Cenchrus polystachios

Veldkamp, J. F., 2014, A revision of Cenchrus incl. Pennisetum (Gramineae) in Malesia with some general nomenclatural notes, Blumea 59 (1), pp. 59-75 : 69-70

12. Cenchrus polystachios (L.) Morrone

Cenchrus polystachios (L.) Morrone in Chemisquy et al. (2010) 129. — Panicum polystachion L. (1759) 870, quoad descr., excl. Gramen vulpinum Rumph. — Pennisetum polystachion Schult. (1824) 146. — Gymnotrix polystachya Sw. ex Trin. (1826) 66. — Lectotype: P. Browne in Herb. Linn. 80.4 (holo LINN,microfiche IDC), designated by Van der Zon (1992).

Cenchrus setosum Sw. (1788) 26. — Pennisetum setosum Rich. (1805) 72. — Pennisetum polystachion (L.) Schult. subsp. setosum Brunken (1979) 63. — Type: Swartz s.n. (holo S).

Pennisetum polystachion (L.) Schult. forma viviparum Fosberg & Sachet (1984 ‘1982’) 86. — Type: Fosberg 59748 (holo US; BISH) .

Pennisetum holcoides auct. non Schult.

Pennisetum indicum auct. non Kuntze.

For further synonymy see Soreng & Pennington (2003).

Annuals or perennials. Culms erect to geniculate at base, not rooting in the decumbent nodes, not stoloniferous, shortly rhizomatous, 1–3 m long, lower ones hollow, upper ones filled with marrow, nodes glabrous. Ligule a setose rim, setae 1.3–3.5 mm long. Blades flat, 5–45 cm by 4–18 mm, margins scaberulous. Peduncle glabrous below the panicle. Panicle exserted, many-spikeled, 5–25 cm long, common axis scaberulous. Involucre not stipitate, disarticulating at base. Bristles many, rather stiff, densely crinkly pilose around the spikelet (some outer ones excepted), a few distinctly longer than the others, 5–11 mm long, longest bristle 10–25 mm long. Spikelets 1 within the involucre, sessile, 3.15–4.5 mm long. Lower glume 0–1 mm long; upper glume 3.2–4 mm long, faintly 5-nerved. First lemma paleate, sterile, erosely truncate, membranous, faintly 5-nerved, glabrous, nerves smooth; second lemma 1.8–2.25 mm long, acute, chartaceous. Anthers 1.1–1.8 mm long, apex glabrous. 2n = 18, 36, 54, also 32, 34, 45, 52, 53, 56, 63, 78.

Distribution — Originally from tropical Africa, introduced elsewhere, Malesia: Malay Pen. (widespread), Singapore (already in cult. in 1929!), Sumatra (Lampung), Java (Bogor), Sabah, Lesser Sunda Isl. (Timor), Philippines (Cuyo Isl.: Pamalican Isl., Luzon, Mindanao, Mindoro, Palawan), New Guinea: Irian Jaya (Jayapura), Papua New Guinea (Manus, Morobe). Undoubtedly much more widespread.

Habitat — Roadsides, abandoned fields, rubber-, oil palm-, and sugar cane plantations, upland rice fields, replacing Imperata cylindrica (!), 0–900 m altitude.

Uses — Introduced as a fodder grass, but developed into a major pest. Culms used for thatching and the weaving of mats. Juice from young culms promotes healing of cuts, wounds, and sores, conjunctivitis. Decoction of the root is antiemetic, of the inflorescence against ear aches, a poultice of the grain for pain in the sides, dislocation of the shoulder, internal pains.

Vernacular names — Barra grass, Feather pennisetum, Matting grass, Mission grass.

Notes — The reference to this species by Miquel (1857) as P. holcoides seems a misidentification of Rumphius’s “ Gramen caricosum prima species ” which is Imperata cylindrica (L.) P.Beauv.

Gramen vulpinum Rumph. cited by Linnaeus (1759) belongs to Setaria parviflora (Poir.) Kerguélen.

PNH 20447 (Mendoza) has proliferating spikelets, which form has been described by Fosberg & Sachet (1984 ‘1982’) as forma viviparum .