466. Carex rara Boott, Proc. Linn. Soc. London. 1: 284. 1845.
松叶薹草 song ye tai cao
Carex biwensis Franchet; C. pseudobiwensis Kitagawa; C. rara var. biwensis (Franchet) Kükenthal ex Matsumura.
Rhizome short. Culms densely tufted, 20-30 cm tall, smooth to slightly scabrous above. Leaves shorter to slightly longer than culm, blades 0.5-1 mm wide, flat or involute, smooth or slightly scabrous on upper margins; basal sheaths split into gray-brown fibers. Inflorescence 1-spiked, terminal, androgynous; male part distinct, linear, 4-12 mm, 5-17-flowered; female part oblong to shortly cylindric, 4-10 mm, densely 6-18-flowered. Female glumes brown but diluted on upper margins, oblong-ovate, 1.5-2 mm, 3-veined, apex rounded-obtuse. Utricles horizontally patent at maturity, equaling to slightly longer than glume, broadly ovate to elliptic-ovate, slightly swollen, trigonous, 1.5-2.5 mm, faintly veined or distinctly veined near base, sometimes with rusty spots, base rounded-obtuse, apex gradually attenuate into a short beak, orifice subtruncate. Nutlet tightly enveloped, elliptic to ovate, trigonous, 1-2 mm; style base not thickened, persistent; stigmas 3. Fl. and fr. Apr-May.
Forests, forest margins, banks of mountain streams, shady and wet grassy places; 1000-3300 m. Anhui, Guangdong, Heilongjiang, Hunan, Jiangsu, Jiangxi, Jilin, Liaoning, Sichuan, Xizang, Yunnan, Zhejiang [Bhutan, NE India, Japan, Korea, Nepal].