Chrysosplenium suzukaense (Saxifragaceae), a New Species from Yoro and Suzuka Mts., Central Honshu, Japan

Abstract

A new species, Chrysosplenium suzukaense, from the northern part of the Yoro Mountains and Suzuka Mountain Range, Central Honshu, Japan, is described. Chrysosplenium suzukaense belongs to ser. Macrostemon, and is most similar to C. fauriei in the C. fauriei group (C. fauriei, C. kiotense and C. nagasei) distributed on the Sea of Japan side of Japan. However, C. suzukaense differs from C. fauriei in always having four stamens opposite the calyx lobes (vs. eight stamens), and smaller stature and flowers. The distribution of C. suzukaense is nearer the Pacific Ocean side, but in an area of much snow in winter, showing climatic conditions similar to the Sea of Japan side. The rosette-like basal leaves retained until end of the flowering time in C. suzukaense and the C. fauriei group may be an adaptation to the Sea of Japan side environment, especially to a much snow. The chromosome number, representing the karyotype, of C. suzukaense was confirmed to be 2n=22, and similar to other members of the C. fauriei group.