The person charging this material is re- sponsible for its return to the library from which it was withdrawn on or before the Latest Date stamped below. Theft, mutilation, and underlining of books are reasons for disciplinary action and may result in dismissal from the University. UNIVERSITY OF ILLINOIS LIBRARY AT URBANA-CHAMPAIGN NAR1{ MAY im Wk FEB 1 2 19?5 EB 1 1 1975 IdEC 4 198 L161 — O-1096 COMMON WES^§«,„Y„pTHE BY PAUL C. STAND 001161934 j.mIVERSITY of ILLINOIS Associate Curator of the Herbariuu Botany Leaflet 17 FIELD MUSEUM OF NATURAL HISTORY CHICAGO 1934 The Botanical Leaflets of Field Museum are designed to give brief, non-technical accounts of various features of plant life, especially with reference to the botanical exhibits in Field Museum, and of the local flora of the Chicago region. LIST OF BOTANICAL LEAFLETS ISSUED TO DATE No. 1. Figs $ .10 No. 2. The Coco Palm 10 No. 3. Wheat 10 No. 4. Cacao 10 No. 5. A Fossil Flower 10 No. 6. The Cannon-ball Tree 10 No. 7. Spring Wild Flowers .25 No. 8. Spring and Early Summer Wild Flowers . . .25 No. 9. Summer Wild Flowers 25 No. 10. Autumn Flowers and Fruits 25 No. 11. Common Trees 25 No. 12. Poison Ivy 15 No. 13. Sugar and Sugar-making 25 No. 14. Indian Corn 25 No. 15. Spices and Condiments 25 No. 16. Fifty Common Plant Galls of the Chicago Area .25 No. 17. Common Weeds 25 STEPHEN C. SIMMS, Directok THE LIBRARY OF THE . OCT 161934 UNIVERSITY OF ILLINOIS Field Museum of Natural History DEPARTMENT OF BOTANY Chicago. 1934 leafi.bt numbek 17 Copyright 1934 by Fikld Museum op Natukai. Hmtoky COMMON WEEDS YELLOW DOCK (Rumez crispus) Like most of our commonest weeds, yellow dock is an immigrant from Eiirope, brought long ago to America, and now thoroughly established in almost all regions as a pernicious weed of cultivated and waste ground. It grows from a thick yellow parsnip-like root, and has succulent wavy leaves. The small green flowers are followed by dense brown clusters of winged fruits, each containing a single 3-angled achene or "seed." In spite of its weedy nature, the plant is of some utility to man, for its leaves often are gathered in spring to be cooked and eaten as "greens." Several other kinds of dock grow plentifully about Chicago, some of them European in origin, others native American plants. (Buckwheat family.) Field Museum of Natural History GREEN FOXTAIL {Setaria viridis) A tall grass, with bright green flower spikes, in appear- ance much like cultivated millet. Even more abundant is the common foxtail, which has tawny yellow spikes. Both these grasses are abundant in summer in fallow fields where oats and wheat have been cut, and one or the other inhabits almost every vacant city lot. (Grass family.) Common Weeds SANDBUR {Cenchrus pauciflorus) Barefooted children know this grass to their sorrow. The sharp-pointed spines of its burs penetrate the skin easily, and are extracted with difficulty. They will even pierce the leather of shoes. In the Chicago region the sandbur grows mostly in sandy fields and on the dunes, but it often invades cultivated fields and pastures. When the plants are too plentiful in hayfields, the crop is worth- less, for cattle will not eat hay filled with burs. This is so pernicious a weed that no labor should be spared to prevent its entry into ground not already infested with it. (Grass family.) Field Museum of Natural History SMARTWEED {Polygonum lapathifolium) Several different kinds of smartweed grow about Chicago. Some are tall plants, and others low, but all agree in having spikes of small, white, red, or pink flowers, which often are rather showy. The smartweeds, as a rule, prefer moist or wet ground. (Buckwheat family.) Common Weeds BLACK BINDWEED (Polygonum Convolvulus) Although black bindweed belongs to the same genus or group as smartweed, the plants are very unlike in habit and general appearance. Bindweed is a slender vine that forms dense tangles over other weeds and shrubbery. It is a great nuisance if it becomes established among garden shrubs, for the stems are so numerous, and so tightly twisted about the branches of the shrubs, that it is difficult to remove them. Black bindweed is a close relative of cultivated buck- wheat, and it is sometimes called wild buckwheat. Its black "seeds" or achenes resemble buckwheat, except for being much smaller. The minute flowers are white or tinged with pink. (Buckwheat family.) Field Museum of Natural History PIGWEED {Amaranthus hyhridus) Several kinds of pigweed are all too common every- where in cultivated and waste ground. Some are low plants that spread closely over the ground; one is a bushy tumbleweed that may be seen blowing across the fields in winter; this is a tall and ugly plant that grows thickly in gardens in late summer after cultivation is discon- tinued. (Pigweed family.) Common Weeds GOOSEFOOT. LAMB'S QUARTERS {Chenopodium album) No weed is more plentiful in gardens and cultivated fields than this, and it thrives equally well in waste ground, reaching sometimes the size of a large shrub, and develop- ing almost woody stems. All parts of the plant are covered with extremely minute, pale globules, that give a whitish or grayish cast to the foliage. It often is called pigweed. (Goosefoot family.) ■•-^a -^ i . ■J 1 •. Common Weeds ii RUSSIAN THISTLE (Salsola pestifer) Russian thistle is one of the worst pests among our weedy plants of European origin. Imported from Eastern Europe with seed grain about fifty years ago, it spread across the United States with astounding rapidity, and caused great alarm among farmers. A huge volume of printed matter was published regarding it. However, in the Eastern States climatic conditions did not suit the plant, and in the West it was found that it could be held in check with proper cultivation. Few weeds are more aggressive than this in the Chicago Region, where it occupies most of the city lots, and large areas of the dunes along the lake shore. After the thick, bushy, somewhat spiny plants have been killed by frost, their short roots are easily pulled from the soil, and as tumbleweeds they are blown about by the wind, until they finally come to rest against some fence or thicket. Thus they distribute their seeds with almost mechanical efficiency. (Goosefoot family.) 12 Field Museum of Natural History -fc 'j*^ ^ • ^^ > MAYWEED. DOGFENNEL {Anthemis Cotula) Barnyards are the favored habitat of dogfennel, but it grows almost as well in vacant lots, and especially on the borders of country roads. It is a low bushy weed, one to two feet high, with white daisylike heads scarcely an inch broad. (Sunflower family.) Common Weeds 27 BURDOCK (Arctium minus) In spring the huge, Hmp, heart-shaped leaves of this plant develop, to be followed soon by the stiff flower stalks with their globular heads of purple or lilac flowers. The heads are covered with green bracts, each tipped with a hooked spine. (Sunflower family.) 28 Field Museum of Natural History CANADA THISTLE {Cirsimn arvense) The plant pest most dreaded by farmers of Illinois and Indiana is the Canada thistle, a weed so pernicious that its destruction is ordered by state laws. The long under- ground rootstocks cause it to spread rapidly and make its eradication difficult. The rose-purple heads are all too handsome for so vile a weed. (Sunflower family.) Common Weeds 29 PRICKLY LETTUCE {Lactuca Scariola) Prickly lettuce grows profusely in gardens in sum- mer after cultivation has ceased, and it thrives in all waste ground, even the most sterile. Its pale yellow flower heads ripen into heads of seeds, each of which bears a tuft of hairs, enabling it to be carried long distances by the wind. Prickly lettuce, a relative of garden lettuce, is a native of Europe. (Sunflower family.) 30 Field Museum op Natural History SOW THISTLE (Sonchiis asper) Sow thistle is found commonly in the sour soil of city alleys or barnyards, and grows almost anywhere that the down-tufted seeds fall. It is a succulent plant, with milky sap and yellow flower head. (Sunflower family.) Common Weeds 81 DANDELION {Taraxacum officinale) One of the earliest flowers of spring, blooming some- times even in winter, there is no dispute that the dandelion is a beautiful plant, but when it invades lawns and crowds out the grass, their owner has little admiration for the plant. It is one of the plant immigrants from Europe that could best be spared. (Sunflower family.) This is the fifth of a series of Field Museum Leaflets dealing with some of the common and conspicuous plants of the Chicago region. The earlier ones treat of the flowers of spring, spring and early summer, summer, and autumn. The photographs of the following plants were obtained from L. W. Brownell: green foxtail, goosefoot, pusley, sweet clover, plantain, galinsoga, mayweed, and dandelion.