Pacific Island Flatsedge

Caespitose perennial, 20-50 cm, with tillers. Stem 1-2 mm diam., trigonous, stiff, smooth, stem base swollen. Leaves shorter than stem; sheaths to 14 cm, green or yellowish, often with reddish tint, one side scarious with small reddish dots, mouth margin slightly concave; blades up to 30 cm, up to 5 mm wide, rather stiff, sometimes curved, keeled, flat, grey-green, margins smooth or slightly scabrous, apex long-attenuate, acute, trigonous, scabrous. Inflorescence a simple anthelodium, clusters of spikes sessile or on elongated primary branches; primary branches 4-10, up to 40 mm, tubular prophyll up to 7 mm; bracts 4-8, foliose, up to 12 cm. Cluster of spikes 15-25 x 6-10 mm, cylindrical, with more than 100 spirally arranged spikes; rachis winged; glume-like bract 1.5-2.5 mm, acute; glume-like prophyll c. 3 mm, blunt; spikes 3.5-5.5 mm, cylindrical, reflexed, usually 2-flowered (upper not developed); glumes c. 3.5 mm, clasping, mid-nerve area green, margins scarious, prominently nerved, apex blunt. Stamens 3. Nut 2.2-2.3 x c. 0.6 mm, elongated, slightly curved, trigonous, more or less plano-convex, yellow-brown, finely papillose.

Distribution: From Pakistan, NW Himalayas and India to China and Japan, south to N Australia, Hawaii, tropical and subtropical Africa, also in W Indies.

Fl. Per.: July - September; according to Bhandari (1990) "almost throughout the year".

Grasslands, weed in waste lands and fields.

Scirpus cyperoides L., Mantissa 1:8. 1771; Kyllinga sumatrensis Retz., Obs. bot. 4:13. 1786; Mariscus sumatrensis (Retz.) J. Rayn. in Adansonia ser. 2. 15: 110 (1975). Mariscus umbellatus Vahl, Enum. Pl. 2:376. 1806. (p.p. fide Kükenthal 1936). Mariscus sieberianus Nees, Linnaea 9:286, 1835 nom. nudum, see Hutchinson (1936) Fl. W. Trop. Afr.; non Cyperus sieberianus Link (1827) nec ? Sprengel. C.B. Clarke, Ill. Cyper.: tab. 23, fig. 5-7. 1909. U. Kühn, in E. Häfliger (ed.), Monocot weeds (Documenta, Ciba-Geigy): 57 (1982; as Mariscus sumatrensis).

Cyperus cyperoides is a species of sedge that is native to parts of Africa, Asia, Australia and Oceania.