Analyses on distribution and species composition of wild seed plant in Beijing Songshan National Nature Reserve.
Distribution status of wild seed plant in Beijing Songshan National Nature Reserve was investigated by means of combination methods of field survey, quadrat and transect, and also, species composition and distribution type were analyzed. Investigation results show that there are wild seed plant of 721 species in 382 genera belonging to 92 families in the reserve, which include gymnosperm of 5 species in 4 genera belonging to 3 families and angiosperm of 716 species in 378 genera belonging to 89 families, and angiosperm includes dicotyledon of 569 species in 298 genera belonging to 78 families and monocotyledon of 147 species in 80 genera belonging to 11 families. There are 7 families containing 20 species or more than 20 species, numbers of genus and species included in these families account for above 40% of total numbers of genus and species in the reserve, with the phenomenon of obvious dominant family. Number of genera of containing 1 species and 2-4 species is 235 and 128, respectively, with absolute predominance. Family distribution type of wild seed plant in the reserve can be divided into 8 types, Pantropic and North Temperate families are the majority except for Cosmopolitan family. Genus distribution type can be divided into 15 types, in which North Temperate genus is the majority, and number ratio of tropic genus to temperate genus is 0.20. There are 2 species of national key protected wild plants and 52 species of Beijing key protected wild plants, which contain 18 species of 14 genera in Orchidaceae, very few Lonicera oblata K. S. Hao ex P. S. Hsu et H. J. Wang and the Beijing endemic species Batrachium pekinense L. Liou. And there are 7 exotic species with invasion tendency in the reserve. In addition, there are 3 new record species of Vicia venosa (Willd. ex Link) Maxim., Orchis roborowskii Maxim. and Gentianopsis contorta (Royle) Ma in Beijing. It is suggested that the flora of wild seed plant in the reserve possesses the typical temperate character and a certain transition property.