Carex tatsiensis (Franch.) Kükenthal (1909: 563) .

≡ C. ferruginea Scopoli (1772: 225) var. tatsiensis Franchet (1898: 55) . Type:— CHINA. Setchuen [Sichuan], Ta tsien lou [Kangding], Kiala, J.A. Soulié 834 (holotype: P-00301062!; isotype: E-00386807!).

= Carex kwangtoushanica K.T. Fu (1976: 447) . syn. nov. Type:— CHINA. Shaanxi, Laoyu, Mt. Guangtou, 24 Jul. 1962, P.C. Kuo 4653 (holotype: WUK!).

From the protologue of Carex ferruginea var. tatsiensis Franch. (1898: 55) (≡ C. tatsiensis, placed in Haematostoma clade in Roalson et al. 2021) and C. kwangtoushanica K.T. Fu (1976: 447, not treated by Roalson et al. 2021), the latter is distinguished from the former in having rhizomes short (vs. rhizomes long and stoloniferous), and terminal spikes 2 or 3 and linear-cylindric (vs. terminal spike solitary and linear). Remarkably, in Flora of China, the authors divided section Aulocystis into two subsections by utricles glabrous or hispidulous, and placed C. kwangtoushanica and C. tatsiensis in each of the two subsections.

We examined the holotype of Carex tatsiensis in P and an isotype in E. The rhizomes are frequently short (three individuals), rarely long with stolons (one individual), and terminal spikes 1–5, linear to linear-cylindric (Figure 4: A, B). Those of C. kwangtoushanica range into the variation of C. tatsiensis . The utricle bodies of C. kwangtoushanica and C. tatsiensis are both glabrous. Accordingly C. kwangtoushanica was reduced as a synonym.