Molecular Phylogeny Of Neckeraceae (S.L.Musci) Inferred From NrDNA ITS Sequence

Neckeraceae, one of the larger families of Hypnobryales,consists of about 10 genera and more than 100 species widespread in the world. The traditional classification of Neckeraceae by Brotherus (192S) has been accepted almost universally. Its systematics position was located between Phyllogoniaceae and Lembophyllaceae and recognized 3 subfamilies (Neckeroideae, Thamnioideae and Leptodontoideae). However, there is lack of consensus with regard to circumscription of family and subfamilies, even to the genera, according to the morphological, anatomical and cell-biological data. DNA is the vector of genetic information. It is the best method in the research of bryophyte molecular systematics based on the direct analysis and alignment of DNA sequences. In an attempt to elucidate the phylogeny of morphologically diverse Neckeraceae, phylogenetic analysis based on the internal transcribed spacers (ITS) of 18—26S rDNA have been conducted using maximum parsimony method (MP) and neighbor-joining method (NJ). 6 genera (5 of Neckeraceae, 1 of Lembophyllaceae) were sampled in this study. Combined with the two related taxa sequences downloaded from GeneBank as outgroup were included in phylogenetic analysis. Phylogenetic trees generated from MP were reasonably in congruence with the result from NJ.The result indicated that Neckeraceae is polyphyletic and the relationship between Neckeraceae and Lembophyllaceae is close. The traditional genera in Neckeraceae fromed two clades, one including the most genera of Neckera, and the other one including genera of Thamniodeae. This supports the morphological study (Norris & Enroth 1990, Wu 2002) to isolate subfamily Thamnioideae from Neckeraceae and recognized as an independent family Thamnobryaceae. Pinnatella is included in the Thamnobryaceae as it formed a sister group with Thamnobryum; The taxa traditionally circumscribed in Homaliodendron are apparently polyphyletic, which nest in the clades formed by genera of traditional Neckeraceae. Homalia trichomanoides is in the clade of Neckeroideae, but Homalia besseri is in the clade of Thamnioideae.