Revision of the genus Oreomyrrhis Endl. (Apiaceae) in Taiwan

Based on a taxonomic study of the genus Oreomyrrhis in Taiwan three species are recognized, all endemic to Taiwan: O. involucrata Hayata; O. taiwaniana Masamune (previously reduced to synonymy under O. involucrata); and, O. nanhuensis C. H. Chen & J. C. Wang sp. nov. Oreomyrrhis nanhuensis is so far known only from exposed gravelly grasslands on the high-altitudinal region (ca. 3,400-3,700 m) of Mt. Nanhutashan in Taroko National Park. The number and shape of pinnatifid-lobes of leaflets, morphology of involucral bracts, and color of flowers are shown to be the most useful characters for separating Taiwanese species. A key to taxa, discussion of taxonomic characters, description, illustration, geographical distribution, specimens examined, and taxonomic notes are provided for each taxon. The chromosome number of n=6 is observed for the new species O. nanhuensis.