Pennisetum clandestinum Hochst. ex Chiov.

Family: Poaceae,  Tribe: Paniceae

Common names:  kikuyu grass

Disseminule 

Several spikelets ((1)2-4(6)) enclosed within subtending leaf sheath, spikelet with involucre, or caryopsis. Disarticulation at base of involucre.

Description

Spikelets subtended by involucre of 3-15 unfused bristles 4-15 mm long, antrorsely barbed. Spikelets of 1 fertile floret and 1 basal sterile lemma. Spikelets long, narrowly lanceolate, dorsally compressed, 10-20 mm long, 0.8-1.5 mm wide. Lower glume absent, or rarely both glumes absent; upper glume hyaline, 1.3-3.5 mm long. Sterile lemma membranous, as long as spikelet, 8-13-nerved. Fertile lemma similar to sterile lemma. Caryopsis oblong, dorsally compressed, 2-3 mm long (1.5-2.5 per www), dark reddish-brown, semiglossy, surface faintly striate.

Identification remarks

The cluster of spikelets enclosed in uppermost leaf-sheath is a distinguishing characteristic of P. clandestinum. Spikelets are solitary in the involucre. See

Pennisetum macrourum Trin.

Pennisetum pedicellatum Trin.

Pennisetum polystachion (L.) Schultes.

Distribution

Africa, Israel, Asia (India, China, Taiwan, Southeast Asia), Australia, New Zealand, Pacific Islands, tropical and subtropical South America, parts of Central America, Jamaica, and Mexico; United States.

Native to tropical eastern Africa.

Habitat

Humid tropics or subtropics. A weed of tended areas, crop land, orchards, forested sites.

General information

Pennisetum clandestinum is a low-growing stoloniferous perennial, to 30 cm tall. Reproduction is primarily vegetative, by its extensive network of stolons and rhizomes. It will only flower and set seed under certain conditions, such as defoliation. This grass has been used widely as a pasture and turfgrass plant, and for erosion control. This has allowed it to quickly spread, invading agricultural fields. It has become a serious weed of crops in many countries.

Fruiting culm

A,B, Spikelet(s) enclosed in leaf sheaths; C-E, spikelets

Caryopses in dorsal view (top) and ventral view (bottom)

A, Fruiting culm; B-C, spikelet in two views; D, caryopsis in ventral view; E, caryopsis in dorsal view

drawing by Lynda E. Chandler