3. Amaranthus floridanus (S. Watson) J. D. Sauer, Madroño. 13: 25. 1955.
Florida water-hemp, Florida amaranth
Acnida floridana S. Watson, Proc. Amer. Acad. Arts 17: 376. 1882
Stems erect, branched, slender, usually (0.5-)1-1.5 m. Leaves: petiole 1/4 length of blade; blade linear to narrowly oblong, usually 10(-20) × 1 cm, base narrowly cuneate, margins entire, plane, apex obtuse to rounded. Inflorescences terminal, linear spikes to panicles. Bracts: of pistillate flowers 1-1.5 mm; of staminate flowers with moderately heavy midrib, 1-1.5 mm. Pistillate flowers: tepals 1-2(-3), unequal, inner tepals lanceolate to narrowly lanceolate, 1-1.5 mm, apex acute to acuminate; style branches spreading; stigmas 3. Staminate flowers: tepals 5, with excurrent midrib, equal to subequal, 2(-2.5) mm, apex acute to indistinctly mucronulate in outer tepals; stamens 5. Utricles reddish to reddish brown, occasionally with indistinct longitudinal ridges, subglobose to broadly obovoid, 1.5-2.5 mm, wall thin or slightly fleshy, irregularly rugose. Seeds dark reddish brown to dark brown, 0.7-1 mm diam., shiny.
Flowering late spring-fall. Coastal dunes, beaches, swamps, marshes, disturbed habitats, such as gardens and fields near coast; 0-10 m; Fla.