Pennisetum pedicellatum Trin.

Family: Poaceae,  Tribe: Paniceae

Common names:  kyasuma grass, kyasuwa grass

Disseminule 

Fertile floret, or involucre of bristles enclosing 1-3(5) spikelets; disarticulation below involucre.

Description

Spikelet cluster subtended by involucre of 15-25 unfused bristles; bristles antrorsely barbed and plumose, 5-30 mm long, with one conspicuously longer bristle, surrounded by outer ring of shorter smooth bristles. Spikelet cluster of 1 sessile and usually at least 1 pedicellate spikelet. Spikelets of 1 fertile floret and 1 basal sterile floret. Spikelets lanceolate, slightly dorsally compressed, 3.4-6 mm long, 0.6-1 mm wide. Glumes hyaline to membranous; lower glume reduced, upper glume and sterile lemma as long as spikelet; sterile lemma trilobed. Fertile floret lanceolate, 2-3 mm long, 0.6-1 mm wide; fertile lemma and palea coriaceous, glossy, translucent, fertile lemma 5-nerved. Caryopsis lanceolate, dorsally compressed, 0.5-2.5 mm long.

Identification remarks

Pennisetum pedicellatum belongs to a unique section of the genus with a trilobed sterile lemma. P. pedicellatum spikelets are in clusters of 1-3(5) in the involucre, lower glume length is at least 50% of spikelet. See

Pennisetum clandestinum Hochst. ex Chiov.

Pennisetum macrourum Trin.

Pennisetum polystachion (L.) Schultes.

Distribution

Tropical Africa, South Africa, Asia (India, Malaysia, Philippines, Thailand), Australia, Fiji, United States.

Habitat

Drier sites, savannahs and woodland margins; a weed in croplands, grasslands, waste places.

General information

Pennisetum pedicellatum is an erect or geniculate annual or perennial grass, to 150 cm tall. It has been introduced as a pasture grass in Asia, Australia and the Americas. However, it invades croplands and cleared lands, and is difficult to eradicate.

Involucres enclosing spikelet(s)

Florets in dorsal view showing lemma (top) and ventral view showing palea (bottom)

Caryopses in ventral view (left) and dorsal view (right)

A, Involucre of bristles enclosing spikelet(s); B, cluster of two spikelets in involucre (some bristles removed); C-D, floret in two views; E, caryopsis in ventral view; F, caryopsis in dorsal view

drawing by Lynda E. Chandler