1. Froelichia floridana (Nutt.) Moq. var. campestris (Small) Fernald (field cottonweed, field snake-cotton)

Pl. 199 f; Map 826

Stems (30–)50–140(–200) cm long, usually relatively stout (to 7 mm in diameter), unbranched or few-branched at the base (but often with more branches above the midpoint). Leaf blades 2–14 cm long, those of the largest leaves (5–)10–30 mm wide, elliptic-lanceolate to oblanceolate, less commonly narrowly oblong-lanceolate. Inflorescences with the spikes 1–8 cm long, 10–14 mm in diameter, often short-stalked, the flowers in a dense, 5-ranked spiral. Calyx tube at fruiting (4.5–)5.0–6.0 mm long, flask-shaped, symmetric at the tip, with deeply toothed longitudinal wings, the basal tubercles blunt. Seeds 1.5–2.0 mm long, reddish brown. 2n=about 78. May–September.

Scattered in the southeastern portion of the state, uncommon farther north and west (Ohio and Kentucky west to South Dakota, Colorado, and New Mexico). Sand prairies and banks of streams and rivers; also fallow fields, pastures, railroads, roadsides, and open, sandy, disturbed areas.

Froelichia floridana is usually treated as comprising two or more varieties, but the genus is in need of more detailed taxonomic study. The var. floridana is widespread along the Atlantic and Gulf Coastal Plains and occurs inland to Kentucky and Tennessee. It is generally more robust (often to 2 m tall) than var. campestris, with leaves that are mostly widest below the midpoint and more gradually tapered to the sharply pointed tip. For a discussion of possible hybridization with F. gracilis, see the treatment of that species.