Chromosome number of Carex siderosticta in Korea (Cyperaceae)

Abstract

Carex siderosticta Hance is characterized by long rhizomes, broad leaves, and wide distribution in East Asia; it is a member of the Siderostictae clade, which is the basal group in the genus. Among the species, diploids (2n = 2x = 12) and tetraploids (2n = 4x = 24) have been reported from Korea (2x), China (4x), Japan (2x and 4x), and Russia (4x). To clarify the ploidy levels in Korean C. siderosticta, 17 populations were sampled and analyzed. Among the 17 populations, diploids (2n = 2x = 12) were observed in 16, and one population counted triploids (2n = 3x = 18). For the first time, triploidy in the species was observed. It can be hypothesized that the triploids are derived by the fertilization of reduced and unreduced gametes of diploids or reduced gametes of diploids and tetraploids. Further investigations of the molecular and cytological characters should be conducted to understand polyploidization in this species.