甘肃省马衔山地区种子植物区系的研究

分析了甘肃省马衔山地区种子植物区系，用主成分分析（Ｐ．Ｃ．Ａ）和信息聚类（Ｉ．Ｃ．Ａ）方法对该区系与国内其它１０个有代表性地区的种子植物区系进行了对比分析。其结果为：１．该区系温带性质十分明显，是一个汇集四大区系成分的过渡带；２．该区系起源于第三纪亚热带亚高山森林植物区系，随青藏高原的隆起和中亚干旱区的形成而分化形成；３．该区系与六盘山植物区的关系最近。该区系隶属于泛北极植物区，中国－日本森林植物

THE STUDY ON FLORA OF MAHAN MOUNTAINS IN GANSU

This paper discussed the characteristics of Mahan Mountains flora with principal Com-ponents Analysis (P.C.A.)and information Cluster Analysis(I.C.A.)comparative studybetween the flora of Mahan Mountains and ten other floristics. The results show:1.The seedplant species are comparatively rich. There are 862 species in Mahan Moutains area which be-longs to 374 genera,84 families.2.Among the areal-types of Chinese genera of seed plants,there are l4 types and l3 subtypes in this area. Only short of Tropica Asia and TropicaAmerica disjunted. The types of temperate zone account for the largest percentage,followedby the medilterranean types.3.The geographical elements of Mahan Mountaims flora are verycomplex,for the area is a convergent and transitional zone of many floristics compositions. Itsmain compositions include the elements of central section of Asia prairie, Qinghai-XizangPlateau,Sino-Japan forest and Sino-Himalayan forest.4.The flora of Mahan Mountains,o-riginating from Tertiary subtropsubapl forest,was generated in the process of the Qinghai-Xizang orogeny and the dry regions in central Asia formation.5.The flora of Mahan Moun-tains has the closest relation to the flora of Lupan Mountains,It belongs to Loess Plateaustibregion,North China region.Sino-Japan forest subkingdom,Holarctic kingdom.