绣球花科西康溲疏及其近缘种变异性的数量分析

NUMERICAL ANALYSES OF VARIATION IN THE DEUTZIA SIKANGENSIS GROUP(HYDRANGEACEAE)

在详细鉴定了四川所有标本馆及云南部分标本馆珍藏的西康溲疏与长叶溲疏、球花溲疏这三种的标本８００余号的基础上，进行了实地采集补充，选出能代表其总体形态变异性的不同地方居群具花标本６０号作分类运算单位（ＯＴＵｓ），而２２个数量性状被测量作变量．分类运算单位间的关系通过聚类分析、主成分分析、散点图及柱状图表述．聚类分析可知，球花溲疏是一独立的种，而西康溲疏与长叶溲疏间有重叠．ＰＣＡ显示所有ＯＴＵｓ沿ＰＣⅠ大致群集成３个分类群，而ＰＣⅡ及ＰＣⅢ轴上则随机散布；前３个ＰＣ揭示了该三近缘种变异性总信息的７８．８５％．由此可知：长叶溲疏种内变异相当活跃，西康溲疏和球花溲疏可能由长叶溲疏分化而来．由于球花溲疏种下极端的同质性，它无疑是一独立种等级．ＰＣⅠ轴特征矢量绝对值大小显示出叶表毛被，萼筒上星状毛在该三种的分类中的重要性．从散点图和柱状图可知，西康溲疏在多项特征上处于球花溲疏和长叶溲疏间，它是否是后二种的杂交种呢？实地考察结合其他证据证明这是不可能的．还结合四川西部和东部冰川作用的不同而导致溲疏属在川东、川西的变异模式的差异，对西康溲疏起源于长叶溲疏的地质年代作出推论，得出了西康溲疏是长叶溲疏种下的一局限分布的、新近分?

Collections were made in Sichuan to supplement existing herbarium holdings kept in all the herbaria in Sichuan and some of Yunnan. At least 800 specimens of the group have been carefuly checked and determined since 1984. Then, 60 flowering specimens representing different local populations and the total morphological variations were selected as OTU′s, while 22 quantitative characters were measured as variables. The relationships between the OTU′s were expressed with the help of cluster analysis, principal component analysis, scatter diagram, and histogram. Clustering dendrogram shows that Deutzia glomeruliflora is a distinct species , while there are some overlapping between D. sikangensis and D. longifolia. PCA shows all the OTU′s roughly grouped along PCl as three taxa , while randomly scattered along PC2 and PC3. The first three PC′s revealed 78. 85% variation messages of the group.From PCA , we can also see remarkable variations occurring in D. longifolia. There seems to be a tendency that D. sikangensis and D. glomeruliflora are derived from D. longifolia. D. glomeruliflora is obviously one species because of its homogeneity infraspecifically, while D. sikangensis shows more variability there. A full discussion on the variation and distribution leads to the conclusion that D. longifolia and D. glomeruliflora can be unambiguously separated as two species, while D. sikangensis is a lately-derived variety of D. longifolia of restricted distribution.