Molecular Phylogeny Of Thuidiaceae (Musci) And Related Taxa

Thuidiaceae, one of the larger families of Hypnobryales, consists of about 19 genera and nearly 311 species widespread in the world. There are 17 genera in china. The traditional classification of Thuidiaceae by Brotherus (1925) has been accepted almost universally. Its systematic position was located between Leskeaceae and Amblystegiaceae and recognized 4 subfamilies (Heterocladioideae, Anomodontoideae Euthuidioideae, Helodioideae). However, there is lack of consensus with regard to circumscription of family and subfamilies, even to the genera, according to the morphological and anatomical data. In an attempt to elucidate the phylogeny of morphologically diverse Thuidiaceae, phylogenetic analysis based on the internal transcribed spacers (ITS) of 18S-26S rDNA have been conducted using maximum parsimony method (MP) and neighbor-joining method (NJ). Eleven genera (7 of Thuidiaceae, 4 of Leskeaceae) were sampled in this study. Combined with the related taxa sequence downloaded from GenBank, about 50 taxa, representing Thuidiaceae, Leskeaceae and Amblystegiaceae were included in phylogenetic analysis. Phylogenetic trees generated from MP were reasonably in congruence with the result from NJ. The traditional genera in Thuidiaceae formed two clades, one including the most genera of Heterocladioideae and Euthuidioideae, and the another one including genera of Anomodontoideae. This supports the morphological study (Noguchi 1985, Buck&Vitt 1990, Wu 2002) to isolate subfamily Anomodontoideae from Thuidiaceae and uplift it to be an independent family Anomodontaceae; Based on the genera Amblystegium, the most genera in Amblystegiaceae form a monophyletic clade, except for the Calliergon, which plus several taxa to form a monophyletic . The result is consistent with the conclusion made by Alain Vanderpoorten(2002) that traditionally circumscribed Amblystegiaceae are polyphyletic and include the Amblystegiaceae s.str. and Calligeronaceae fam. nov. The genera traditionally circumscribed in Leskeaceae are apparently polyphyletic, which nest in the clades formed by genera of traditional Thuidiaceae.