梾木属康定梾木复合群的性状分析及分类处理

TAXONOMY OF CORNUS SCHINDLERI COMPLEX BASED ON QUANTITATIVE ANALYSIS OF SOME CHARACTERS

本文是应用形态一地理学方法、综合数量统计分析方法对未做过居群研究的复合群进行合理划分的一个成功尝试。康定梾木群(山茱萸科、梾本属)共包含9个名称,分布从横断山区到湖北西部。该合复群内形态变异复杂,特别是交叉变异很多,虽有九个名称,却没有一个性状能将它们间断分开,使标本鉴定极为困难。为弄清其性状的变异规律以进行合理划分,作者将分布区划为四个小区随机取样,选择6个常用作分类特征的数量性状做统计分析,并对有关分类特征作形象化散点图分析,与地理分布综合考虑,得出该合群为两个亚种组成的一个种之结论。

The Cornus schindleri Wangerin complex in Cornus subgen. Kraniopsis Raf.consists of several taxa namely C. schindleri Wanger. (1907), C. mombeigiiHemsl. (1909), C.poliophylla Schneid. et Wanger. (1909), C.mombeigii Hemsl.subsp. crassa & subsp. populifolia Fang et W. K. Hu (1980), C. poliophyl?aSchneid. et Wanger. var. praelonga Fang et W. K. Hu (1981), C. ixienensisFang et W. K. Hu (1981), C. malifolia Fang et W. K. Hu (1981), C.daijinensis Fang et W. K. Hu (1981), It is widespread from Hengduan Mo-untain region to western Hubei, and easily distinguished from the othermembers of the subgenus by leaves with crisped hairs and not harsrsh totouch beneath, cymes arranged in corymbs and cylindric style. But withinthe species complex, the variation is so wide that even two most distinctspecies can not be recognized. In this paper, quantitative ana lysis is maedfor six characters which are usually used for classification, i. e., thelength of petiole, the length of style, the length of petal, the length ofpeduncle, the ratio of the length of filament to that of petal, the ratio ofthe length of leaf to width, combined with geographical-morphologicalmethod in order to understand the variation of the complex and arrive ata reasonable classification. About 100 herbarium specimens are sampledfrom the distribution region of the complex divided into four samplingareas (tab. 3), each including the localities of the type specimens of oneor two names. The statistically analysed data are listed in Tab. 4, 5, 6and pictorialized scatter diagram of herbarium speciemens is presented inFig. 2. The result indicates that it is impossible to separate the complex intotwo distinct species on the basis of these characteristics. Here I recognizetwo subspecies within the complex treated as a single species, Cornus schind-leri Wanger. The diagnostic characters & distribution range of these twosubspecies are given below: 1. Filaments≥1.4 as long as petals; midrib with scattered, appressedbrown hairs beneath; mature flower buds subrotund; hairs on the sur-face of ovary usually appressed...........sub. po iophylla (Schneid. et Wanger.) Q. Y. Xiang (mainly distributed in Western Hubei, Northea-# stern Sichuan, Southern Shaanxi, Southeastern Gansu, fig. 3 '▲').1. Filaments<1.4 as long as petals: midrib with yellowish or yellowcrisped hairs beneath; mature flower buds conical; hairs on the surfaceof ovary usually patent...........................subsp. schindleriWanger. (mainly distributed in Southern & Western Sichuan, Nor-theastern &Northwestern Yunnan, Southeastern Xizang, fig. 3. '●'.) The reason wby I have chosen to designate them as subspeciespreviously treated as species is that although they differ from each otherin seveval characters and have a definite geographical range, many interm,ediate forms are present in Western Sichuan where these two subspeciesare in contact.