摘要
对桔梗科44个属的分布作了分析,发现属的3个频度分布中心:东亚区(13个属),开普区(10个),地中海区(14个)。东亚区有12个属集中分布于中国西南部(云南东部和北部、四川西南部和贵州西南部);在地中海区属的分布相对均匀,但巴尔干半岛比较集中,有9个属。因此中国西南部是桔梗科属的最集中分布的中心。对桔梗科作了尝试性的划分,将该科分为6个类群,7个亚类群。东亚是类群和亚类群最集中分布的地区,因此可以称为类型的多样性中心。本文选择Polemoniaceae为外类群,把Cyphi-aceae和Lobeliaceae作为参考类群,并考虑一般承认的进化原则,据此分析了26个性状的演化趋势,进而计算出每一个属的性状原始指数,并据此确定各属的原始性和进化性。最原始的属和大部分比较原始的属分布在东亚,因而可以认为东亚,特别是中国西南部,是桔梗科的原始类型中心。这个地区也就是康滇古陆的所在地,地史上一直稳定,为桔梗科原始类群的分化提供了历史地理背景,这里就是原始类群分化、发展的地区,推测桔梗科起源于白垩纪,但具体的起源地难于判断。
t The distribution pattern of 44 recognized genera in the Campanulaceae (s. str. ) was analysed. Genera-contour lines were constructed, which showed three centres of frequency of genera; the Eastern Asiatic region, Cape region and the Mediterranean region. Thirteen genera are found in E. Asia: Adenophora, Asyneuma, Campanula, Campanumoea, Codonopsis, Cyananthus, Cyclocodon, Echinocodon Hong, Homocodon Hong, Leptocodon, Peracarpa, Platycodon, and Wahlenbergia. Twelve of the 13 genera ( except for Echinocodon) can be found in a small area of SW. China ( E. & N. Yunnan, SW. Sichuan and SW. Guizhou). This is the most concentrated region of genera in the family. The Cape region has 10 genera: Craterocapsa, Merciera, Microcodon, Rhigiophyllum , Prismatocar-pus, Roella, Siphocodon, Teilera, Treichelia and Wahlenbergia. Although the figure is not very high, the region is also concentrated one of genera, considering its small area. The last region possesses 14 genera: Adenophora, Asyneuma, Campanula, Edraianthus, Feeria, Ja-sione, Legousia, Mindium, Petromarula, Physoplexis,Phyteuma,Symphyandra,Tracheli-urn and Wahlenbergia. The region is relatively large and the genera are rather evenly distributed ; a relatively concentrated area is the Balkan Peninsula, where there are nine gener-a. The three centres totally has 32 genera, taking up 73 percent of the total number of genera in the family.
Kolakovsky's (1987) classification system of the Campanulaceae, the only one for the whole family since Schonland (1889), could not be accepted. Instead, the present author tentatively recognizes six generic groups in the family,i. e. the Cyananthus Group, with two subgroups, the Cyananthus Subgroup and the Codonopsis Subgroup; the Platycodon Group, with two subgroups, the Platycodon Subgroup and the Campanumoea Subgroup; the Ostrowskia Group; the Wahlenbergia Group, with four subgroups, the Wahlenbergia Subgroup, the Prismatocarpus Subgroup,the Siphocodon Subgroup and the Merciera Subgroup; the Jasione Group; the Campanula Group, with three subgroups, the Campanula Subgroup,the Mindium Subgroup and the Musschia Subgroup. It is found that E. Asia possesses four generic groups consisting of six subgroups, the highest among the three centres. Therefore, E. Asia is the centre of form diversity in the Campanulaceae. The evolutionary trends of 26 characters in the family were inferred based on the analysis of the outgroup, Polemoniaceae, and the reference to the related families, Cyphiaceae and Lobeliaceae. The character primitiveness index was calculated for each genus. The most primitive genus, Cyananthus, and most of relatively primitive genera are concentrated in E. Asia, with the highest average character primitiveness index of genera. The region could be considered as the centre of primitive forms, and the other two regions as the differentiation centres. SW. China (E. & N. Yunnan, SW. Sichuan and SW. Guizhou) , where 12 genera are found, is so-called Kan-Dian Old Land, and has been stable even since the Paleozoic,providing a condition for the differentiation of the primitive forms in the Campanulaceae. The present author speculates that the differentiation and dispersal of primitive forms in the family took place not later than the end of the Cretaceous and the family originated ever earlier, but he considers that the origin place of this family can hardly be inferred, considering the distribution pattern of the family and the distribution of the Polemoniaceae, Cyphiaceae and Lobeli-
出处
《植物分类学报》
CSCD
1995年第6期521-536,共16页
Acta Phytotaxonomica Sinica
基金
国家自然科学基金
关键词
桔梗科
地理分布
分布中心
Campanulaceae
Geography
Frequency centre
Centre of diversity
Centre of primitive forms
Evolutionary trends
Character primitiveness index
