Pennisetum polystachion (L.) Schultes
Family Poaceae, Tribe Paniceae
mission grass, thin napiergrass
Fascicle consists of unfused bristles; outer bristles 13–30, 1.2–5 mm long, antrorsely scabrous; inner bristles 6–14, 4.3–11.5 mm long, long ciliate; primary bristle solitary, conspicuously longer than other bristles, to 25 mm, long ciliate. Spikelets solitary, sessile, lanceolate, mildly dorsally compressed; 2–5 mm long, 0.6–0.9 mm wide; consisting of 1 fertile floret and 1 basal sterile floret. Lower glume absent or a vestigial scale; upper glume 3–4.5 mm long, glabrous, trilobed. Sterile lemma membranous, as long as spikelet, 5–7-nerved, trilobed, ciliate; sterile palea 2.9–3.7 mm long. Fertile floret cream to light brown, narrowly lanceolate, 1.7–3 mm long, ca. 0.5–0.6 mm wide; fertile lemma and palea coriaceous, glossy, with truncate-ciliate apices, lemma 5-nerved.
Pennisetum clandestinum Hochst. ex Chiov.
Pennisetum macrourum Trin.
Pennisetum pedicellatum Trin.
tropical Africa, India to Southeast Asia, Australia, New Zealand, and the Pacific Islands; Mexico, tropical South America, United States
native to tropical Africa
tropical scrublands; a weed of roadsides, waste places, arable lands, and disturbed sites
Pennisetum polystachion is an annual or perennial grass, to 200 cm tall, that has been widely introduced as a fodder grass. It reproduces solely by seed, yet production of the highly viable grains is prolific, enabling the grass to quickly invade cultivated fields. Disseminules are dispersed by water, by clinging to animals, or as hay and grain contaminants. This grass has become a dominant weed in cleared forest lands in Southeast Asia and the Pacific Islands.