新疆种子植物科的区系地理成分分析

ANALYSIS OF THE FLORISTIC GEOGRAPHICAL ELEMENTS OF FAMILIES ON THE XINJIANG' S SPERMATOPHYTIC FLORA

对新疆种子植物区系及其科的组成和地理成分进行研究，结果表明：（１）新疆野生种子植物中科的优势现象很明显，种类趋向于集中在少数科内。（２）科的地理成分方面，世界广布科占有很高的比例（ ３５． ０％），说明新疆区系具有明显的过渡性；但各类温带分布科比例更大（ ５２． ０％）。（ ３）新疆区系的表征科有特殊性，如含有世界广布的基科、十字花科、茨科、石竹科等，这是与热带、亚热带区系的组成完全不同的；但其它表征科、优势科仍以温带科或主产温带的科为主。

In this paper, the floristic constitute and geographical elements of families of Xinjiang's spermatophytic flora were analyzed. The results showed: (1) There was 3 423 species belonging to 715 genera and 100 families in Xinjiang. In view of the quantitative feature, there markedly were 16 dominant families, which occupies only 16 % of total families, but they consist of 482 genera and 2 429 species and posses 73. 8% of total genera and 79.3 % of total species respectively. (2) On the geographical elements of families, the cosmopolitan families were dominant (35. 0 % ), they indicated that Xinjiang's flora was existed obvious transition; but the temperate families (52. 0% ) were more predominant, for example, the typical temperate distribution has 23 families, tropical to temperate has 26 families, and subtropical to temperate has 3 families. Then, the tropical and tropical to subtropical distribution families are only 13 (13. 0% ). All those were adapted with the latitude zone in Xinjiang, they reflected that plant distribution was closely related to the local climatic conditions. (3) The typical families of Xinjiang's flora was very special, because they were also included in some cosmoPOlitan families, e. g. Chenopodiaceae, Cruciferae, Polygonaceae, Caryophyllaceae, etc., which differed from tropical or subtropical floras. Of course, a great of typical and dominant families of Xinjiang's flora still were temperate families or those mainly distributed in temperate zone, e. g. Tamaricaceae, Salicaceae, Papoveraceae, Zygophyllaceae, Ranunculaceae, Plumbaginaceae, Pinaceae, Ephedraceae, Rosaceae, etc., and above cosmopolitan families mainly distributed in temperate zone, so all evidences indicate that Xinjiang's flora was characterized by the typical temperate properties.