关键词: 种子植物, 植物区系, 地理成分, 区系特征, 天津

Abstract: There are 1 471 species (including infraspecific taxon) of the seed plants belonging to 140 families and 720 genera in Tianjin. Among them, they include 16 species of gymnosperm belonging to 10 genera and 7 families and 1 455 species of angiosperm belonging to 710 genera and 133 families. In addition, there are 11 Chinese endemic genera to China. Based on the analysis of compositions and the geographical elements and characteristics of the flora, the paper has discussed the major characteristics of the flora as follows: the flora contain abundant plant species; the flora is ancient origin, but also has younger elements; the geographical elements of the flora are comparatively complex, and the genera of north temperate are the dominant areal types, but there are so large proportional genera and species of tropic, subtropic in the region of temperate show that the flora of temperate relates to the flora of tropic, presenting transitional features from the subtropical zone to the temperate zone; the flora is crisscrossing and assembling of diversified geographical elements, and widely relate to their surrounding flora; the geographical elements of the flora is mainly made up of the North China components.

Key words: seed plants, flora, geographical elements, characteristics of the flora, Tianjin