Cenchrus purpureus (Schumach.) Morrone

Veldkamp, J. F., 2014, A revision of Cenchrus incl. Pennisetum (Gramineae) in Malesia with some general nomenclatural notes, Blumea 59 (1), pp. 59-75 : 70

14. Cenchrus purpureus (Schumach.) Morrone

Cenchrus purpureus (Schumach.) Morrone in Chemisquy et al. (2010) 129. — Pennisetum purpureum Schumach. (1827) 44. — Type: Thonning 355 (holo C; BM).

Perennials. Culms erect to geniculate at base, rooting in the decumbent nodes, stoloniferous (stolons up to 1 m long), rhizomatous, 1–4(–6) m long, solid, nodes glabrous or rarely pilose. Ligule a setose rim, c. 0.2 mm long, setae 2–3 mm long. Blades flat, 16–150 cm by 4–40 mm, margins spinulose. Peduncle pilose below the panicle. Panicle exserted, many-spikeled, 7–30 cm long, common axis pubescent. Involucre stipitate, disarticulating at base. Bristles many, rather stiff, the inner ones pilose, one distinctly longer than the others, 5 –12 mm long, longest bristle 14–25 mm long. Spikelets 1–4 within the involucre (1–2 bisexual, the others male, shortly pedicelled, 1-flowered), pedicelled, the bisexual ones 5.5–6.5 mm long. Lower glume 0–1 mm long, 0–0.1 times as long as the upper glume; upper glume 1–3 mm long, 0–1-nerved. First lemma usually epaleate, sterile, sometimes paleate, male, rarely bisexual, acute to acuminate, membranous, 3–5-nerved, glabrous, nerves scaberulous; second lemma 5.5–6.5 mm long, acuminate, membranous. Anthers 2.25–3.75 mm long, apex penicillate. 2n = (14, 21, 27) 28, 32, 56.

Distribution — Native to tropical Africa, cultivated and escaping elsewhere, in Malesia widely cultivated and escaping along roadsides, fallow fields, etc.

Habitat — Pioneering species in wet, disturbed sites, stream banks, roadsides, fallow fields, gaps in tropical rain forest, but also drought tolerant, 0–1900 m altitude.

Uses — Cultivation started in southern Africa. Grown below 1400 m altitude as a valuable forage crop, but will not stand intensive grazing; also as carp food, windbreaks, thatching, etc. Suitable for paper making. Culms used for fences, walls of huts, etc. When uncontrolled may choke young tree and sugarcane plantations.

Young leaves are rich in protein, carbohydrates, fat, vitamins, but cyanic acid has been reported.

Extracts are strongly diuretic.An infusion of foliage and culms is used in anuria, a root decoction for blennorrhoea, a leaf infusion for gargle and mouthwash. Sap from young shoots is used for cataracts, healing wounds, and ear trouble. The caryopses are used to cure headache.

Vernacular names — Elephant grass, Merker grass, Napier fodder or -grass.

Notes — A collection from near Wanariset, SE Borneo (Ambriansyah 1419, L, WAN) perhaps belongs here, but differs in a number of features. Unfortunately anthers are lacking: Ligular setae c. 1.5 mm long. Margins of blades scaberulous. Longest bristle 12–13 mm long. Lower glume c. 1.35 mm long, acute, 0.28–0.3 times as long as the 4.65–4.9 mm long, 5-nerved upper glume.