Culms 2-80 cm. Blades 2-11 cm long, 4-9 mm wide, margins ciliate basally. Primary branches to 8 cm, widely spaced, often separated by more than their own length. Spikelets with 4-9(20) florets, densely clustered, appressed to and concealing the branch axes; lemmas about 3.5 mm. 2n = unknown.

Cladoraphis cyperoides was once collected on a ballast dump at Linnton (near Portland, Oregon). It is not known to have persisted in North America. The spinelike leaves and panicle branches would probably make an encounter memorable.