14.12 BECKMANNIA Host
Stephan L. Hatch
Plants annual and tufted, or perennial and rhizomatous. Culms 20–150 cm, sometimes tuberous at the base, erect. Leaves mostly cauline; sheaths open, glabrous, ribbed; auricles absent; ligules membranous, acute; blades flat, glabrous. Inflorescences dense, spikelike panicles; branches 1-sided, racemosely arranged, secondary branches few, at least some branches longer than 1 cm, with closely imbricate spikelets; disarticulation below the glumes, the spikelets falling entire. Spikelets laterally compressed, circular, ovate or obovate in side view, subsessile, with 1–2 florets; rachillas not prolonged beyond the base of the distal floret. Glumes subequal, slightly shorter than the lemmas, inflated, keeled, D-shaped in side view, unawned; calluses blunt, glabrous; lemmas lanceolate, inconspicuously 5-veined, unawned; paleas subequal to the lemmas; lodicules 2, free; anthers 3; ovaries glabrous. Caryopses shorter than the lemmas, concealed at maturity. x = 7. Named for Johann Beckmann (1739–1811), a German botanist and author of one of the first botanical dictionaries.
Beckmannia is a genus of two species: an annual species usually with one fertile floret per spikelet that is native to North America and Asia, and a perennial species with two fertile florets per spikelet that is restricted to Eurasia.
SELECTED REFERENCE Reeder, J.R. 1953. Affinities of the grass genus Beckmannia Host. Bull. Torrey Bot. Club 80:187–196.
1. Beckmannia syzigachne (Steud.) Fernald
American Sloughgrass, Beckmannie à Écailles Unies
Plants annual; tufted. Culms 20–120 cm. Ligules 5–11 mm, pubescent, entire or lacerate, usually folded back; blades 4–10(20) mm wide, flat, scab-rous. Panicles 7–30 cm; branches spikelike, usually 1–2 cm. Spikelets 2–3 mm, round to ovate in side view, with 1 floret, a second undeveloped or well-developed floret occasionally present. Glumes appearing inflated, strongly keeled, 3-veined, apiculate; lemmas 2.4–3.5 mm, unawned, sometimes mucronate; paleas subequal to the lemmas, acute; anthers 0.5–1(1.5) mm, pale yellow. Caryopses shorter than 2 mm, light to medium brown. 2n = 14.
Beckmannia syzigachne grows in damp habitats such as marshes, floodplains, the edges of ponds, lakes, streams, and ditches, and in standing water. It is a good forage grass, but frequently grows in easily damaged habitats.