11. Bidens vulgata Greene (beggar-ticks, sticktight)

B. vulgata f. puberula (Wiegand) Fernald

Pl. 274 c, d; Map 1159

Plants annual, terrestrial, usually with taproots. Stems 30–150 cm, erect or ascending, glabrous or inconspicuously pubescent with sparse, cobwebby hairs, mostly at the nodes. Leaves all more or less similar, short- to more commonly long-petiolate, opposite, the blade 3–15 cm long, broadly ovate-triangular in outline, all except rarely those of the uppermost leaves 1 time ternately or pinnately divided or compound with 3–5 segments or discrete leaflets, these lanceolate to narrowly ovate, angled or tapered at the base, each with a well-developed stalk (this sometimes narrowly winged), tapered to a sharply pointed tip, the margins usually sharply and finely to coarsely toothed, sometimes minutely hairy, the surfaces glabrous or the undersurface sparsely to moderately pubescent with minute, fine hairs. Inflorescences of solitary terminal heads or appearing in loose, open clusters or small panicles, the heads discoid or apparently discoid, rarely nodding at fruiting. Involucre with the outer series of 10–21 bracts 10–20(–40) mm long, ascending to spreading, leaflike, linear to narrowly oblong-oblanceolate or narrowly oblanceolate, the margins entire but with short, spreading hairs, at least toward the base, the outer surface glabrous or sparsely to moderately pubescent with minute, fine hairs, especially toward the base; the inner series of 8–14 bracts 5–9 mm long, oblong to narrowly ovate or ovate, glabrous. Chaffy bracts narrowly oblong to oblong-lanceolate, with narrow to broad, yellowish margins but sometimes purplish-tinged at the tip. Ray florets absent or 1–5, the corolla inconspicuous, 2–4 mm long, yellow. Disc florets 40–100(–150), the corollas 2.5–4.0 mm long, yellow. Pappus of 2 awns 3–7 mm long, these with downward-pointed barbs, erect to somewhat spreading at fruiting. Fruits 5–12 mm long, wedge-shaped to oblong-obovate, 1 or both faces sometimes with a fine longitudinal nerve or ridge, the angles with minute, stiff, usually ascending hairs, the faces dark brown to black, sometimes with minute, purplish spots, glabrous or sparsely pubescent with fine, more or less appressed hairs. 2n=24, 48. August–October.

Scattered to uncommon nearly throughout the state (U.S. [except some southwestern states], Canada; introduced in Europe). Banks of streams and rivers, margins of ponds and lakes, and sloughs; also ditches, fallow fields, railroads, roadsides, and moist, open, disturbed areas.

This variable species can be difficult to distinguish from B. frondosa. It tends to be more robust than that species. Some botanists separate plants with more finely divided leaves occurring to the north of Missouri as var. schizantha Lunell, and plants with hairy leaves and outer involucral bracts (which occur sporadically in Missouri) have been called f. puberula (Wiegand) Fernald.