The flora characteristic of seed plants in the Southern and Northern Mountains of Lanzhou

In order to understand the distribution characteristics and geographical elements of flora and fully reveal the process of natural history in the Northern and Southern Mountains of Lanzhou, the present study investigated the seed plants in this area. The results showed that the germplasm resources in the studied areas were relatively abundant which included 155 seed plant species belonging to 39 families and 115 genera in both gymnosperm and angiosperm although only 1 species in gymnosperm. The dominant families were Gramineae, Compositae, Leguminosae which were large families including 10~29 species. The middle family including 2~9 species was the main composition of flora in the study area. The families dominance was obvious and the family, genus and species of Gramineae, Compositae and Leguminosae accounted for 7.69%, 43.48% and 45.80%, respectively. The genus species distribution was loose with rich diversity and poor advantage. The geographical elements of spermatophytic families had 5 types and 4 subtypes. The dominant families in the studied area belonged to cosmopolitan which accounted for 53.85% of total families. Excepted with cosmopolitan, the tropical and temperate families were 25.64% and 6.96% of total families, respectively. The geographical elements of spermatophytic genera had 12 types and 9 subtypes. The temperate genera were dominant which accounted for 50.44% and the genera of tropical and Mediterranea accounted for 15.65% and 6.96%, respectively, which revealed that the flora in studied area had relationship with Paleo-Mediterranean flora. The composition of Central Asia and East Asia elements was weak. There was no family endemic to China and 1 genera endemic to China which was Xanthoceras. The distribution difference of germplasm resources in Southern and Northern Mountains indicated that species richness in the Northern Mountains was more abundant than that in Southern Mountains, however, the density, coverage degree, biomass, plant height, canopy and other growth indices in Southern Mountains were higher than those in Northern Mountains.