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: May to September.
Seed-time: July to November.
Range: South Dakota to Tennessee, Mississippi, Texas, and Mexico. Locally in the Eastern States.
Habitat: Plains and prairies, foothills; meadows, pastures, cultivated ground, waste places.
This is one of the weeds frequently transported in baled hay, and its appearance in eastern localities has usually been first in vacant lots near city livery stables and on near-by farms where such stable refuse has been purchased for manuring the land. Also the burs are distributed in the wool of sheep, as they formerly were in the matted coats of the buffalo herds, the plants being always abundant about the "buffalo wallows." (Fig. 257.)
Stem one to two feet high, much branched, covered with yellowish, star-shaped hairs, and densely set with slender, awl-like, yellow spines. Leaves long oval in outline but once or twice pinnatifid, the segments often not opposite and very irregular in size, but the terminal one being usually largest, covered with rayed hairs, the midribs and the petioles prickly. Flowers in open racemose clusters, on prickly peduncles from the side of the stem, the corolla wheel-shaped, nearly an inch broad, golden yellow, its five lobes slightly irregular, the stamens and the style the lowest of the five stamens much longer than the others and with an incurved beak; calyx densely prickly, becoming the bur that encloses the fruit. The plant frequently becomes a tumbleweed, distributing its burs as it rolls before the winds.
Fig. 257. -Buffalo Bur (Sola-num rostratum). x 1/4.
Prevent seed production. Being annual the weed can readily be suppressed if it is persistently cut or pulled while in early flower. Other tasks may well be postponed for a day or two in order to rid the ground of so undesirable a tenant.