99. Carex sociata Boott, Mem. Amer. Acad. Arts, n.s. 6: 420. 1858.
伴生薹草 ban sheng tai cao
Carex atronucula Hayata; C. daibuensis Hayata; C. ligata Boott ex Bentham var. strictior (Kükenthal) Kükenthal; C. nexa Boott ex Bentham var. strictior Kükenthal; C. transalpina Hayata; C. uraiensis Hayata.
Rhizome short. Culms tufted, 20-50 cm tall, slender, smooth. Basal sheaths bladeless, dark brown, disintegrated into fibers. Leaf blades 3-6 mm wide, flat, rather stiff to herbaceous, with rather short sheaths. Lower 2-4 involucral bracts leaflike, nearly equaling inflorescence, lowest one with rather long sheath. Spikes 4-8, spaced or upper 2 or 3 contiguous; terminal spike male, green, linear-cylindric, 1.5-3 cm; lateral spikes female, rarely androgynous or very rarely with a few male flowers at base, single or binate at each node, green, cylindric or oblong-cylindric, 15-40 × 3-4 mm, densely flowered; peduncles slightly exserted or enclosed in involucral bract sheaths. Female glumes oblong, ca. 3 mm (including awn), membranous, 1-3-veined green costa excurrent into a short awn 0.7-1 mm. Utricles elliptic-fusiform, trigonous, ca. 2.5 mm, puberulent, many veined, abruptly contracted at both ends, apex shortly beaked, orifice shallowly 2-toothed. Nutlet tightly enveloped, ca. 1.5 mm, trigonous, abruptly contracted at both ends, apex discoid-annulate; style base thickened; stigmas 3.
Grasslands, forests. Taiwan [Japan].
No specimens have been seen by the present authors. The description is largely taken from Fl. Taiwan (5: 338-340. 1978).