This section is from the book "A Manual Of Weeds", by Ada E. Georgia. Also available from Amazon: A Manual Of Weeds.
Native. Annual. Propagates by seeds.
Time of bloom: July to September.
Seed-time: August to November.
Range: Pennsylvania to Wyoming, southward to Louisiana, Texas, and Mexico.
Habitat: Rich, moist soil; fields, meadows, waste places.
A robust-looking, grossly feeding weed, transforming into its poisonous foliage much of the fertility needed by its wholesome neighbors. Stem eight to twenty inches high, somewhat woody at base, erect and branching. Leaves two to four inches long, the upper ones opposite but at base alternate, varying in shape from ovate to nearly linear, coarsely toothed, hairy, with prominent veins on the under side, and with hairy petioles. Involucres in clusters at the ends of stem and branches on very short peduncles; they are bell-shaped, with five oblong, sharply toothed lobes, bearing usually one or sometimes several short-stalked, yellowish glands without appendages. Capsules smooth, with rounded angles, nearly one-sixth of an inch in diameter. Seeds ashy-gray, obscurely four-angled, bluntly ovoid, the surface tuberculate; they are often an impurity of grass and clover seeds. (Fig. 188.)
Fig. 188. - Toothed Spurge (Euphorbia dentata). X 1/4.
Infested meadows should be harvested early, before the first flowers mature seed. The poisonous qualities of the milky juice are volatile and disappear with heat or drying, and such hay is wholesome. In grain fields the seedlings should be harrowed out in the spring, for the spreading habit of growth of the plant will crowd and starve the crop; if practicable, hand-pull the survivors; if not, burn over the stubble. In cultivated ground tillage should be late in order to prevent the maturing of late-developed seed.
 
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