毛茛科金莲花亚科植物的地理分布

本文对毛茛科金莲花亚科各属的地理分布作了分析,该亚科植物除了少数属的一些种分布到南半球的温带地区,一些种分布或延伸到亚热带山地、非洲东部和北部的干旱、半干旱的地区外,绝大部分的属、种均分布于泛北极区域。根据其17个属的地理分布式样,把它们划分为8个分布区类型:(1)北温带分布类型4属;(2)北温带和非洲分布类型1属;(3)北半球温带和南半球间断分布类型1属;(4)欧洲和东亚间断分布类型1属;(5)西亚分布类型1属;(6)地中海分布类型3属;(7)欧亚和温带亚洲分布类型1属;(8)东亚分布类型5属。本文以形态特征为主,结合花粉和染色体的性状分析,认为东亚特有的鸡爪草属、Megaleranthis和铁破锣属可能分别是联系驴蹄草属和金莲花属,鸡爪草属和金莲花属以及金莲花族和升麻族的中间类型。另外,文中详细地统计了该亚科的不同等级分类群及特有种在各个植物区的分布,并从系统发育的观点讨论了各个植物区所具有的原始类群和进化类群,提出了如下论点,即东亚植物区(特别是中国西南部)不但是金莲花亚科植物分布的多度和多样性中心以及特有类群的分布中心,而且还是原始类群的保存中心,伊朗-土兰区及地中海周围是第二分布中心。

THE GEOGRAPHICAL DISTRIBUTION OF SUBFAM. HELLEBOROIDEAE (RANUNCULACEAE)

The subfamily Helleboroideae (Ranunculaceae) consists of 4 tribes, 17 genera and 885 species; Helleboreae (Caltha, 12 species, Calathodes, 3 species; Trollius, 31 species; Megaleranthis, 1 species; Beesia, 2 species; Helleborus, 15 species; Eranthis, 8 species ), Cimicifugeae (Soulia, 1 species; Anemonopsis, 1 species; Cimicifuga, 17 species; Actaea, 6 species), Nigelleae (Komaroffia, 2 species; Nigella, 18 species; Garidella, 2 species), Delphineae (Aconitum, about 400 species; Delphinium, about 320 species; Consol-ida, 46 species). According to modern distribution of the genera, eight distribution patterns of Helleboroideae are recognized: 1) the North temperate distribution pattern: Trollius, Cimicifuga, Actaea, Aconitum; 2) the North temperate plus African distribution pattern: Delphinium; 3) The Northern Hemisphere temperate and the Southern Hemisphere temperate disjunct pattern: Caltha; 4) the Europe and eastern Asian disjunct pattern: Helleborus; 5) the Western Asian distribution pattern: Komaroffia; 6) the Mediterranean distribution pattern; Nigella, Garidella, Consolida; 7) the Eurasian and temperate Asian distribution pattern: Eranthis; 8 ) the eastern-Asia endemic pattern : Calathodes, Megaleranthis, Beesi-a, Souliea, Anemonopsis. The morphological, palynological and cytological characters of the genera of Helleboroideae are analysed. Among them, Calathodes is probably a link between Caltha and Trollius; Megaleranthis is a link between Calathodes and Trollius; and Beesia is a link between the tribes Helleboreae and Cimicifugeae. On the other hand, statistic data shows that the eastern Asiatic Floristic region (especially Southwest China) is the richest in number of genera, species and endemic species of the Helleboroideae, and there occur many primitive or relatively primitive taxa and most or relatively advanced taxa of this subfamily in that region. To sum up, the eastern Asiatic Floristic region (especially Southwest China) is not only the distribution centre, diversity centre and the centre of endemic groups ( certain genera, sections and species ) , but also the preservation centre of the primitive taxa and the differentiation centre of the Helleboroideae.