Rhynchospora robusta Boeckeler

Perennial, glabrous except the inflorescence branches; culms leafy, 6-10 dm. high; leaves shorter than the culms, about 6 mm. wide, prominently striate, glaucous; cymes much-branched, large and broad, the acute glaucous-brown spike-lets numerous, 7 mm. long; achene obovate, biconvex, 2.5 mm. long, stipitate, pale brown, the surface spinescent-papillose and lightly transversely ridged, style-base nearly as long as the achene, obtuse, glaucescent, the two lateral lobes promi-nent; bristles none.