黄荆种以下分类群的聚类与演化趋势分析

Analysis on clustering and evolutionary trends of infraspecific taxa of Vitex negundo L

通过数量聚类和演化趋势分析的方法,讨论了以前的分类学处理和演化趋势。研究结果表明,黄荆种以下分类群组成2个类型:花序展开型,包括变型laxipaniculata和变型alba,和花序狭窄型,包括其他5个变种。在黄荆中,花序类型表现出一定的分类学重要性,将变型laxipaniculata和变型alba归并为黄荆异名的分类处理在本研究中没有被支持。本文还通过原始性状与衍生性状的比较,确定了黄荆种以下分类群是以黄荆为原始分类群,形态特征向着4个方向演化,形成目前种以下分类群的格局。本文还报道了原变种黄荆在河北省东部的地理分布与荆条小叶羽状分裂这一形态特征的新资料。

In this study, the analysis on clustering and evolutionary trends using mathematical algorithms was carried out to assess former taxonomic treatment and evolutionary trends within the species. The results showed that infraspecific taxa of V. negundo L. were divided into two groups： one with spreading inflorescence including forma laxipaniculata and forma alba, the other with narrow inflorescence including the other five varieties. The inflorescence character shows some taxonomic value, and reduction of forma laxipaniculata and forma alba to the synonyms of V. negundo was not supported. By comparison between the primitive and derived characters infraspecific taxa within the V. negundo L. were recognized and evolutionary trends were assessed. Vitex negundo var. negundo is detected to be the most primitive taxon in the species complex and its morphological characters may have evolved toward four directions, e. g. , from integrate leaf margin to lobed leaf margin, large leaflets to relatively small leaflets, glabrous leaf blade to hairy leaf blade, narrow inflorescence to spreading inflorescence, and finally forming the current patterns of infraspecific taxa and their distribution. This paper also reported new geographical distributions of V. negundo var. negundo in eastern Hebei Province and new pinnately lobed leaflet character of V. negundo var. heterophylla.