1. Pennisetum clandestinum Hochstetter ex Chiovenda, Annuario Reale Ist. Bot. Roma. 8: 41. 1903.
铺地狼尾草 pu di lang wei cao
Perennial, low, sward forming with slender rhizomes and extensive, stouter, much branched stolons. Vegetative shoots up to 20 cm tall, flowering shoots compact, 2–4 cm tall. Leaf sheaths loose, imbricate, subinflated; leaf blades linear, up to 15 × 0.2–0.5 cm on vegetative shoots, 1–4 cm on flowering shoots; ligule ca. 1.2 mm. Inflorescence reduced to 2–4 spikelets enclosed within the uppermost leaf sheath, only spikelet tips protruding; bristles very delicate, 1/2–3/4 as long as spikelet, scaberulous to ciliolate. Spikelets linear-lanceolate, 13–20 mm, acuminate; lower glume absent; upper glume cufflike, 1–3 mm or sometimes absent; lower floret neuter, lower lemma as long as spikelet, 10–13-veined, palea absent; upper lemma similar; anthers long exserted on threadlike filaments up to 5 cm; stigma simple or shortly bifid, up to 3 cm. Fl. and fr. summer–autumn. 2n = 36.
Naturalized. Taiwan, Yunnan [native to E Africa].
This is a most unusual species of Pennisetum with a highly reduced inflorescence. The bristles must be searched for within the uppermost leaf sheaths. The anthers emerge at night on their long filaments and are visible in the morning as a grayish white haze over the sward.
This species is widely introduced in upland areas of the tropics and subtropics on fertile soils as a pasture and lawn grass (Kikuyu Grass). It has now become an invasive, difficult to eradicate weed in some parts of the world.