Taxonomic revision of the fern family athyriaceae in Thailand

Abstract

The most up-to-date account of the Athyriaceae is in Flora of Thailand. This account includes seven genera, i.e. Athyrium, Anisocampium, Cornopteris, Deparia, Diplazium, Hypodematium and Kuniwatsukia. Previously, the taxonomic relationships among genera were ambiguous and not well understood. The existing keys and descriptions are uncertain and do not include some unknown taxa. This research aims to clarify the taxonomic status of this family and its genera based on morphological, anatomical, palynological and molecular data. The results indicated that the types and shapes of frond, scale types, sorus shapes, shapes of vascular bundle and ornamentation of spores are valuable characters for genus and species determination. The molecular results are congruent with other previous results that the Athyriaceae consisted of 5 genera, i.e. Athyrium, Anisocampium, Cornopteris, Deparia and Diplazium. The genus Kuniwatsukia was merged with Anisocampium and the genus Hypodematium was excluded from the Athyriaceae. In all, forty seven species of athyriaceous fern and four species of Hypodematium were recognized. Of these, two new species, namely Hypodematium boonkerdii Pongkai, Li Bing Zhang & Pollawatn and Diplazium thailandicum Pongkai, Boonkerd & Pollawatn were published. Eight new records were reported, i.e. Anisocampium niponicum (Mett.) Hance., Athyrium biserrulatum Christ, A. brevisorum (Wall. ex Hook.) T. Moore, A. pachyphyllum Ching, A. wangii Ching, Diplazium bellum (C.B. Clarke) Bir, D. pallidum (Blume) T. Moore and D. procumbens Holttum. The name: D. bellum (C.B. Clarke) Bir. and D. petelotii Tardieu are lectotypified. Diplazium axillare Ching was considered a synonym of D. bellum (C.B. Clarke) Bir. Key to the genera and key to the species were re-constructed, together with descriptions, line drawings and distribution.