A study on the Flora in Xinjiang Horgos River Basin

The initial investigation shows that there are 85 families,463 genera and 1153 species of wild vascular plants(including subspecies and varieties) in the Horgos River Basin,among which there are 8 families,11 genera and 23 species of fern,3 families,3 genera and 10 species of gymnosperm,74 families,449 genera and 1120 species of angiosperm(63 families,376 genera and 910 species of dicotyledonous,11 families,73 genera and 210 species of monocotyledon).And new distribution sites of rare species of Helianthemum songaricum and one unrecorded species of Betula were found in the basin.The analysis on the geographical elemental type of the seed plants flora shows that the North Temperate and Old World Temperate distribution dominated the distribution rate of the plant genera and species here,with totally 238 genera and 656 species,making up 60.10% and 72.97% respectively of the total plant genera and species in the basin.The second dominated distribution are the Mediterranean,west Asian to central Asian,and Central Asian distribution,with totally 113 genera and 169 species,making up 28.53% and 18.80% respectively of the total plant genera and species.The third dominated distributions are the Temperate Asian distribution with 14 genera and 21 species,make up 3.54% and 2.34% respectively of the total plant genera and species.There are 6 genera and 6 species of Eastern Asian distribution,making up 1.51% and 0.67% respectively of the total plant genera and species.Eastern Asian North American distribution only share 2 genera and 2 species,making up 0.51% and 0.22% respectively of the total plant genera and species.The above analysis indicates the most interflows between the flora in this area with those in the Old World Temperate and Mediterranean,W.Asia C.Asia,some interflows with Tropical flora and Temperate Asian and Eastern Asian flora,and the least interflows with Eastern Asian and North American and the Old World Tropical flora.