Froelichia floridana (Nutt.) Moquin–Tandon, field snake–cotton. Annual, taprooted, flat–rosetted, several–stemmed at base, branches ascending to spreading, in range to 70 cm tall; shoots with bicolor basal leaves and cauline leaves, woolly and pustulate having hairs with swollen bases.
Stems cylindric, to 7 mm diameter, tough, gray–woolly.
Leaves opposite decussate, simple, petiolate, without stipules; petiole deeply channeled, to 11 mm long, indistinct from blade, 3–veined with a pair of lateral ridges; blade lanceolate to elliptic, < 25—106 × < 10—43 mm, tapered at base, entire, ± obtuse to rounded at tip, pinnately veined with principal veins sunken on upper surface and raised on lower surface, upper surface green and bumpy with fine pustulate villous hairs, lower surface gray–green with dense cover of woolly hairs.
Inflorescence spike or with new branch at base axillary to bract, paired at node, in range > 10—40+ × 10—13 mm, flowers helically alternate without internodes, bracteate, densely white–woolly; principal axes with nodes widely spaced 40—70+ mm long; bract subtending lateral spike scarious, ovate, to 4 mm long, 1–veined, sparsely woolly on base, persistent; bractlet subtending sessile flower, scarious, acuminate–ovate and cupped, < 3 × 1.3 mm, entire, 1–veined with greenish veins raised on lower (outer) surface, aging papery, lower surface woolly, upper surface glabrous, persistent; bracteoles subtending flower 2, opposite, scarious, broadly ovate to roundish, 2—2.3 mm long, weakly 1–veined with vein not raised, truncate to shallowly notched at tip, upper surface glabrous, lower surface fine–hairy.
Flower bisexual, radial, at anthesis oblanceoloid with perianth lobes touching < 1—1.2 mm across; perianth (calyx) 5–lobed, at anthesis ca. 4 mm long; tube fused to below midpoint, green, densely woolly; exposed tips of lobes triangular, ca. 1 × 0.5 mm, white, 3–veined, often inrolled eventually and ascending to spreading, stamens 5, fused as cylinder with petal–like erect lobes, ca. 2.5 mm long, blotched purplish next to anther, the lobes acute to obtuse, 0.4—0.7 mm wide, at anthesis colorless to yellowish with recurved tips aging brownish; anthers dorsifixed, dithecal, erect, eventually exserted to 0.8 mm, 0.85—1 mm long, orange–yellow to yellow–orange, longitudinally dehiscent; pollen orange; pistil 1, 1—1.5 mm long, mostly rose; ovary superior, ovoid, to 0.8 mm long, 1–chambered with 1 ovule; style ca. 0.6 mm long, with terminal, papillate, rose stigma.
Fruit achenelike (anthocarp), flask–shaped, with hard, bony calyx tube enclosing utricle, anthocarp flask–shaped, body pyramidal 5–sided, ca. 3 × 3 mm, densely woolly, base with depressed center, 5–ridged with 2 lateral wings, wings papery and fishfinlike, to 1.5 mm high with jagged margin (visible above wool), other ridges with low tubercles or even a hook, woolly hairs 5+ mm long; top of anthocarp persistent with scarious perianth lobes; utricle papery and pinkish, 1–seeded.
Seed kidney–shaped, ca. 2 × 1.2 mm, reddish tan, weakly wrinkled.
A. C. Gibson