Time of bloom: July to October. Seed-time: August to November. Range: Newfoundland to Minnesota and Nebraska, southward to Georgia and Missouri. Habitat: Pastures, fence rows, roadsides, and waste places.
In order to mature fruit these plants must remain undisturbed until the second year of growth; the first season produces only a deep taproot crowned by a large, tufted, spreading rosette of leaves, three to six or more inches long, lance-shaped, deeply pinnatifid, the lobes tipped with spines, the upper surface deep green and rough-hairy but the under side clothed with brownish, webby wool which disappears as the plants grow older. Stems two to four feet high, stout, branching, leafy to the heads. Leaves decurrent on the stem, the wings extending to the axil of the leaf below, the edges very prickly. Heads large, about two inches high and nearly as broad, mostly solitary at the ends of stem and branches, the bracts of the involucre lance-shaped, long-pointed, all tipped with needle-like spines; florets all tubular, five-lobed, deep purple, fragrant. Achenes light-colored, oblong, slightly flattened and curved, with long, plumose, white pappus. (Fig. 354.) Goldfinches are very fond of these seeds and usually build their nests of Thistle-down, a habit which has gained for them the name of "Thistle-birds."
Deep spudding or hoe-cutting of first-year rosettes; flowering stalks should be cut below the crown, before the first flowers mature; if cut above the surface of the ground, they will stool and require attention a second time. Cultivation of the ground at once destroys these plants.
Fig. 354. - Common or Bull Thistle (Circium lanceolatum). X 1/4.