Abstract: Dayao Mountain in Guangdong Province, is located at the middle sub-tropical region and at long.113°13'02"E. by lat. 25°11'18"N. Recent investigation on flora of vascular plant shows that it has a total species (including varieties) of 1411 belonging to 194 families and 701 genera. The fern of 132 species has a high rate in the flora and indicates the flora is an old one. The characteristic families of flora and vegetation are Fagaceae, Theaceae, Lauraceae, Magnoliaceae, Hamamelidaceae, Moraceae, Myrsinaceae, Symplocaceae, etc., all of which are the basic elements of Cathayasian flora. Phytogeographically, the pan-tropical genera are common, meanwhile the tropical elements and temperate elements also appear in this area, but most of them include only a few species. It's possible to believe that this area is the north border of the tropical plant and the south border of the temperate plant. The composition, which is complex, shows the nature of old origin and species diversity of plant are typical in the flora of Dayao Mountain.

Key words: vascular plant, flora, characteristic, Dayao Mountain