Carex tsushimensis (Ohwi) Ohwi, a newly recorded species of Cyperaceae from Zhejiang in East China, with morphological comparisons among related species

Carex tsushimensis (Ohwi) Ohwi, is reported as a newly recorded species in China. It is distributed in the Tsushima Islands of Kyushu in Japan and Suichang County of Zhejiang Province in China and grows along streams under forests. With nutlets discoid-annulate at the apex, C. tsushimensis belongs to sect. Mitratae and morphologically resembles C. chinensis Retz., C. sociata Boott, and C. longkiensis Franch. It differs from closed species, C. sociata, by leaf blades 2 - 4 mm wide, spikes 4 or 5, terminal staminate spike distant from lateral ones, and pistillate scales with ca. 3 mm long scabrous awn at apex.