Schoenoplectus triangularis is a 0.5-1.2m tall perennial herb found in ponds, marshes, or riversides. Sharply 3-ridged stems grow in clusters to build big masses. Leaves are nothing but leaf sheaths as blades have degenerated themselves. Stem tips give birth to single 3-7cm long erect or divaricate bracts, at the bases of which 4-10 spikelets set themselves. The spikelets are 1-2cm long, 4-6mm wide, and in a long oblong shape. Bloom time: August-October.