Perennial. Leaves very gradually narrowed to the acute tip, glabrous, smooth except for the retrorsely scaberulous tip, 3-4 mm wide; Inflorescence narrow, 5-15 cm long, consisting of a terminal panicle and about 3 short, lateral ones, the latter single or binate at the nodes, 2-3 cm long, with very short branches;
Asia-Tropical: Malaya (Peninsular Malaysia present), Banka present, Pahang present, S. Sumatra present, Tasek Bera present, W. Borneo present, West Malesia present
West Malesia: Malay Peninsula (Pahang: Tasek Bera), S. Sumatra, Banka, W. Borneo; rare.
HOLTTUM placed S. cyathophora next to S. motleyi, obviously because of its trigonous nuts, and I have followed him by placing the two species in the same section. Indeed, 5. cyathophora has several characters in common with the group to which S. motleyi belongs, especially with S. papuana. However, in the other species of this group the spikelets are either all bisexual or the nut-bearing ones have a well-developed, several-flowered ♂ part, whereas in S. cyathophora this part is reduced to a single ♂ or frequently sterile flower. Also the resemblance in habit to the other species is rather slight.