Flora of Barro Colorado Island

Polytrias amaura

 (Buse ex Miq.) O. Kuntze, Rev. Gen. Pl. 2:788.1891

P. praemorsa (Nees) Hack.

Java grass

Stoloniferous perennial, to 35 cm tall; culms decumbent­-spreading, slender, glabrous with some nodes pubescent. Sheaths glabrous to pilose, longer than the internodes except near apex; blades 2-6 cm long,   l-3 mm wide, pilose on both surfaces, the margins scabrid. Racemes terminal, solitary, 2.5-5.5 cm long, brown; rachis pubes­cent; spikelets densely brown-pubescent, 2 or 3 per node, 1 or 2 sessile, l pedicellate, all perfect, 3-4 mm long excluding awn; first glume truncate and fimbriate at apex; sterile lemma lacking; fertile lemma awned, the awn 6-8 mm long, geniculate, twisted. Croat 12827.

Common along the stairs at the Laboratory Clearing. Generally appearing in large flushes in late rainy and early dry seasons.

The genus is supposed to have two sessile spikelets at each node, but specimens from BCI and other areas of Central America (R. Pohl, pers. comm.) have only one sessile spikelet per node.

Introduced from Java into various parts of the Western Hemisphere. In Panama, known only from tropical moist forest in the Canal Zone (BCI and Summit Garden).