Biosystematic studies on the genus Heloniopsis (Melanthiaceae) II. Two new species from Korea based on morphological and molecular evidence

Abstract

Two new species of Heloniopsis (Melanthiaceae) endemic to Korea are described: H. tubiflora and H. koreana. Heloniopsis tubiflora is similar to H. orientalis, but the former has flowers at anthesis arranged obliquely downward (to pendulous) and has a basally tubular perianth, usually recurved apically (rarely straight) and bluish-purple to purple (but usually whitish near the apex when mature). Heloniopsis koreana differs from H. orientalis in having leaves that are usually spathulate, rarely oblanceolate, with minutely undulate margin, and with tepals slightly saccate to non-saccate at the base. Through comparison of herbarium specimens, we conclude that all plants in Korea comprise these two new endemic species. Based on the molecular phylogeny resulting from combined analyses of trnK 5′ intron and matK DNA sequence data, Heloniopsis comprises three lineages: (1) five species in Japan and Taiwan; (2) H. koreana; and (3) H. tubiflora.