芨芨草属的地理分布及起源

STUDIES ON THE GEOGRAPHICAL ORIGIN AND DISTRIBUTION OF THE GENUS ACHNATHERUM

利用种数分布表和种数分布图对芨芨草属植物的地理分布进行了研究,并探讨了芨芨草属的地理起源和演化问题。认为芨芨草属植物的现代分布中心在我国青藏高原的东缘,即四川省西北部、甘肃省南部、西部和青海省东部。该中心位于古地中海区亚洲中部亚区西藏省青海亚省东部与亚洲东部亚区交接的地方。结合芨芨草属外部形态性状和解剖性状,该中心含有最多的特有种和许多古老性状,认为该中心可能是芨芨草属植物的起源中心。同时,该中心还含有许多具有进化性状的种,认为该中心又是芨芨草属植物的多样性中心。因此,芨芨草属植物的起源中心和多样性中心与现代分布中心是相重合的。

In this present paper,the authors have studied the geographical distribution of the genus Achnatherum in detailed with the method of the form and map of species numbers distribution,and also probed into the geographical origin and evolution of the genus.It's considered that the centre of modern distribution of this genus in the eastern fringe of Qingzhang pleateu,mean the range of northwest part of Sichuan.south and west parts of Gansu and east part of Qinghai.The centre is situated in the connect of the centre Asia subregion with the east Asia subregion. Combined the morphological and anotomical characteristics of this genus,the centre include the most peculiar species and many characteristics,and it's thought that the centre maybe the originated centre of this centre. meanwhile,the centre also have many species with evolutionary characteristics,and the centre also is the diverstical centre of this genus. Therefore, the originated centre.diverstical centre and the centre of modern distribution is the same centre.