Systematics of Begonia sect. Coelocentrum (Begoniaceae) of China
| Autor: | Shin-Ming Ku, 古訓銘 |
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| Rok vydání: | 2006 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 94 Begonia is a large genus comprising over 1,500 species throughout tropical and subtropical Asia, Africa and America. Begonia sect. Coelocentrum was established by Edgar Irmscher in 1939, based mainly on the parietal placentation and geographical distribution. Plants of Begonia sect. Coelocentrum are confined to the Karst areas in southern China and northern Vietnam. Most of them are rare and/or highly localized. They occur exclusively on semishady to shady limestones hills or in caves at elevations of ca. 100-1,400 m. Many are highly ornamental, displaying an amazing variety of shapes, colors, patterns and textures in their leaves. This study provides a systematic account of Begonia sect. Coelocentrum that are naturally distributed in China. Using 85 OTUs and 204 characters from morphology, chromosome numbers and distributional ranges, a numerical analysis was conducted. PCA weighting method was applied. As a result, 51 taxa including 47 species and 4 additional varieties were recognized for Begonia sect. Coelocentrum in China. All but B. masoniana are endemic to China. Begonia pseudodryadis is distinct enough to be considered the only member of the new subsection Pseudodryades here erected. Begonia jingxiensis, B. mashanica, and B. suboblata, formerly misplaced in sect. Diploclinium, were transferred to sect. Coelocentrum. Begonia mashanica was sunken as a variety of B. jingxiensis. Begonia umbraculifolia var. flocculosa was elevated to the species rank. In addition, seven new species and an additional new variety were here described, namely, B. bamaensis, B. chongzuoensis, B. detianensis, B. fengshanensis, B. hurunensis, B. koi, B. linguiensis and B. picturata var. wanyuana. Through intensive taxonomic studies and field inventories, the species number of Begonia sect. Coelocentrum more than doubled from four years ago when this study started. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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