Pennisetum clandestinum

Name and classification

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 enclosed by fascicle consisting of bristles (disarticulation below fascicle), or caryopsis

Description

Fascicle consists of outer and inner bristles, which are unfused, similar, and number 3–15. Bristles up 15 mm long, antrorsely scabrous; primary bristle usually not conspicuously longer than other bristles. Spikelets of 1 fertile floret and 1 basal sterile floret (usually just the lemma). Spikelets long, narrowly lanceolate, dorsally compressed, 10–22 mm long, 0.8–1.5 mm wide. Lower glume absent or to 0.5 mm long; upper glume hyaline, 0–1.3(3.5) mm long. Sterile lemma membranous, as long as spikelet, 8–13-nerved. Fertile lemma similar to sterile lemma; palea 2–7-nerved. Caryopsis oblong, dorsally compressed, 2–3 mm long (1.5–2.5 per www), dark reddish-brown, semiglossy, surface faintly striate.

Identification considerations

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

fruiting culm

A-B, spikelets enclosed in leaf sheaths; C–E, spikelets

A-B, spikelets enclosed in leaf sheaths; C–E, spikelets

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

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

A, fruiting culm; B–C, spikelet in two views; D, caryopsis in ventral view; E, caryopsis in dorsal view; drawing by Lynda E. Chandler