Pennisetum polystachion

HABIT Annual, or perennial; caespitose. Culms geniculately ascending; 30–200 cm long. Lateral branches ample. Ligule a ciliate membrane. Leaf-blades 10–40 cm long; 3–16 mm wide.

INFLORESCENCE Inflorescence a panicle.

Panicle spiciform; linear; straight, or curved; 3–25 cm long; (0.6–)0.8–1(–1.5) cm wide (excluding bristles). Primary panicle branches accrescent to a central axis; with sessile scars on axis. Panicle axis with briefly decurrent ribs; glabrous; bearing deciduous spikelet clusters.

Spikelets subtended by an involucre. Fertile spikelets sessile; 1 in the cluster. Involucre composed of bristles; oblong; 4–12 mm long; base obtuse. Involucral bristles deciduous with the fertile spikelets; numerous; with an outer whorl of thinner bristles; with one conspicuously longer bristle; 6–25 mm long; terete; flexible; antrorsely scaberulous; glabrous, or ciliate.

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets lanceolate; dorsally compressed; 2–5 mm long; falling entire; deciduous with accessory branch structures; readily shedding fertile florets.

GLUMES Glumes one the lower absent or obscure, or two; dissimilar; reaching apex of florets; thinner than fertile lemma. Lower glume lanceolate; 0–1 mm long; 0–0.2 length of spikelet; hyaline; without keels; 0 -veined. Lower glume lateral veins absent. Lower glume apex obtuse, or acute. Upper glume oblong; 1 length of spikelet; membranous; without keels; 5 -veined. Upper glume apex acute; muticous, or mucronate.

FLORETS Basal sterile florets male, or barren; with palea, or without significant palea. Lemma of lower sterile floret similar to upper glume; oblong; 1 length of spikelet; membranous; 5 -veined; dentate; 3 -fid. Fertile lemma oblong; 2–3 mm long; coriaceous; shiny; without keel; 5 -veined. Lemma margins flat. Lemma apex obtuse. Palea coriaceous.

FLOWER Lodicules absent. Anthers 3; anther tip smooth.

DISTRIBUTION Africa: Macaronesia, west tropical, west-central tropical, northeast tropical, east tropical, southern tropical, and western Indian ocean. Asia-temperate: Arabia, China, and eastern Asia. Asia-tropical: India, Indo-China, Malesia, and Papuasia. Australasia: Australia. Pacific: southwestern, northwestern, and north-central. North America: southeast USA and Mexico. South America: Mesoamericana, Caribbean, northern South America, western South America, and Brazil.

NOTES Paniceae. FTEA.

Please cite this publication as detailed in How to Cite Version: 3rd February 2016.