but little wood in the stem and 
which dies down to the ground each year. 
55 



866 WEED FLORA OF IOWA 

Herbaceous. Having the characters of an herb. 

Hermaphrodite. Perfect, having both stamens and pistils In the 
same flower. 

Hilum. The scar of the seed ; its place of attachment. 

Hirsute. Clothed with rather coarse or stiff hairs. 

Hispid. Beset with erect stiff hairs or with bristles. 

Hypoderm. Beneath the epiderm. 

Hypogynous. With parts under pistil. 

Imbricated. Overlapping either vertically or spirally like 
shingles of a roof. In aestivation, one piece is wholly external and 
one wholly internal. 

Imperfect. Applied to a flower lacking either stamens or pistils. 

Included. Opposed to exserted; not protruding from the en- 
velope. 

Incumbent. Applied to cotyledons when the radicle is folded 
back against one of them. 

Indehiscent. Not opening by valves or slits. 

Indeterminate Inflorescence. Flowers arise laterally and suc- 
cessively as floral axis elongates. 

Indurated. Hardened. 

Inflexed. Bent abruptly inward or downward. 

Inflorescence. The flowering part of a plant. 

Inserted. Attached to or growing out of. 

Integuments. Coats of ovule. 

Intemode. Any part of a stem situated between two nodes. 

Interrupted. Applied to surface or series the continuity of 
which is broken. 

Involucre. A circle or collection of bracts immediately subtend- 
ing a flower or inflorescence. 

Isodiametric. Equal in three dimensions. 

Joint. A node. 

Keel. A ridge somewhat resembling the keel of a boat; applied 
especially to the two anterior united petals of a papilionaceous 
flower. 

Lamella. A thin plate. 

Lamina. Blade or expanded part of leaf. 

Lanceolate. Lanee-shaped ; tapering abruptly toward the base 
and gradually toward the apex. 

Lenticular. Lentil-shaped ; in the shape of a double convex lens. 

Ligneous, lignose, lignified. Woody in texture. 

Ligulate. Refers to the strap-shaped corolla of composite flow- 
ers, as Dandelions, 



HISTORY AND BIBLIOGRAPHY 867 

Ligule. A. A strap-shaped corolla, as in the ray flowers of 
composites, like the sunflower. B. A membranous projection on 
inner side of leaf at top of sheath of some, grasses, 

Linear. Long and narrow with nearly parallel margins. 

Lobe. A rounded portion or segment of any organ. 

Locule. Cavity within ovule. 

Lumen. Internal space or cavity of a cell. 

Lyrate. Lyre-shaped. 

Membranaceous or membranous. Thin, soft, and generally trans- 
lucent. 

Malpighian Cells. Palisade cells in which one or more light lines 
are present. 

Mesocarp. Middle layer of pericarp. 

Mesophyll. All of the fundamental tissue within the epidermis. 

Micropyle. Opening through which poUen tube passes. 

Monadelphous. Stamens united in one set. 

Monocotyledon. One cotyledon. 

Monoecious. "With stamens and pistils in separate flowers on 
the same plant. 

Mother Cells. Large dense cells in pollen lobes. 

Mucronate. Tipped with a short stiff point. 

Multiple. Compound. 

Muricate. Beset with short and hard or prickly points. 

Nerve. Any vein on the floral envelopes of grasses. ' 

Node. The place on a stem where one or more leaves are at- 
tached; the joint. 

Nucellus. Nucleus of an ovule. 

Oblanceolate. Lanceolate with the broadest part toward the 
apex. 

Oblong. Widely linear. 

Obovate. Inverted ovate. 

Obtuse. Blunt or rounded at the apex. 

Orbicular. Circular. 

Osteoselerids. Cells generally accompanying Malpighian Cells 
in LeguminosEe. They vary in shape and length, sometimes marked 
by longitudinal canals. 

Ovary. Seed case of pistil. 

Ovate. Outline like that of an egg, with larger part downward. 

Ovule. Unripe seeds in ovary. 

Palet. Upper bract of the flower in grasses. 

Palisade cells. Elongated cells perpendicular to epidermis on 
upper side of leaf. 



868 WteED FLORA OF lOWA 

Palmate. Radiately lobed or divided. 

Panicle. Loosely, irregularly branched raceme. 

Papilionaceous. Butterfly -shaped, like the corolla of the pea, etc. 

Papilla. A soft elongated projection. 

Papillate. Having papillae. 

Pappillose. Papillate. 

Pappus. The modified limb of the calyx in corn, in Composite, 
especially, when the summit is developed in a feathery or plumose 
manner. 

Parenchyma. All tissue composed of cells not having tapering 
extremities; soft cellular tissue like that of pith. 

Parted. Cleft nearly or quite to the base. 

Pedicel. A branch of inflorescence- supporting one or more 
flowers. 

Peduncle. A flower-stalk. 

Perennial. Living more than two years. 

Perfect. Having both pistil and stamens. 

Perianth. The floral envelope including calyx and corolla (or 
calyx alone when corolla is absent) whatever their form. 

Pericarp. The matured ovary. 

Perigynia. The bodies around the pistil. 

Perigynous. Parts around pistil. 

Persistent. Remaining longer than usual, as calyx upon fruit, 
or leaves which die but remain on trees through the winter. 

Perisperm. The albumen of a seed. 

Petal. A division of the corolla. 

Petiole. The stalk of a leaf. 

Phloem. Portion of fibrovascular bundle containing the bast 
and sieve tissues. 

Photosynthesis. Process by which sugar and starch are pro- 
duced in a plant by means of the chlorophyll grain. 

Pilose. Covered with long soft hairs. 

Pinnate leaf. Compound with leaflets arranged on each side of 
a common petiole. 

Pinnatifid. Pinnately cleft. 

Pistil. The central seed-bearing organ of the flower consisting 
of ovary, style and stigma. 

Pistillate. Provided with pistils; properly, without stamens. 

Placenta. The part of the ovary to which the ovules are attached. 

Plumose. Like a feather, having fine hairs on each side, as in 
the pappus-bristles of thistles. 

Pod. Any dry, dehiscent fruit. 



HISTORY AND BIBLIOGRAPHY 869 

Pollen. The fertilizing powder produced in the anthers. 

Pollination. Transferring pollen from anther to stigma. 

Polygamous. Plants bearing both perfect flowers and flowers 
of either sex, or of both, as in the soft maple. 

Pore-canal. Passage through a pit between adjoining cells. 

Prickles. Short, stiff, spinelike growths from the epidermis, as 
in the rose. 

Proeambium. Fibrovaseular tissue of an organ formed before 
it is differentiated into xylem and phloem. 

Prostrate. Lying flat on the ground. 

Protein. A plant food manufactured in the plant from starch or 
sugar by the addition of one of the compounds of nitrogen, phos- 
phorus, potassium or other similar substances. 

Protogynous or proterogynous. Having pistils ready for fertili- 
zation beifore anthers are matured. 

Puberulent. Minutely pubescent. 

Pubescent. Covered with fine, soft, short hairs. 

Raceme. A simple indeterminate inflorescence of pediceled flow- 
ers arranged along a rather long, common axis. 

Rachilla. Axis of spikelet in grasses. 

Rachis. The axis of a spike or other body. 

Radical. Proceeding from the root or base of stem. 

Raphe. The continuation of the seed-stalk along the side of an 
anatropous ovule or seed. 

Receptacle. Summit of flower-stalk. 

Reflexed. Abruptly bent or turned downward. 

Repand. Having a slightly undulating miargin. 

Respiration. Process of absorption of oxygen and giving out of 
carbon dioxide. 

Reticulated. Net-veined. 

Retrose. Directed backward or downward. 

Rhizome. Any subterranean stem, usually rooting at the nodes 
and rising at the apex.. 

Rib. A primary or prominent vein in a leaf. 

Root. The descending axis of the plant, which supplies it with 
nourishment. 

Root-stock. See Rhizome. 

Runcinate. Sharply toothed, the teeth directed backward. 

Runner. A slender stolon that roots and forms new plants at 
intervals. 

Sagittate (leaves). Arrow-shaped, lobes with acute lobes and 
apex. 



870 WEED FLORA OF IOWA 

Scabrous. Having a rough surface. 

Scale. Any thin appendage, morphologically a modified, degen- 
erated leaf. 

Scape. A peduncle rising from the root, without proper foliage. 

Scapose. Resembling a scape. 

Scarious. Dry and membranous. 

Sclerenchyma. Lignified tissue as applied to thick-walled fibers. 

Sclerotic. Consisting of sclerenchyma. 

Seed. The ripened ovule, enclosing a rudimentary plant, and 
the food necessary for its germination. 

Sepal. A division of the calyx. 

Serrate. Having sharp teeth pointing forward. 

Serrulate. Finely serrate. 

Sessile. Without a stalk ; thus a leaf is sessile when the blade is 
seated directly upon the stem. 

Sheath. A tubular envelope as the sheath of grasses. 

Shrub. A woody perennial smaller than a tree and usually hav- 
ing several stems. 

Simple. Without subdivisions, opposed to compound; leaves, as 
oak, dock, etc. 

Sinuate. Having strongly wavy margin. 

Sinuous. Wavy, curving back and forth. 

Sinus. The cleft between two lobes or divisions. 

Spatulate. Shaped like a druggist's spatula, rounded at the 
summit and gradually narrowed downward. 

Spicate. Arranged in a spike. 

Spike. An inflorescence like a raceme, except that the flowers are 
sessile. 

Spikelet. The characteristic inflorescence of grasses. 

Spindle-shaped. See Fusiform. 

Spine. A sharp, rigid process growing from the stem. 

Sporangium. Spore case. 

Spore. Pollen grain ; reproductive body of flowerless plants. 

Spreading. Applied to branches that bend outward at less than 
a right angle. 

Stamen. A pollen-bearing organ of a flower. 

Staminate. Applied to a flower or plant which has stamens, but 
no pistils. 

Stellate. Star-shaped. 

Sterile. Unfruitful, as a flower without a pistil or antherless 
stamen. 



HISTORY AND BIBLIOGRAPHY 871 

Stigma. That part of the pistil which receives the pollen. 

Stipules. Leaf-like appendages arranged in a pair at the base 
of the leaf stalk. 

Stolon, or stole. A trailing or reclining and rooting shoot. 

Stoma. Opening into the epidermis by which air enters and 
moisture escapes. 

Striate. Marked with parallel lines or ridges. 

Style. The slender part of a pistil supporting the stigma. 

Sub-. A prefix meaning somewhat or slightly. 

Succulent. Juicy, fleshy. 

Suspensor. Filament of cells in ovary. 

Tapetal Cells. Cells surrounding mother cells in pollen and con- 
taining food material. 

Terete. Long and round. 

Terminal. Attached to or pertaining to the extremity or apex, 
as the terminal bud. 

Testa. Outer seed coat. Sometimes both coats are spoken of as 
the testa. 

Tomentose. Densely pubescent with matted wool. 

Tomentum. Matted, woolly hairs. 

Toothed. See Dentate. 

Trailing. Prostrate on the ground but not rooting. 

Transpiration. Process by which leaves lose moisture. 

Trichome. A plant hair of any kind. 

Truncate. Ending abruptly as if cut off transversely. 

Tuber. A short thickened subterranean branch. 

Turbinate. Top-shaped. 

Turgid. Thickened like a tuber, or distended with a liquid (never 
with air) . 

Umbel. Any indeterminate inflorescence in which the peduncles 
or pedicels of a cluster seem to rise from the same point. 

Umbellate. Like an umbel. 

Undulate. Having a wavy surface. 

Urtieating. Stinging. A term applied especially to the plant 
hairs of members of the Urticaceae, some of which are poisonous. 

Utricle. A small inflated membranous 1-seeded fruit. 

Valve. 1. One of the parts of a dehiscent fruit. 2. Applied 
also to the top of a pitcher in the Sarracenia. 

Vein. A bundle of threads of fibro-vascular tissue in a leaf or 
other organ. 

VerticiUate. Whorled. 

Villous. Bearing long, soft, straight hairs. 



872 WEED FLORA OF IOWA 

Viscid. Sticky, glutinous. 

"Wavy. Margin forms wavy line bending inward and outward 
in succession. 

Wedge-shaped. See Cuneate. 

Whorl. An arrangement of organs in a circle around a stem. 

Wing. 1. Any thin or membranous expansion attached to or 
bordering an organ. 2. The lateral petal of a papilionaceous 
flower. 

Winter annual. See Annual. 

Xylem. Woody part of fibrovaseular bundle containing larger 
continuous air-containing vessels; the water-conducting tissue. 



INDEX 



ABBREVIATIONS. 
f=figrure. 
in=inap. 
sp=species. 
syn=synonyin. 



Abbey. W. L. 766 
Absinth 307 

Abutilon theophrasti (,syn. avicennae) 
215-218, 718, 790, 796, 799. f. gl6, 
nt, IIS 

Distribution 734, 762, m. 216 

Seed 5S7-558, f. 559 
Acacia, False 

Distribution 718 
Acaena ovina 849 
Acalypha virginica 205-207, 788, f. 206 

Distribution 718, m. 207 

Seed 457, f. isr 
Acer saccharinum. Seed f. 63i 
Achene 862 

Achillea millefolium 358-360, 778, 787, 
f. SS9, 7il 

Chemical composition 674 

Distribution 698, 720, 736, 740, m. 
S59 

Seed 491, f. m 
Acidia heraclei 677 

Acloque, A. 731, 737, 738, 740, 754, 837 
Acnida tamariscina 118 

tuberculata 118-119, 789, f. 118 

Distribution in. 119 

Seed 435, f. iS5 
tuberculata v. prostrata 

Distribution 716 
Adams, G. E. 846 
Adaptation of plants 637 
Aderhold, R. 846 
Adulterated seed 811-815, 827. S56. 857. 

858, 859. 860 
Adulteration and Seeds Act 793 
Adventive plants 696-697, 707 
Aegopodium poda^raria 

Distribution 736 
Aerial roots 862 
Aethusa cynapium 663 

Distribution 736 
Africa, Weeds, 722, 731, 732, 733, 734 
African Colonies, South 

'Weed laivs 793 
Agastache scrophulariaefolia 

Seed 567, f. i70, 567 
Ageratum conyzoides 

Distribution 734 
Agoseris cuspidata 502, f. 501 
Agrimonia striata 

Distribution 734 
Agropyron caninum 

Distribution 715 
repens 53-58, 664, 774, 796, 799. f. Sh 
775 

Chemical comoosition 57-58 

Distribution 715. 736, m. 55 

Root system 652, f. 6-',3 

Seed 421-423, 810, f. i;2. CSS 
smithii 53 

Distribi'tio" vi. 56 

Seed 423, f. ^23 
tenerum 

Distribution m. 56 

Seed f. r2 
Agrostemma sithaEro 125-136, 789, 819, 
f. 195, 100 

Distribution 699, 716, 735. 736, m. 
lie 

Seed 436, 776, 810, 829, f. iS6, 688 

56 



Agrostis alba 667 
Distribution 715 
Seed 415, 811, 813, f. -in 
canina 677 
hyemalis 

Distribution 732 
sp. 664 
spica-venti 

Distribution 736 
vulgaris 851 
Agueweed 780 
Aira caespitosa 667 

AIZOAGEAE 

Distribution 723 
Alabama Flora 707-708, 722-723 
Alberta weed legislation 793 
Albugo Candida f. 681 
Albumen 862 
Alchemilla arvensis 664 
Aleurone cells 524, 530, f. 523, 529 
"fleck" 553 
grains 862 

layer 510, 519, 549, 572, f. 518 
Alfalfa 183, 852, f. 595 
Dodder 

Seed 810 
Rocket 159 

Seed 810, 811, 812, 828. 831, 833, 855 
Impurities 712, 833. 834, 836, 839, 
856, 857, 858. 859 
Alfilaria 

Distribution 725 
Seed 457, f. .(57 
Alice, G. 847 
Alien plants 697-698 
Alkali soils. Weeds 820 
Alkanet 256 

Allitim eanadense 67, 623, 787, f. 68 
Distribution 67, 68 
carinata 

Distribution 839 
vineale 

Distribution 715 
Almond 175 

Alopecurus agrestis 664, 665 
Distribution 736 
geniculatus f. 7SB 

Distribution 715, 732-740 
pratensis 

Distribution 715 
Alpers 713, 738, 740 
Alsike Clover 

Seed 460, 810. 812. 830, f. .',51, 6S8 
Impurities f. 638 
Alternate flowers 862 

leaves 594. 862 
Alyssum, Hoary 147-149, f. m 
Distribution 717, ni. liS 
Sweet 142 
Amaranth 

Family 113-119 
Distribution 723 
Seed 434-435 
Purple 697 

Rovoh syn. Rough Pigweed 
sp. f. 636 
Spiny 697 

Distribution 723 
Svreading syn. Prostrate Pigweed 
Tumbling syn. Tumbling Pigweed 



874 



INDEX 



Amaranthaoeae 3, 113-119, 434-435 

Bibliography 582 

Distribution 716, 723 
Amaranthus blltoldes 117-118, 788, t- 

m 

Distribution 716, m. Ill 

Seed 434, f. m 
graecizans 115-116, 788, f. 116 

Distribution 690, 716, 738 

Seed 434, f. m, 6S1 
hybridus 

Distribution 723 
panlculatus 697 
retroflexus 113-115, 790, f. 116 

Chemical composition 115 

Distribution 716, 723, 734, 737, 
m. 115 

Seed 434, f. J,S5, 676 

Trichomes, f. lis 
sp. Distribution 705, f. 595 
spinosus 697 

Distribution 723 
viridis 

Distribution 843 
Ambrosia artemisiifolia 328-331, 778, 
789, 849, f. SSO, SSI 

Distribution 698, 704, 720, 730, 740, 
m. SSI 

Seed 482-483, f. IfiS, ST/ 
bidentata 

Seed 483, f. iSS 
psilostachya 331-332 

Distribution 689, f. SSB 

Root 651 

Seed 484, f. m 
trifida 326-327, 691, 789, f. S21, 672 

Distribution 691, 720, m. S27 

Seed 484, 574, f. JfiS 

Germander 272-273. 469, 470, 789 
Gromwell, 467 
Weeds 698 
Amsinckia 

Distribution 725 
intermedia 

Distribution 844 
Anacaediaceae 4, 213, 214. 215 
Anagallls arvensis 

Distribution 719, 740 
Anaphalis margaritacea 

Distribution 740 
Anatropous seed 862 
Anderson, J. P. XI, 751 
Anderson, D. 860 
Andropogon furcatus 688 
scoparlus 688, f. 689 
sorghum technicus 512, f. SIS, Slli, 515 

Seed 512-515 
sp. Distribution 701 
virginicum 

Distribution 722 
Anemia 

Distribution 693 
Anemone cvlindrica 
Seed 439, f. 489 
Long-fruited 

Seed 439, f. JiS9 
ANGIOSPBRMAB 3. 6-587 
Angiosperms 6-587, 862 
Angium 862 
Angle-pod 787 
Animals. Seed scattered by 629, f. 63S, 

6SS 
Annual 647, 650. 691, 862 
Brome grass syn. Soft Chess 
Meadow Grass 664 
Morning Glory 244, 245, 563, 564, 696 
Sow Thistle 391-393 
Sunflower 730. 756 
"Winter 647-648, 660, 691, 786, 862 
Antennaria margaritacea 
Distribution 705 
plantaginifolia 
Distribution 705 



Anthemis arvensis 

Distribution 735-736 
cotula .360-362, 778, 788, f. 361 

Distribution 696, 720. 736, m. SCI 
Seed 491, f. m 
Anther 615, 862, f. 615 
Anthoxanthum odoratum 
Distribution 693, 714 
Apera svicaventi seed f. 6S9 
Apetalous flowers 609, 862 

Pepvergrass syn. Large Peppergrass 
Apex 862 
Aphis 

Bean 677 
rumlcis 677 
Aplopappus sp. 846 
Apoctnacbab 4, 234-237, 701 

Distribution 719. 723 
Apocynum androsaemifolium 235 
Distribution 719, m. 2S.5 
androsaemifolium hypericifolium f. 

Z36 
cannabinum 235-237, 788, f. 236 
Distribution 719, m. 237 
Root 651 
Apple 175, 632 
Leaf, f. 591 
May 618 
-of-Feru 

Distribution 737 
Wild Balsam 573 
Seed 574 
Arable land. Weeds of 664, 665 
Arbutus. Trailing 702 
Arcangeli. G. 731, 737, 738. 740, 838 
Arctium lappa 370, 371, 778, 789, 796, 
799, f. 370, 37 1, 779 
Distribution 721, 725, m. S71 
Root system 644 
Seed 493, 576-577, f. m. 577 
sp. 577, 701 
Argemone intermedia, 441, f. W) 
Distribution 729 
mexicana 

Distribution 696 
platyceras syn. A. intermedia 
Argentine, Weeds 757 
Aristida dichotoma 28-29, 790, f. 28 
Distribution, m. 29 
sp. Distribution. 701 
tuberculosa 29-30, f. SO 
Arizona seed investigations 834 
Arkansas weeds 757 
Armstrong 768 
Arnica cordlfolia 

Distribution 695 
Arrhenatherum avenaceum 
Seed 813 
avenaceum v. bulbosum 851 
Artemisia biennis 367-368, 790, f. 367 
Distribution 705. 721, m. S68 ■ 
Seed 492, f. m 
ludovlciana 366-367, 790, f. S66 
Distribution m. SSI 
Arthur, J. C. 746. 751, 758, 766. 767, 

826, 838 
Artichoke 307, 346-348, 790, f. 3!^, Si7 
Distribution 691, 740, m. 31,7 
Trichomes f. 488 
Arum 

Distribution 693 
ASCLBPIADACBAE 4, 237-241. 634 
Bibliography 582 
Distribution 719 
Seed 462-463, 562-563 
Asclepias cornuti syn. A. syriaca 
incarnata 777 

Seed 462, f. ^63 
speclosa 237-238, 787, f. 238 

Distribution 719. m. 238 
syriaca 239-241, 777. 788, f. 239-21,0 
Distribution 691, 705, 719, 794, m. 



INDEX 



875 



Root system 651, f. eJfi 
Seed 462, 562-563, f. 1,6S, 568, 632 
tuberosa 

Seed 463 f. JfiS 
verticillata 

Seed 463, f. JfiS 
Ash 6, 632 
Ashton, W. M. 766 
Asia, Weeds of 731, 732, 733, 734 
Asparagus 6 
Aspens 703 
Aster azureus 689 
drummondii 481 

Trichomes f. <82 
laevis 481, 689 

Trichomes f. liS2 
macrophyllus 481 

Trichomes f. ^82 
Many-flowered 317-318, 790, f. Slf 

Distribution 689, m. $18 
multiflorus 317-318, 790, f. S18 
Distribution 690, m. 318 
Trichomes f. 481 
novae-angliae, Trichomes f. 481 
novi-belgii. Distribution 737 
oblongifolius, Trichomes f. iSl 
paniculatus f. 320 
parviflorus 

Distribution 737 
sahcifolius 319-320, 790, f. SW 
Distribution 737, m. S20 
Seed 481, f. m 
Trichomes f. i81 
sp. 594 
tradescanti 320 

Trichomes f. 781 
White. See Many-flowered 
Willow-leaved 319-320, 790, f. 319 
Distribution m. 3W 
Seed 481, t- iSl 
Astragalus canadensis 193, f. 19lf 

mexicanus 554 
Atriplex hortense 
Distribution 736 
patula V. hastata 109-110, f. 110 
Distribution 716, 740, 789, m. 110 
Seed 433, f. m 
Atropa belladonna 

Distribution, 736 
Aughey 765 
Auricle 862 

Australia. Flora of 696, 731, 732, 733, 
734, 763 
Seed investigations 837 
Weed legislation 793 
Weeds 839 
Australian Burr 849 
Avena fatua 40-41. 789, f. 1,0 
Distribution 71'^. 736. m. 1,1 
Seed 415-416, 810, 829, f. J,16 
glabrata 

Seed 829 
sativa 
Seed 813 
Avens, Seed 449. 788, f. W 

White Sim. Stickfeed 
Awn 609, 8S2, f. 609 
Awned Brome grass syn. Downy 
Brome Grnss 
Wheat erass 7i5 
Awnless Brome Grass 812 
Axil 862 
Axillary flowers 610 

Placenta f. erg 
Axis, Floral, 611 

Babcock, O. G. 74 8 
Bachelor's Button 

DiFtribut'on 727 
Rachmann, B. 586 
Bailey, B. H. S. 837 
Bailey, F. M. R'"! 
Bailey, L. H. 847, 860' 



Baldwin's Ironweed 309-310, f. SIO 
Distribution m. 310 
Seed 477, f. 1,17 
Ball, C. R. 745, 760, 834,-855 
Ball, O. M. 834, 855 
Ball Mustard 163, 717, 814 
Balsam Apple 573, f. S'J, 
Bamber, M. K. 847 
Barbarea vulgaris 170, 787, f. 170 

Distribution 717, 733, 740, m. 171 
Seed 447-448, 544, f. I,h7 , 51,2 
Barber, C. J. 750 
Barberry, 678 

Family, Distribution 723 
Barley 8 

Blight f. 680 
Blindness of 677 
Grass 667 
Little 61-63, f. 62 

Chemical composition 61, 63 
Distribution 715, m. 62 
Seed f. i2i 
Seed 812 

Transpiration 673 
Wild syn. Squirrel-tail Grass 
Barnaby's Thistle syn. Knapweed 
Barnet. 664 

Barnyard Grass 16, 790, f. 16, 330 
Chemical compositicn 17 
Distribution 731. m. 16 
Seed 411-412, 506, f. 1,12, SOS, 729 
Base 862 

Bartlett, J. M. 853 
Barton, L. W. 833 
Barton, W. M. C. 773, 853 
Basil 286 

Distribution 720 
Basswood seed 631, f. 6S2 
Beach, C. L. 855 
Beach, D. D. 834 ■ 
Beal, W. J. XI, XIII, 24, 824, 830, 838, 

855 
Bean 67, 180, 621 
Aphis 677 
Castor-oil 205 

Distribution 696 
Coffee 180 
Trailing wild 

Distribution 718 
Transpiration 673 
Wild 199-200 

Distribution 718, m, 200 
Seed 455, f. iSS 
Beard Grass 862 

Distribution 722 
Beard-tongue 845 
Bebb, M. S. 747 
Beck 765 
Beck, G. 553. 585 
Beck, L. C. 838 
Bedford, S. A. 57 
Bedstraw 572. 594. 663. 665, f. 573 
Distribution 693, 741 
Seed 476, f. 1,76 
Bee-plant. Rocky Mountain 173-175, 
f. m, 175 
Distribution 729, 730, m. 17i 
Seed 448, f. 1,1,8 
Beet 99 

Distribution 712, 725 
Root system 648 
Sugar 99 
Beetle. Colorado 677 
Flv 676 

Turnio Flea 676 
Beggar's Lice 259-260, 788, f. 259 
Distribution 821 
Seed 466, f. 1,67 
Beggar-ticks 351-352, 624, 664, 789, 
822 f 351 
Distribution 617. 720, 740. in. .'!52 
Root system 645 



876 



INDEX 



Seed 489, t Ifi9, SiS, 6S5 
Black ayn. Beggar-ticks 
Small 

Distribution 720 
Sp. Seed f. i89 
BelUs perennls 667 
Bennett, J. L. 766 
Bent Grass 667 
Pine 664, 665 
Reed, Distribution 736 
Silky, Seed f. 639 
Bentham, G. 731, 838 
Beebebidaobab, Bibliography 582 

Distribution 723 
Bermuda Grass, Distribution 732 
Bergen, J. W. 838 
Bergen and Davis XII 
Berlin Botanical Garden, weeds dis- 

trtbuted by, 753 
Bemholtz, L. 748 
Berry 625 
Bersch. W. 847 

Berteroa incana 147-149, 788, f. US 
Distribution 700, 713, 717, m. liS 
mutabllis 

Distribution 700 
Bessey, C. E. 288, 584, 748, 755, 756, 

758, 760, 761, 825, 847 
Bessey, E. A. XII, 831, 855 
Beta 532 

vulgaris 725 
Bettomer, Ellen 755 
Bexar 767 
Bibliography 

Anatomical study of seed coats 

580-587 
Chemical composition of weeds 837 
Distribution of weeds 837-846 
Eradication of weeds 846-853 
Medical plants 853-855 
Weed laws 860 
Weed seeds 855-860 
Bidens 624, 633, 789 

aristosa 352-354, 489, 790, f. S5S 
Distribution m. S5i 
Trichome f. Ii90 
blpinnata. Distribution 696, 734 

Seed 489, f. J,89, 6SS 
cemua 489, 789 
Distribution 740 
Trichome f. 1/90 
dlscoldea 349-351, 789, f. 350 
Distribution 691, 720, m. mO 
Seed 489, f. J,89, 577 
frondosa 351-352. 664, f. SH 

Distribution 691, 720, 740, m. 352 
Seed 489, >. 1,89, ms, 6SS 
leucanthus. Distribution 740 
pilosa 697 
Biennial Gaura 718 

Wormwood 367-368, 790 
Biennials 648, 786, 862 
Blgelovia nudata, Trichomas f. 1,82 
Bigelow, Jacob 708, 711, 751, 773. 853 
Bignonla Family 
Distribution 723 

BiGNONIACBAB 

Distribution 723 
Bindweed, Black 97-99, 663, 677, 789, 
f. 98 
Distribution 696, 698, 716, 829, 

m. 99 
Seed 429, 528-531, f. Ji29, 526j 528, 529, 
5H0, 531 
European 248-250, 663, 665. 777, 787, 
844, f. 21,9, 593, 59/, 
Distribution 719, 727, 735, m. 21,9 
Root system 651, f, 553 
Seed 463, 563, /. m 
Hedge 245-248, 848, f. 8^6 
Distribution m. 2i6 



Small syn. Europeam. 
Wild syn. Black 
Birch sp. Distribution 673 
Birds destroy seeds 629, f. 636 

distribute seeds 629, 636, 859, f. 
687, 638 
Blrd's-foot Trefoil 734 

Seed 815 
Blrkett 824 

Birllngmair, R. H. XII. 657 
Bisexual flowers 605 
Bishop, J. J. 336-337 
Bitter, Dr. 707, 713, 737, 738, 740 
Bitter Dock, 78-79, 428, 595, 726, 774, 

789 
Black Beggar-ticks syn. Beggar-ticks 
Bindweed 97-99, 429, 526, 528-531, 

677, 696, 698, 716, 789, 829 
Cherry, Wild 637 

Couch Grass syn. Fine Bent Grass 
Henbane 277, 709, 736 
Knapweed 664, 725 
Medic 190-191, 453, 546-549, 688, 718, 

725, 728, 729, 734, 761 
Mustard 142, 157-159, 445-446, 541- 
543, 605, 696, 701, 717, 725, 776, 
7