A morphological study of Korean Astilbe (Saxifragaceae)

Abstract

Abstract To understand the variation limit of taxomomic characters, the Korean Astilbe species were reviewed exomorphologically. Based on the results, it was revealed that two types of trichomes on young shoots and inflorescence rachises are most important characters for identifying Astilbe species: multicellular long nonglandular hair and multicellular short glandular hair. On the basis of type specimens, original descriptions, and relevant articles, Astilbe chinensis is a more reasonable scientific name than Astilbe rubra. The restricted natural habitats, such as high rocky terrains of Mt. Halla-san, shorter or smaller vegetative organs, distinctly shorter primary and secondary inflorescence rachises, and larger size of\xa0flowers and floral organs made it possible to distinguish Astilbe\xa0taquetii from other species. Astilbe\xa0koreana is also verified, with its identity distinguished from other species by having one rhizomatous leaf and dense multicellular short glandular hairs on the young shoot, stem, and inflorescence. Because the angle between the secondary leaf axes and the extent to which the secondary inflorescence axis droops showed great variations among species and even in a species, it could not be used as diagnostic characters.