Cyperus alternifolius (PROSEA)

Cyperus flabelliformis Rottb., C. involucratus Rottb.

• Umbrella plant (En)
• Indonesia: papayungan (Sundanese), mansiang babunga (Sumatra)
• Thailand: kok rangka (Bangkok)
• Vietnam: thủy trúc.

Native from Arabia to South Africa and the Indian Ocean Islands. In South-East Asia and elsewhere in the tropics cultivated as a fibre plant (the Philippines, China, Hawaii, Argentina, the Canaries) or ornamental (Java). Sometimes escaped from cultivation, e.g. in Indonesia (Sumatra, Java), the Philippines, Australia, New Caledonia and Hawaii.

The stems are used for mat-making in the Philippines. Pulping experiments have shown that the stems can be pulped with yields of 50% or more at 100°C and atmospheric pressure. The strength of unbeaten pulp was similar to that of beaten softwood pulps, but drainage was very slow. Reasonably strong paper was obtained by blending with unbeaten wood pulps. C. alternifolius is widely grown as an ornamental, also indoors in temperate climates. In Kenya it is also used as forage and, possibly because the plant contains alkaloids, in Africa decoctions are taken to cure digestive system disorders and fevers, and ash is applied to disinfect wounds.

A perennial herb with a short woody rhizome; stem subdensely tufted, obtusely trigonous to terete, 50-170 cm × 5-10 mm. Inflorescence umbel-like, 15-30 cm in diameter; involucral bracts many, leafy, 20-50 cm × 5-15 mm, stiff; primary rays numerous, 7-10 cm long, each bearing 4-10 secondary rays up to 1.5 cm long; spikelets in clusters of 3-10, elliptical, 3-9 mm × 2-3 mm, densely 5-40-flowered; glumes ovate, 2 mm × 1.5 mm. Fruit a nut, 3-sided, 0.6-0.8 mm × 0.5 mm, brown. In South-East Asia C. alternifolius is found naturalized at altitudes up to 1200 m, in waste places, wet-rice fields and along river banks and ditches.

Two subspecies are sometimes distinguished:

• subsp. alternifolius . Native to Madagascar, Mauritius and the Mascarenes, not growing wild elsewhere; distinctive characteristics: stem with homogeneous chlorenchyma, involucral bracts glabrous, glumes lanceolate, fruits longer than 1 mm.

• subsp. flabelliformis (Rottb.) Kük. Native to tropical Africa and Arabia, widely cultivated and escaped; in South-East Asia only this subspecies occurs; distinctive characteristics: stem with heterogeneous chlorenchyma, involucral bracts scabrid, glumes broadly ovate, fruits shorter than 1 mm.

If these subspecies are elevated to species rank, which has sometimes been done, the correct names become C. alternifolius and C. involucratus Rottb. respectively, and the South-East Asian plants would be named C. involucratus . Here the one-species concept has been chosen.

6, 7, 39, 47, 66, 96, 96a, 158, 160, 161, 185, 187.

M. Brink, P.C.M. Jansen & C.H. Bosch