世界蓑藓属植物分布式样及其系统演化和生物地理学意义

Geographical Distribution Pattern of Macromitrium in the World and Its Biogeographical Significance

蓑藓属(Macromitrium)是苔藓植物分类、生态学研究及生物多样性保护的重要类群。以"Index Muscorum"中的14个藓类植物地理分布单位为分析区域,基于标本信息和相关文献,在分类修订的基础上,统计了世界蓑藓属274种植物在14个地理单位的分布数据,基于这些数据,应用聚类分析和除趋势对应分析法,分别得到了14个地理单位的聚类图和三维空间图,直观展示了世界蓑藓属植物的地理分布格局。发现蓑藓属植物区系在东亚(As2)、大洋洲(Oc)、南亚和东南亚(As3,As4)、非洲(Afr2,Afr3,Afr4)、中美洲—南美洲(Am2,Am3,Am4,Am5)、澳洲(Austr1,Austr2)存在区域分化。热带亚洲和热带美洲是世界蓑藓属植物的多样化中心。除长柄蓑藓(M.microstomum(Hook.&Grev.)Schwgr.)在14个地理单位均有分布外,大部分种类分布限于少数或仅一个地理单位。蓑藓属植物在东亚、热带亚洲、热带美洲和澳洲不仅种类存在明显分化,而且形态性状也有区域特点。根据蓑藓属植物的现代分布式样,探讨了其系统演化和生物地理学意义。

The genus Macromitrium（Orthotrichaceae, Bryophyta） is an important taxon in bryological systematics, ecology and biological conservation. On the basis of our taxonomical revision of the genus, we got the distribution data of 274 species of the genus in 14 geographical unites（suggested by ＂Index Muscorum＂） in the world. By using Clustering Analysis and Detrended Correspondence Analysis （DCA）, we got a dendrogram and a three-dimensional scatter plots to reveal the distribution pattern of the genus visually. The results showed a distinctive floristic differentiation of Macrornitrium among As2, Oc, As3-4, Mr2-3-4, Am2-3-4-5, and Austrl-2, with highest diversity in Tropical Asia and Tropical America. Except M. microstomum（Hook. ＆ Grey. ） Schwagr. , all other species were recorded from a single or a few geographical unites. Among different global regions, Macromitrium differentiated not only in its floristic elements, but also in their morphological characters. We discussed the systematic and biogeographical significances of the genus according its global distribution pattern.