天津市种子植物区系成分分析

天津市共有种子植物1 471种（含种下等级），隶属于720属140科，其中裸子植物7科、10属、16种；被子植物133科、710属、1 455种。另外，具有中国特有属11属。通过对天津种子植物区系的组成、地理成分、区系特征进行分析，得出主要结论如下：种子植物较丰富；植物区系起源古老，但也具有年轻性；区系成分复杂，特别是北温带成分占优势，但是在温带地区内有大比例的热带、亚热带属种的出现，说明本植物区系有着更为喜暖的祖先；多种区系成分汇集，与周邻联系广泛，地理成分以华北成分为主。

Floristic Analysis of Seed Plants in Tianjin

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.