武义薹草 wu yi tai cao

Rhizome short. Culms tufted, 40-65 cm tall, acutely trigonous, smooth, scabrous above, clothed at base with dark brown bladeless sheaths, some sheaths disintegrating into reticulate fibers. Leaves longer than culm, blades linear, 3-5 mm wide, flat. Involucral bracts leaflike, lowest one surpassing inflorescence. Spikes 4; terminal spike male, narrowly cylindric, ca. 50 × 2 mm; lateral spikes female, rarely with male flowers at base or apex, cylindric, 45-50 × 4-5 mm. Female glumes ferruginous, oblong, ca. 2.8 mm, green 3-veined costa forming a short awn at subrounded apex. Utricles slightly longer or broader than glume, elliptic, ca. 3 × 2 mm, densely papillose, conspicuously veined, base broadly cuneate, apex abruptly contracted into a short beak, orifice entire. Nutlets brown, slightly loosely enveloped, obovate, ca. 2 × 1.5 mm; stigmas 2. Fl. and fr. Apr.

Pond margins, slopes. Zhejiang [Japan].