| Summary: | 碩士 === 國立臺灣大學 === 森林環境暨資源學研究所 === 104 === The liliaceous Tricyrtis Wall. is an East Asian endemic genus of ca. 20 mainly perennial herbaceous species inhabiting humid temperate environments. Previous biogeographic hypotheses were proposed based on inferences of morphology, ecology, and inadequately executed molecular phylogenetic studies with poor supports. Morphologically, the Taiwanese Tricyrtis are distinct and ecologically exceptional in their mainly subtropical distribution. However, the unsettled taxonomy of Taiwanese Tricyrtis as manifested by a long list of nomenclatural also suggests that further study is needed. This study aims to test the biogeographic hypothesis of the genus and improve the taxonomic treatment of Taiwanese taxa by reconstructing phylogenetic relationship based on DNA sequence data. This study reconstructs phylogenetic relationships of Tricyrtis based on DNA sequences of 5 chloroplast regions (rps16 intron, trnL-trnF, atpF-atpH, psbM-ycf6, rpl32-trnL spacer) and nuclear ribosomal intergenic transcribed spacer (ITS). To test species hypothesis of Taiwanese Tricyrtis, haplotype networks were reconstructed using rps 16 intron and ITS. Biogeographic analyses based on molecular phylogenetic relationships show that current species of Tricyrtis is most likely originated in Japan and subsequently dispersed to Korea, China and other regions. Haplotype networks of both chloroplast and ITS sequences of Taiwanese species reveal non-monophyly of T. formosana, T. lasiocarpa, and T. ravenii, suggesting incomplete speciation of the three taxa. The taxonomic treatment of treating them as three varieties under T. formosana is proposed.
|
|---|
