国产柳属繁柳组植物叶脉序研究及其分类学意义

Leaf Venation and its Taxonomical Significance in Sect. Denticulatae(Salix) of China

采取脉络法,对柳属(Salix)繁柳组(Sect.Denticulatae C.K.Schneid.)17种及1变种进行叶片脉序观察。结果表明:繁柳组植物叶脉序类型均为直行羽状脉,表现出较高的一致性。该组植物均有二级间脉,但类型各有不同;三级脉及较高级脉序大体有三种类型;网眼发育完善或不完善;盲脉偶有不分枝;不同种之间网眼的发育以及盲脉分枝具有显著差异,是有价值的分类性状。根据聚类分析,繁柳组植物叶脉序分为两种类型:草地柳(S.praticola Hand.-Mazz.ex Enander)类型及腹毛柳(S.delavayana Hand.-Mazz.)类型,研究结果与形态学结果基本一致,但叶脉序提供了新的分类学性状,可为柳属植物疑难种的分类寻找新的依据。

Comparative observation on leaf venation of 17 species and 1 variety from Salix Sect. Denticulatae were made performed in order to provide new morphological evidence for the classification of Salix by the means of this section. The results showed that the venation of all taxa was found to be craspedodromously pinnate. Most species have intersecondary veins. Tertiary and higher level veins were divided into three types. The areoles are regular or irregular. Veinlets are branched or absent. The results also indicated that the areoles and veinlets were stable characters which showed significant differences bwteeen species. Based on the UPGMA analysis for venation pattern of Sect. Denticulatae C. K. Schneid. , S. praticola Hand.-Mazz. ex Enander types and S. delavayana Hand. -Mazz. types were founed. Leaf venation characters provides new characters. They could be used, therefore, as important diagnostic features for identifying these species.