Chromosome numbers of 28 taxa in 10 genera of the Ranunculaceae (buttercup family) from the Korean peninsula

Somatic chromosome numbers of 28 Korean native species in the buttercup family are observed and analyzed. The plants include 10 genera with seven endemic taxa to the Korean peninsula, and most of them are the first reports from Korean populations. In particular, the chromosome numbers for the two taxa are reported for the first time: Clematis fusca var. coreana (H. Lév) Nakai (2n = 16) and Thalictrum aquilegiifolium var. sibiricum Regel & Tiling (2n = 42). The Ranunculus type chromosomes (R-type, c.3-12 μm long) are found in Megaleranthis, Actaea, Cimicifuga, Anemone, Clematis, Hepatica, and Ranunculus, whereas Aquilegia and Ranunculus have the Thalictrum type chromosomes (T-type, c.1-1.5 μm long). The two types of chromosomes in Ranunculus, one of the species-rich genera in the family (c.600 species worldwide), suggest that chromosomal differentiation plays an important role in species diversification in the genus. Evaluation of cytogenetic features in a phylogenetic frame is suggested for a better understanding of the evolutionary history of the family.