中国独活属叶柄的解剖学研究

本文首次观察了我国独活属１５种地柄解剖的结构的基本特变异幅度。根据叶柄的维管束排列，结合横切面形态，近轴面沟槽的有无及形态周缘的变化及髓腔的有无等特征，把１５种独活的叶柄剖分为５个类型。依据各类型的结构特点结合其植物的外部形态，以及细胞学和花粉形态等特征，讨论了这５个类型可能的演化关系和独活属的属下分类问题，作者认为我国西南部的横断山区不仅独活属植物的种类丰富。是该属的频度中心，而且形态分化活跃，

ANATOMICAL STUDIES ON PETIOLE OF HERACLEUM FROM CHINA

Southwesten of China is one of the two centers of distribution of Heracleum in the world. In this paper, fifteen species distributed in this area was dissected and observed. The anatomical characters of 15 species are very diverse and listed in Table 1 and Figure 1 to 3.Comparing the petiolar anatomy of & populations belonging to 4 species which distributed in different area or altitude,it is shown that the anatomical charecters of petioles of Heracleum possess certain stability except with some variations in numbers of vascular bundles and size of the cross section within a species, andcan be used as a useful taxonomical evidence.According iD the pattern of vascular bundles'distribution, combined with theshape of the cross section, the presence and shape of the groove on the adaxialside, smooth or undulate margin and the presence and shape of pith cavity, theanatomical structures Df petioles of 15 species are divided miD 5 forms (see fig. Ito 3). According to the charecters of 5 forms petiDles, combined with charecters ofeXterior shape, pollen morphology and cytology, the probable evolutionary relationships of the 5 forms of petiolar anatomy and the classification to genus Heracleumare discussed.In the end,by analysing the regular of distribution of Heracleum in China. thespecies with the 5 forms of petiolar anatomy and many other species of Herucleumare concentrated in Hongduan Montains of Southwesten in China. As a result,Hongduan Montains is not only the center of abundance but also the biggest centerof diversity of this genus.