Japan Flora: Rhizomes covered with yellow-brown fibrous remains of leaf-sheaths; leaves narrowly linear, nearly as long as the culms; basal sheaths yellow-brown; terminal staminate spikelet 5-10 mm. long; lateral pistillate spikelets globose, 3-6 mm. across; bracts setaceous; pistillate scales elliptic- to oblong- ovate, yellow-brown with a lighter colored margin, short-cuspidate; perigynia narrow-obovate, 2.5-3 mm. long, trigo- nous, almost nerveless except the lateral 2 keels, short-stipitate at base; achenes elliptical; otherwise with the characters of C. oxyandra.

Honshu (Mount Tateshina, Shinano Prov.); rare.