Pennisetum purpureum

HABIT Perennial. Stolons present. Culms erect, or geniculately ascending; robust; 100–600 cm long. Ligule a fringe of hairs; 3–5 mm long. Leaf-blades 30–120 cm long; 20–40 mm wide. Leaf-blade margins cartilaginous; scaberulous.

INFLORESCENCE Inflorescence a panicle. Peduncle pubescent above.

Panicle spiciform; linear; 7–30 cm long; 1–3 cm wide. Primary panicle branches accrescent to a central axis; with lateral stumps on axis, or with sessile scars on axis. Panicle axis terete; pubescent; bearing deciduous spikelet clusters.

Spikelets subtended by an involucre. Fertile spikelets sessile; 1 in the cluster. Companion sterile spikelets pedicelled; 0–4 in the cluster. Involucre composed of bristles; oblong; 8–16 mm long; base obtuse. Involucral bristles deciduous with the fertile spikelets; numerous; with one conspicuously longer bristle; 10–40 mm long; terete; flexible; glabrous, or ciliate.

STERILE SPIKELETS Companion sterile spikelets well-developed; male; lanceolate; dorsally compressed; 4.5–7 mm long; as long as fertile; deciduous with the fertile. Companion sterile spikelet lemmas 2; exserted from glumes.

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets lanceolate; dorsally compressed; 4.5–7 mm long; falling entire; deciduous with accessory branch structures.

GLUMES Glumes both absent or obscure, or one the lower absent or obscure; shorter than spikelet; thinner than fertile lemma. Upper glume lanceolate, or ovate; 0.75–3 mm long; 0.25–0.5 length of spikelet; membranous; without keels; 0–1 -veined. Upper glume primary vein absent, or distinct. Upper glume apex obtuse, or acute.

FLORETS Basal sterile florets male, or barren; with palea, or without significant palea. Lemma of lower sterile floret lanceolate; 0.66–1 length of spikelet; chartaceous; (1–)2–5(–7) -veined; acute, or acuminate. Fertile lemma lanceolate; 5–7 mm long; coriaceous; shiny; without keel; 5–7 -veined. Lemma margins flat; eciliate. Lemma apex acuminate. Palea coriaceous.

FLOWER Lodicules absent. Anthers 3; 2–3.1 mm long; anther tip penicillate. Styles connate below.

FRUIT Caryopsis with adherent pericarp; ellipsoid, or ovoid; dorsally compressed; concealed by floret; 1.8–2.2 mm long.

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

NOTES Paniceae. FTEA.

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