Composition and geographic elements of the flora in Nuluer Hushan National Nature Reserve, Liaoning of northeastern China

This paper studies the composition and geographic elements of flora in Nuluer Hushan National Nature Reserve of Liaoning Province, northeastern China by applying the methods of phytogeography, and based on field plant investigation and the relevant literatures. The results showed that there were 1 006 vascular plant species, belonging to 412 genera and 97 families, among which angiosperms play the leading role and accounted for 86.6%, 95.3% and 95.5% of all the families, genera and species, respectively. At family level, the singlespecies families and middle\|size families were the main part of the local flora, which accounted for 73.2% of all families; At genus and species levels, over 20 species families were the main part of the local flora, which accounted for 51.3% and 56.2% of all genera and species, respectively. The ratio of species to family could indicate the degree of floral differentiation, which was 10.37 in this nature reserve, and greater than other areas of the same latitudes, representing the higher level of flora differentiation. The flora showed the composition of temperate zone remarkably, temperate genera accounted for 80.29% of all genera, although there was a certain relationship with the flora of tropic zone, and tropic genera accounted for 19.71% of all genera. Meanwhile, cosmopolitan genera accounted for a considerable proportion(13.53%), which was far above the countrywide level (3.34%), showing that the local flora is vulnerable and transitive of geographic element.