Confirmation of Two Endemic Athyrium Species (Woodsiaceae) in Taiwan

Abstract

Two endemic species, Athyrium tripinnatum Tagawa and A. minimum Ching are confirmed to exist in Taiwan. Their taxonomic descriptions, pictures of living plants, illustrations, and additional notes are provided The most recent checklist of Taiwanese ferns contained 18 species and 2 hybrids in the genus Athyrium (Lu and Yang, 2005). Several scientific names recorded in Flora Reipublicae Popularis Sinicae (Wang, 1999) were not recognized by Lu and Yang. However, based on recently collected materials, we believed that at least two of them, A. tripinnatum Tagawa and A. minimum Ching, should be re-established. In the past, these two species were less- known and usually treated as taxonomic doubtful species in the local flora of Taiwan (Yang and Liu, 2002). Athyrium tripinnatum was based on the materials from Alishan area, Central Taiwan, and Sziyuanyako area, NE Taiwan. Kuo (1985) synonymised it into Athyrium foliolosum T. Moore ex R. Sim., which is a misapplied name of A. fimbriatum (Hook.) T. Moore in Taiwan (Fraser-Jenkins, 1997; Wang, 1999; Liu and Fraser-Jenkins, 2006). Wang (1999) treated it as a distinct species under the section Mackinnoniana (Ching & Y. T. Hsieh) Z. R. Wang, but suggested that the relationship between it and A. foliolosum (section Polystichoides Ching & Y. T. Hsieh) needed further study. Liu et al. (2000) and Lu and Yang (2005) accepted Kuo's classification and regarded it as A. foliolosum (5 A. fimbriatum). After a detailed observation of the morphological characters and spore ornamentation, we confirm A. tripinnatum as a valid species and distinct from A. foliolosum and A. fimbriatum which belong to section Polystichoides. The second species, Athyrium minimum, was based on a single collection by Hancock from Tamshui, north Taiwan (Holotype: Hancock s.n., PE!) in 1881. Three small plants were mounted on a specimen sheet with the largest one less