2. Froelichia gracilis (Hook.) Moq. (slender cottonweed, slender snake-cotton)

Pl. 199 g, h; Map 827

Calyx tube at fruiting 3.5–4.5 mm long, flask-shaped to more commonly conical, asymmetric at the tip, with longitudinal rows of individual short spines, the basal tubercles often also spiny. Stems 15–45(–70) cm long, usually relatively slender (to 3 mm in diameter), usually several- to many-branched at the base. Leaf blades 2–8(–12) cm long, those of the largest leaves 5–10(–15) mm wide, linear to narrowly lanceolate or narrowly oblanceolate. Inflorescences with the spikes and/or clusters 0.7–3.0 cm long, 5–10 mm in diameter, sessile, the flowers in a dense, 3-ranked spiral. Calyx tube at fruiting 3.5–4.5 mm long, flask-shaped to more commonly conical, asymmetric at the tip, with longitudinal rows of individual short spines, the basal tubercles often also spiny. Seeds 1.2–1.5 mm long, tan to yellowish brown or reddish brown. 2n=54. May–September.

Scattered nearly throughout the state, but apparently absent from the northwestern portion of the Glaciated Plains Division (Indiana to Arkansas west to Wyoming and Arizona; Mexico; introduced eastward to the Atlantic seaboard, also Canada). Sand prairies, upland prairies, tops of bluffs, openings of mesic upland forests, and banks of streams and rivers; also fallow fields, pastures, roadsides, railroads, and open, sandy or rocky, disturbed areas.

Froelichia gracilis is often found growing in mixed populations with F. floridana but is more widely distributed in Missouri. Steyermark (1963) cited a single specimen from Jasper County as somewhat morphologically intermediate between F. gracilis and F. floridana and suggested that it might represent an interspecific hybrid. Such plants probably are more common but presumably have been overlooked by collectors.