Taxonomic revision of fern genus Tectaria Cav. (Tectariaceae) in Thailand

Abstract

Due to a great number of variations in morphological characters and the ambiguity of some diagnostic characters using in a key and descriptions of Tectaria Cav. in the Flora of Thailand leading to confusing in species determination in most Thai herbaria. Moreover, some new taxa were added to the Thai Flora without any amended key-to-species. On a worldwide basis the genus boundary of Tectaria was extended to include some related genera based on recent phylogenetic studies. Thus, the preceding taxonomic information of Thai Tectaria was inappropriate. The objective of this research was to revise the genus Tectaria in Thailand based on the existing herbarium specimens in Thailand and abroad, together with some additional field collections. Intensive morphological, anatomical and palynological examinations were carried out, especially in pair/group of confused species. Frond and scale characters, venation patterns, sori distribution, and perispore ornamentation are important and useful characters for species delimitation. Fifty-four species are recognized which included five species of the previously recognized Heterogonium C. Presl and Quercifilix Copel. Among these 11 species are new records, viz. T. acrocarpa (Ching) Christenh., T. aurita (Sw.) S. Chandra, T. chattagramica (C.B. Clarke) Ching, T. hymenophylla (Parish ex Bedd.) Holttum, T. kehdingiana (Kuhn) M.G. Price, T. multicaudata (C.B. Clarke) Ching, T. poilanei Tardieu, T. subpedata (Harr.) Ching, T. subvariolosa S.Y. Dong, T. trichotoma (Fée) Tagawa and T. zippelii S.Y. Dong, nine species tend to be new to science and 11 species are endemic to Thailand. Lectotypification of 16 species and epitypification of T. keckii are proposed. A key to the species is provided, as well as descriptions, illustrations, photograph, synonymy, and a list of examined specimens for each species. The evaluation of some critically endangered species are discussed.