Carex transcaucasica Egor.

Jiménez-Mejías, Pedro, Rodríguez-Palacios, Giovanni E. & Martín-Bravo, Santiago, 2015, Taxonomic notes on some problematic Carex (Cyperaceae) names from SW Asia, Phytotaxa 219 (2), pp. 183-189 : 185

1) Carex transcaucasica Egor.

Carex transcaucasica was described by Egorova (1989: 11) to accommodate the Caucasian populations of what she considered to be distinct C. nigra -like plants. She stressed as differences between C. transcaucasica and C. nigra the relative length of the lower bract (shorter than the inflorescence vs. longer or about as long as the inflorescence, respectively), the utricle indumentum (without papillae vs. papillose), and the basal sheaths color (generally blackpurple vs. brown, reddish or yellowish-brown). Those populations are relatively geographically isolated from the typical C. nigra populations from the neighboring non-Caucasian Russia and Anatolia (cf. Hultén 1950, Nilsson 1986, Jiménez-Mejías et al. 2013).

Samples referable to C. transcaucasica were included in a previous genetic study (Jiménez-Mejías et al., 2013) and found to be embedded within the genetic variation of the typical European forms of C. nigra . Therefore, these Caucasian populations should be better considered as conspecific with C. nigra . Nonetheless, we studied eastern Turkish and Caucasian materials of C. nigra -like plants (Appendix I) and observed that the distinct morphological reproductive characteristics pointed out by Egorova (1999) are rather constant. Differences in the basal sheaths ( Egorova 1999) were found to be inconsistent, probably due to the different conservation of the sheaths in wet and drier soils, as observed in other Carex sect. Phacocystis species (pers. obs.). In any case, the morpho-geographic compartmentalization of the Caucasian populations stresses it as a taxonomic unit within C. nigra (cf. Stuessy 1990). Therefore, we propose combining C. transcaucasica as a C. nigra subspecies (see below).