Great Western Fireweed (Epilobium an gusti folium). A weed in clearings following fires, especially in the North, Rocky Mountains and the Pacific Coast. The seeds are carried by the wind. (Photograph by Charlotte M. King.) WEEDS OF THE FARM AND GARDEN & ^^ By L. H. PAMMEL, B. Agr., M. S., Ph. D. Professor of Botany, Iowa State College, and Botanist Iowa Agricultural Experiment Station NEW YORK ORANGE JUDD COMPANY LONDON KEGAN PAUL, TRENCH, TRUBNER & CO., Limited 1912 Copyright, 1911, by ORANGE JUDD COMPANY All Right* Reserved ENTERED AT STATIONERS' HALL LONDON. ENGLAND Printed in U. S. A. This work *s dedicated to the Honorable Secretary of Agriculture, James Wilson, under whose auspices as Secretary of Agriculture, a great stimulus has been given to American Agriculture. The Author PREFACE There has long- been needed a book describing the more important weeds of the United States, although there are numerous publications of the United States government and state experiment stations that treat of the more im- portant weeds of the United States and Canada and their eradication. The demand for publications of this kind is so great that the editions soon become exhausted. This work on weeds is here presented to bring some of the more important phases of the subject together in one treatise. Comparatively few books on this subject have been published in America. The treatise by Fletcher and Clark, and a second edition revised by Clark, treat the subject admirably. The work of Darlington and Thurber, " American Weeds and Useful Plants." found a welcome place in the botanists' library. The little book by Prof. Thomas Shaw also filled a most useful place in the agricultural literature of this country. The weeds described in the present manual by no means cover all that are injurious, and we have de- scribed many more from eastern North America than from the Pacific coast or the southern states. In a work of limited scope it has been impossible to include more than a fraction of the weeds of the country. Those who are interested in a further study of the plants should provide themselves with such admirable manuals as the seventh Revised Edition of Gray's Manual by Robinson and Fer- nald, Nelson and Coulter's New Manual of Rocky Moun- VI PREFACE tain Botany and Britton's Manual, Chapman's Flora of the Southern States, Small's Flora of the Southern States and a Flora of California soon to be issued by Professor Jepson. The chapters on eradication of weeds, how weeds are disseminated, the farmer's interest in good seed, as well as the method of weed propagation, should be of special interest to the farmer. The illustrations should be help- ful to those who are not familiar with the technical terms used in the descriptions of plants. Some of the figures were drawn by Miss Charlotte M. King, generally not indicated except by her initials, others by Miss Ada Hay- den, all indicated except figures redrawn from other sources. To both I express my thanks for the artistic sketches. Many of the remaining figures have been taken from publications of the United States Department of Agriculture and the Iowa Agricultural Experiment Sta- tion. Credit has been given in every case. I am also greatly indebted to Miss Harriette S. Kellogg for the preparation of the bibliography, index, the reading of the manuscript and proof. L. H. PAMMEL. Ames, Iowa. April 5, 1911. TABLE OF CONTENTS Chapter Page I. Weeds: Injury to Crops and Nature of I II. Kinds of Weeds as to Duration 7 III. Dispersal of Weed Seeds 14 IV. The Farmer's Interest in Good Seed, and How to Test Seed 27 V. Weed Impurities in Agricultural Seeds 32 VI. Some Weed Laws and Seed-Control Laws.. 43 VII. Weeds of Special Crops 50 VIII. Poisonous Weeds 63 IX. Table of Noxious Weeds 65 X. Migration of Weeds 76 XI. Extermination of Weeds 87 XII. Treatment for Special Weeds 104 XIII. Morphology of Weeds 114 XIV. Descriptions of Some Common Weeds 135 XV. Partial Bibliography, Consisting of Easily Accessible References, Arranged by Har- riette S. Kellogg 255 Til LIST OF ILLUSTRATIONS FIGURE PAGE Fireweed— Frontispiece 1. Canada Thistle Seed 7 2. Woolly Thistle Plant 8 3. Pigeon Grass 9 4. Root of Milkweed 11 5. Scattering of Red Cedar by Birds 14 6. Tumble Weed 15 7. Bull Thistle "Seed" 16 8. Seed of Vegetable Oyster 17 9. Ragweed Sunflower, and Foxtail Seeds 17 10. Seed of Sedge 18 11. Arrow-Head Seed 18 12. Cast from Crow Containing Various Seeds 19 13. Goldfinch Eating Dandelion Seeds 20 14. Pod of Licorice; "Seed" of Cocklebur; Section of Carrot Seed 20 15. Burdock Head 21 16. "Seeds" of Pitchforks 21 17. Seeds Scattered through Explosive Properties 21 18. Explosive Seeds and Fruits 22 19. Seeds Distributed with Wheat Seed 23 20. Russian Thistle Seed 24 21. Ragweed Seed 24 22. Foxtail Seed 24 23. Plaintain Seed 25 24. Smartweed Seeds 25 25. Wild Carrot Seeds 25 26. Canada Thistle Seeds 26 27. Impurities in Red Clover Seeds 34 28. Red Clover and Sweet Clover Seeds 35 29. Impurities in Alsike Clover Seeds 35 30. Impurities in Alfalfa Seeds 36 31. Seeds of Kentucky and Canadian Blue Grass 36 32. Seeds of Various Grasses 37 33. White Weed 53 33a. California Poison Ivy 63 33b. Poison Ivy 64 33c., 33d., 34., Maps Showing Distribution of Various Weeds 77, 79, 82 34a. Wild Morning Glory 113 35. Fibrous Root of Crab Grass 114 36. Root Cap 114 37. Root Hair 115 38. Wild Buckwheat 116 39. Brace Roots of Corn 117 40. Cross-Section of an Endogenous Stem of Corn 118 41. Tendrils of Japanese Ivy 118 42. Tendril of Star Cucumber 119 43. Horse Chestnut Leaf 119 44. Rose Leaf 120 45. Parts of a Leaf 120 46. Parallel-Veined Leaves 121 47. Sassafras Leaf 121 48. Aconite Leaf 122 49. Leaves of Various Types 122 50. Radiate-Veined Leaves 122 51-57. Various Types of Leaves 123 58. Catkin of Birch <. 124 59. Cymose Cluster of Pink- 124 60. Spike of Cat-Tail 125 61. Head and Achene of Ragweed 125 ix LIST OF ILLUSTRATIONS FIGURE PAGE 62. Raceme of Barberry . . . 125 63. Panicle of Grass 126 64. Head of Clover 126 65. Head of Wild Lettuce 126 66. Flowers of Barberry 127 67-68. Flowers of Tomato 127 69. Flower of Bean 127 70. Aconite Flower 128 71. Larkspur Flower 128 72. Strawberry Flower 128 73. Rose Flower 129 74. Pollen Grains of Various Types 129 75. Different Stages of Pollen Grains 130 76. Fertilization in Cotton Plant 131 77. Carpels of Indian Mallow 131 78. Follicle of Larkspur 131 79. Castor Oil Bean 131 80. Bean Seed 131 81. Cotyledons of Bean Plant 132 82-83. Germinating Pea 133 84. Squash Seed Germinating 134 85. Cross-Section of Buckwheat Seed 134 86. Cross-Section of Date Seed 134 87. Longitudinal Section of Kernel of Corn 134 88. Common Brake 138 89. Smooth Crab Grass 140 90. Green Foxtail 144 91. Muhlenbergia racemosa 148 92. Crowfoot Grass 150 93. Quack Grass 154 94. Little Barley 155 94a. Plain Wild Barley 156 95. Northern Nut Grass 158 96. Slender Rush 159 97. Common Nettle 161 97a. Sour Dock 163 98. Dooryard Weed * 165 99. Smartweed 166 100. Pennsylvania Smartweed 167 101. Slender Smartweed 167 102. Winged Pigweed 168 103. Goosefoot 169 104. Russian Thistle 170 105. Orach 171 106. Prostrate Pigweed 172 107. Wild Four o'Clock 173 108. Chickweed 174 109. Evening Catchfly 175 110. Corn Cockle 176 111. Cow-Herb 177 112. Purslane 178 113. Crowfoot 179 114. Pennycress 180 115. Pepper Grass 1! 1 16. Common Mustard 182 117. Tumbling Mustard 183 118. Stinkweed 185 119. Five Finger 186 120. Yellow Sweet Clover 189 121. Black Medick 190 122. Alfllaria 192 123. Caltrop '193 124. Spotted Spurge 194 125. Creeping Spurge 195 126. Spurge 196 LIST OF ILLUSTRATIONS XI FIGURE PACE 127. Balloon Vine 199 128. Butterprint 200 129. Shoofly t 202 130. St. John's Wort 203 131. Evening Primrose 205 132. Cowbane 206 133. Water Hemlock 207 134. Wild Carrot 208 135. Milkweed 210 136. Hedge Bindweed 212 136a. Clover Dodder on Alfalfa 213 136b. Field Dodder 214 137. Hoary Vervain 218 138. Dead Nettle 219 139. Black Nightshade 220 140. Horse Nettle 221 140a. Purple Thorn Apple 223 141. Toadflax 224 142. Rugel's Plantain 226 143. Buckhorn 227 144. Bracted Plantain 228 144a. Ironweed 230 145. Whiteweed 232 146. Horseweed 233 147. Marsh Elder 234 148. Small Ragweed 235 148a. Young Plant of Smaller Ragweed 236 149. Greater Ragweed •. 237 150. Young Cocklebur 238 151. Sunflower 239 152. Meadow Sunflower 240 153. Young Plant Beggar-Ticks 241 154. Beggar-Ticks 242 154a. Ox-Eye Daisy 244 155. Wormwood 245 156. Fireweed 246 157. Burdock 247 158. Bull Thistle 248 159. Canada Thistle 249 160. Cat's Ear 251 160a. Sow Thistle 252 161. Prickly Lettuce 253 CHAPTER I WEEDS: INJURY TO CROPS AND NATURE OF What Is a Weed? — A weed has been defined as a plant out of place. If we accept this definition, pump- kins growing in a cornfield, if they are not wanted, are weeds ; oats and barley growing in with wheat are to be regarded as weeds. Perhaps we may define " weed " by saying that it is a plant injurious to agriculture and hor- ticulture, but I am reminded that many people have dif- ferent notions in regard to weeds. A great many people call every plant a weed the flower of which is not ornamental. The plants found in a for- est would thus be regarded as weeds. As a matter of fact, these very plants found in the forest are important for the forest and cannot be regarded as weeds ; they are a part of that particular plant community. Weeds a Money Loss to the Farmer. — Weeds are of tremendous economic importance to all tillers of the soil. A crop shortage on many farms in this country is in part due to the growth of weeds. Farmers everywhere could increase their crops at least one-third by preventing the growth of .weeds. The loss to farmers in every state would pay the taxes. In the fall of 1908 the writer had some of his students make an estimate in different parts of the state of the in- juriousness of weeds to a corn crop. It was found, for instance, that corn fields kept clean produced a one-third larger crop and that an estimate of the loss .of corn from the growth of weeds in the state of Iowa amounts to $7,000,000 to $9,000,000 annually. In all of our great crop-producing states the losses are equally great. The injury from weeds in the United States is not far from 2 WEEDS OF THE FARM AND GARDEN $100,000,000 annually. All of this could be prevented by applying better methods of cultivation. I have also had a very complete illustration that the removal of weeds increased the crop greatly in the case of a cornfield which contained a great deal of quack grass. In 1908 this field was cleaned and the present season has been in oats. The treated field contained one-third more oats to the acre than the weedy adjacent fields. The same has been shown to be true also in some ex- periments made by Professors Edson and Eaton, for Vermont; they report not only a much larger yield but more fodder. The yield in fodder in some cases was two and one-fourth tons. Why Weeds Are Injurious. — Weeds are injurious to the farmer because they exhaust the soil of the valuable nutrient material required for the crop. No one succeeds in obtaining a good yield of corn, wheat or other culti- vated crop where weeds are allowed undisputed sway. The difference can be noticed at once when one farmer keeps his field clean and his neighbor allows weeds to grow. The one may obtain 60-70 bushels per acre from his field, while the latter has but thirty-five. Surely it does not pay to allow weeds to grow on land worth seventy-five or eighty or one hundred dollars per acre- Prof. H. L. Bolley says: "It is quite evident that if one sows enough seed wheat or other cereal to give a proper planting for the largest possible yield of grain, that it will not be possible to obtain this fullest yield if the ground already contains countless seeds of many sorts of weeds. One of the worst fallacies that is known to farming is indicated at this point. Almost every farmer knows some sort of weed which he thinks, or at least says he thinks, is of no harm to the wheat crop. For example, many persons have said French weed does not hurt the wheat crop, and many persist in saying that common mustard does not reduce the yield of wheat or WEEDS: INJURY TO CROPS AND NATURE OF 3 oats. One might thus make a list covering practically all kinds of weeds. A peculiar feature is observed, how- ever. It is never said of the weedy plant that it is not injurious to crop yield until it becomes so abundant on the man's farm or in a particular neighborhood that it seems practically impossible for the farmers concerned to get rid of it. It is then tolerated and finally the evil ef- fects condoned in the manner indicated. " A growing crop or plant gets its food material by ab- sorbing the soil solutions. The excess of water is evapo- rated by the leaves. No more water is taken up by the crop than is evaporated by the leaves. " If the leafy growth of a cereal crop is not normal in extent, but weakened and insufficient because of crowd- ing out by other plants which exclude light and proper air supply, then the rate of water evaporation from the leaves, and consequent absorption from the soil, will be greatly diminished. Thus even if there is an abundance of water and food materials, the cereal crop does not get its just supply if it is unduly crowded by other weedy growths. When drouthy times occur the weeds are able to do their greatest destruction." " We have made many examinations of this question and have almost invariably come to the conclusion from our studies that where a normal stand of grain or other crop is upon the ground the yield of the crop will be found to be reduced in approximately direct proportion to the weeds which are developed on the ground during the growth season. This assumes that the water and soil conditions are normal. If, however, such conditions are abnormal during the maturing period of the crop, the loss in yield occasioned is often very much greater than that indicated. This is especially true if a drouthy time occurs just while the grain is filling." A part of the depletion of our soils must be attributed to the growth of weeds on the farms, some weeds being 4 WEEDS OF THE FARM AND GARDEN much more exhaustive than others. We need conserva- tion of the fertility of soil by preventing the growth of weeds. Another reason why weeds are injurious, especially to young crops, is because they crowd out the useful plants. This is particularly true of such weeds as nut grass in our cornfields, mustard, at times, in oats and flax fields. Some weeds are injurious because they are poisonous to man and the lower animals. Cowbane and water pars- nip are powerfully poisonous ; the seed of corn cockle poisons grain ; squirrel-tail, wild barley and awned brome grass are injurious because the awns work into the gums, causing serious inflammation and consequent loss of teeth. Weeds are injurious because, on account of their pres- ence, it is much harder to remove the crop. It is much more difficult to harvest wheat where Russian thistle is present. It is much more difficult to harvest small grain where wild buckwheat and morning glory occur. The spines of rose stems often inflict injury to persons obliged to shock and stack grain. Weeds are frequently injurious because they harbor fungi. The well-known club root of cabbage occurs on mustard and on other allied plants ; also on common pepper grass, and Dr.Halsted has shown that this is a frequent source of the disease on cabbage. Rust is often found on squirrel- tail grass. Professor Bolley says : " Weeds, because of their rank foliage, tend to keep the atmosphere cooler and moist, keeping the stems and foliage of the grain plants befogged with clew and other moisture when or- dinarily it would remain comparatively dry. This ac- counts for the rust getting a stronger infection in the wheat fields than upon a clean, open crop. Later, when the grain is strongly attacked by the rust fungus and is in great need of water to keep up the supply which is being evaporated from the straw or stems where the rust has WEEDS: INJURY TO CROPS AND NATURE OF 5 broken them open, the weeds cause the greatest damage by robbing the soil of the necessary moisture ; the grain must, therefore, be shriveled in maturing." Root rot of cotton is abundant on many plants, but es- pecially so on members of the mallow family, as sida and shoofly. In this way this fungus is transmitted to cotton, sweet potato and the apple tree. It is not unusual for owners of elevators to dock wheat containing a great deal of any weed seed proving difficult of removal, although the wheat itself might be graded No. i. The seed of kinghead cannot be taken out by the proper elevator machinery, hence the elevator men at Duluth decided that after August I, 1910, they would dock wheat that contained a great deal of kinghead. In the grain-growing states of the Dakotas and Minnesota, there is considerable dockage on account of weed seeds and the same is also true of the Canadian Northwest provinces. The loss to the farmers must amount to mil- lions of dollars a year. Certain weeds are injurious because when they be- come mixed with small grain, they must be removed be- fore it can be sold as " A " wheat or oats, although all other conditions may be fulfilled. Where there is much mustard in oats, the grain will not bring so good a price as clean oats do, and the same may be said of wheat containing cockle, vetch, cow herb, garlic, sweet clover, etc. Some Weeds Are Useful. — Weeds may in some cases serve some useful purpose. Digitalis is obtained from foxglove ; hyoscyamine from black henbane ; daturin from Jimson weed. Many weeds, like tansy and hemp, have medicinal properties. Others serve culinary pur- poses, as when the roots of chicory are used as a substi- tute for coffee. Lamb's quarter, dandelion and the young shoots of pokeweed are used as spring greens. The roots of tan weed or shoestring (Muhlenberg's WEEDS OF THE FARM AND GARDEN smartweed) were formerly used in the process of tanning. The tubers of the cultivated artichoke are used as food, and the Indians used the wild artichoke in the same manner. The meadow sunflower was another plant that furnished food to the Indians. Sweet clover is an excellent bee plant, a good forage plant and a satis- factory soil renovator. Dr. Millspaugh states that many weeds possess good fertilizing properties,. Weeds are of value if, when added to the soil, they give looseness and furnish a plant covering. Professor Bolley says : "The plant growths, consisting largely of common weeds and grasses which at once occupy idle land, keep it from be- coming a useless dust bed and finally a mass of shifting sand. In shiftless and improper crop rotation the weeds and grasses which intervene may be looked upon as savers of soil quality. Those with tap roots bring up the substances from a greater depth than some of the ordinary crops ; and by their varied characters introduce essential elements of proper crop rotation and in other ways reinstate the humus of the soil, which, by poor cropping methods, is often quickly removed. Under cer- tain conditions large crops of weedy growths plowed under by shiftless farmers produce conditions of green manuring which, while not of the best type, are essential in preventing an entire loss of humus." . CHAPTER II. KINDS OF WEEDS AS TO DURATION Weeds may be grouped with reference to their duration under the following classes : Annual, biennial, and peren- nial. An annual plant is one which germinates from seed in the spring, produces flowers and seed the same season, after the accomplishment of which it usually dies. Ex- amples of annual weeds are foxtail, ragweed, and smart- weed. The members of this class1 vary greatly. Some an- nuals approach biennial in habit and are called winter annuals. Seeds of winter annuals ger- minate in the fall and produce a good growth until checked by frost. In the succeeding spring they make rapid growth, mature fruit, and die. Examples of win- ter annuals are speedwell, shep- herd's purse, and chickweed. The biennial plant, during the first season, produces vegetative seed" a common source of growth only, this often consist- *Pre*din£ the weed* (c- • r e i M. King.) ing of a rosette of leaves close to the ground. In the second season, a flower stem is pro- duced. Examples of biennial weeds are bull thistle, mul- lein, burdock, parsnip and carrot. Biennial weeds do not appear when the ground has been properly plowed. The perennial plant has a natural existence of more than two years. These plants produce stems and roots which send up flower stalks year after year. Examples of this class are morning glory, milkweed, horse-nettle, and horse-radish. i. Canada thistle 8 WEEDS OF THE FARM AND GARDEN How Weeds Spread. — Weeds are spread by means of seeds, by vegetative reproduction, or by both seeds and vegetative reproduction. Reproduction by Seeds. — Most weeds reproduce them- selves by seeds. One of the exceptions to this rule is the horse-radish, which does not, so far as we know, seed in Iowa. It has been our observation that the Canada thistle usu- ally does not seed in Iowa, although spec- imens of heads con- taining seed have been received from different parts of the state. It is also probable that the Canada thistle does not seed so frequent- ly in Iowa or in the United States as in Europe. Vegetative Repro- duction. — Many weeds multiply by means of roots, Fig. 2. Woolly thistle, a type of perennial _tp nr uni.u rn root. as» l quack grass, one means of multiplication is by stems commonly called "roots," which are divided into a series of joints at which new shoots are produced. The same structure occurs in germander or wood sage. Horse-radish may be propa- gated by roots exclusively. In another type, like the KINDS OF WEEDS AS TO DURATION 9 Canada thistle, morning-glory, and horse nettle, a small part of the underground portion is stem, the rest being Fig. 3. Pigeon grass, a type of annual plant. (U. S. Dept. Agrl.) true root. On these roots buds are produced which send up new shoots each year. Some plants, like wild onion, produce bulbletS'. In others, as crab grass, the stem above the ground may IO WEEDS OF THE FARM AND GARDEN strike root at the nodes, or roots may be produced at the joints, as in purslane. These roots and stems, capable of producing new plants, are widely scattered in fields by means of the culti- vator and plow. They may be dispersed with undecom- posed manure, packing materials, or imported fruit trees. Mice and gophers may scatter roots, to different parts of the field. Character of Root Systems of Weeds. — The root sys- tems of weeds vary greatly. The term root, as ordinarily used by the farmer, may mean a rootstock, as in the case of quack grass or nimble will. A great many weeds, es- pecially perennials, have not only perennial roots but rootstocks also. A rootstock is simply a stem growing beneath the surface of the ground. Many weeds have strong tap roots, this being especially true of biennial weeds like the Canadian lettuce, mullein, hemp, cocklebnr, wild carrot, ragweed, prickly lettuce, pigweed, mayweed, lamb's quarter, bull thistle, and field thistle. The roots of many annual plants are fibrous and without any distinct tap roots. Moreover they are shal- low, like those in the buckhorn, foxtail, plantain, yellow oxalis, and bootjack. The roots, of plants in the same order may differ greatly, but their general habit depends a little on the character of the season. During moist seasons they become quite shallow, while after the sea- son becomes drier, they descend obliquely. The com- mon spurge (Euphorbia Preslii) has a straight taproot with horizontal roots near the surface of the ground which descend obliquely later. The common field thistle (Cirsium discolor) has a straight tap root with portions frequently enlarged bearing several more or less promi- nent lateral roots. The cocklebur, which belongs to the same family, has a tap root which is considerably thickened near the sur- face of the ground, and which has large lateral roots. It KINDS OF WEEDS AS TO DURATION II may likewise produce a few nodal roots, but these are generally small and fibrous. The large ragweed (Am- brosia trifida) has a straight tap root with numerous small fibrous roots that descend obliquely into the lower strata of the soil. The horseweed of the same family has a straight tap root, numerous small fibrous roots, and one or more prominent lateral roots. These are at first hori- zontal, descending obliquely later. The Spanish needle (Bidens frondosa) and its ally, stick-seed (B. discoidea), are fre- quently found in moist places. Although they belong to the same family as the sunflower and ragweed, they do not ordinarily produce tap roots, but large lat- . , Fig. 4. Root of common milkweed, roots instead, s;ngle root 14 feet long, with numerous which SOOn descend lateral roots. The points indicate Obliquely into the -where "™ root* and stems are form- J ing. Root method of spreading the ground. The Canadian weed. (C. M. King.) goldenrod (Solidago canadensis), with a horizontal rootstock, produces small lateral roots which soon begin to descend. The ox-eye (Heliopsis scabra), related to the golden- rod, also produces a rootstock from which grow fibrous roots, horizontal at first and then gradually de- scending. In the common mayweed of the same family the straight tap root produces numerous fibrous roots which descend obliquely. The buckhorn and plantain produce a large number of whitish, fibrous roots which are at first horizontal and then descend gradually into the soil. In some plants, as in cowbane, the roots are fas- cicled. In the wild parsnip and the garden parsnip the 12 WEEDS OF THE FARM AND GARDEN roots are conical. Common quack grass, wood sage, and peppermint produce numerous horizontal rootstocks that are found close to the surface of the ground, 75 per cent of the rootstocks being found within four inches of the surface. From the nodes there arise numerous small fibrous roots. The roots of many perennial plants, like Canada thistle, morning-glory, horse nettle, and milkweed, spread exten- sively through the ground. The root of a common milk- weed was traced by Mr. Garner and Mr. Lyle Clapper for a distance of 14 feet through the soil. Dr. Byron D. Halsted, who made a study of the roots of various weeds, comments as follows concerning the char- acter of roots : "By means of the root system most plants become anchored to the soil ; therefore, other things re- maining the same, among those species that live from year to year, the size of the root becomes an index of the persistency and pestiferousness of the plant." Then he comments upon the length of roots of a great many different weeds, stating that the common dandelion (Taraxacum officinale) had a root an inch in diameter and fifteen inches in length, but the writer has found a root of the dandelion more than four feet in length. It should be remembered also that in many cases when the root is injured near the top that a multiple root development follows. The burdock and dock frequently produce numerous roots when the plants are injured, although ordinarily these roots are straight and produce a single thick fleshy root. The characters of roots sometimes differ very materially in closely related species of plants. The common sour dock has a straight fleshy root, whereas the smooth or peach-leaf dock produces a num- ber of branched roots, making it rather difficult to ex- terminate. The following tables give the depth of roots and area covered by some of the common weeds. These figures KINDS OF WEEDS AS TO DURATION indicate that the weeds may effectively rob the soil of many valuable constituents. TABLE I Weed Depth Spread Weed Depth Spread Buckhorn 2-8 in. 24 sq. in. Pennsylvania 1-4 in. 45 sq. in. Plantain 3-13 30 ' Smartweed Wild Hemp 1-6 10 Lady's Thumb 1-4 " 90 Evening Primrose Beggar Ticks Dog Fennel 3-5 3-5 2-3 30 40 4 Yellow Oxalis Prickly Lettuce Cocklebur 1-2 " i-2i 4-10 24 6 425 Rudbeckia hirta 3-6 20 Greater Ragweed 4 48 long Goldenrod 5 70 Rough Pigweed 7-14 144 ft. White Vervain 2-4 36 Horseweed 7-14 144 in. Canadian Lettuce 5-7 144 Tumbleweed 2-8 60 Field Thistle 8 50 Small Ragweed 8-9 60 Burdock 40 150 Spanish Dagger 5-8 42 Black Nightshade 1-4 80 TABLE II o A J3 o O 0 a a Kind of weed |.s 4 Kind of weed fj j 111 "1 111 1 o O ^ 6.SJ Jj O z £.£.S J Quack Grass 1 6 32 Quack Grass 24 7 2 41 24 25 7 60 3 51 34 26 8 38 4 5 14 27 6 42 5 51 18 Horse Nettle* 1 30 30 6 6 2 29 i 29 7 5 3 30 30 8 51 16 4 27 27 9 51 20 5 32 32 10 3 6 30 30 11 31 7 26 26 12 21 24 8 36 36 13 3 Milkweed 1 36 48 14 21 2 42 64 15 3 14 3 48 60 16 31 4 36 30 17 3 12 5 32 39 18 3 6 30 31 19 21 9 7 36 108 20 4 56 8 32 72 21 6 22 8 44 23 6 *The roots of horse nettle extend straight down into the soil. CHAPTER III DISPERSAL OF WEED SEEDS Scattering of Plants. — After the seed is formed it must be placed in a congenial soil so that its kind may be per- petuated. This scattering of seeds and fruits is therefore important. The following are the different ways by which plants are scattered : I. WIND. A. Tumble weeds, Russian Thistle. B. Winged fruit appendages, Maple. C. Winged seed appendages, Milkweed. D. Parts of inflorescence with modified expanded bracts, etc., Basswood. E. Parts of the seed or fruit inflated, Balloon Vine. Fig. 5. Scattering of red cedar by birds. (U. S. Dept. Agrl.) 14 DISPERSAL OF WEED SEEDS II. WATER. A. Seed with light, inflated pods, Sedges. B. In large receptacles, Nelumbo (Water Chinquapin). C. Mucilaginous seeds, Pepper Grass. D. Currents of water in a mechanical way, Driftwood. E. Plants floating on water because provided with air spaces, Lemna (Duckweed). III. SNOW AND WIND COMBINED. Many weed seeds. IV. ANIMALS. A. Fleshy, edible fruits and seeds, Nightshade, Cherry B. Edible seeds not fleshy, Sunflower, Acorn. C. Fruits with hooks or barbs, Bidens (Beggar-ticks). D. Seed or fruits with webs, Blue Grass. Fig. 6. A tumble weed, winged pigweed (Cycloloma atriplici- folium), scattered by its tumble habit. The Russian thistle and a kind of pigweed are scattered in the same way. (U. S. Dept. Agrl.) VI. VII. EXPLOSIVE PROPERTIES OF FRUITS AND SEEDS. A. Contraction of seed vessel, as in Hura crepitant B. Twisting of pod, Vetch. C. Tension in pod, Impatiens (Jewel-weed). D. Shooting of seeds, Oxalis. E. Turgidity of fruit, Squirting Cucumber. CREEPING MECHANISMS AND BY THE SEEDS BURYING THEMSELVES. A. Hygroscopic movements, Stipa. B. Cleistogamous flowers, Violet. MAN As AN AGENT. A. Impure seed, Clover Dodder. i6 WEEDS OF THE FARM AND GARDEN B. Common carriers, Russian Thistle. C. Nursery stock and flowers, Canada Thistle. D. Hay and wool, Buffalo Bur. E. Plants grown for ornamental purposes, and as food plants, Ox-eye Daisy, Chicory. Wind. — Many of our weeds are scattered by the wind. The squirrel-tail grass, which is permitted to grow in an unobstructed manner in pastures and on roadsides, is car- ried to adjacent fields where it did not occur. Tumbleweed and Russian thistle have the rolling habit, and when growing along the roadsides or the railway they get into adja- cent fields. In prairie coun- tries the tumble habit is common for many weeds, as shown many years ago Fig. 7. Bull thistle "seed" scat- by Dr. Bessey. The seeds of tered by the wind. milkweed with a light fluffy coma are carried for some distance. The "seeds" of dan- delion with cylindrical body and a tuft of capillary bris- tles are carried for long distances from roadsides to fields and meadows. The bull thistle "seed" with hairy ap- pendage is, carried from the roadside to fields and pastures. Wind and Snow. — Many seeds glide over the frozen snow and become deposited in the field. Greater ragweed is frequently carried in this way. So, too, are the foxtails. Prof. H. L. Bolley states that January 20, he found in the contents of a snow drift of 28 square feet, 2 seeds of pig- eon grass, 5 of French weed, 2 of biennial wormwood, and 10 of barnyard grass. He also reports having dis- tributed, on January 31, a peck of mixed seeds 30 rods distant from a drift of snow 4 rods long. In 10 min- utes this had caught a large number of millet, IQI DISPERSAL OF WEED SEEDS wheat, 53 flax, 43 buckwheat, and 91 ragweed seeds. The wind was blowing at the rate of 20 miles per hour. There can be no question but that a drift holds a large number of weed seeds1. Along our highways one may find, where the snow has drifted, the ragweed and this- tle growing in large numbers. Fig. 8. The seed of vegetable oyster plant scattered by the wind. Fig 9. Various "seeds" scattered by drifting snow. A, small rag- weed; B, sunflower; C, foxtail. Water. — A number of our very troublesome weeds are carried by the water. This is notably true for the "seeds" of docks. Three of the sepals or outer floral envelopes of the flower of the docks each bear an enlarged body called the tubercle, which is hollow. This body, com- bined with the calyx, enables it to float on the water. During our recent wet years, it has been noticed by i8 WEEDS OF THE FARM AND GARDEN farmers that these docks are unusually common on low ground, having been carried thither by water. Many seeds, like those of pepper grass, are mucilaginous. In walking through a patch of this weed with moist shoes, many seeds are caught and carried to new situa- tions. Wild oats and many other seeds may be found on land subject to overflow. These seeds are scattered in a mechanical way. Animals. — Many of our weeds are scattered by animals, this being brought about either because the plants offer something for food, as in Fig. 10. The "seed" the ground-cherry, black nightshade, of a common sedge dandelion and thistle, or because the surrounded by an in- fruit js accidentally carried. Exam- flated sac, scattered by , ,. ., , , , c- • 1 the water. (Beal.) Ples of the Iatter. class are Spanish bayonet or bootjack, cocklebur or stick-seed, burdock, sandbur, and tick trefoil. Explosive Properties. — We have but one weed the seeds of which have explosive properties. This is the yellow sorrel (O.valis), which is com- mon in some fields. The outer coat of the seed separates and the seed is forced out of the pod as though shot from it. Creeping Mechanisms. — The needle-grass is important as a weed at times only, in gravelly pastures. The seed of this grass has a sharp- pointed callus and hairs above this , - • 11*1 J * *£* * A A I1C octunivt point that project obliquely upwards, fruit of arrow-head, It has a long, twisted awn, and in scattered by water, this way the seed not only creeps (Bea1-) Fig. ii Theseedlike DISPERSAL OF WEED SEEDS over the ground, but becomes buried. The wild oats also has a creeping arrangement. Man as an Agent. — Nursery stock is responsible for the scattering of a number of weeds and weed seeds. The scattering of quack grass in this way had been reported to us. Canada thistle, ox-eye daisy, and other peren- nial weeds are known to have been car- ried and scattered by this means. Wool. — Wool is often responsible for the introduction of a great many differ- ent weed seeds. Around woolen mills it is common to find Fuller's teasel, which is so commonly used in carding of wool. The western storksbill (Erodium cicutarium) no doubt owes its origin in this section to having been introduced with wool. There is con- stant danger when getting live stock from the western states that weeds of this character will be introduced. Some members of the borage family like Lappula floribunda have been scattered in this way. Cultivation. — It is not uncommon to find that weeds are carried from one field to another by cultivators or plows. This is particularly true of quack grass and Johnson grass. Impure Seed. — Many bad weeds are introduced with im- pure seed. We have during the past season received many specimens of weeds found in clover meadows. These weeds were undoubtedly introduced with clover seed. In nearly all instances the farmers stated that they had not observed these weeds, before. Not all of the clover seeds sold by seed merchants contained these weed seeds, much of it being of good quality. Fig. 12. Seeds scattered by birds. A cast from crow containing seeds of poison ivy, etc. (U. S. Dept. Agrl.) 20 WEEDS OF THE FARM AND GARDEN As examples of presence in clover fields of weeds intro- duced with seed, a few selected areas observed July, 1908. may be cited. Three areas 10 feet square situated south- Fig. 13. Goldfinch eating the seed of dandelion. (U. S. Dept. Agrl.) Fig. 14. A, a, b, pod of wild licorice. B, c, "seed" of cocklebur; d, section of carrot seed; scattered by animals. (Dewey, U. S. Dept. Agrl.) DISPERSAL OF WEED SEEDS 21 west of Ames averaged 53 vigorous specimens of rib- grass. Two areas 12 feet square upon a farm near Mar- Fig. 15. Burdock head with many "seeds" scattered by animals. (Dewey, U. S. Dept. Agrl.) Fig. 1 6. "Seed" of pitchforks, Spanish needle, scattered by animals. (U. S. Dept. Agrl.) athon averaged six ribgrass and three wild carrot plants. In another piece of the same field not cut at Marathon, Fig. 17. Seeds scattered by explosive properties. A, geranium; B, wood sorrel; C, pod or common vetch. (U. S. Dept. Agrl.) 22 WEEDS OF THE FARM AND GARDEN DISPERSAL OF WEED SEEDS 23 were found night-flowering catchfly, corn cockle, and bull thistle. Grain Seed. — The wild oats is frequently scattered with oats, but there is little of this weed in Iowa except in a few counties in northern and northwestern parts. Mustard is also frequently scattered with oats. There is some danger of scattering quack grass seed with oats. Quack grass seed found maturing with oats will germinate. In one case 8 per cent, of the seed was capable of producing new plants. In an investigation of quack grass in north- ern Iowa and Minnesota it was found that it is nearly always scattered near the grain elevators. Straw is an Fig. 19. Seeds distributed with wheat seed; a and b, wheat; d and e, cockle; c, common chess. (U. S. Dept. Agrl.) important factor in scattering quack grass. A single farm has been responsible for scattering quack grass along the highway in every direction leading from the farm. The straw, with its seed of quack grass, fell along the roadside, and in a few years quack grass, was observed along the highway. One farmer said the quack grass was introduced on his farm by using oat straw for cover- ing his grapes. Many other similar cases, are on record. Cockle, cowherb and vetch are frequently scattered with wheat seed. Garden Seed and Ornamental Plants. — Shoofly, which has been widely cultivated as an ornamental plant in this state, has scattered to the fields and has become a troublesome weed in grain fields. Mexican fireweed, WEEDS OF THE FARM AND GARDEN thistle, distributed with grain. King.) M' cultivated as an ornamental plant, is; becoming trouble- some in many places. Butter-and-eggs was not only introduced as an ornamental plant and cultivated, but since has spread because sent out with horticultural plants. The bouncing bet, used as an ornamental plant, has become troublesome in north- western Iowa along the roadsides and in fields;. Other plants, as horse- radish and ground-ivy, have become weeds in the same way. Railways. — Some railways are Fig. 20. Russian using various kinds of screenings to sow along their right of way to cover the steep fills. A variety of weeds may be found here. Other weeds are scattered from passing cars. Rus- sian thistle, buckhorn, ox-eye daisy, thistle, and other varieties of weeds may be found along the right-of-way. On a patch of ground of not more than two square rods in extent in a town in Central Iowa, in August r^llsli llF 1908, the following weeds were ob- ^|g|r served by Miss Kellogg: Wild , morning glory, hedge bindweed, Fig. 21. Kinghead r ragweed distribut- prickly lettuce, sow thistle, pigweed, ed with grain. (C. M. lamb's quarter, purslane, velvet weed, mallow, chickweed, shepherd's purse, sweet clover, burdock, curled dock, sheep sorrel, horseweed, pepper grass, wild-radish, black bindweed, water pepper, smartweed, milkweed, black mustard, ragweed, dog-fennel, mullein, creeping Charley, five-finger, squirrel-tail grass, sandbur, yellow foxtail, sedge, wire grass, and horse- King.) 1 Fig. 22. (C. M. King.) DISPERSAL OF WEED SEEDS tail. It is but fair to say that these weeds were mostly on soil that had been brought in by the railway company for the purpose of raising the grade of the road bed. Many of these weeds Fig. 23. Plantain. (C. M. King.) Fig. 24. Two kinds ef smartweed. (C. M. King.) have, however, in the course of five years, spread to the surrounding territory, and the problem of eradi- cating them has already become serious. Highways. — Highways are an important factor in the distribution of weeds to adjacent fields. No matter how clean the fields are kept, if the seeds of plants like the Fig. 25. Seeds found in red clover, i, 2, wild carrot. (C. M. King.) cocklebur, Canada thistle, sweet clover, thistle, ragweed, and squirrel-tail grass are permitted to develop and mature along the highways they will naturally spread to 26 WEEDS OF THE FARM AND GARDEN the adjacent fields. Vehicles passing from a field infected with weeds, especially when the roads are moist, are sure to leave weed seeds along the roadsides. Then the driving of cattle, and the carrying of grain, all contribute to the weeds that are found along the road- sides, and to the scattering of the same. The following is a partial list of weeds commonly found along the roadside : Poison ivy, horse-radish, horse-weed, bull thistle, sweet clover, squirrel-tail grass, Russian thistle, tumbling mustard, cockle- Fig. 26. 13, 14, Canada bur, mustard, large ragweed, small thistle. (C. M. King.) , , , ., ragweed, foxtail, crab grass, par- tridge pea, wild blackberry, burdock, wild morning glory, milkweed, velvet leaf, and wild parsnip. CHAPTER IV. THE FARMER'S INTEREST IN GOOD SEED, AND HOW TO TEST SEED The farmer is especially interested in obtaining seed free from such noxious weeds as Canada thistle, quack grass and dodder. To avoid the introduction of such weeds, the seeds should be examined by the experiment station in the state in which the farmer is located or by the U. S. Dept. of Agriculture. It is customary in the seed laboratory to secure an average sample, thoroughly mixed, of the seed to be examined ; then to weigh out 2 or 5 grams and separate out the impurities, such as weed seeds, dirt, chaff, etc. The remaining seed is then weighed and the amount of impurities determined. When a given quantity of weed seed is large this is weighed separately and the per cent of impurity obtained. A more accurate way is to use the table given below. This, method is fairly accurate. We have for a number of years checked these results with those determined by weighing. If the weighing method is used, the analyst gives the total impurities and names those found. The following table showing the number of seeds to the gram of various species of weed seeds was compiled by D. C. Snyder and Charlotte M. King in the Botanical Labora- tory of the Iowa state college. To ascertain the number of seeds per pound in any given variety multiply the num- ber per gram by 453-584- NUMBER OF SEEDS TO THE GRAM IN WEED SEEDS FOUND AS IMPURITIES IN CLOVER SEED. PREPARED BY D. C. SNYDER AND C. M. KING Abutilon Theophrasti (Velvet Leaf) 109 Acnida tuberculata (Water Hemp) 2,800 27 28 WEEDS OF THE FARM AND GARDEN Amarantus retroflexus (Tumbleweed) 2,684 Arctium Lappa (Burdock) 320 Brassica arvensis (Field Mustard) 496 Brassica niara (Black Mustard) 1,280 Camelina saliva (False Flax) 900 Cassia Chamaecrista (Partridge Pea) 119 Chenopodium album (Lamb's Quarter) i(44° Cirsittm arvense (Canada Thistle) 880 Cirsium discolor (Field Thistle) 174 Cirsium lanceolatum (Bull Thistle) 620 Cirsium lanceolatum (dup.) 456 Cuscuta arvensis (Dodder) i,68S Cuscuta Epithymum (Clover Dodder) 3>84o Cyperus esculentus (Nut Grass) 540 Datura Stramonium (Jimson Weed) 146 Diaitaria sanauinalis (Crab Grass) 3,640 Echinochloa crus-aalli (Barnyard Grass) *,4°° Euphorbia Preslii ( Spurge) 1,720 Hibiscus trionum (Bladder Kermia) 304 Jpomoea purpurea (Morning Glory) 41 Lepidium apetalum (Pepper Grass) 2,515 Medicaao lupulina (Trefoil) 692 Medicago sativa (Alfalfa) 452 Melilotus alba (Sweet Clover) 490 Monarda fistulosa ( Horsemint) 1,080 Nepeta Cataria (Catnip) 1,076 Oxybaphus nyctaginea (Oxybaphus) 404 Panicum capillare (Old Witch Grass) 2,592 Phleum pratent (Timothy) 2,888 Plantago aristata (Bracted Plantain) 760 Plantago lanceolata (Ribgrass) 1,156 Plantago Ruaelii (immature) 2,176 Plantago Rugelii (Rugel's plantain) 1,704 Poa pratensis (Blue Grass) 17,050 Poa serotina (False Red Top) 10,370 Polygonum Convolvulus (Bindweed) 216 Polygonum Lapathifolium (Pale Smartweed) 640 Polygonum pennsylvanicum (Smartweed) 200 Polygonum Persicaria (Lady's Thumb) 712 Potentilla monspeliensis (Five-finger) 11,880 Rumex Acetosella (Sheep Sorrel) 200 Rumex crispus (Curly Dock) 728 Rumex obtusifolius (Dock) 846 Saponaria Vaccaria (Cowherb) 228 Scrophularia marilandica (Simpson Weed) 6,690 Setaria alauca (Pigeon Grass), immature 815 Setaria alauca 3^6 Setaria italica (Millet) 544 Setaria viridis (Green Foxtail) , immature 2,140 Setaria viridis 823 THE FARMER'S INTEREST IN GOOD SEED 29 Silene stellata (Catchfly) 900 Thalictrum purpurascens (Meadow-rue) 496 Trifolinm hybridum (Alsike Clover) 1,604 Tri folium pratense (Red Clover) 662 Trifolium repens (White Clover) 1,904 Verbena stricta (Vervain) 1,028 Verbena urticaefolia (Vervain) 2,408 Mr. J. R. Campbell has kindly worked out the following formula for determining the percentage of impurities in some of the different agricultural seeds. A table is here- with appended giving the number of seeds in one per cent of one teaspoonful or 5 grams of clover seed, and one per cent of one teaspoonful or 4 grams of timothy seed. Analysis of Seed (Approximate). — In making an analy- sis of red clover or any other seed, the sample should be thoroughly mixed. If we have a sack of seed, a hand- ful should be taken from the top, another from the middle, and another from the bottom of sack. Mix them in a pasteboard box, plate or anything handy; then take a pinch here and there until we have a slightly rounding teaspoonful. (Use common tin teaspoon.) Do not have it more than slightly rounding or the figures will be inac- curate. Pour this out on a sheet of white paper, or glass, and with the aid of a toothpick, lead pencil or anything con- venient, separate the good clover into one pile and the weed seed and dirt into another. Then with the help of the manual in identification, separate the different weed seeds and count them. Next find the percentages of each, using the table for this purpose. For example, s,uppose there are 120 seeds of crab grass and 16 seeds of buck- horn. The table says 182 seeds of crab grass are equal to i per cent. Therefore 120 seeds equal 12%s2 of i per cent, or .659 per cent, and since 57 seeds of buckhorn equals J per cent, 16 seeds equal J%7 of i per cent, or .28 3O WEEDS OF THE FARM AND GARDEN per cent. The sum of both is .939 per cent, a little less than one per cent. The weight of the dirt will have to be guessed at, as it varies greatly with different kinds. (The above method is for the use of those who have not the apparatus for an exact analysis. The results are, of course, only approximate, but are near enough for the purpose of the law.) NUMBER OF SEEDS REQUIRED TO MAKE I PER CENT BY WEIGHT OF 5-GRAM SAMPLE (EQUAL TO ONE TEASPOONFUL OF SEED) TIMOTHY CLOVERS OR MILLET Alfalfa 22 18 Alsike 80 64 Barnyard grass 70 56 Black bindweed n 9 Black mustard 64 51 Blue grass 852 68a Bracted plantain 38 30 Buckhorn 57 45 Bull thistle 23 19 Burdock 16 12 Canada thistle 44 36 Catchfly 45 36 Catnip 53 43 Chicory 40 32 Cinquefoil 594 475 Cirsium discolor 9 7J/j Cow herb '. n 9 Crab grass 182 1-15 Curled dock 36 28 Cuscuta arvensis 84 67 Cuscuta trifolii 192 156 Cyperus esculentus .- • • • 27 25 Dog fennel 210 168 False flax 45 36 False red top 518 414 Foxtail 40 32 Horsemint 54 43 Jimson weed 7 5 Lady's thumb 36 28 Lamb's quarter 72 57 Mallow :... 15 12 Meadow-rue 24 20 Millet 27 21 Morning glory 2 I 3-5 THE FARMER'S INTEREST IN GOOD SEED 31 TIMOTHY CLOVERS OT MILLET Oxybaphus 20 J6 Partridge pea 6 5 Pepper grass 126 100 Pigeon grass 20 16 Pigweed 134 "8 Polygonum pennsylvanicum 10 8 Quack grass 18 14 Ragweed 18 13 J4 Red clover 33 26 Rugel's plantain 85 68 Rumex obtusifolius 43 34 Sheep sorrel 100 80 Simpson weed 334 4*>7 Smartweed 32 25 Smooth crab grass 185 148 Spurge 86 68 Sweet clover 24 19 Timothy 144 "5 Velvet leaf • 5 4 Verbena stricta 51 41 Water hemp 14° 1 12 White clover 95 7<» Wild carrot 62 50 Wild mustard 25 20 Wildcats 2 iVi Witch grass 13° IO4 Yellow trefoil 34 27 CHAPTER V. WEED IMPURITIES IN AGRICULTURAL SEEDS A large number of weed seeds of different kinds occur in various commercial seeds. These weed seeds vary, depending on the character of the crop and locality where the commercial seed was grown. The foreign material in the seed is largely accidental. For instance, the Iowa- grown clover seed contains pigeon grass, foxtail, smart- weed and other weed seeds found in the Iowa clover meadow. Clover seed grown in Missouri will have a great deal of bracted plantain, while eastern-grown seed has much buckhorn. Alfalfa seed grown in Utah is likely to have dodder, black medic, etc. Minnesota-grown wheat is sure to have corn cockle and vetch, while seed oats from the same state may have quack grass. Mustard is certain to occur in Iowa-grown oats. The fault is not always with the seed merchant. The farmer demands a cheap seed and in doing so is likely to buy seeds that contain many weed seeds. It is always better to buy the better quality of seed. I knew of a case where the farmer was selling his neighbor red clover seed at $9 per bushel, when he could have bought good clover seed for a little more. Thirty-four per cent of the seed con- sisted of weed seeds and dirt. He was paying more for this seed than the best seed on the market was selling for. The only way to buy seed is on a guaranty. It is an easy matter for the seed merchant to make a statement that his seed contains a given per cent of purity and is free from noxious weeds of a certain type. I believe most seed merchants are beginning to realize the importance of selling good seed. The matter of germination is so WEED IMPURITIES IN AGRICULTURAL SEEDS 33 unreliable and the seed varies from year to year so much that very little that is definite can be given on this point. Impurities of Red Clover Seed. — The kind of impurities found in red clover seed varies somewhat with the local- ity in which the clover is grown. In the United States the more common impurities reported are as follows: Rugel's plantain (Plantago Rugelii), green foxtail (Seta- ria viridis), lady's thumb (Polygonum Persicaria), lamb's quarter (Chenopodium album), ribgrass (Plantago lance- olata), curled dock (Rumex crispus), yellow foxtail (Seta- ria glauca), sorrel (Rumex Acetosella), large spotted spurge (Euphorbia nutans), bracted plantain (Plantago aristata), timothy (Phleum pratense), witch grass (Pani- cum capillare), smooth crab grass (Digitaria humifusa), crab grass (D. sanguinalis), tumble weed (Amarantus albus), alsike clover (Trifolium hybridum), night-flower- ing catchfly (Silene noctiflora), blue vervain (Verbena has- tata), mayweed (Anthemis Cotula), ragweed (Ambrosia artemisiae folia), barnyard grass (Echinochloa crus-galli), white clover (Trifolium repens), wild pepper grass (Le- pidium virginicum), bull thistle (Cirsium lanceolatum), Can- ada thistle (Cirsium arvense), field dodder (Cuscuta arven- sis), wild carrot (Daucus Carota), black mustard (Brassica nigra), chicory (Chicorium Intybus), yellow trefoil (Med- icago lupulina), five-finger (Potentilla monspeliensis), nim- ble will (Muhlenbergia mexicana and glomerata). To illustrate the quality of seed in general use, the fol- lowing statement of red clover seed, analyzed in Iowa, may be given: One hundred and thirty samples of weighed red clover were examined for impurities and adulteration, the aver- age per cent of impurities was 1.93, the highest per cent was 33.2, only two samples consisted of pure seed. The following impurities were found in 255 samples of red clover seed in percentages, as follows: Timothy, 64.8; Canada thistle, 9.2; foxtail, 54.0; dodder, 4.0; bull thistle, 34 WEEDS OF THE FARM AND GARDEN 6.0; sheep sorrel, 34.4; dock, 44.0, and others. Of the unweighted samples 63.8 per cent contained foxtail, 57.1 per cent timothy, 51 per cent curled dock, 47.8 per cent green foxtail, 38.6 per cent rib plantain, buckhorn, or ribgrass; 28.5 per cent sheep sorrel, and 11.9 per cent Canada thistle. Of the two hundred and fifty-five samples examined timothy was found in 162, sand and dirt 138, yellow foxtail 135, green foxtail 128, curled dock no, sheep sorrel 86, bracted plantain 38, evening cockle 22, Canada thistle 24 and dodder 10. It will be seen from the above partial list that many bad weed seeds are found in clover seed. We found, further, that clover seed in some in- Fig.27. Some impurities in red clover stances showed a very seed, i, wild carrot; 2, buckhorn, two views; 3, Canada thistle; 4, clover dodder; 5, green foxtail, two views; 6, curled dock; 7, bracted plantain. (C. M. King.) low vitality. Only four of the samples showed a vitality of 99 per cent and over. There was a considerable number below 80 per cent and twenty-one samples above. Impurities of White Clover Seed. — The more common impurities are sorrel mayweed, lamb's quarter, the plan- tains, dooryard knotgrass, night-blooming catchfly, five- finger and chickweed. The following illustration is given of samples exam- ined in Iowa: The impurities found in weighed samples of white clover were sheep sorrel, 44.4 per cent; plantain, 33.3; bracted plantain, n.i; lamb's quarter, n.i. Of these the sheep sorrel, dock and plantain are bad weeds. In the unweighed samples sheep sorrel occurred in 80 per WEED IMPURITIES IN AGRICULTURAL SEEDS 35 cent of the samples. Slightly different results have been obtained in other localities. The kind of impurity will depend on locality. Meadow Fescue: Common Impurities or. — Yarrow, Rugel's plantain, sedge, cinquefoil, chess or cheat, pepper grass, sorrel, brome grass, orchard grass, velvet grass (quack grass a possi- bility), English ryegrass. Kentucky Blue Grass: Com- mon Impurities of.— The im- Fig. 28. i, three seeds of red , r T^ 1 t_i clover; 2, two seeds of sweet Pu»ties of Kentucky blue clover. (Hillman.) grass are practically the same as given for meadow fescue. although Kentucky blue grass may contain Canadian blue grass and English blue grass (meadow fescue). Alsike: Common Impurities of. — Timothy, sheep sor- rel, lamb's quarter, night-flowering catchfly, dooryard plantain, pigweed, pepper grass, red clover, wild clover, five-finger, crab grass, mayweed, curled dock, blue grass, hair grass. Alsike clover is not generally adulterated, but impurities were found as follows in Iowa : Sheep sorrel, 86.1 per cent; plantain, 33.3 per cent; Canada thistle, 25 per cent ; buckhorn or rib plantain, 11:1 per cent. Alfalfa: Common Im- purities of. — Green fox- tail, yellow foxtail, red clover, bur clover, barn- yard grass, yellow tre- foil, crab grass, chicory, centaurea, alsike, sweet clover, wild rye, grinde- lia, Rugel's plantain, talum); 4, 'sheep sorrel (Rumex Acelo- The chief impurities sella)> with covering; 5, timothy, r j , r ir hulled and unhulled; 6, sweet clover. tound in alfalfa are (c. M. King.) Fig. 29. Impurities in alsike. i, clover; pepper WEEDS OF THE FARM AND GARDEN horn, 62.5; cockle, black medic, bur clover and sweet clover. The im- purities found in samples examined in Iowa are alfalfa dodder, 4.1; knot weed, 4.1; rib grass or buck- 12.5; Canada thistle, 8.3; sheep sorrel, 4.1 ; plantain, 4.1 ; bracted plantain, 4.1 ; yellow foxtail, 33.1 ; curled dock, 8.3. Impurities in Orchard Grass. — The more im- portant impurities found in orchard grass are, fescue grass (Festuca Fig. 30. Some impurities in alfalfa, pratensis), velvet grass i, alfalfa; 2. seeds of vellow trefoil; /•LJ-J,.. }„„„!... \ 3! pod of same; 4, seed of sweei (HolciiS lanatus), espe- clover; 5, pod of sweet clover; 6, cially in New Zealand- chicory; 7, spotted clover; 8, bur grown seed ; English clover. (C. M. King.) ,, ,. rye grass (Lolium pcr- enne), blue pearl grass (Molinia caerulea), crested dog's- tail (Cynosurus cristatus), dock (Rumex crispus), sheep sorrel (Rumex Acctosclla), pepper grass (Lepidium apcta- lum and L. virginicum). The Vitality of Weed Seeds. — Some weed seeds show prolonged vitality; this is especially true of seeds that belong to the pulse and mallow fami- lies. The earliest re- / z 3 'seeds of Kentucky blue prolonged vitality of grass, the scales cover the seed; 5-8, seeds are those of De Canadian blue grass. Notice the dif- ference in shape. (Hillman and King.) Candolle. I his writer found that certain members of the mallow, pulse, and mint families had a prolonged vitality. Later BecquereJ also made a study of the prolonged vitality of seeds, and he found of the 550 WKKD IMPURITIES IN AGRICULTURAL SEEDS 37 species studied by him, the age of seeds varied from 125 to 135 years, and that a few of the old seeds germinated, notably those belonging to the pulse, water lily, and mallow families. In this connection the study made by Ewart on the Longevity of Seeds is of interest. Thus in some of the common Indian mallow or butter-print, 6 per cent of seed germinated after the lapse of 57 years, the common shoo-fly after 57 years, the seed of white sweet clover showed germi- nation after 77 years, and 52 per cent after 44 years, chicory after 10 years. In this con- nection the experi- ments conducted by Dr. W. J. Beal are also of interest. A number of years ago he made an inter- esting experiment on the prolonged vitality of the seeds of some common plants, testing for vitality at different periods of 5, 10, 15, 20, and 25 years1. The seeds were placed in sand in bottles slanting downward so that water could not enter, and buried in the soil, 20 inches below the surface. The seeds were all grown the year they were buried. The * indicates that the seed germinated. The following table indicates the vitality at these periods : Fig. 32. Seeds of some grasses, i, quack grass; 2, 3, orchard grass; 4, 5, meadow fescue; 6, English rye grass. (Hillman.) NAME OF SEED 5TH YEAR * IOTH YEAR * I5TH YEAR * 20TH YEAR * 25TH YEAR * o O O O o o « * * * .... o o o o o Cdpsflln bursa-pdstoris * o * * * IZrechthites hitracifolia , . . . . o o o o o Eu-bhorbia. marulala . . o o o o o 38 5TH IOTH I5TH 2OTH 25TH NAME OF SEED YEAR YEAR YEAR YEAR YEAR Lepidium virginicum * * * Lychnis Githago o o o o o Anthemis Cotula * * * o * Malva rotundifolia * o o o Oenothera biennis * * * Plantago major o o o o Polygonum Hydropiper o Portulaca oleracea o Quercus rubra . . . o Rumex crispus * Setaria glauca Stellaria media Thuja occidentalis o o o o o Trifolium repens o o o o o Verbascum Thapsus * ? Prof. L. R. Waldron has shown that in the case of some weeds there is delayed germination. He experi- mented with seven different kinds of weed seeds, as fol- lows : Great ragweed or kinghead, wild oats, green fox- tail, shepherd's purse, wild mustard, wild buckwheat and French weed. In the fall of 1889 there were planted in a seed bed out of doors at depths of I, 2, 3, 4, 5, 7, and 10 inches the above seeds. During the same fall shepherd's purse pro- duced a few plants at depths of i and 2 inches ; French weed, 25 plants at I inch ; wild mustard, many plants at i, 2, and 3 inches; wild oats, several plants at i, 2, and 3 inches. During 1900 the seeds continued to germinate, and it was true of them that the small weed seed did not come up through 2 inches of soil; no seeds buried below 3 inches germinated except kinghead or great ragweed and wild oats, which came up through 5 inches of soil. The writer, Miss King and Mr. Fawcett have conducted some experiments on delayed germination of weed seeds. It was found that the seeds of different species showed great differences in germination ; in general the results WEED IMPURITIES IN AGRICULTURAL SEEDS 3Q of 1902 and 1903 indicated that stratification in sand and freezing were favorable to germination. Per cent of germination Weed Before stratification After stratification Milkweed (A. syriaca) o 12 Western ragweed o 18 Lamb's quarter o 88 Cocklebur o 25 Mr. H. S. Fawcett made a study of 52 species of weed seeds. The samples were gathered after maturity in Septem- ber, October and November of 1904. The seeds were threshed out, and placed in paper envelopes. Fifty seeds of each kind were placed in November in sand in boxes kept during the winter in the greenhouse under uniform conditions. Similar plantings were made each month until May. The sand in all these germination trays was kept moist. In addition a large number of weed samples was placed out of doors for the purpose of subjecting them to freez- ing and thawing. The seeds were placed in sacks in a wooden box and covered with a thin layer of sand ; the box was then deposited about one foot below the surface, where it remained till spring. The general effect of freezing and thawing was to increase the percentage of germination and lessen the dormant period, especially in case of seeds with hard coats ; in all cases the dormant period of hard-coated seeds seems to be greater than that of thin-coated seeds. The following examples illustrate these differences : The dormant period of common pigweed (Amarantus •retro fle.vus) was nine and one-third days when kept in packages in a dry room, and six and one-third days after having wintered out of doors; its germination was in- creased from 40 to 50 per cent. In common pigeon grass the average dormant period was lessened from eleven to seven and one-quarter days; the percentage of germina- 4O WEEDS OF THE FARM AND GARDEN tion increased from 34^2 to 38 per cent. In wild rye the dormant period was lessened from nine to five days ; the germination increased from 22 to 48 per cent. It was found that the longest dormant period was found in those seeds which have the hardest and thickest seed-coats. Some of the ragweed seeds had a dormant period of 152 days, while some seeds of barnyard grass had a dormant period of 178 days. The highest average percentage of germination was observed in common mustard, which was 100 per cent, and for the six tests, 90.3 per cent. It has long been known that many seeds refuse to germinate until they have passed a period of rest. Nobbe and Hanlein made a study of the seeds of 31 species of weedy plants, continuing the experiment for 1,173 days. A number of these weeds showed germination after a lapse of 1,173 days; among them were Campanula persi- cifolia, silvery cinquefoil (Potentilla argentea), mouse-tail (Myosurus minimus), hoary plantain (Plantago media), and field penny-cress (Thlaspi arvense). It would seem that freezing is decidedly favorable for the germination of many weed seeds. Of 65 species planted November, 1908, four species failed to germinate ; of 60 species planted in Decem,ber, 48 failed ; of 63 species planted in January, 44 failed; of the March planting of 62 species, 27 failed ; of 59 species planted in April, 46 failed ; of the seeds exposed to the weather, 64 species, 24 failed to germinate. With the closest care and observation there was lack of constancy in the germination, resulting in marked ir- regularities not to be attributed to known causes, due possibly to inherent qualities. Germinability of Weed Seeds After Having Been Kept in Compost and Manure. — There is a widespread impres- sion that germinable weed seeds may be scattered with WEED IMPURITIES IN AGRICULTURAL SEEDS 4! manure. This is true so far as seeds which get into manure not thoroughly composted are concerned. Mr. E. I. Oswald made a series of experiments to ascer- tain the vitality of seeds when placed in manure under different conditions. Three kinds of manure were used — horse manure, cow manure, and horse and cow manure mixed in equal parts. The manure was placed in sepa- rate piles, and seeds inclosed in gauze bags were placed in the manure and allowed to remain for varying periods of time, in some cases 60 days, in others six months. This lot contained 52 different kinds of seeds. After the re- quired length of time, the seeds were planted in the green- house, and it was found that they had become thoroughly rotted and their vitality destroyed. In order to cover the conditions usually followed by dairymen and gardeners, where the manure remains but a short time, another set of experiments was started in the fall. The seeds re- mained in the pile only one month and were then planted as in the previous experiment. The results of the exper- iments entirely confirmed the previous ones, except in the cases of the seeds of ribgrass, horse nettle, common plantain, large ragweed, bitter dock, and mallow, which were still firm. Early in the summer of 1908 we placed 31 different seeds of weeds and seeds of a few cultivated plants in gauze bags and left them in horse manure for five weeks. The seeds were placed in this manure on May 10 and were removed June 19. The seeds were then germinated in the greenhouse. Only a small percentage of the fol- lowing weed seeds were capable of germination. We also conducted some experiments in feeding vari- ous weed seeds to animals, among them sour dock, quack grass, and sunflower; very little seed was capable of germination after it had passed the digestive tract of the animals. It is well-known, however, that hard-coated seeds do pass the digestive tract uninjured. Numerous WEEDS OF THE FARM AND GARDEN cases of animal dissemination of seeds such as mesquit, acacia, and honey locust, are on record. In some cases even the seeds of corn, oats, millet, and foxtail have been found capable of germination after they have passed the digestive tract of animals. However, there is little dan- ger from these in manure. The Results of a Test of Germinability of Seeds which Had Been Deposited in Manure for Five Weeks. NAME Number seeds planted 1/5 ts o c 1^ (S u 3 00 ts 8 3 & cs > •3 Percen- tage of germi- nation •s-J! HI Not so treated White Clover, Trifolium repens 2 Red Clover, Trifolium pratense Black Medic, Medicago lupulina 200 200 200 200 200 200 200 200 200 200 200 200 200 200 200 200 200 200 200 200 200 200 200 200 200 200 200 200 200 200 1 1 1 1 1 1 1 1 1 1 1 1 1 0 0 0 1 0 0 1 0 0 1 4 0 0 0 I 0 0 0 0 0 0 1 0 0 0 1 -o 0 0 4 98 96 72 8 32 8 20 10 62 26 88 98 54 98 98 0 20 10 88 28 30 26 22 Lady's Thumb, Polygonum Persicaria. Chess Bromus secalinus Pepper grass, Lepidium virginicum. . . . Sweet Clover, Melilotus alba Large Ragweed, Ambrosia trifida Hedge Mustard, Sisymbrium offlcinale.. Common Pigweed, Amaranlus retro- flexus Squirrel-tail, Hordeum jubatum Lamb's Quarter, Chenopodium album. . Wheat, Triticum sativum Quack Grass, Agropyrum repens Corn, Zea Mays Oats, Avena saliva Water Horehound, Lycopus rvbellus . . Bull Thistle, Cirsium lanceolatum Crab Grass, Digilaria sanguinalis .... Wild Rose, Rosa arkansana Whorled Foxtail, Selaria verticillata . . . Curled Dock, Rumex crispus Green Foxtail, Setaria viridis Bur Clover, Medicago denticulala .... Pigeon Grass, Setaria glauca Sunflower, Helianthus annuus Buckhorn, Plantago lanceolata Bracted Plantain, Plantago aristala . . Cocklebur, Xanthium canadense Rugel's Plantain, Plantago Rugelii CHAPTER VI. SOME WEED LAWS AND SEED-CONTROL LAWS In connection with weed control the following laws are published herewith : The Iowa Weed Law, the Iowa Seed Law, which has formed the basis for seed laws of several states, and the seed law proposed for general adoption, prepared by a committee of the American Seed Trade Association and the American Association of Official Seed Analysts. THE IOWA WEED LAW SECTIOK i. LAND OWNERS OR TENANTS TO DESTROY WEEDS; WHEN. — It shall be the duty of every person, firm or corporation owning, oc- cupying or controlling lands, town and city lots, land used as right of way, depot grounds or for other purposes to cut, burn or otherwise en- tirely 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. SEC. 2. Noxious WEEDS. — The following weeds are hereby de- clared to be noxious weeds, namely: Quack grass (Agropyron repens), Canada thistle (Cirsium arvense), cocklebur (Xanthium canadense), wild mustard (Brassica arvcnsis), sour or curled dock (Rumex crispus), smooth dock (Rumex altissimus), buckhorn or ribbed plantain (Plan- tago lanceolata), and wild parsnip (Pastinaca sati injuries to cattle that may result in death. Broom sedge (Andropogon virginicus) is a most troublesome weed in meadows from southern Missouri, southeast to Virginia. Sweet clover (Melilotus alba), one of the most common weeds of pastures, is regarded by bee keepers as a valua- ble honey plant ; but in the North is little esteemed as a forage plant. In the South it is valuable for reclaiming waste land, as it grows not only on rich land, but will thrive in the poorest soil. Professors Tracy and Goff both recommend it as a soil renovator. Although occa- sionally useful in Iowa as a bee plant, a soil renovator, and a forage plant, we must nevertheless regard it as a weed. A few members of the mustard family are troublesome in the pastures and meadows of Iowa. Among these are pepper grass — Lepidium apetalnm and L. virginicum — the former of which is abundant, especially in timothy seed. Its brown color enables it to be easily detected. The wild carrot (Daucus Carota) is common in the East in some clover meadows, having been introduced largely with clover seed. The bracted plantain looks much like buckhorn, but has 56 WEEDS OF THE FARM AND GARDEN narrower leaves. It is common in Missouri, Illinois, Iowa, Nebraska and Kansas, extending- east as far as the Atlantic coast. Field dodder is common not only on native herbage clear across the continent, but also occurs on clover. The clover dodder appears in California, Utah, Colorado, Montana, Missouri, and Iowa on alfalfa and clover. Pepper grass (Lepidium virginicum) furnishes an im- purity for alsike and blue grass. Persicaria, or lady's thumb (Polygonum Persicaria), and the two ragweeds are common in many meadows. Among the common weedy grasses are foxtail (Setaria glauca), crab grass (Digitaria sanguinalis) and barnyard grass (Echinochloa crus-galli). On the plains and ranches in Colorado and Utah occur many bad weeds. The Russian thistle (Salsola Kali, var. tenuifolia) is easily one of the most common weedsi in eastern Colorado, coming up not only in the streets, but also along roadsides and in fields. In the early days of the Russian thistle it was thought that it would prove a very troublesome weed in the more humid conditions of our country. Thus far it has not, but in the West it has found ideal conditions for development. Another weed which has become abundant is the tumbling mustard (Sisymbriuin altissimum) , which is found in many places. It has light yellow, mustard-like flowers, and later stiff pods without leaves. Sweet clover grows everywhere along roadsides and streets in eastern Colorado and stands drought well. On some of the foothills and streets of the eastern slope of the Rockies a species of brome grass (Bromus tectorum) is becoming abundant. It is an annual which grows! with very little moisture and is crowding out many more valuable grasses, and alfalfa. It is particularly common near Colorado Springs, Salt Lake Basin and in California. It has little value for forage pur- poses; the hay is light, and moreover the plant is injuri- WEEDS OF SPECIAL CROPS 57 ous to stock in much the same way that squirrel-tail is ; i. e., it gets into the mouth, producing inflammation and causing severe ulceration. Squirrel-tail grass is abundant where seepage water occurs, and like the brome grass just mentioned causes much injury to stock. Little can be done to check it as long as it isi allowed to go to seed. In Utah another annual brome grass, the quaking brome (Bromus brizacformis), is often seen, also several species of squirrel-tail grass (Hordeum jubatum, H. caespitosum), common in the East, and wild barley (H. murinum). Storksbill (Erodium cicutarium) is common on much of the western country to California. Wild oatsi (Avena fatua) is frequently seen. In most meadows of Utah there is an abundance of a species of thistle (Cirsium scariosum). It is a large stocky plant with very spiny, light-colored leaves and light pur- ple flowers. In some places the green hellebore (Vera- trum viride) is common. In low meadows or sandy, moist meadows, of the North the common horsetail (Equisetum arvense) is abundant and troublesome. In the Pacific Northwest another large species is common. The common brake (Pteris aquilina) is common and troublesome in the same region. Both the brake and horsetails are poisonous. Weeds of Grain Fields: Small Grains. — The kinds of weeds found in small grain fields vary with the locality; although some kinds are quite universal. Among these are mustard, corn cockle, cowherb and vetch. Many others are local. Among these may be named Russian thistle, in the West ; wild garlic, pennycress, mustard, tumbling mustard, foxtails, crab grass, germander, smartweed, lady's thumb, corn gromwell, Canada thistle in the East and Canada ; perennial sow thistle in Minne- sota and North Dakota; ragweed, milkweed, artichoke, 58 WEEDS OF THE FARM AND GARDEN morning glory, wild oats, cocklebur, chess (Bromus scca- linus), cockle, cowherb, vetch, rose, etc. Corn. — Many of the foregoing weeds also occur in corn fields. To them we might add velvet weed, shoofly, sida, chicken corn, horse nettle, shoestring, meadow sunflower, cocklebur, artichoke, large ragweed, nut grass, quack grass and buffalo bur. Weeds of Gardens. — The more important weeds of gardens; are prickly lettuce, annual sow thistle, lamb's quarter or goosefoot, purslane or pusley, lady's thumb, pigweed, five-finger, crab grass, horseweed, quack grass and nimble will. The character of weeds of gardens naturally differs in various parts of the United States. In New England and the Central States such weeds as goosefoot, fall dande- lion, smartweed, sheep sorrel, crab grass, common mouse- ear chickweed, purslane, celandine, shepherd's purse, horse-radish, sweet clover, milk spurge or milk purslane, cheeses, wild carrot, blueweed, corn gromwell, henbit or dead nettle, speedwell, small ragweed, toadflax, burdock, bootjack, prickly lettuce, green foxtail, pigeon grass, but- tercups and Canada thistle, chicory, quack grass, are all common weeds. The weeds of the central northern Mississippi valley are much the same, except the larger ragweed, squirrel- tail, Pennsylvania smartweed, bindweed or wild buck- wheat (Polygonum Convolvulus) ; dropseed grasses (Muhl- enbergia mexicana and M. glomerata), are abundant, and occasionally night-flowering catchfly (Silene noctiflora). In the latitude of St. Louis, a wild bean (Strophostyles pauciflora), the southern morning glory (Ipomoea hed- eracea), European bindweed (Convolvulus arvensis), bone- set (Eupatorium serotium), Mexican tea, spiny pigweed, Indian mallow or velvet weed, galinsoga, ironweed (Verno- nia noveboracensis), aster (Aster Tradescanti and A. sali- cifolius), goldenrod (Solidago serotina) ; the boneset, WEEDS OF SPECIAL CROPS 59 asters, goldenrod and European bindweed, are perennial. Marsh elder (Iva ciliata), poverty grasses (Aristida dicho- toma), dead nettle or henbit (Lamium anplexicaule), are abundant annuals. The Virginia plantain (Plantago vir- ginica), pokeweed (Phytolacca decandra), Carolina crane's-bill (Geranium carolinianum), turkey-foot grass (Eleusine indica), and sida (Sida spinosa) are the common weeds; the large and small ragweeds should also be in- cluded in this list. From! western Iowa to Denver the weeds are much the same as in Iowa and New England, except the false rag- weed or marsh elder, Mexican fireweed, yellow and white sweet clover, Russian thistle, buffalo bur, vegeta- ble oyster plant, wild licorice, tarweed or rosin weed (Grindelia squarrosa), perennial ragweed (Ambrosia psil- ostachya), prickly poppy (Argemone intermedia), woolly thistle (Cirsium canesccns), Fremont's goosefoot (Chen- opodium Fremontii) and annual sunflowers (Helianthus annuus and H. petiolaris) are common. The latter are abundant from western Iowa to Texas. The cleome is abundant on the plains. In the interior basin, awned brome grass, conium, wild barley, peppermint, caraway, horehound (Marrubium vulgare), pineapple weed and black medic are among the common weeds. In California the more important weeds are wild lic- orice, spiny cocklebur, wild heliotrope, crowfoot grass, crab grass, milk thistle, storksbill, bur clover, tarweed, wild carrot, etc. In Maryland and Virginia, wild onion, dandelion, wild carrot, prickly lettuce, sweet clovers, horseweed, cockle- bur, Mexican tea and pigweed are common. In the Gulf states the narrow-leaved sneezeweed, pig- weed (Boerhaavia), sida, morning glory (Ipomoea hedera- cea), croton (C. capitatus and C. monanthogynus), crab grass, etc., are the common weeds, and westward in 60 WEEDS OF THE FARM AND GARDEN Texas the buffalo bur; the prickly poppy (Argemone mexicana) is one of the most common weeds. Many of these annual weeds are easily exterminated by cultivation, but attention must be paid to weeds which occur in waste places where they produce seeds in enor- mous quantities. Weed seeds often retain their vitality for a considerable period of time. Even though the first crop is removed, a second crop appears from, the seeds buried somewhat deeper in the soil. Weeds of Vacant Lots. — The vacant lots of all parts of our country are a continual menace to the agricultural community. Many of our worst weeds start in the city. The writer has observed the spreading of orache (Atri- plex) from a small beginning in an Iowa city over a con- siderable area. There are hundreds of acres of Canada thistle in Chicago, and in some streets much of the peren- nial sow thistle, which is such a menace to the agricul- ture of Canada, the eastern states, northern Minnesota and North Dakota. The bouncing bet and toadflax are spreading rapidly to the adjacent country from such cit- ies as St. Paul, Minnesota, La Crosse, Wisconsin, and Chicago. The unoccupied lands are great weed patches and in most cases are very unsightly. In an interesting article on "Weedsi of Cities and Towns" by Lyster H. Dewey, the statement is made that "the weeds of cities and villages are usually of the mi- gratory class, cosmopolitan in character, and capable of thriving under a wide range of environment. According to the early European works on botany, plants from Asia, adventive in Europe, usually appeared first in cities. Many of these plants* are found about the cities and towns of this country. Others are native plants which have withstood the changed conditions due to cul- tivation and have acquired a weedlike habit. In the eastern cities and in those on the Pacific coast Old World species predominate, while in the cities of the interior, WEEDS OF SPECIAL CROPS 6l especially in those west of the Mississippi river, there is a larger proportion of native plants. The species vary in different cities, in different years, and in different sea- sons." These weeds can be removed by sowing these lots and vacant areas with clover and grasses. These plants will effectually prevent the growth of many weeds, except the annual spear grass (Poa annua), dandelion, wild onion (Allium vineale), star of Bethelem (Ornithogalum umbel- latum) and cat's-ear (Hypochaeris) ; or they can be uti- lized for the growth of vegetables, like the potato. Where there are large areas, these weeds can be kept down by allowing sheep to graze ; this method is followed in New York and Philadelphia. These animals are ex- cellent lawn mowers. The driveways of parks and walks can be kept clean by spraying with iron sulphate or some other herbicide ; however, the iron sulphate will be more effective than most of the other herbicides. The method has been described in full in another connection. In many sitates there are laws on the extermination of weeds, and while they may be enforced in the country, no attention is paid to them in cities. The municipal author- ities should enforce the laws. It may be necessary to appoint a weed commissioner who shall work under the authority of the street or park commissioner. Dewey suggests that "a few good examples, which may be pro- duced through individual effort or by the united action of a small community, will demonstrate the practical utility of the work and lead to its extension. Examples of this kind are now found in many villages and suburban towns. If the practice can be made general in the cities and towns throughout the country it will cut off one of the principal avenues for the introduction of foreign weeds." Roadside Weeds. — There is very little excuse for the appearance of many of the weeds that appear along road- sides, the character of these differing only with the local- 62 WEEDS OF THE FARM AND GARDEN ity. Among the most conspicuous roadside weeds are the greater ragweed, small ragweed, meadow sunflower, arti- choke, bull thistle, dog fennel, beggar-ticks, marsh elder, fetid marigold, velvet weed, Jimson weed, cocklebur, mustard, mullein, Canada thistle, woolly thistle, squirrel- tail grass, wild barley, sweet clover, annual brome grass, black medic, bur clover, dodder (the last three espe- cially common in Colorado), tumbling mustard, Russian thistle, fireweed (especially common in the West), Mex- ican poppy (Texas), capitate croton (Missouri to Texas), sneeze weed, and buffalo bur (common from Col- orado to Texas). Sunflower and marsh elder are very frequently seen in Kansas, Nebraska, the Dakotas and Colorado. Weeds of Yards. — The weeds of yards, especially of barnyards, also vary greatly. In nearly all cases they are such as can stand considerable tramping over, or else they are weeds that are avoided by stock, because of siome injurious properties residing in the plants. In the North the most common barnyard weeds are dog fennel, barnyard grass, cheeses or small mallow, Jimson weed, dock, fetid marigold (in Iowa, Nebraska to Kansas), smartweed and dooryard knotweed. In the Southwest, buffalo bur and smartweed are common. Weeds of Lawns. — Blue grass, during the dry season, may become weedy. In the greater part of the Missis- sippi valley, the most common weed on lawns is the smooth crab grass which fruits so closely to the surface of the ground that the lawn mower will not catch all of the seeds. Yellow foxtail or pigeon grass is also com- mon where the lawn is not properly cut. Chickweed is one of the m/ost common weeds in the North. Dandelion is one of the most common weeds in lawns in the North- west. Cat's-ear (Hypochacris radicata) is common on the Pacific coast, in Washington and Oregon. CHAPTER VITI. POISONOUS WEEDS A great many people are ignorant of the presence of poisonous plants growing in their neighborhood. In the list given below are some of the most common species. While some of these are found more frequently than are others, it is also true that some in the list are more virulently poisonous than others. In wet places in the North, the cow- bane is one of the most poison- ous of weeds ; the fleshy roots with a pungent odor are eaten, people mistaking them for parsnips. The hemlock of the ancients, a common plant in the West, contains a deadly poison. The seeds of Jimson weed are also poisonous. The nectar in the flowers of this weed and of Wright's datura Fig~ 3a. California poison have caused the death of chil- ivy (Rhus diversiloba). Many clren people poisoned by touching T ' .. j j u i the Plant (U- S- DePt- ASr1-) In the list appended below, the more poisonous species are printed in bold face type. Anemone or wind flower, black henbane, black locust, black nightshade, bloodroot, bouncing bet, buck- wheat, bunchflower, bulb-bearing hemlock, calycan- thus, caper, celandine, choke cherry, cockleb ir, com- mon brake, common juniper, corn cockle, crimson clover, crowfoot, cursed crowfoot, cypress spurge. 64 WEEDS OF THE FARM AND GARDEN darnel, elderberry, flax, flowering spurge, fly agaric, hellebore (green and false), hemp, hogwort, horse chestnut, horse-radish, horsetail, Indian hemp, In- dian tobacco, Jimson weed, Kentucky coffee tree, large blue flag, larkspurs, lepiota, lily of the valley, lima bean, mandrake, marsh marigold, monkshood, moonseed, mustard, needle grass, opium, osage orange, partridge pea, pasque flower, peach, poison hemlock, poison ivy, pokeweed, prickly poppy, purple foxglove, purple Jimson weed, ragweed, rattlebox, rose, sleepy grass, smartweed, sneezeweed, sorghum, spotted spurge, spreading dog- bane, stemless loco weed, stinging nettle, stonecrop, swamp camas, sweet clover, tansy, some toadstools, to- bacco, tree of heaven, water hemlock, water parsnip, white snakeroot, wild barley, wild black cherry, wild in- digo, wild oats, wormseed, Wright's datura, yellow lady's slipper, yew. Fig. 33b. Poison ivy (Rhus Toxicodendron), common in eastern North America. Many people are sensitive to its poison. CHAPTER IX. TABLE OF NOXIOUS WEEDS In the table which follows the most troublesome weeds of North America have been given. No doubt there are many other plants which should be classified as weeds, but it is difficult to always draw a sharp line ; moreover, it is a difficult matter sometimes to determine the worst weeds for a given locality and even more diffi- cult to determine the worst weeds for the entire country. A weed may be very bad in Iowa and yet comparatively harmless in Missouri, Arkansas, and Florida. For in- stance, the sow thistle is certainly a very bad and aggressive weed in the Canadian Northwest and on the borders of North Dakota and Minnesota; the orange hawkweed is a troublesome weed in the New England states and New York, the same is true of the ox-eye daisy, but it is not troublesome in Iowa, Nebraska, Kan- sas, or Missouri. Quack grass is an extremely trouble- some weed from the New England states to Minnesota and is becoming troublesome in northern Iowa. Some years ago Dr. Byron D. Halsted published a paper giving a scale of points of our worst weeds.1 The report was based upon reports received from more than one hundred replies from different parts of the United States. It was found that the following weeds were re- ported the most frequently: Canada thistle 10 times, pigweed 10 times, purslane 14 times, cocklebur six times, and so on. That is to say the correspondents mentioned these as the worst weeds in their particular locality. Dr. Halsted considers the following as important in 1 Proc. Soc. Prom. Agrl. Sci., 1889:43. 66 66 WEEDS OF THE FARM AND GARDEN determining the scale of points: I, the recognition of the steed ; 2, separation of the seed ; 3, recognition of plant ; 4, prevalence ; 5, robbing soil ; 6, seeding capacity ; 7, dis- semination; 8, vitality of seed; 9, longevity; 10, root and stem propagation; n, obnoxious qualities; 12, forage value; 13, resist eradication; 14, aggressiveness; 15, har- bor fungi; 16, harbor insects; 17, soil habitat; 18, climate habitat; 19 and 20, miscellaneous. Dr. Halsted gives a tabulated scale showing the characters of the worst weeds of the country as follows : Purslane (Portulaca oleracea) Ox-eye Daisy (Chrysanthemum Leucanthemum) Canada Thistle (Cirsium arvense) Narrow Plantain (Plantago lanceolata) Sorrel (Rumex Acetosella) lb ^wi o-d-2? s§§ Efc-2 •ill °Wh3 Quack Grass (Agropyron repens) Dandelion (Taraxacum officinale) 1 Recognition of Seed 4 4 4 4 3 3 5 4 2 Separation of Seed . . 1 4 4 4 2 3 4 4 3 Recognition of Plant . . . 2 3 4 3 3 2 3 1 4 Prevalence 3 3 4 4 4 3 3 3 5 Robbing Soil 3 5 5 2 2 2 4 2 6 Seeding Capacity 5 5 5 3 3 2 1 3 7 Dissemination 1 4 5 2 2 1 1 5 8 Vitality of Seed f ? ? ? y f p j 9 Longevity 2 5 5 4 4 3 4 4 10 Root and Stem Propagation . 11 Obnoxious Qualities 0 0 3 3 5 5 1 1 1 1 1 0 5 0 1 0 12 Forage Value 4 4 5 2 4 3 3 4 13 Resist Eradication 3 4 5 1 1 1 5 1 14 Aggressiveness 4 5 5 1 1 2 5 3 15 Harbor Fungi 1 0 0 0 0 0 1 0 16 Harbor Insects 0 0 0 3 0 0 0 3 17 Soil Habitat 3 3 4 2 2 2 3 3 18 Climate Habitat. . . 4 4 4 2 2 2 3 4 19 ] & \ Miscellaneous 4 5 5 4 3 2 4 1 20 J Total Points 44 64 74 43 38 31 54 46 For the state of Iowa the weeds given in the Iowa Weed Law are the most injurious with the possible ex- ception of the squirrel-tail ; they are as follows : Quack grass, Canada thistle, cocklebur, wild mustard, sour or TABLE OF NOXIOUS WEEDS 67 curled dock, smooth dock, buckhorn, or ribbed plantain, wild parsnip, horse nettle, velvet weed or button weed and burdock. The Canada thistle, quack grass, horse nettle, cockle- bur, and squirrel-tail grass are the most injurious in Iowa, while Dr. Halsted gives some of the worst weeds found in the state of New Jersey as follows: Canada thistle, wild carrot, docks, ox-eye daisy, ragweed, sorrel and narrow plantain. In Wisconsin the worst weeds are quack grass, Canada thistle, mustard, dock, ragweed, wild carrot in some places, and cocklebur. The worst weeds for Indiana, according to Mr. J. R. Campbell, are white weed in clover and timothy meadows, cocklebur in corn fields, horse nettle, buckhorn, and in the southern part of the state wild garlic, while in Kentucky the star of Bethlehem has become a most pestiferous weed in gardens and fields. In parts of Canada, especially the province of Manitoba, they consider the Canada thistle, perennial sow thistle, wild oats, and marsh elder to be the most troublesome of their weeds. H. L. Bolley, in his account of the weeds of North Dakota, gives the following as some of the most troublesome: Kinghead, Canada thistle, French weed, mustard, and wild oats. Dr. Millspaugh reports the ox- eye daisy, yarrow, broom sedge, and blue thistle as the worst weeds in the northeastern part of West Virginia. The broom sedge here listed is generally a troublesome weed in many parts of Virginia and' other southern states, where it is considered one of the worst of weeds, as it is also so considered in Ohio by Professor Selby. Dr. A. Nelson considers Russian thistle, squirrel-tail grass, cockle, Canada thistle, bull thistle, buffalo bur, prickly lettuce, among the worst weeds of Wyoming. ** hi S^OOI JO UOfVBJtlQ * * * * * * * * ****** * •i«o * ***** •BU'B^UOJ^ tpnn **** **** UTXOSSTJ^ * ****** * *** ** * * ***** •q^N ***** *** **** **,-L. •UUTJAJ ******* **** ***** "III ** ***** * **** * *** * *** •puj ***** ** ** ** * ** ******** * *** * *** ** ****** *** ****** ** if fei| 8M&&-2 g'S-illl 1 1 ll'Isiililllllll i P.J3 UorSi-,"T!T.dc«iuSoCg3ooortg 3--^ dda'a'rtrtrtS 1 it s 2 s Is i ilfilljjjjiill JteJGQE^ftiaiftitt^^UU , < o o t> ^§ :J1 Jr1" • « Di I !f Sgrt^uu*0 8 a 5,3 a a w *; OUUOOOUUOOUOOCJCJOCJOodcjOOOOOUOOOQQQQQQQQQQ ,< Sljiliill a « 2 II §^ ti >lll llllimJilHilliiimUiliiii >ll1i I ! S^OOJ JO UOI^BJTIQ ** *#* »* ** * * * * *»** * ** » **** <».* * * unossip^ •3HJQ ' « * * * * •ni * * * * * *** # * * * 70 ; 3,8 a s s.s.s.s a a a |^'""a'S, ^^,-2-2._ _ ._ ******* sssssofeL^QW'^^*! ^*"-* 2 o o *^ s I? o ^§§1 in |^ | |i||| 11! i-i 111 m A (^ < O, <; (X 0« (i, < •< < 0* < is- E K 3 1 X Amarantus spinosus Phytolacca decandra Rhus Toxicodendron Argemone platyccras Argemone mexicana 1 " >§. ° ••» S »»».,3 1 II 2 fJail. § -S "§ I:S :-l iilgl uil 2«« lllsrl fe«'5 -2s §f»^l lllti iHi| Hi! !ilS*ll!a8l|2|fi|lHl «*«« ^^•i-S-S ^2 2 1 5 -2 °-§ s-2.«.« *^ 8^^ §,.« J4'a 's's « £ s «X*0, < «<*< C^a^^O^C^^f^*^ M<« * * * * * *•» * * * * * * * # * * * * * * * * * ******* * * * # * * * * * * * * * * * **<«. * * * * * * * * * * * * * * * * n. * * * ** ***#** #* » (V. **** **** # #* ** # * * »*****#** * * #### »* * #####**•»# #** ** * »** * * * * * * * * 5 g ; ~3 • le • • • ::::::::::: •%::::: :g : : : : : : : : : : : :-g : :g : : : i;;^jl;;; fe§ igal ij :e' ;1 ; i ;s ; :|; 11*;; ° • -3-a 2 § • ; • » 8 s 2 • 8 a » -^ :B : §J • • °» : • » • . 15 J3 • • Ji^!! jiJiilllllitllli JS i It IHtil § h: 11s«>;>;tog^'S28SS§'3X«^«*-«JS'*^»2;-4J>>>-*J --J «*••- OJcJfrt^Oj »-'tf-Q-*->7jNNCt3"-l-i*Td IUJISI P liijvln 8" 8ii Illllblll t felilllii .ilr.iir OOOOOCP?1 [•ro;oa)XX3.2r^GrtOOdC cacxa P-tPnP-iPHPHP^PHpHPH O*K K W PHP4PMPHP4P4PHP^C/3C/2C/2C/2C/2C/2C/2(/2C/2(/2C/2W2C/2 C/2C/3COC/5 73 Xanthium spinosum Euphorbia maculata Euphorbia Preslii Jatropha stimulosa li , «| ! , i "trlllliflJIIllliH.] 2 •§ o o g •? « s K O SJ .* O «•§ |2-S S^OOJ JO <«A. **««*«**«*»***<***«*• ii«a,< •qstiM * **** **** * * TO * *** ****** * * * w»V»W * wn * * * * * * » 74 Verbena urticifolia Verbena hastata Vicia sativa Hierochloe odorata Holcus lanatus Panicum capillare Artemisia biennis Artemisia Ludoviciana Achillea millefolium lists, therefore, will includ< **« ** •5 M •0 s o 13 O Ji ********* 3 S? * * * * * * * * * • o *** ***** 1? * * - « * * * * * * •o •a 3 i a * * * * * * * U *O 3 a) BH" «"§ 3.5 Iff ********* w * * * c^ ******* * ts W-JJ ^>2 «p< ::::::- IS i| |||f§ ilffliiif The weed most of the weeds 76 CHAPTER X. MIGRATION OF WEEDS The study of the abundance of weeds and their dis- tribution is one of great importance to the cultivator of the soil. Many of our common weeds occur from the Atlantic to the Pacific. Many of them are of European origin. Some weeds are native to the soil ; others are tropical in origin. It will be found from the list of weeds appended that many of them are common from the Gulf of Mexico to British America. It is also true that Texas has some of its own weeds; that the eastern Gulf states have some peculiar weeds ; that the states west of the Missouri River to the Rocky Mountains also have their own characteristic weeds and some localized weeds are found upon the Pacific coast. It may be interesting to observe in this connection that some weeds require a considerable length of time before they are permanently established and become a part of our flora. In other instances certain weeds are crowded out. During recent years the writer has found very little evidence of the black mustard in this state, mlost of it being replaced by the charlock, or wild mustard of our oat fields. In Utah the awned brome grass has crowded out the quaking brome grass. In 1898, when the writer visited the region of Salt Lake and Og- den he found quaking brome grass the predominating grass on the hillsides, but now the hillsides are covered with the awned brome grass and very little of the quak- ing brome grass could be seen. Our eastern weeds are in a large part native to Europe, but there are a number native to Iowa, while others have come from the South and West. The question of 76 MIGRATION OF WEEDS 77 migration of weeds is1 an interesting one. In the East the European weeds predominate. In the Southwest and the prairie states west of the Missouri many of the trouble- some weeds are indigenous to the soil. I can recall but a few troublesome weeds in Texas that have come from Europe. The Texas weeds are either of tropical origin or else indigenous. However, there are some troublesome European weeds in Texas, but they do not cover the * Brasjico arvensis. , olpomoeo heJeTaceo/ftorninq-qlort. X •>- / •*•*• *• i^ t~ * r ICenloc/reo SolsTilia/is KnahvoeJ Burctovtc Fig. 330. Distribution of some weeds. Mustard (Brassica), morn- ing glory, etc. (C. M. King.) landscape as they do in the North and East. The narrow leaf sneezeweed is a dominant weed everywhere through- out the state ; and the buffalo bur, which is indigenous to the plains from western Texas to Colorado, is one of the dominant weeds. These weeds have largely spread since the rebellion, 1865. In the West, particularly Utah and the mountainous countries, the scarious leaf thistle is at once a dominant species, although in places it vies with the bull thistle and in all clearings of Oregon and Washington the fireweed (Epilobium angustifolium), cov- ers thousands of acres, while with it we may find patches 78 WEEDS OF THE FARM AND GARDEN of foxglove, pansy, and a great deal of velvet grass and much Canada thistle, besides numerous other plants which are carefully cultivated in the eastern states for ornamental purposes. Dr. Gray has somewhere said that most of the trouble- some weeds of western Europe originated in the East. It is certainly true that as conditions are prepared, weeds spring into existence. Such plants as are best adapted to stand adverse conditions assert themselves and become the pests of the farmer. Annual weeds seem to have a better chance to adapt themselves than perennial. Of the annual weeds we may mention the purslane, Jimson weed and Indian mallow. It does not require much botanical knowledge to recognize the similarity of the flora of our "great plains." Many of the prairie plants are common from Texas to Manitoba. The compass plant (Silphium laciniatum), buffalo bur (Solatium rostratum), common sunflower (Helianthus annuus), etc., are alike common to the prai- ries of Texas, Kansas, Nebraska and the Dakotas. It is remarkable how rapidly European weeds have spread in parts of South America. In the neighborhood Df Buenos Ayres, are found bur clover (Medicago hispida), its allies, and a composite (Silybum marianum), which has also become noted as a pest in California ; Cynara cardun- cidus covers the pampas for miles. The European grasses, like the perennial rye grass (Lolium perenne), squirrel grass (Hordeum murinum) and other wild bar- leys (H. pratense) have rapidly taken the place of native grasses. The interesting observation has been made in South America and Australia, that indigenous (native) plants have been crowded out by closely related European species. In Australia, common sow thistle (Sonchus oleraceus), a truly cosmopolitan weed, has established itself in low grounds near streams and has crowded out a native species of sonchus. It is possible that some of MIGRATION OF WEEDS our native plants are affected in this way. Common purslane (Portulaca oleracea) has without doubt in some places replaced native forms. Bull thistle (Cirsium lanceolatum) without doubt trespasses on the ground of some of our native species. C. altissimum, C. iowense and C. discolor are undoubtedly affected in this way. These thistles are certainly less abundant where bull thistle occurs. In Manitoba the Canada thistle is much more abundant than th bull thistle. In places it occurs not only in fields, but in the woods. The sow thistle (Son- + Car,oJa 1t,;stft , Wafer Hyacinfli I wum i;neaif Fig. 33d. Distribution of some weeds. Canada thistle, etc. (C. M. King.) chus arvensis) is abundant everywhere in fields. There is little of the annual species (S. oleraceus). Most of our common weedy plants are of European origin. This is true for certain parts of the United States only, notably New York, Massachusetts, Ohio, Illinois, and other states that belong to the North Atlantic sec- tion. Yet the weeds of the interior region, the territory embracing our prairies, include a surprising number of na- tive plants that are weedy in their nature. A few of the 80 WEEDS OF THE FARM AND GARDEN European weeds are, however, great pests. Tumble weeds (Cycloloma atriplicifolium and Corispermunt hys- sopifolium) and ragweed (Ambrosia trifida) may be men- tioned among the troublesome weeds of the West. The preponderance of these weeds is possibly due to the new- ness of the country, or it may be because of the plasticity of the plants themselves or on account of certain climatic conditions. In southern Atlantic states there is a sur- prising number of weeds that are of tropical origin. Among these are the spiny amaranth (Amaranthus spino- sus), Mexican tea (Chenopodium ambrosioides), senna (Cassia occidentalis), common morning glory (Ipomoea purpurea) and I. hederacea. Quite a number have come from India, as Jimson weed (Datura Stramonium), helio- trope (Heliotropium indicum), etc. Others are European. Turning to the weeds of the Pacific coast, it may be said that its weed flora is entirely different. Dr. Hilgard, in an interesting series of .articles, "The Weeds of Cali- fornia," in Garden and Forest, says : "The broad fact in the premises that first strikes the newcomer in California is that a number of plants that are subjects of careful culture east of the Rocky moun- tains, as well as in Europe, and which quickly succumb when deprived of artificial protection there, are here among the most persistent and obnoxious weeds ; while very many of those that are troublesome in the Atlantic region are conspicuously absent on the Pacific side. Rad- ish, beet, celery, carrot, are conspicuous weeds. The smartweeds (Polygonum) are almost entirely absent on the Pacific coast. Amaranths flourish. Pusley, so troublesome in eastern states, has appeared in but few localities. As- yet it has made no headway as a trouble- some weed. Bur clover (Medicago dcnticulata), so troublesome in South America, was one of the earliest of European introductions in California, and is a great pest." These illustrations suffice to show the differences MIGRATION OF WEEDS 8l in the character of the weed flora in various parts of the United States. Of the cosmopolitan weeds, shepherd's purse (Capsella Bursa-pastoris), occurs everywhere in Europe, Persia, In- dia, Japan, United States, Chili, South Africa and Can- ada. Pusley occurs in India, Egypt, Europe, South Africa, Japan, China, Java and Philippine Islands ; horse weed (Erigeron canadensis), everywhere in the United States from Maine to California, Brazil, South Italy, Russia, Sweden, Persia, North India, South Africa. It is sometimes a very difficult matter to decide whether plants are strictly native to a country or have been introduced, so thoroughly have they established them- selves. Pusley is an excellent illustration. It is believed to be a native to the southwest. Lines of Travel. — Weeds in their migration have fol- lowed certain well-defined lines of travel. The floras of our Atlantic states mention the occurrence of certain weeds commonly found where the ballast material was discharged. The list of ballast plants on the Atlantic and Pacific coast is constantly increasing. In speaking of the means of transportation of weeds, Dewey says that the routes of transportation are indi- cated by the names, ballast plants, roadside weeds, weeds along the towpath, and railway weeds. Mr. Dewey says : "One hundred and three species were taken in bal- last from Buenos Ayres to New. Zealand within a period of a few years." There is no doubt that the Crusaders brought many weeds back from western Asia into Europe. Thus plants like the horse-radish, mustard or charlock, hemp (Can- nabis sativa), are Asiatic plants. Kabsch notes that most of the weeds of cereal crops like Centaurea Cyanus, Ag- rostemma Githago, Raphanus Raphanistrum and Myagrum sativum are foreign to Europe. But Europe has also re- ceived a number of American weeds from us, like the 82 WEEDS OF THE FARM AND GARDEN Erigeron canadensis, the common horseweed. The Oenothera biennis became a settler of Padua, Italy, in 1812; the Erigeron canadensis near Paris in 1835. Our common rice cut grass (Leersia orysoides), according to Buchenau, made its appearance in Italy many years ago. The chicory was introduced near Dorchester, Mass., in 1875, and since then has spread chiefly through the northern states. The ox-eye daisy was carried to Rhode Island about 1815, and since then has spread throughout Fig. 34. Distribution of some weeds, quack grass, etc. (C. M. King.) the northern states. Purslane was cultivated as early as 1672 in Massachusetts, and since then has spread to all portions of the United States. Were it not for some of these records it would be quite impossible to say whether a plant was indigenous or native. We have better rec- ords of the appearance of later introductions, like the golden hawkweed, first found in the eastern states, where it has become a troublesome weed and occasionally found now in the western states, even in Iowa. While some MIGRATION OF WEEDS 83 weeds have spread westward some of our western plants have spread eastward. Generally speaking, the move- ment of weeds in our own country has been westward, although niggerhead, squirrel-tail, marsh elder, and sun- flower have moved eastward. In Gray's "Manual," sixth edition, the distribution of marsh elder is given as follows : Northwest Wisconsin to Minnesota and Kansas westward. It must, indeed, originally have been quite local in many places in this region. It is only recently that this weed has attracted attention. Another illustration is buffalo bur. In Gray's "Snyoptical Flora," the distribution is given as "Plains of Nebraska to Texas and Mexico." In Gray's "Manual," sixth edition, the statement is made, "spread- ing eastward to Illinois and Tennessee." Britton, in his "Manual of Botany," says, "On prairies, South Dakota to Texas and Mexico. Occasionally in waste places as a weed, Ontario to New Hampshire, Massachusetts and New Jersey, adventive from the West." This plant has certainly spread to many different points in the Eastern States. The Canada thistle was early introduced in the East, but now occurs, according to Dewey, in all of the North- ern states and in Canada across the continent. Its dis- tribution shows the lines of tension in its northern exten- sion. The same may be said of the bull thistle, which is as abundant in Montana and Utah as it is in Oregon and Washington. Where new lines of railway are opened in Canada these European immigrants follow. Few of the southern plants have spread northward. Among these, however, we may cite the horse nettle (Solatium carolinense). The record of sand brier or horse nettle forms an interesting chapter in the migration of perennial plants from one part of the country to another. It is much easier for an annual to become acclimated than a perennial. Throughout the Mississippi valley 84 WEEDS OF THE FARM AND GARDEN there are tropical plants which have become thoroughly naturalized, as Amaranthus retroflexus, A, albus, A. spino- sus, Abutilon Theophrasti and Sida spinosa. Within the memory of the present generation Indian mallow has been naturalized in western Wisconsin ; Argemone wiex- icana in a comparatively short time has found its way into Kansas, Iowa and Illinois. Cardiospermum Halica- cabum of the southwest is common in Illinois opposite St. Louis. Of our early weeds reliable information is often want- ing, although in some cases the history is well known. Prickly lettuce (Lactuca Scariola) made its appearance in eastern Massachusetts first in 1863, but is now found in mlany states of the Union, growing like a native plant. Mention of this weed was made by Professor Arthur in an early catalogue, but it either failed to establish itself or it escaped the notice of botanists. In Europe, we have reliable information concerning the spreading of a num- ber of weeds. Water weed (Elodea canadensis), a most harmless water plant in North America, first appeared in Ireland in 1838; in 1846 it was recorded in Scotland; in 1860 it was observed on the continent; in 1862, it be- came generally distributed. Dr. Webber thinks that the gradual lessening of this weed in Europe may have been due to some natural enemy. The water hyacinth (Eichornia crassipcs) has become a serious menace to navigation in Florida. This plant, which is a native to South America, has long been culti- vated in northern greenhouses. Dr. Webber, who made quite an extensive study of this weed, states that it was probably introduced into the St. John's river about 1890, about four miles above Palatka, where it was grown in a pond. The pond was cleared and the material thrown into the river and from thence it spread to other streams, having been scattered by boats. It became abundant in 1894, having been carried up the Ocklawaha River, from MIGRATION OF WEEDS 85 whence it was spread to all the lower streams of the St. John. Squirrel-tail grass was common about the great lakes, where it was indigenous, but was not common in many parts of Wisconsin in 1883, although, even then, it was frequently seen in low grounds about Madison, and is now abundant. It was in parts of Iowa in 1865, and now occurs in every county of the state. The hawkweed, according to Dr. Jones of Vermont, became a weedy plant between 1860 and 1875. Mr. W. H. L. Truman of Brockport, N. Y., referred to it as spread- ing from cultivation. It was introduced as a cultivated plant in 1818. It was recorded in Vermont in 1873, and, at about the same time, in Rhode Island. With these annuals, it is only essential that they ma- ture their seed, but with perennials they must not only mature their seed, but the plants must be able to survive the winter. Those who hold that perennials cannot be acclimated will find an exception in Solatium carolinense, Darlington, in his "Flora Cestrica," makes the statement that it was introduced by the late Humphrey Marshall into his botanical garden at Marshalltown. Beck, in 1833, gave its distribution as Pennsylvania to Carolina, west to Mississippi. In the second edition of Gray's "Manual," Connecticut is included ; it is also included in the fifth edition ; and in the "Synoptical Flora" it is said to occur from Connecticut to Illinois and southward. Dr. Eaton, however, writes me that he has not seen it, and there is no record of its occurrence in that state, except the specimens found by Dr. Robbins. That the weed is still spreading in West Virginia is indicated by Mills- paugh. In 1852, Brendel found it native in Peoria, Illi- nois. Solanum carolinense also occurs in Wisconsin. In recent years, many weeds have been introduced by means of impure seeds. Throughout the state of Iowa, one will find that our clover meadows contain carrot, 86 WEEDS OF THE FARM AND GARDEN buckhorn, chicory, evening catchfly, dock, bull thistle, sheep sorrel, and many others that might be enumerated and which have come in with impure seeds. These are treated more at length under the head of "How Seeds Are Scattered." CHAPTER XL EXTERMINATION OF WEEDS Among the most important considerations in connection with the extermination of weeds are prevention of the maturing of seed and the sowing of good seed only. In the long run the more expensive clover seed is better than the cheaper grade. Manure should be thoroughly decomposed to prevent the scattering of weed seeds. I .found that seeds of various weeds placed in manure that underwent decomposition were destroyed. Cultivation. — No other method is so good for the ex- termination of weeds as cultivation by keeping the fields clean. With ordinary cultivation the annual weeds are readily destroyed. Where the field is very weedy it may be necessary with perennial weeds to summer fallow, and perhaps we may as well give the methods for destroying a few of the perennial weeds. Take quack grass as an illustration, which is the most injurious weed in the state of Iowa, especially in the northern part of the state. The difficulty in exterminating weeds is due, in many cases, to the prolonged vitality which many weed seeds possess. Indian mallow, shoofly and other members of the mallow family retain their vitality for years. The seeds of many Leguminosae display the same character- istic. Cases may be cited where fields which had been in meadow for years upon being plowed soon abounded in the greater ragweed, in the grain crop. Such weed seeds may have been scattered by freshets, but the coats of the involucre being very hard the seeds were thus able to delay germinating. In the case of the cocklebur, one "seed" germinates one year and the other the next. When the seeds' coats are hard the seeds may retain 87 88 WEEDS OF THE FARM AND GARDEN their vitality for long periods. Manure should not be applied on fields until it has been thoroughly composted, and thus the weed seeds contained in it thoroughly de- stroyed. This is not the usual practice. When fresh manure is spread on the field, the straw should be reason- ably clean. Clean seed should be sown. In the general treatment of weeds, in order to exter- minate them, it is first always important to prevent the formation of seed and secondly to prevent the formation of roots. This subject will be discussed under the fol- lowing heads: (i) Rotation of crops. (2) Treatment of annual weeds. (3) Treatment for biennials. (4) Treatment for perennials. (5) Treatment for special weeds : a, in meadow and pasture ; b, in grain fields ; ba, among small grains ; bb, in corn fields ; c, in gardens ; d, on roadsides, in yards; /, lawns; g, summer fallow. (6) Treatment with herbicides. (7) Fungi destructive to weeds. Rotation of Crops. — It is a well-known fact that a soil long cultivated with the same crop is generally not as1 remunerative as where rotation of crops prevails. A piece of land grown continually in wheat, oats, or flax will leave the field full of foul weed seeds. The continu- ous cropping of flax and oats in the northwestern states has left the fields so full of mustard that in some places there is almost as much mustard as oats or flax. , The continuous cropping with corn, combined with poor cul- tivation, has left many fields in southern Iowa and north- ern Missouri full of cocklebur. The continuous cropping with oats has often resulted in large quantities of wild oats growing with the tame. The continuous use of the pasture without renewal has caused blue vervain to. be- come a bad weed. Professor Spillman gives the following as a definite suitable rotation : When sod is plowed, the land is planted in corn, then wheat is sown and grass follows. A freshly broken sod, brought into good condition will EXTERMINATION OF WEEDS 89 be much easier to take care of than a piece of wheat or oats ground. It will contain a far smaller number of weeds, and consequently fewer weed seeds. Corn in such ground is usually quite clean by the time it is "laid by," and there is less chance for weed seeds to mature than in a "small grain" field. This method of cropping insures a smaller number of weed seeds when this corn field is placed in small grain the following year. After the small grain is removed it is always advisable to plow as soon as possible and then harrow in order to expose the roots of weeds already in the soil. If the small-grain crop is followed by clover a crop fairly free from weeds should be produced. It would be better if the clover meadow could be converted into blue grass pasture. When there is a tendency for weeds to appear, the blue grass should be encouraged to occupy the vacant spaces. In the East, where alfalfa is grown it should be treated in the same way as clover, but Mr. J. E. Wing of Ohio keeps all of his land, so far as possible, in alfalfa. In the West, especially in the Rocky Mountain country, it is far better to retain an alfalfa meadow for a long term of years. There are some notable illustrations in western Wis- consin, eastern Minnesota and northeastern Iowa, where mustard and wild oats were, at one time, as abundant as in the small grain-growing section of Minnesota and the Dakotas ; but by converting the tillable lands largely into pastures and meadows these weeds have ceased to be so troublesome. Small grain fields where rotation has been practiced are almost entirely free from weed seeds. So far as annual weeds are concerned there is no better way of treating them than by a systematic rotation of crops. Treatment of Annual Weeds. — The most important point in connection with annual weeds is to prevent the formation of seeds. Cultivation of a field should be thor- ough at all times. The best time to kill these annual QO WEEDS OF THE .FARM AND GARDEN weeds is when they are young. The roots of all seedling plants- are 'readily killed by being exposed for a short time to the sun. A field or garden should be plowed and then brought into a good state of tilth by using the har- row. When planted with small grain or any other crop, a little more labor in the spring may mean the saving of much labor later. All of the annual weeds mentioned in the list of most troublesome weeds should be treated in this way. It may be difficult to destroy older plants of purslane, for example, but young seedlings are easily de- stroyed. Many of the annual weeds may be destroyed with a solution of iron sulphate or copper sulphate. Treatment for Biennial Weeds. — The biennial weeds are not nearly so numerous in kind as the annual or perennial and are much more readily destroyed than the latter. The bull thistle, burdock and other biennial weeds of this character are readily destroyed by cutting the plants off a few inches below the surface of the ground. A small spade will do this easily. In cutting, it is, of course, essential to cut the root below the buds. The bull thistle produces a mat of leaves close to the ground the first season ; by cutting these off, as stated above, the plant will not shoot up the second season. Treatment of Perennial Weeds. — Perennial weeds are nearly always difficult to destroy, much depending upon the character of the "roots" produced by them. The first and most important consideration is clean cultiva- tion. At no time should leaves be permitted to appear, as these are the organs which make plant food. As an ex- ample, nimble will may be cited, which is so common in the Mississippi valley. The "roots" of these plants (there are several different kinds) are clustered. By plowing the field, and running a harrow through it, then later giving it thorough cultivation, the weeds can nearly always be destroyed. They do not persist long in a pas- ture in competition with blue grass. Dr. C. E. Bessey EXTERMINATION OF WEEDS 9 1 has well emphasized the importance of cultural methods in the extermination of perennial weeds. The horse net- tle is quite as difficult to destroy as any of the perennial weeds. Like milkweed, it produces a long root, some- times three to four feet long and when the root is sev- ered, it produces buds that form new plants. The "smothering" method has proven efficacious. This is probably the most effective and at the same time the least expensive method of removing horse nettle. Rape is probably the most suitable crop to employ for this pur- pose. If the soil is not already rich, a liberal dressing of barnyard manure should be applied during the winter or spring and the soil should be harrowed or cultivated fre- quently until the time of seeding, which may be at any time during the months of May or June. This cultiva- tion will prevent weed growth and at the same time will assist in the retention of moisture. If the rape is sown in drills, about two pounds of seed per acre is a 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 lacking in vegetable matter, it is a good practice to plow the crop under when it is properly matured. The latter is not necessary when the object is merely to destroy the nettle, as the rank growth of the crop is very effective in completely smothering the weed. Other Methods. — Planting to. corn or roots is a method much in vogue for the destruction of horse nettle. As in the method described above, the plant should be kept down before seeding time. When the crop appears above ground, the use of the horse and hand hoes should be un- 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 removed, and even then it may be neces- sary to give attention to this pest. There is no question about this mode of treatment being effective if properly 92 WEEDS OF THE FARM AND GARDEN carried out, but failure often results from negligence dur- ing the latter part of the season. Of course, it is possi- ble that seeds may be lying dormant in the soil and make their appearance the next season, but it is taken for granted that all measures to eradicate the plant by pre- venting the production of seed have been used. Treatment for Meadows. — The treatment of a meadow necessarily varies according to conditions. If the pasture is very weedy, it is probably due, partly, to overgrazing. In such cases, some of the stock should be removed and the perennial grasses allowed a chance to form a turf. Mowing the weeds once or twice before the seeds are allowed to mature is an excellent plan. Sheep are better weed exterminators than most other animals and will keep many of the noxious weeds down. For some weeds such as buckhorn and wild carrot it may be wise to prac- tice rotation. Treatment for Grain Fields. — In order that fields be free from weeds, the first essential is to sow clean seed, which will do much to aid in keeping weeds down. Early fall plowing will do much to remove many annual weeds. The common custom in a corn country of sowing wheat on corn stubble, where disking alone is resorted to, is poor practice, because in many cases the corn fields are not clean. It is far better to cut the corn, shock it and then plow. It is not a bad practice in the fall to turn sheep into a corn field to pick out the weeds. Treatment for Corn Fields. — There is no danger of in- troducing bad weeds into the soil with seed corn; but bad perennials are scattered by the cultivator, such being the case with quack grass and Johnson grass. Cultiva- tion aggravates the trouble. Where these weeds occur the hoe must follow the cultivator, and this must be kept up during the entire season, hoeing at least once a week. The ground of a corn field should be clean and should be plowed in the fall and again in the spring, being both EXTERMINATION OF WEEDS 93 disked and harrowed. It will then be ready to be planted in corn, which should be followed by harrowing, and cultivation should then begin as soon as possible. This will keep all of the annual weeds down. By the time the corn is ready to be put by, there will be no weeds. Where quack grass occurs, plowing in the fall should be at least nine or ten inches deep. Treatment for Garden Weeds. — The annual weeds are easily destroyed by giving thorough cultivation ; the perennial are less readily subdued. In the case of nimble will, the "roots" should be exposed to the sun, being killed after a few days of drying. Where quack grass appears, the roots should be removed and the ground given shallow cultivation. As roots appear they should be cut off each week until the close of the season. Occa- sionally this method is not sufficient; then it is advisable to cover the patch with tarred paper allowing it to re- main for six months. Weeds of the Roadsides. — Many of these weeds are an- nuals, and by mowing them at the beginning of the flow- ering1 season, may be destroyed. If they reappear they should be mowed again, and, if possible, clover and grass should be induced to grow in place of the weeds, where they will undoubtedly thrive. The roadsides on the clay soil of northeastern Iowa contain comparatively few weeds, clover and blue grass occupying the vacant places. The same conditions may be brought about in many other sections of the country. Some states, notably Iowa, have passed a law that roadside weeds must be cut early in the summer, but the law is often violated. Treatment for Weeds in Yards. — These weeds in most cases are annuals and can easily be destroyed by cutting them off at the time of flowering. Generally, this will suffice. In many cases the seeds are allowed to mature. This should be prevented. Use iron sulphate as a spray. Summer Fallow. — The summer fallow is much em- 94 WEEDS OF THE FARM AND GARDEN ployed to destroy noxious weeds, especially where n Is difficult to remove them by ordinary cultivation. In the summer fallow the annual weeds will spring up and soon cover the ground. These weeds should be turned under when green, as they will add much to the fertility of the soil. In the case of perennial weeds, it may be necessary to cultivate the field frequently every week, especially in the case of quack grass and horse nettle. It is certain that the summer fallow, with frequent cultivation, will do much to destroy quack grass. Destruction of Weeds by Chemicals or Herbicides.— For many years, both in this country and in Europe, ex- periments have been made with various substances look- ing toward the destruction of fungi by chemical means. For nearly a century, blue vitriol has been used to de- stroy the spores of smut. It has been known also for many years that certain chemicals, known as herbicides, are valuable for the destruction of weeds. While cer- tain substances, as copper sulphate, for example, are gen- erally recommended for the destruction of fungi, some persons hold that copper, in some of its forms, is injuri- ous to vegetation. However this may be, it is also true that copper sul- phate in various forms, chiefly in the preparation known as bordeaux mixture, is one of the most valuable means that the horticulturist has for combating fungous diseases. It is likewise true that copper sulphate, in some of its forms, when used to kill the smut spores in corn, is more or less injurious to the young plantlet. The injury here retards! somewhat the development of the oat or wheat plant, but the plant recovers completely later. The discovery was made in France about a dozen years ago that copper sulphate destroyed charlock and mustard. The discovery was accidental, but it led'M. Aime Girard to experiment with various materials in the same line, and since then many experiments with these EXTERMINATION OF WEEDS 95 herbicides have been made, both in this country and in Europe. The substances experimented with by M. Girard, were common salt (NaCl), copper sulphate or blue vitriol (CuSO4), iron sulphate (FeSO4), sulphuric acid (H2SO4), sodium nitrate (NaNOg), ammonium sul- phate, (NH4)2SO4, potassium sulphide (K2S), basic slag (a mixture of lime phosphate, lime sulphate and some other substances), carbolic acid (CeH5OH), slaked lime, and formaldehyde (CH2O). Very successful results from the treatment of weeds have been reported by Sommerville, Foulkes, and Voelcker of England, Steglich, Aderhold, Frank, and Heinrich of Germany, and by Girard, Dusserre, Marre, and Heuse of France. In this country, some of the earliest experi- ments were made in 1897 by Jones and his co-workers, Orton, Morse, and Edson, of the Vermont Agricultural Experiment Station by destroying the hawkweed with common salt. In 1898, an experiment was reported with salt, copper sulphate, kerosene, " potassium sulphide, white arsenate of soda, and commercial weed killers. In 1900, Professor Bolley reported the successful treat- ment of weeds with copper sulphate and later reported the treatment with equal success of Canada thistle, dande- lion, mustard, false flax, worm-seed mustard, corn cockle, shepherd's purse, bindweed, pigweed, kinghead, red river-weed, ragweed, and cocklebur. The rose was not destroyed and leaves of wheat were injured but slightly. The chemicals used were common salt, iron sulphate, and corrosive sublimate. I reported on the effect of car- bolic acid on the Canada thistle and of copper sulphate and bordeaux mixture upon two types of mustard. Pro- fessor Shutt and Fletcher of the Canada station also report- ed the successful killing of weeds by herbicides. Wilson of Minnesota reported on the use of some chemicals with quack grass and found kerosene ineffectual ; salt, how- 96 WEEDS OF THE FARM AND GARDEN ever, being effectual where a sufficient quantity was used. Stone of Cornell University Experiment Station also re- ported on the successful treatment of certain weeds with copper sulphate, and Moore of Wisconsin reported on the successful treatment of mustard with iron sulphate. The above gives an idea of the activity along this line. Perhaps we can do no better than to discuss the different chemicals and their action on weeds separately. Copper Sulphate. — This well-known fungicide has been found effective for the destruction of certain weeds. At the Iowa station it has been found that it destroyed the leaves of burdock, prickly lettuce, common mustard, prostrate pigweed, and goosefoot. It was ineffectual on the leaves of morning glory, and was only slightly effectual on knotgrass. It did not seriously affect the leaves of the foxtails. The copper sulphate, to be effectual, should be applied ac- cording to the following formula : 12 Ibs. copper sulphate to 52 gallons of water. Spraying should be done in dry weather If it rains immediately after spraying, the spraying should be repeated. Prof. Bolley finds this strength solution is as effective for weeds as 100 pounds of iron sulphate. Professor Howitt of Guelph tells me it is not as effective on mustard as iron sulphate. Sodium Chlorid. — Salt with some of the weeds experi- mented on by Bolley gave good results, using it at the rate of one-third barrel for fifty-two gallons of water. It is certain, however, that in many of the perennial weeds this will not be effective. It is certainly not effective in the case of the Canada thistle, quack grass, morning glory and milkweed. Salt has been repeatedly recom- mended for Canada thistle, but it is only efficacious where large quantities are used and where cattle are allowed to tramp around or utilize the salt thrown around the roots. Salt has long- been recommended to exterminate cer- tain weeds, but Professor Jones of Vermont has shown that while an application of salt may have killed some weeds EXTERMINATION OF WEEDS 97 and benefited the grass it also killed the clover, the rea- son for this destruction being due to the power of the salt to draw the moisture from the plant. It was found that dry salt killed greater quantities of grass than when wet. Prof. L. R. Jones and A. W. Edson in some experi- ments made in 1900, concluded that common salt was less efficacious for miscellaneous weed killing than arse- nate of sodium, carbolic acid or sulphuric acid, but is the best chemical for the destruction of orange hawkweed. We found that dry salt in concentrated form will kill quack grass when applied at the rate of about 600 barrels per acre, but close to the edges of the patch, quack grass, treated thus, sprouted out as before. A much smaller quantity than this might be used, but even in considerably less amounts the salt renders the soil unfit for the growth of agricultural crops, and cannot, therefore, be recom- mended as a weed exterminator, especially for quack grass. Professor Bolley has found salt effective against kinghead and mustard at the rate of one-third barrel of salt to 52 gallons of water. Carbolic Acid. — This well-known germicide has also been usied to kill weeds. Jones found it to be very quick in action, but observed that it does not penetrate into the soil deeply enough to kill all the root, hence the treated plants invariably recovered. An experiment was made with carbolic acid on quack grass, using the acid at the rate of 2^4 barrels to the acre, two applications being made, one on October loth, and a second on October 26th. The growth of the quack grass had been very rank and vigorous and while it was temporarily checked by the carbolic acid, the roots were not destroyed. Therefore, we cannot recommend the use of carbolic acid for treating quack grass. Other weeds, especially annuals, were affected in a similar manner, but did not recover as the perennial weeds did. 98 WEEDS OF THE FARM AND GARDEN We may note that carbolic acid was found destructive to pigweed, smartweed, and pigeon grass. The amount of material used would make it so expensive that its use cannot be recommended to kill quack grass or other weeds mentioned in the above list. An experiment was made at the Iowa station with the Canada thistle, using the carbolic acid at the rate of one part of acid to four parts of water, the solution being thor- oughly agitated in order to make a good mixture. At first an ordinary garden sprinkler was used, but this method was found to be expensive and not effective, the tops alone being killed. In another experiment a small mechanic's oil can was used and the acid was placed in direct contact with the root, the effect penetrating from eight to ten inches below the surface of the ground, but below this point the roots sprouted out again in many instances. This method was not considered entirely ef- fective for the destruction of Canada thistle. Sulphuric Acid. — This has also been recommended as an herbicide. Professor Jones used it at the rate of one part to forty parts of water, applying at the rate of forty gal- lons to the square rod. It did not kill the weeds, espe- cially the roots, presumably because it formed an insolu- ble compound. Where the fluid came in contact with the plants they were killed, but they soon recovered, produc- ing new shoots. Slaked Lime. — Slaked lime has been recommended for the extermination of certain classes of weeds, the lime being spread broadcast over the weeds; however, this has not proven a very effective remedy. In an experi- ment with lime at the rate of 484 barrels per acre, it was not effective with quack grass or morning glory, milk- weed, foxtail, or other weedy grasses. While it did, to some extent, decrease the number of quack grass plants coming out, it did not eradicate them. The same may be said of morning glory and milkweed. EXTERMINATION OF WEEDS 99 Formaldehyde. — Formaldehyde, although an excellent germicide, has been recommended for the extermination of weeds, but it is less effective than carbolic acid. In 1907 an experiment was conducted with formaldehyde, using 4 per cent formalin at the rate of 2 3-4 barrels per acre. The plants experimented with were quack grass, pigweed, foxtail, and lamb's quarter. While the plants were injured somewhat by the treatment, the annuals more than the perennials, soon after the treatment they became as vigorous as ever. Corrosive Sublimate. — This powerful disinfectant has been used for the destruction of potato scab and to some extent for the destruction of the spores of fungi. Professor Bolley has found it successful in the treatment of potato scab when used in the following proportions : 2^2 oz. corrosive sublimate to 15 gallons of water. It is an excellent germicide and antiseptic, but its use as an herbicide cannot be recommended because of the great danger involved from the poisonous character of the chemical. Sodium Arsenite. — Bolley finds this a valuable spray when used at the rate of i^ Ibs. to 52 gallons of water. Professor Bolley recommends the use of sodium arsenite only where weeds grow in clumps, like the Canada thistle, bur- dock, and other weeds with persistent underground stems. In such cases the solution can be applied by hand, or if applied with a machine it can be done without regard to the injury of the crop. He considers this the best weed killer on the market. The product on the market frequently contains sodium arsenate, which is very destructive to grains. The arsenical solutions are poisonous and must be used with caution. Sodium Arsenate. — Sodium arsenate has proven very successful in the extermination of some weeds. Jones and Orton, Edson and Jones, reported it as satisfactory when used in the proportion of one pound of arsenate to IOO WEEDS OF THE FARM AND GARDEN eight gallons of water. This is also a poison. Use with caution. Iron Sulphate. — For a number of years experiments have been conducted by a number of experiment stations with reference to the extermination of weeds by this chemical. It has been found at the Iowa Experiment Station that a number of weeds like dandelion, dooryard knotgrass, purslane, yarrow, sorrel, large ragweed, hedge mustard, sour dock, smartweed, mustard, velvet leaf, small ragweed, lamb's quarter, pepper grass, sow thistle, bull thistle, wild carrot, pigweed, shepherd's purse, and spurge can be destroyed by this substance. Bolley finds that it is not effective on pennycress and hares' ear mustard. The grasses are resistant. This substance should be used at the rate of 100 pounds to a barrel of u'ater. A dust spray has also been used ; it is effective when there is sufficient dew on the plants. In order to make the spraying effective, however, the application should be made sometime before the mustard or other weeds are in bloom. It is advisable to begin spraying in a grain field when the mustard is from 6 to 12 inches in height. Bolley puts it third to fifth leaf. The spray should be evenly spread over the leaves on a quiet day with no rain for two or three days. Damp weather is effective if sunshine follows. It is better to use a large machine having a capacity of 160 gallons, and if the ground is not too soft two horses can pull the ma- chine readily. The machine should have wide tires. The trouble, as Bolley well says, is because nozzles and machines are not efficient. The cost of spraying is approximately $1.25 per acre and the iron sulphate can be had approximately from $1.00 to $1.15 per 100 pounds in the northern Mississippi valley. Professor Selby briefly sums up the matter of spraying, as follows : EXTERMINATION OF WEEDS 101 "Weed sprays, when properly adapted, should be avail- able for the destruction of the larger portion of our pas- ture and grain field infesting weeds, when the methods are rightly and economically developed. It would cer- tainly be a travesty on our methods of culture to expect to substitute weed sprays for culture in the growing crop, such as in corn fields and the like." Lawn Spraying. — It is desirable to spray a lawn for dandelion, or chickweed ; for this purpose a hand sprayer with a Vermorel type of nozzle can be used. I am of the opinion that this spray will be very valuable for lawns and parks. Professor Bolley, who originated the idea to use this substance for lawns, recommends two pounds to the gallon of water. We have found that iron sulphate will do effective work in killing dandelions when a much weaker solution is used, namely, one pound to a gallon of water. This solution should be applied when the dan- delion begins to bloom or later, a few days after the lawn has been mowed. It is best to spray on a bright day. A dew will help, perhaps, because the iron sulphate can en- ter the stomata. Many other weeds of the lawn can be treated in the same way. Spraying should find general application. It should be borne in mind, however, that this substance will not destroy crab grass, foxtails or other weedy grasses and that it is injurious to clovers. Meadows and Pastures. — Iron sulphate spray can be used for many types of weeds like the ragweed in pas- tures, dandelion, etc., but not where clover is abundant. Grain Fields. — Iron sulphate should certainly be used in the grain fields; by its judicious use a larger grain crop can be produced and such weeds as mustard and king- head can be eliminated. Manufacturers should introduce better machinery. Precautions. — The iron sulphate should be of the gran- ulated form. The solution should not stand overnight; it should be made up in wooden barrels and then placed IO2 WEEDS OF THE FARM AND GARDEN in brass tanks. Use a hand sprayer for patches; in the field a large sprayer with nozzle to spray a fine mist. Spray in bright sunshiny weather, at least not to be fol- lowed by rain for a few days. It is best to have the spray followed by a dew. This is true in particular of the dust spray. It should be remembered in this connection that spray- ing cannot be done indiscriminately to all kinds of plants. It will not do to spray a clover meadow, since the iron sulphate is quite as injurious to the clover as to the weeds, nor is it advisable to use the sprayer in a corn field, because many of the common weeds, like the foxtail, crab grass, and pigeon grass, cannot be killed by this spray. But it is certain that the iron sulphate has a wide application in grain fields. Mr. R. I. Anthony, who has had some experience in spraying, notes some of the conditions which may cause failure or success, as follows : "Spraying for the eradication of weeds started in Europe — in France and Germany. These two countries possess a climate very different from anything I know in this country. When the procedure was studied a set of rules for guidance quickly found place and one of these was that the spraying should be carried on only on bright, still days. "In my work from time to time I have met with fail- ure and have as often been puzzled to discover why. On collating the work it is clearly evident that the weather conditions play a great part. French weed in certain stages of growth is completely destroyed by the sulphate of iron spray — when the day is overcast and the relative humidity high. On the contrary, when the day is bright, hot, and the humidity low, the plants are resistant. The same is true of mustard in a less degree. "Work at Warren this year has so far been a failure, with atmospheric conditions as follows : Bright skies, low EXTERMINATION OF WEEDS IO3 relative humidity, high temperature, high wind and NO dew. "At Hunter the work started off in the same way as at Warren, but the timely appearance of dew turned the scale and we succeeded where failure seemed certain. "Here are the observations : White incrustation ap- peared on sprayed leaves in three to five minutes, and in some instances white pellicles of sulphate could be seen scudding along the ground. At the end of twenty-four hours white incrustation undiminished and weeds show- ing no signs of distress. But let the dew fall and the white incrustation disappears like magic and the plants show signs of mortal injury, and in a few hours small plants shrink to bunches of shapeless tinder and large plants droop and brown and shrivel." Fungi Destructive to Weeds. — In various parts of the world certain fungi are known to be quite destructive to weeds. In the East a rust (Puccinia suaveolens) destroys large quantities of Canada thistle. In other places ex- tensive patches of foxtail are exterminated by the downy mildew of the foxtail (Sclerospora graminicola). Foxtail smut (Ustilago neglecta) destroys a great deal of the seed of this weed. Related smuts, as quack grass smut and one found on stink grass, are also very destructive to weedy grasses. The spot disease of crab grass (Pyri- cularia gricea) is very destructive -to crab grass ; so is the spot disease of smart weed (Septoria Polygonorum). Many other fungi might be named in this list. There is no doubt that these fungi are important factors in the de- struction of weeds. CHAPTER XII. TREATMENT FOR SPECIAL WEEDS Quack Grass. — Quack grass is one of the most persistent of the perennial weeds in the state of Iowa and the North. The roots of quack grass are shallow, the vast majority occurring within less than six inches of the surface of the ground. The following methods have been suggested for its extermination : The Crop Method.— The land is brought into as good a state of tilth as possible and sown thickly with millet, buckwheat, sorghum, or rape. This method does not destroy the roots of quack grass. It does, however, re- duce their vitality to such an extent that they are not as vigorous after the removal of millet or sorghum. Then the field should be given a shallow plowing and the roots exposed to the sun. This cannot usually be done in the state of Iowa until the middle or latter part of September. In nearly every season we have very dry weather in Oc- tober, and after harrowing two or three times most of the roots will be killed by drying. A second method, which has been followed successfully by some of the German farmers in northern Iowa, is this: To plow the field, harrow, and remove and burn as many of the quack grass roots as can be seen. Then give clean culture throughout the entire season. By digging up the roots with a spade or fork and giving clean culture, hoe- ing, if necessary, quack grass can be removed. This has been done, not only in our own experiments, but many farmers have tried the same, successfully. It is a rather expensive process, however. Summer Fallow. — The summer fallow method has been tried frequently in northern Iowa. The land is 104 TREATMENT FOR SPECIAL WEEDS 10$ plowed in the spring, disked, and kept clean by harrowing at least once each week during the entire season. Several fields so treated have been investigated by the writer and show no quack grass, but there is a loss of an entire crop. Small Grain and Cultivation. — Inasmuch as rotations of corn, oats, clover, and pasture are common in the state of Iowa, and since corn is one of the most important crops, it is a question how to proceed to destroy quack grass under these conditions. Experience has shown that quack grass spreads less frequently in a pasture crop or an oats crop than it does in corn. If the field is sown with oats it should be given a shallow plowing as soon as the crop is removed, and harrowed at least once a week during the late summer and fall. This will destroy much of the quack grass by the end of the season. The field can be put into corn the following year. Pasture. — Many farmers have called attention to the fact, which many of us have observed before, that quack grass does not spread very rapidly in a pasture, and that the roots are small and more superficial than in cultivated corn or a cultivated field. Professor Spillman, who has taken up this question, states as follows : "Quack grass, which is as common in many parts of New England as Kentucky blue grass is in Kentucky, is now spreading over a great part of the middle west. . . . You may be interested in . knowing the methods which are common on the heavier types of soil in Eng- land for dealing with quack grass, or, as they call it, 'Couch' grass. In the old country a meadow is quickly taken by quack grass, and when this is plowed up and put in rotation the following method is used : "First, the sod is plowed, then it is harrowed two or three times to bring the quack grass root stocks to the surface, then a chain drag is run over the land to roll the rootstocks up, after which wagons with hay frames IO6 WEEDS OF THE FARM AND GARDEN are brought on and the roots are removed by hand. Then the land is plowed again and the same process gone over with. After this has been done from three to five times the land is practically free from the rootstocks, and the rotation can be run through without serious trouble from quack grass." Mr. J. S. Gates, of the office of Farm Management, has made a careful study of quack grass for some years past, and has developed a very much simpler and less ex- pensive method than the above, a method, however, which is not applicable to all situations. Mr. Gates' method is based on the following principles : "If the quack grass sod be left undisturbed, as would be the case in a meadow or pasture, for two years, the grass meanwhile being cut for hay or kept down by pas- turing, all of the deep-lying rootstocks decay, and the new ones that form are all within two or two and a half inches of the surface. After this condition has been brought about, if the field is plowed just deep enough to turn up all of the rootstocks, which will usually be two to two and a half inches, the grass is very easy to kill. This plowing should be done in midsummer after haying time. A few harrowings after this shallow plowing com- pletely destroy quack grass unless it happens to be a very wet season, when the roots are kept alive by the moisture. "It is of the greatest importance not to plow deeper than necessary in this work. If one plows, say four inches deep, then the rootstocks must be harrowed out from the depth or they will take root and grow again. If the plowing is only two inches deep the frequent harrow- ings keep the rootstocks from connecting with the -sub- soil until they have completely perished. "We have found a good many New England farmers who had dropped on to this method of killing quack grass, and they no longer consider it a serious menace." Deep Plowing. — Another method is to plow the sod at TREATMENT FOR SPECIAL WEEDS IO7 least six inches deep. Our experience has shown that quack grass roots do not penetrate through the soil much beyond a depth of four or five inches, very few going be- yond six inches. The following season sow with grain. After the grain is removed plow the land and harrow in such a way as to get all the roots on the surface, and re- peat the disking and harrowing as often as the grass occurs, once a week if necessary. The Cover Method. — Covering with tarred paper, ma- nure, or straw is effective when well done. When tarred paper is used the edges should be thoroughly cov- ered with dirt. The grass must remain covered at least six months. If manure is used it must be compact, a foot or more in depth. Straw, which is much looser, must be several feet in thickness. Professors Eaton and Edson of Vermont report success in the treatment for quack grass, "no matter how seriously infested, by the following procedure: (i) Ridg- ing the rows just before the corn sprouts, using a disc hoe or any other tool which makes a ridge over the row. (2) Cultivating three days later with a five-toothed culti- vator, or a heavy two-horse hoe, carrying side hoes, (such as potato-hilling hoes turned backwards), draw- ing the soil away from the sides of the ridges previously made, so that the subsequent harrowing can more effec- tively level them. (3) Harrowing or weeding (prefer- ably the former) the same day. (4) Cultivating twice thoroughly, a week or ten days later. (5) Weeding the same day, still further leveling the ridges and improv- ing the soil mulch. (6) Cultivating thoroughly and shal- low every week or ten days thereafter, so long as it can be done without injuring the crop, the oftener the better. (7) Hand hoeing in mid-July." Perennial Sow Thistle. — The perennial sow thistle is one of the most troublesome weeds of eastern Canada and in a few of the northern states. Prof. J. E. IO8 WEEDS OF THE FARM AND GARDEN Howitt suggests that sheep be turned in after harvest; these animals, by close cropping, weaken the underground rootstocks. He suggests, further, that the field be cultivated until about the middle of June ; to keep the tops down and weaken the roots, slightly ridge up the land with a double moldboard plow, then sow rape at the rate of one and one-half pounds per acre ; cultivate the rape every week until it occupies all of the ground. He considers the rape a most excellent weed extermina- tor, which might be applied to many perennial weeds. Canada Thistle. — The Canada thistle can be treated with the sodium arsenite. No other chemicals, so far as our experiments extend, will entirely destroy this weed. Carbolic acid only partially destroys the roots and the plants shoot up again from below the point of injury, but by repeating the process the Canada thistle can ultimate- ly be exterminated. A good method to eradicate 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 cul- tivation will be of no avail. After 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 appear- ance in this place. Various crops, such as clover and sorghum, are said to be effective in subduing the thistles. Of the various chemicals which have been used to ex- terminate Canada thistles none is more effective than sodium arsenite. It is applied at the rate of one and one- half pounds to 52 gallons of water. Carbolic acid at the rate of one part to one part water destroys the root where it comes in contact with the mix- ture, and for a little distance beyond. This is not an effective method, as the roots sprout out from below. TREATMENT FOR SPECIAL WEEDS IOO, In response to circulars of inquiry sent out by the Iowa Experiment Station, the majority of correspondents recommended 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 where it is applied directly to the stem. Tarred paper in a few instances gave success, as did also the method where the thistle was covered thickly with straw or manure. The depth of covering was not, however, given. Milkweed. — Milkweed, like the morning-glory, is a deep-rooted perennial, and where abundant in small grain fields it is rather difficult to remove. The plowing here should always be shallow, as the roots are deep seated and new plants spring up from where the roots are cut off. The plowing should be followed by disking and harrowing to expose as many of the roots as possible and it should be turned into pasture as soon as possible. It is seldom that milkweed becomes injurious to pastures, as the plants lose their vitality. It is by continuous cropping of one crop that the weed becomes pernicious in its character. In response to a query sent out one correspondent recommended oats one year, clover one year, corn two years, saying the weed is not troublesome in the pasture after the second year. Some have advocated pulling the weed by hand. This is not practical. Horse Nettle. — In southern states north to Iowa the horse nettle is one of the most troublesome weeds to deal with. Like morning glory and milkweed, it is a deep- rooted perennial. The roots are known to extend into the soil as much as three to four feet. The cultivation here should be shallow. When the weed is common, disk thoroughly and harrow, exposing the roots. When a IIO WEEDS OF THE FARM AND GARDEN field is covered with it, it is better to summer fallow, then cultivate thoroughly and hoe during the entire season, or sow with oats ; plow when harvested ; disk and harrow for the remainder of the season. The same method used for Canada thistle may also be applied. Wild Timothy or Dropseed Grass. — The Iowa station has received many letters complaining about this weed. The character of the "roots" is so different from that of the roots of quack grass and the other perennial weeds that we have mentioned before that it is not difficult to ex- terminate. The "roots" of this weed and the allied species are more or less clustered. In an experiment conducted to exterminate this weed we found that by giving a shal- low plowing 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 isi not effective during rainy weather. Cocklebur. — The cocklebur is a serious menace to cul- tivated crops in many parts of the United States, more es- pecially in southern Iowa and the South. A large number of queries sent out to farmers in different parts of the state brought many responses. Nearly every correspondent re- ported the weed. The seed habit of cocklebur differs ma- terially from that of many annual weeds that belong to the same family. The bur has two so-called seeds, one of which has a slightly different position from the other; the seed coat, too, is slightly different in structure and, accord- ing to Dr. Crocker, this is the reason for delayed germina- tion. Dr. Arthur, in a study of the same seeds, deter- mined that the opinion generally prevailing, that one seed will germinate one season and the other the following, is essentially correct. We have found in our own work that occasionally both seeds germinate the same season. It is very plain, therefore, that if cocklebur occurs in the soil you cannot hope to destroy more than about one-half of the seeds in one season, and if the same TREATMENT FOR SPECIAL WEEDS III field is cultivated with corn the next year, another crop of seedings will come on. How long the seeds will retain their vitality has not been definitely determined. The best method of combating the cocklebur is the ro- tation of crops and clean culture. When a field is in corn, the field should be thoroughly cultivated and none of the plants allowed 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. This certainly eradicates the cocklebur, ragweed and many other annual weeds. Foxtail. — It is not generally recognized, but it is prob- ably true, that more money is spent in the extermination of foxtails 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 corn should be cultivated as fre- quently as possible, at least four or five times. This method should prove effective for the destruction of fox- tail and pigeon grass. Squirrel-tail or Wild Barley. — Squirrel-tail or wild barley is a most pernicious weed along road sides and in pastures and meadows; pernicious because it not only prevents the growth of the better grasses, but it is in- jurious to live stock. As this weed is most common in the pasture, 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 annual, this would effectively dis- pose of the plant were it not for the fact that the seed is 112 WEEDS OF THE FARM AND GARDEN blown in from neighboring fields and roadsides. Cultiva- tion will readily destroy the weed and where it is abun- dant in fields shallow cultivation, followed by the disk and harrow, should be effective. Mustard. — 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, prefer- ably fields that have been in pasture or meadow. Noth- ing 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 previous season. Having sown the small grain on a clean field, there is always a chance that some of the seeds will retain their vitality in the soil. If much of this mustard should come up it may become necessary to spray 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 one hundred pounds to a barrel of water. Indian Mallow or Butter Print. — Much complaint has come to us about Indian mallow or butter print. This weed, which is very common in many parts of the country, is of course readily destroyed by cultivation. The only trouble is that so much of the seed retains its vitality for a considerable length of time, how long has not been definitely determined. The best treatment for this plant is to get the field into meadow or pasture, leaving it in this condition for a number of years and then planting to corn and following the usual rotation. Morning Glory. — The morning glory, though a trouble- some weed in many parts of the North, does not seem to be quite as pernicious in its character as quack grass. In response to the queries sent out it is found that the best treatment that can be given the morning glory is to turn it into pasture. Cattle, sheep and hogs are very effective TREATMENT FOR SPECIAL WEEDS 113 in keeping this weed down. One writer states that by keeping it in pasture four or five years the weed is killed. Mr. Cox, in addition to cultural methods, recommends the use of alfalfa as a weed exterminator. The plowing should be thor- ough and done as soon as the grain is removed in July or Au- gust, but it need not be deep, as the roots extend several feet into the soil and cannot be reached by plowing. Where Fig. 34A. Wild morning glory or bindweed (Convolvulus sepium). (Photograph, Charlotte M. King.) the weed is common the plowing should be followed by disking and harrowing and the roots should be exposed to the sun. One correspondent recommends corn, oats, and pasture. Another recommends millet, sorghum, and buckwheat as effective in the destruction of the weed. When a cornfield contains a considerable amount of the morning glory the cultivation must be frequent and the hoe should follow the cultivation, especially to destroy the plants which make their appearance around the hills. CHAPTER XIII. THE MORPHOLOGY OF WEEDS The Root. — In the higher plants we are usually able to make out three conspicuous organs, namely : The root, stem and leaf, and at certain stages of development, a fourth organ, the flower. The root, stem and leaf have to do with the nutrition of the plant and the flower with its re- production. In our study of a type plant, let us begin with the root. Roots naturally occur in the ground; they fix the plant in the soil and absorb water that holds in solution certain mineral constituents. The root increases in length from a point just back of the tip, growth taking place at this point. The tip of the root is and is contin- Fig. 35. Fibrous root of crab grass. called the root-cap ually wearing away, while new cells are as constantly being added from the growing point. Not far from the tip also are the root hairs, which absorb moisture from the soil. These become covered with particles of sand, because the cell walls are mucilaginous. There are four types of roots, classi- fied according to duration : Annual, win- ter annual, biennial and perennial. In plants with annual roots, the seeds germinate, the plants produce flowers , FiS; 36- Root- ft , , , ,. showing root cap. and seeds the same season and then die. (Leavitt.) 114 THE MORPHOLOGY OF WEEDS 1 15 The following are illustrations of this type: Awned brome grass, black medick, bracted plantain, brome grass, bur clover, buffalo bur, cheeses, chess, cockle, cocklebur, common sunflower, cowherb, dooryard knotweed, dog fennel, fetid marigold, Fuller's teasel, goosefoot, great ragweed, green foxtail, hairy brome grass, hedge mustard, horseweed, Jimson weed, marsh elder, Mexican fireweed, mustard, pepper grass, pigeon grass, pigweed, prairie bitterweed, prickly lettuce, purs- lane, Rocky Mountain bee plant, Russian thistle, small ragweed, smartweed, squirrel-tail grass, tumbling mustard, velvet weed, vetch, wild barley, wild oats. The seeds of winter annuals ger- ^j^^ .^^ minate in the fall, the plants live through the winter and in the spring produce flowers and seeds; shepherd's purse, speedwell, winter rye and win- ter wheat are types of this class. Such plants are more common southward than in the North. Plants which in the North are annuals may become winter annuals in the South. The seeds of biennials germinate in the spring, producing a growth of short stems and leaves the first season, but Fig. 37. Root hair, no flowers; in the second season the (Leavitt.) stem elongates, produces flowers and seeds. The follow- ing weeds are biennial: Bull thistle, burdock, mullein, Nelson's thistle, parsnip, and sweet clover. Other repre- sentatives: Cultivated beet, cabbage, carrot, and parsnip. Perennial plants produce roots which continue to live year after year. All of our trees and shrubs and the fol- lowing weeds are perennial : Blue lettuce, buckhorn or ribgrass, Canada thistle, common nettle, common plan- tain, cowbane, curled and smooth dock, dandelion, dog- bane, gaura, germander, horse nettle, ironweed, milk- n6 WEEDS OF THE FARM AND GARDEN weed, morning glory, nimble will, northern nut grass, quack grass, tanweed, western nettle, wild liquorice, wild poppy, wild timothy, woolly thistle, yarrow. Other kinds of roots are the aerial, which are produced in the air, an example of this class being the roots of the poison ivy, the brace roots of Indian corn, trumpet creeper, etc. The brace roots of corn become absorbing organs as soon as they strike the ground. In the poison ivy, they assist the plant in climbing, taking the place of ten- drils. In one class, including certain orchids, the plants be- come attached to other plants, but do not take any nourishment from them. These are known as epiphytes. In a third class, the roots are not only attached to other plants, but obtain nourish- ment from them. These are called parasitic plants, in which group are the clover dodder and green parasites such as mistletoe. Some roots become greatly thick- ened, such as in the sweet potato, dahlia, carrot and turnip, the up- per part of the turnip, however, being really a stem. Roots of this class store food for future use, and are known as fleshy roots. They are conical, as in the carrot ; fusiform, as in the dahlia ; turnip-shaped, or napiform when like those of the turnip. The Stem. — The stem occurs in an abbreviated form in the seed; but as we ordinarily see it, it is above the ground. It is spoken of as the ascending axis, and is divided into nodes and internodes, the leaves making their appearance at the nodes. In addition to the stems Fig. 38. An annual weed, wild buckwheat (Poly- ffonum Convolvulus). THE MORPHOLOGY OF WEEDS UJ occurring above ground some are underground, which are often merely disguised "stems," like the quack grass stem. Buds are really branches and bear small scales, which are only modified leaves. The bud terminating a branch is called a terminal bud. Fleshy buds are those having fleshy scales. When more than one bud occurs in the axil of the leaf, they are called ac- cessory buds, as in the case of the butternut and honeysuckle. Buds also occur under the petiole of the leaf, as in the sycamore, and are called sub-petiolar buds. Some buds are so concealed that they cannot be seen until growth begins. These are known as latent buds. Adven- titious buds are such as develop without any regular order from any part of the stem or from roots. The sweet potato root develops these adventitious buds and many plants such as the plum produce suckers from them. The stems of grasses, lily, and onion are endogenous ; the outside is the epidermis and the bundles are distributed through the mass. The stem of pigweed is exogenous, and consists of pith, wood and bark. Most plants of our region form a definite annual growth with a ter- minal bud, hickory and horse chest- j.^8' nut being examples of these. Some(C. M n8 WEEDS OF THE FARM AND GARDEN plants, as the grape, grow until killed by frost, whatever buds are not fully developed at that time being killed. This is known as indefinite growth. Leaves. — Leaves are borne on stems at the nodes. They are usually expanded and are nearly always for the purpose of making plant food. In some cases they store food, as in the leaf of the century plant; the bud scales of the hickory are Fig. 40. Cross section of an modified leaves, the small endogenous stem of corn (Zea Mays). S, node; A, sheath of leaf. The small dots, the fibro- vascular bundles. (C. M. King.) scales on the rootstock of quack grass are also modified leaves. A typical leaf consists of a blade, the stalk or petiole, and a pair of stipules. In some cases the stalk may be wanting and the leaf is said to be sessile, in others the stipule is wanting and in a few the blade is wanting. The blade is the expanded part of the leaf and is for the purpose of making food. The petiole is the stalk and serves to fix it to the stem. The stipules are a pair of small scales at the base. There is great variation of the different parts of the leaf. rr,, i • j <• i Fig. 41. R, R, tendrils of There are two kinds of leaves japanje ivy, modified as to venation. Corn and other stem. THE MORPHOLOGY OF WEEDS 119 grass leaves are parallel veined, the leaf of the canna has a similar venation. The veins or lines run parallel with each other from the base to the end of the leaf. Plants with such venation have a single seed leaf or cotyledon. In netted-veined leaves the veins run together or anastomose, form- ing a network, as in the maple, oatc, and potato ; all of our trees have netted-veined leaves. Fig. 42- x, tendril of star cucumber. There are tWO types of these, the palmately veined, when the veins start from a number of ribs, as in the grape and maple, or pinnately veined, where one rib runs through the leaf from the base to the tip, as in milkweed. Leaves are divided into simple and com- pound. In a simple leaf, like the maple, there is a single stalk and a blade. In com- pound leaves there are , , a , , Fig. 43. Palmately netted-vemed, several leaflets, each compound leaf of horse chestnut. I2O WEEDS OF THE FARM AND GARDEN usually with its own stalklet, as in the rose. Compound leaves are of two kinds: pinnately compound, in which the leaflets are arranged on the sides of a main stalk, as in rose and ash ; and palmately compound leaves, in which the leaflets are borne on the end of a leaf stalk, as in the horse-chestnut and Virginia creeper. Clover has a trifoliate compound leaf, e. g., a leaf with three leaflets. Some leaves have two leaflets, these are bifoliate. Some leaves, like the honey locust, are simply pinnate, but occasionally on young shoots they are divided again ; these, then, are twice pinnate. The palmately compound leaves of meadow rue are in threes or ternately compound, or four times compound. When a leaf is twice compound it is biternate. There are many different forms of leaves, the more important being as follows : Linear, a narrow leaf much longer than broad, like blue grass; lanceolate, a leaf which is longer than broad, tapering toward the apex, outline lance-shaped ; oblong, when longer than broad ; elliptical, like an oblong leaf, but the ends of the same width ; ovate, longer than wide, the base wider than the end, like a hen's egg in outline ; orbicular, circular in outline ; oblanceolatc, like a lanceolate leaf, but the apex wider than the base ; spatu- late, shaped like a spatula, apex rounded; obovate, like an ovate leaf, a fcS;45;, but the apex wider than base; cuneate, /.petiole;' £, blade. Fig. 44. Pinnately netted-veined leaf of rose. (Ada Hay- den.) THE MORPHOLOGY OF WEEDS 121 a wedge-shaped leaf ; cordate, leaf with a wide and round- ed base, forming a notch where the petiole is attached ; renifonn or kidney-shaped leaf, like the leaf of wild ginger; auriculate, leaf with a pair of small blunt pro- jections at the base ; sagittate, like an auricu- late, but the projections are sharp, as in sagitta- ria ; hastate, like the last, but with lobes pointing outward ; pel- tate, the petiole at- tached to the lower surface, like the man- drake ; acuminate, the apex of leaf prolonged into a tapering point; . Two types of parallel-veined fl^ where the ,eaf ends in a sharp point rather abruptly; o&- tuse, where the leaf has a blunt or rounded apex ; mu- cronate, where the apex of the leaf is tipped with a small and short point ; truncate, with the end as if cut off square ; retuse, where the summit of the leaf has a small notch ; emarginate, with a decided notch ; obcordate, the reverse of cordate, the upper end larger, like the leaf of white clover ; cuspidate, leaf with a Fig. Lobed leaf of sassafras. 122 WEEDS OF THE FARM AND GARDEN sharp and rigid point; aristate, when the end is tipped with a bristle point ; entire, when the leaf is entirely filled out ; serrate, when the margin is cut with sharp teeth ; dentate, when the teeth point outward; crenate, leaf with round- ed teeth; rcpand, when the margin of the leaf forms a wavy line; incised, when the margin is cut into sharp, deep, and ir- regular teeth ; lobed, when the leaf is Fig. 48. Lobed deeply cut. It is generally said to be !/CA ^ £f ,ac°nite- lobed where the divisions do not extend (Ada Hayden.) more than half way between the mar- gin and the midrib, the divisions being more or less rounded ; cleft, where the divisions extend more than half Fig. 49. Leaves of various types: i, undulate; 2, thistle leaf with acute lobes; 3, lobed leaf of oak; 4, lyrate; 5, pinnately divided leaf; 6, pinnatisect. A leaf may be pin- way and are sharp; parted, where the divisions extend deeper, but do not reach the middle; divided, where the divisions extend nearly to the midrib. nately lobed or palmately lobed ; palmately cleft or pinnately cleft, etc. Some leaves, like those of pea and many other plants of the same order, are provided with a . Fie- 5°- Radiate - veined ' F leaves: 4, 5, cordate; 6, 7, kid- slender filiform body called a ney; 8, peltate* THE MORPHOLOGY OF WEEDS 123 Fig. 51. i, cor- date leaf; 2, ovate leaf. Fig. 55- 3, ellipti- cal; 4, oblong leaf; 5, obovate; 6,cuneate or wedge shaped. 7 8- 7 'o Fig- S3- 7. lanceo- late leaf; 8, linear; 9, oblanceolate; 10, spatulate. Fig. 52. i, sagit- tate; 2, auriculate; 3, halberd shaped. /~\r\ Fig. 54. Apex of leaves: i, 3, types of obcordate leaves; 2, emarginate; 4, truncate. or 6 7 Fig. 56. Apex of leaves: 5, obtuse leaf; 6, acute; 7, acuminate; 8, 9, mucronate. Fig- 57- 7, shield-shaped leaf; 8, acutely three-lobed leaf; 9, pel- tate palmately lobed leaf of castor oil; 10, n, types of palmately com- pound leaves. 124 WEEDS OF THE FARM AND GARDEN tendril. These tendrils are modified leaves, while those of the grape are modified stems. , Flowers. — Flowers are for the purpose of producing seed and are merely altered branches; the parts of flow- ers are therefore altered leaves. The manner in which flowers are borne upon the stem is important in enabling one to distinguish different plants. The manner in which the flowers are borne is called the inflorescence, and there are two types : the de- terminate, where the terminal bud opens first; and the indeter- minate, where the flowers develop from below. The more important types of indeterminate inflores- cence are the following: Raceme, a simple flower cluster in which the flowers are attached to a little stalk called a pedicel, and are arranged along a common axis. Ex- amples are : The cur- rant, shep- herd's purse, and lily of the valley. A corymb is much like a raceme, ex- cept that the flowers are more or less level at the top and the ped- icels are of different lengths. In an umbel the flower cluster is much the same as in a corymb, but the stalks are all of the same length; in other words, the flowers p.g ^ Inflorescence> come from the end of the stalk. Cymose cluster of pink. Fig. 58. Inflorescence. Catkin of birch: 2, stamin- ate flowers; 3, pistillate flowers. THE MORPHOLOGY OF WEEDS 125 Fig. 60. Inflor- branched escence. Spike of the deter- cat-ta.iL geon.) The milkweed and carrot have umbels. The spike is like a raceme with a lengthened axis, the flowers being- sessile, like those of the plantain. A head is a roundish cluster of flowers which are ses- sile, as in the clover and buttonball. The spadix is a fleshy spike, as in the Indian turnip, the spathe being the leaf over the spadix; the flowers of the spadix are im- perfect. The catkin is a type of inflores- cence found in the willow and hickory. The panicle is a compound flower cluster found in many grasses ; that is to say, it is like a raceme, but the stalks are again. Of minate inflorescence the most important is the cyme. The cyme is a flat topped or convex flower clus- ter somewhat like the corymb, but with the terminal flower developing first. A glomerule is a cyme very much compacted, resembling a head. Flowers are perfect or hermaphrodite when provided with the essential or- gans, stamens and pistils ; complete when they have all the floral envelopes, calyx, corolla, and stamens and pistils; regular when all the parts of each set are of the same shape and size, like the rose; irregular when some of the dif- ferent floral circles are dissimilar or unequal, as in the clover, wood sage, and mint ; monoecious when Fi£- 6z- Inflorescence u .< • j • ,.,i - Raceme of barberry. (C. M. both staminate and pistillate King.) Fig. 61. Inflo- rescence. Head of ragweed, achene above. (C.M.King.) 126 WEEDS OF THE FARM AND GARDEN Fig. 63. Inflores- cence. Panicle of grass. flowers are produced by the same in- dividual plant, as in corn ; dioecious when the two kinds are borne on dif- ferent plants, as in willows, poplars, hemp, and moonseed. Polygamous when some of the flowers are perfect Fig. 64. Inflorescence. Head of clover. (C.M.King.) and some have pistils or stamens only-. Flowers in which the petals are sepa- Fig.65. Inflorescence. rate are called polypetalous ; when the Head of wild lettuce, petals are united, gamopetalous; when The type of inflores- the petals are wanting, apetalous. cence in the sunflower T r family. (C. M. King.) ^n some flowers different parts or THE MORPHOLOGY OF WEEDS I27 circles of the flower are united, this is adnation; perigynous flowers are where pistils and stamens are inserted on the calyx ; occasionally they are borne from the very summit ; Fig. 66. Flowers of barberry: c, sepals; c', petals; s, stamens; p, pis- til; a, anther; n, nectar gland; s', stamen. Fig. 67. Flower of to- mato; small dark bodies, lobes of calyx; inner, larger lobes of petals. Stamens removed. Pis- til in center. (U. S. Dept. Agrl.) epigynous, that is adnate to the ovary ; the term hypogyn- ous is used to designate when the parts of the flower are free; such flowers are said to be superior, having a supe- rior ovary ; when adnate to the calyx, inferior. The different types of corolla are : Wheel- shaped, like a tomato flower, parts diverge from the center ; salver- shaped or salver-form 0 —c -ex -— st Fig. 68. Flower of tomato: ex, calyx; c, corolla; p, pistil; st, stigma; s, sta- men; o, ovary. (U. S. Dept. Agrl.) Fig. 69. Irregular flower of bean, the upper part stand- ard or beaier, the two lower wings and the coiled keel. 128 WEEDS OF THE FARM AND GARDEN Fig. 70. Ir- regular flower of aconite or Monk's hood. (Ada Hayden.) when raised on a narrow tube and diverg- ing at right angles, like some species of the phlox family, such as gilia; bell-shaped or campanulate, with a broad and short tube like a bell, as in the common harebell ; funnel-shaped or funnel-form, like the flow- ers of the common morning glory ; tubular, when prolonged into a tube, like the trum- pet honeysuckle ; in some cases there are little projections from the corolla, known as claws, as in the com- mon soapwort ; the conspicuous marginal flowers of the sunflower are called ray flowers; the central flowers are disk floivers, and the strap-shaped corollas are spoken of as ligulate F5g yj Irreguiar Corollas ; the two-lipped corollas of the flower of larkspur, mint are called labiate corollas; the (Ada Hayden.) flowers of the sweet pea and clover are called papilionace- ous; the chafflike scales of grass flowers are called glumes. When the stamens are in- serted upon the petals, they are called epipetalous; when the pistils and stamens are united, they are gynandrous; when the stamens are entire- Fig. 72. Regular flower of straw- ly separate, they are said to berry: <; petals, 5 green sepals. be distinct; when the stamens The petals of separate pieces, .,11 ,1 c.\ •_ polypetalous. (Ada Hayden.) are united by the filaments in THE MORPHOLOGY OF WEEDS 129 one set, they are monadelphous ; when in two sets, dia- delphous, and so on. When there is one stamen, the flow- er is monandrous ; two, diandrous ; and so on. The parts of the stamen are the filament, anther, and pollen. When the pollen is united in a mass it is spoken of as a pollinium, Fig. 73. Regular flower of rose: 5 green reflexed sepals, 5 petals (Ada Hayden.) as in the milkweed. When the filament is attached in the middle it is versatile, when attached by its base it is innate, when attached by one face it is adnate. When the anther opens outwardly it is extrorse; inwardly, in- trorse. Ovules, Fruits and Seeds. — There are two classes of flowering plants classified with reference to the manner in which the ovules occur. In the Gymnosperms, the ovules and seeds are borne on the face of a scale, as in the pine, spruce and cedar. In the Angios- perms, the ovules and seeds are contained in a closed ovary, as in the bean, corn, maple, etc. The carpel is a modified leaf forming- the ovary or a part of the compound ovary. The Fig. 74. Pollen grains of dorsal suture corresponds to the yarious types. (Redrawn . , ., »,••»,« , from Hamilton-Gibson. C. M. midrib of the leaf, the ventral King.) 130 WEEDS OF THE FARM AND GARDEN suture is where the leaves meet. The placenta Is that part of the ovule where the ovules are borne. An axile placenta occurs in a compound pistil where two or more closed carpels cohere ; such ovaries are two, three or more celled. A parietal placenta appears in a compound pistil when the ovules are borne on the walls of the ovaries, as in the poppy and Rocky Mountain bee plant. In pinks and purslane, the compound pistil is one-celled with a free placenta. The parts of an ovule are the two coats, an Fig. 75- Pollen grains in a stage preceding the formation of a pollen tube. A-F, different stages. (Caldwell-Coulter.) outer and an inner, the chalaza at the base where the coats and nucellus blend; the nucellus, is the body of the ovule. The micro pyle is the opening left after the passage of the pollen tube into the ovule. There is usually a stalk called the funiculus on the seed ; the embryo sac contains the egg cell. Ovules may be erect when they arise from the bottom of the cell ; ascending, when extending upward and attached at the side ; horizontal, when borne on the side horizontally as in mandrake; suspended, when hanging from the apex ; pendulous, when more or less hanging or THE MORPHOLOGY OF WEEDS declining from the side. The term orthotropous is applied to the straight ovule, as in buckwheat; campylotropous, Fig. 77. A clus- ter of carpels of Indian mallow or butterprint. (C. M. King.) Fig. 76. Fertilization in the cotton plant. P, pollen tube passing down the style; E, egg cell in em- bryo sac, which unites with a cell of the pollen tube. (Duggar.) Fig. 78. Fruit known as a fol- licle of larkspur. (Ada Hayden.) Fig. 79. Two views of castor oil bean ; car., caruncle. (C. M. King.) Fig. 80. Bean seed: m, micropyle; h, hilum; r, radicle; c, caulicle; cot., cotyle- don. (C. M. King.) WEEDS OF THE FARM AND GARDEN when the ovule is curved on itself, as in chickweed; am- phitropous, when the body of the ovule stands trans- versely to the stalk; anatropous, when the ovule is in- verted and the opening close to the hilum; the ridge extending along the ovule is called the raphe. The fruit is the matured pistil, including whatever parts are attached to it. The seed vessel is called the pericarp. The principal kinds of fruit are: The simple fruit, resulting from the ripening of a single pistil, an ex- ample being the bean pod; the simple fruits are divided into the dry fruits, stone fruits and berries; an aggregate fruit formed when a cluster of car- pels of a single flower are crowd- ed in a mass, as in the rasp- berry; and multiple fruit formed by the union of a cluster of pistils of several flowers, as in Fig. Sl> Two cotyledons r of bean; r, radicle; p, plum- the mulberry, ule. An exalbuminous seed Fruits may also be divided into dehiscent and indehiscent. The dehiscent fruits are repre- sented by the legume, a true pod which comes from a simple pistil with dehiscence on both sides, as in the pea and bean ;the follicle, a pod formed from a simple pistil and dehiscent by the ventral suture, as in the larkspur ; capsule, a dehiscent fruit of a compound pistil. Modifications are a pyxis, which opens by a circular line, as in the purslane and plantain ; silique, like the pod of the mustard, which has two parietal placentae. The indehiscent fruits are nearly always one- seeded, the more important kinds being the achene (ache- nium), a one-seeded, seedlike fruit, like that of the sun- flower, buttercup and smartweed ; samara, a keylike fruit provided with a wing, as in the maple and ash ; the utri- cle, somewhat like an achene, but with a loose membrane, THE MORPHOLOGY OF WEEDS 133 as in goosefoot or lamb's quarter ; caryopsis, a grain fruit in which the wall of the ovary and the testa are closely united; a nut, a hard one-celled and one-seeded fruit, usually produced from an ovary with two or more cells, as in the hazelnut and acorn ; and the paired fruits, as the cremocarp of the parsnip, each half of which is a mcricarp. The more important fleshy fruits are represented by the drupes or stone fruit, such as the peach and plum ; the pome, as the apple, the fleshy part of which is the en- larged calyx; the pepo or gourd fruit, like the squash; the berry, as the grape, which is fleshy. The fruit of the pine is called the strobile. The Seed. — The seed is the fertilized ovule and con- sists of the following parts : The funiculus (occasionally lacking) or the stalk; the outer and inner coats — the outer, frequently hard, called the testa, the inner known as the tegmen; the micropyle or place where the pollen tube enters the ovule; the hilum or scar showing where the seed was attached to the ovary. The albumen, when present may be all endosperm, as in the starchy part of corn, or perisperm, as in canna; this corresponds to the nucellus of the ovule. Some seeds may contain both endosperm and perisperm, as in the pepper, m-g pea. Most seeds have a small quantity of peri- Cotyledons re- Fig. 82. A, germinating pea; r, root; p, young stem. B, Two cotyledons of pea; p, plumule; c, caulicle. (C. M. King.) Ger- sperm present. The embryo of the seed gives ^l?1" ™ . , ° , (C. M. King.) rise to the new plant and consists of the 134 WEEDS OF THE FARM AND GARDEN radicle, or true root ; the caulicle, or stem ; and the cotyledons. When there is one cotyledon the plant is monocotyle- donotts, when two it is dicotyledonous, when three or more, polycotyledonous ; the plumule rises from the cauli- cle. In germination, the cotyledon or cotyledons may re- main in the seed, in which case they are said to be hypogaeous, as in the pea ; when they are pushed out, as in the bean, they are epigaeous. Seeds may be smooth, as in the bean ; rough, as in corn- cockle; they may have a thin membrane growing out from the surface, in which case the seed is said to be winged. Fig. 85. Fig. 86. Fig. 84. Squash seed germinating. Root below and cotyledons push- ing out: pp, pumpkin peg holding the testa. (C. M. King.) Fig. 85. Cross section of buckwheat "seed," an achenium: e, wall of ovary, inner line represents the testa. Embryo with two cotyledons surrounded by the endosperm; seed albuminous. (C. M. King.) Fig. 86. Cross section of date seed: en, hard and horny endosperm, embryo small in lower part of seed. Seed albuminous. (C. M.King.) Fig. 87. A longitudinal section of kernel of corn; an albuminous seed: ce, endosperm; pi, plumule; sc, scutellum; c, caulicle; pr, primary root; h, point of attachment of kernel to cob; rs, root sheath. The darker portion represents the endosperm, light portion embryo or germ. (C. M. King.) CHAPTER XIV. DESCRIPTIONS OF SOME COMMON WEEDS The More Important Families of Weeds. — The weeds described in the following- pages are quite widely dis- tributed. Many of them are as common in New England as in the Northern Mississippi valley and many of them are common on the Pacific coast. Some weeds are local, such as the tarweed of California. Those who are especially interested in a further study of the various regions should consult some of the manuals and floras, such as Robinson and Fernald, Gray's "New Manual of Botany" and Britton's "Manual of Northeastern United States." KEYS TO FAMILIES 1. Plants producing spores, in spore cases or sporangia. Rushlike and jointed (Equisetaceae). P. 138. Not rushlike nor jointed (Polypodiaceae). P. 137. Plants producing pollen and ovules, which develop into seeds. 2 2. Embryo of one cotyledon ; stem endogenous with no distinc- tion between pith wood and bark; leaves generally par- allel veined (Monocotyledoneae) 3 Embryo usually with two cotyledons; stems with distinct wood pith and bark; leaves netted veined (Dicotyledoneae) 6 3. Flowers with small bracts or scales 4 Flowers with a perianth, petal-like, and having parts colored alike (Liliaceae). P. 159. 4. Scale i (Cyperaceae). P. 157. Scales more than one 5 5. Scales in pairs (Gramineae). P. 139. Perianth of six similar scales (Juncaceae). P. 158. 6. Petals absent 7 Petals present 12 7. Flowers monoecious, dioecious or polygamous. Fruit, a three-lobed, three-seeded capsule. Plants with milky juice (Euphorbiaceae). P. 193. Fruit, one-seeded (Urticaceae), P. 160. 8. Fruit, not an achene; fleshy plants with a coiled embryo 9 Fruit, an achene. 135 136 WEEDS OF THE FARM AND GARDEN Flowers with sepals, embryo straight (Polygonaceae). P. 162. Flowers without floral envelopes (Piperaceae). , P. 160. 9. Fruit, an utricle 10 10. Flowers, with bracts (Amaranthaceae). P. 170. Flowers, without bracts n 11. The persistent calyx inclosing the fruit (Nyctagineaceae). P. 162. Calyx not persistent ; sepals green or greenishfChenopodiaceae.) P. 167. 12. Flowers, polypetalous 13 Flowers, gamopetalous 27 13. Stamens numerous 14 Stamens few, as many as the petals, or not more than twice as many 20 14. Calyx free from the ovary; pistil, one or more than one 15 15. Pistils numerous, or more than one 16 Pistils, one or few 17 16. Stamens inserted on the calyx (Rosaceae). P. 185. 17. Stamens, monadelphous or diadelphous. Fruit a legume (Leguminosae). P. 187. Pistils united into a ring (Malvaceae). P. 136. Stamens, not monadelphous 19 18. Stamens inserted on the receptacle, leaves not punctate (Ra- nunculaceae). P. 177. Stamens inserted on the receptacle in clusters, leaves punctate, flowers yellow (Hypericaceae). P. 202. 19. Ovary compound, one-celled ; fleshy herbs (Portulacaceae). P. 176. Ovary compound; pistil one, carpels two or more; plants with milky or colored juice (Papaveraceae). P. 178. 20. Calyx free from the ovary 21 21. Ovary i, 2 — 4-lobed, or entire (Sapindaceae). P. 198. Ovary 2 — 5, or more, celled 22 22. Leaves dissected (Geraniaceae). P. 191. Leaves trifoliate (Oxalidaceae). P. 191. Leaves pinnately compound (Zygophyllaceae). P. 192. Ovary compound, one-celled 23 Ovary compound, two or more celled 25 23. Flowers, irregular, stamens five (Violaceae). P. 203. Flowers, regular 24 24. Flowers, perfect, regular (Caryophyllaceae). P. 173. Flowers, monoecious or dioecious (Euphorbiaceae). P. 193. 25. Ovules, solitary, trees or shrubs (Anacardiaceae). P. 198. Ovules few, stamens six, tetradynamous (Cruciferae). P. 179. Ovules few, stamens six, not tetradynamousf Capparidace ae). P. 184. 26. Ovary 2 to several-celled, stamens 8 or 4 (Onagraceae). P.-2O4. Ovules and seeds, only o'ne in each cell, stamens five, flowers in umbels (Umbelli ferae). P. 205. 27. Calyx free from the ovary, superior. 28 28. Corolla, regular 29 Corolla, irregular 35 29. Ovaries of two carpels . 30 DESCRIPTIONS OF SOME COMMON WEEDS 137 Ovary one ; 31 30. Pollen in pollinia, stamens monadelphous (Asclepidaceae). P. 209. Pollen not in pollinia (Apocyanaceae). P. 208. 31. Ovary deeply four-lobed, leaves opposite (Labiatae). P. 218. Leaves alternate (Boraginaceae). P. 215. 32. Fruit a berry (Solanaceae). P. 220. Fruit not a berry 33 33. Ovary i — 2-celled, seeds mucilaginous (Plantaginaceae). P. 225. Ovary 2 — 3-celled, parasitic or twining, large or small flowers (Convolvulaceae). P. 210. Ovary 2 — 3-celled, plants not twining 34 34. Pod, many-seeded, styles two (Hydrophyllaceae). P. 214. Style i, branches or lobes of stigma 3 (Polemoniaceae). P. 214. 35. Ovary four-lobed 36 Not four-lobed 37 36. Stamens inserted on the corolla tube, stem not four-sided, leaves alternate (Boraginaceae). P. 215. Stamens not inserted on the corolla tube 38 37. Ovary one-celled (Orobanchaceae). P. 225. Ovary one, pod two-celled (Scrophulariaceae). P. 223. 38. Stamens united by their filaments, ovary one-celled (Com- positae). P. 229. Stamens united by their filaments, ovary two or more celled. Corolla irregular (Lobeliaceae). Corolla regular (Gampanulaceae). P. 229. Stamens not united by their filaments 39 39. Ovary 2 — 5-celled leaves whorled, with or without stipules; fruit an indehiscent capsule (Rubiaceae). P 227. Ovary 2 — 5-celled, leaves not whorled, but with small stipules (Caprifoliaceae). P. 228. Ovary one-celled (Dipsaceae). Fern Family (Polypodiaceae). — Plants with horizontal rootstocks; leaves entire, pinnate, pinnatifid or decom- pound; sporangia (spore cases) collected in dots (sori) on the back of the frond, either covered with a mem- branous indusium or naked ; sporangia from an incom- plete, many-jointed ring. A large order of about 3,000 species of wide distribution, a few of which, like the shield fern (Asplenium FilLv-mas), are used in medicine. Common Brake (Pteris aquilina, L.). — A dull-green, tough frond from a stout, black, woody rootstock; very variable in height, varying from two to six feet; stipe straw-colored or brownish ; branches of frond twice-pin- nate; pinnules oblong-lanceolate, the upper undivided; 138 WEEDS OF THE FARM AND GARDEN sori on margin of frond. Found across the continent, also in Europe. Horsetail Family (Equisetaceae.) — Rushlike herbs with jointed and hollow stem from running rootstocks ; the fer- tile stem, with a conical or spikelike body which contains a shield-shaped body beneath, the spore case, which con- tains the spores ; spore is furnished with two straplike bod- ies called the elaters ; the spores develop into the prothal- Fig. 88. Common brake (Pteris aquilina). (Ada Hayden.) lus from which the horsetail develops. The family con- tains a single genus, Equisetum, with 25 species. Common Horsetail (Equisetum arvense, L.). — An an- nual-stemmed perennial producing two kinds of plants; the fertile from four to ten inches high, yellowish brown in color, sheaths eight to twelve-toothed ; the sterile plants slender branched, with four-angled stem and four-toothed DESCRIPTIONS OF SOME COMMON WEEDS 139 sheaths. Common in moist, sandy soil and fields, and along railways. Grass Family (Gramineae). — Fibrous-rooted annuals or perennials, rarely woody, with hollow stem; alternate, two-ranked leaves ; sheaths split or open on the side op- posite the blade ; flowers consisting of two-ranked glumes, forming a one to many-flowered spikelet; flowering glumes inclosing a small bract called the palet ; stamens one to six, usually three ; anthers versatile, two-celled ; stigmas hairy. A large family of about 3,500 species, many of which, such as wheat, corn, oats, and wild rice, are very important to man. Sorghum and sugar cane, which fur- nish the sugar of commerce, also belong to this family. Johnson Grass (Sorghum halapense, (L.) Pers.). — An erect, stout perennial three to five feet tall, with simple, smooth stem, and strong creeping rootstocks ; leaves elongated, acute, and, where the leaf-blade joins the sheath, the back is more or less pubescent ; open panicle six to twelve inches long, the whorled branches being naked below, with three to five-flowered racemes clus- tered near their extremities ; pedicels of the staminate or neutral spikelets armed with stout hairs, the sessile spike- let broadly lanceolate, acute, pale green or violet, becom- ing dark or nearly black at maturity; first glume five to seven-nerved, second glume similar and equaling the first, third shorter, outer ones faintly two-nerved and the fourth two-lobed, awned, ciliate,' one-half as long as the second; blooming period all summer. This plant has been introduced and cultivated in many parts of the southern states for hay, but has become, in various sec- tions, a dangerous weed and is difficult to exterminate. Smooth Crab Grass (Digitaria humifusa, Pers.). — An annual from six inches to two feet tall, closely resembling finger grass (D. sanguinalis), in habit, but is smooth throughout excepting for a few hairs at the throat of the sheath; spikes two to six, widely diverging and smaller 140 WEEDS OF THE FARM AND GARDEN than those of finger grass ; first glume very minute, second and third larger and nearly of equal length, or the second a little shorter than the fourth, the upper empty glume equaling the flower. The blooming period from June to September. Quite common in eastern and central Iowa, Fig. 89. Smooth crab grass (Digitaria humifusa). (U. S. Dept. Agrl.) DESCRIPTIONS OF SOME COMMON WEEDS 14! especially in the flood plains of streams, and becoming troublesome as a weed on lawns. Finger Grass or Crab Grass (Digitaria sanguinalis, (L.) Scop.). — A leafy, much-branched annual, one to three feet high, spreading on the ground, with erect, smooth, spreading stems, frequently rooting at the lower joints, which are sometimes smooth, but, more often, bearded with deflexed hairs ; sheaths loose, generally hairy, es- pecially on the margins, with a membranaceous ligule; leaves from two to four inches long, with rough margins and occasionally hairy at the base; flowers produced in digitate spikes (hence the name finger grass) ; spikelets in pairs, less than one-eighth inch long, one being nearly sessile, the other on a small stalk ; each flower consists of two sterile glumes and the flower proper, which is made up of two glumes ; the first glume is very small, the sec- ond about one-half to two-thirds as long as the spikelet, the third somewhat longer than the fourth, and the fourth, five-nerved and usually silky haired along the marginal nerves, smooth and acute; fruit minute, pitted and cross-striated, light straw colored, except where the sterile glumes remain attached. These are gray and minutely hairy. Blooming period from June to Septem- ber. Common in the bottom lands along streams and occasionally troublesome in corn fields, but more of a pest on lawns. Since it roots at the joints, it is somewhat difficult to remove. Old Witch Grass (Panicum capillare, L.). — An annual, usually displaying coarse, branching stems, one to three feet high, with very hairy leaf sheath and wide-spreading panicles, which are terminal on the stem and branches; stem jointed, branching near the base and hairy below the bearded nodes; sheaths have spreading hairs and densely ciliate short ligules ; leaf blade flat, lanceolate or linear and sparingly hairy on both sides, with rough margins ; hairs throughout spring from small papillae, those on the leaf 142 WEEDS OF THE FARM AND GARDEN blade being confined to the principal nerves ; panicle dif- fuse, branches solitary, in pairs, or whorls ; spikelets very small; blooming' period from July to October. Quite common throughout the state and frequently becoming a weed. Rather variable in appearance ; in cultivated fields being stout and bristly, but in moist meadows and old lake beds becoming slender and hairy rather than bristly. Sprouting Crab Grass (Panicum dichotomiflorum, Michx.). — An annual with a thick, spreading or ascend- ing, branching, glabrous stem, two to six feet high ; leaves flat, seven to fourteen inches long; panicles diffuse, termi- nal or lateral ; sheaths smooth, lax, somewhat flattened ; spikelets rather crowded upon short, scabrous pedicels; anthers saffron-yellow ; blooming time from July to Octo- ber. Low waste grounds and cultivated fields from Maine to Nebraska and southward. Barnyard Grass (Echinochloa crus-galli, (L.) Beauv.). — A coarse, ascending, leafy annual from one to five feet high ; stems frequently branched near the base ; sheaths loose and smooth as a rule, although occasionally appear- ing rough ; leaves broad, flat and six inches or more long, smooth or rough with rough margins ; spikelets densely crowded in several rows along one side of the spikelike branches of the panicle ; outer glume or bract from one- fourth to one-half the length of the spikelets, second and third glumes smooth and hairy or rough along the nerves, third glume awnless or short pointed ; blooms all sum- mer. Common throughout eastern United States except in the extreme northern parts. Yellow Foxtail or Pigeon Grass (Setaria glauca, (L.) Beauv.). — An erect annual, one to two and one-half feet high, with flat leaves and a bristly cylindrical spike, one to three inches long; heads slender with tawny red bris- tles, five to ten on each spikelet ; axis of the flowering stalk densely pubescent ; blooms from June to September. DESCRIPTIONS OF SOME COMMON WEEDS 143 Wide!}r distributed all over northern United States, and a pernicious weed in cultivated fields. Bristly Foxtail (Setaria verticillata, (L.) Beauv.). — A low, spreading, much-branched annual from one to two and one-half feet high ; lanceolate leaves, two to seven inches long, somewhat narrower than those of 5\ viridis, and from one-fourth to one-half inch wide ; sheaths smooth, rough on the margins and veins ; spike cylindri- cal from one to five inches long, composed of short, cylin- drical clusters, with short bristles, a little longer than the spike, either single or in pairs and barbed downward; seeds • small, greenish, minutely cross-striated and wrinkled ; blooming time from June to September. Quite abundant in the East, and west to Nebraska; unless strong measures are taken to eradicate "it, it will soon be- come as troublesome as the other species. Because of its downwardly barbed bristles, it is easily disseminated by animals. Green Foxtail (Setaria viridis, (L.) Beauv.). — A smooth, erect annual, from one to three feet high, with leaves long, rough margined, greenish, more or less com- pound, cylindrical spikes from one to six inches long, with few bristles; spikelets shorter than the bristles, about one-half inch long, the chaff of the second and third glumes equaling the minute chaff of the fourth glume, which is faintly transversely wrinkled below or only striate and pitted; blooms 'from July to September. A single head of the green foxtail produces an enormous number of seeds, which appear to have considerable vital- ity, hence when the plant once becomes established in a field, it is very difficult to remove it. This difficulty is in- creased by the habit of the grass of forming tufts. The species common in the northern states and a trouble- some weed in corn fields. Sandbur (Ccnchrus tribuloides, L.). — An erect annual one to four feet high, with spreading, or ascending, much- 144 WEEDS OF THE FARM AND GARDEN branched stems, rarely a foot high, somewhat compressed ; leaves flat or simply folded, linear, about six inches long, Fig. 90. Green foxtail (Setaria