Perennial with annual aerial parts. This perennial species lacks a true rhizome and has elongate, subterranean propagative stems (soboles) with collateral vascular bundles. In its aerial parts it resembles some species of S. dregeana in having unbranched glomerate-spicate inflorescences. The achenes are tuberculate and differ from the tuberculate achenes of some specimens of S. dregeana in that the distal tubercles are no more prominent than the proximal ones, and in having a pattern of ridges, troughs and fine transverse bars between the stipe and body of the achene. At high magnification it is possible to discern a pattern of fine raised, more-or-less horizontal ridges on the crests of the tubercles created by the proud-standing, silicified radial walls of groups of horizontally elongated epidermal cells. Such a pattern is absent from the crests of the tubercles of the achene of S. dregeana.
Perennial. Rhizome none. Soboles trigonous, 1-1.5 mm thick, hard, whitish with wine-red blotches; scales purple-red. Culms 0.18-1.01 m tall, glabrous or glabrescent. Leaves 1.1-2.6 mm broad, glabrous adaxially, sparsely hirsute abaxially; mouth of sheath truncate, hirsute. Inflorescence unbranched, 20-65 mm long. Glomerules 2-6, of 2-6 sessile spikelets. Bracts glabrous, the margins sparsely hirsute, shortly awned, pale stramineous with red striae, Spikelets c.4 mm long. Glumes 1.7-2.6 mm long, glabrous or sparsely hirsute or midrib stramineous with red striae. Achene subglobose, 1.5-1.8 x 1.2 mm, glabrous, undulate-tuberculate, with a series of deep horizontal troughs separated by horizontal and vertical ridges at junction of stipe and body, grey.