龍門山圈域의 植物區系를 규명하기 위하여 1983年 5月부터 1984年 9月가지 10回에 걸쳐 調査을 하였다. 龍門山圈域의 韓國檀物區系上 位置는 서나무(Carpinus cordata), 졸참나무(Quercus serrata)등이 나타나는 溫滯中部區系로 판단되었다. 所産植物은 84科, 280屬, 501種, 65變種, 및 11品種으로 도합 577種類이었다. 이 중 韓國特産植物은 14科, 17屬, 3種, 5變種으로 도합 18種類이었다. 所産植物 중 北方因子는 3種, 南方因子는 2種이었고 龍門山圈域과 각지와의 共有　數는 雉岳山이 379種類로 가장 많았으며, 江華島가 179種類로 가장 적었다. 범의귀科의 좁은잎댕강목(Deutzia coreana var. angustifolia)는 變種으로 인정하기 어렵다. 벼科의 흰줄갈풀(Phalaris arundiacea var. picta)은 龍門山에 한정 분포한다. 양귀비꽃科의 금낭화(Dicentra spectabilis)는 自然種으로 생각된다. 格子數가 703個인 龍門山圈域의 綠地自然性은 平均綠地自然度가 4.19로 낮으며 現存量과 純生産量은 각각 3059140T, 699470 T/year이었다.

The research was taxonomic study of vascular plants and assessment of green capacity in Mt. Youngmun district from May 1983 to Sept. 1984. The flora of vascular plants investigated in this district was 577 kinds belonging to 84 families, 280 genera, 501 species, 65 varieties and 11 forms. Among them korean endemic taxa distributed in Mt. Youngmun were 18 kinds belonging to 14 families, 17 genera, 13 species, 5 varieties. The floristic composition in this region was the highest similarity with Mt. Chiak and the lowest with Kanghwa Island. Deutzia coreana var. angustifolia of Saxitragaceae is not confirmed as a variety. Phalaris arundiacea var. picta of Gramineae was confined to Mt. Youngmun from Korea. As a species of naturalized plant, natural habitat of Dicentra spectabilis was founded in this district The forest zone of Mt. Youngmun was the middle temperate zone represented as Carpinus-Quercus vegetation. Six different Degree of Green Naturality ; 0, 1, 2, 6, 7, 8, have been registered in this district. Average Degree of Green Naturality was recognized as 4.19 for the 703 meshes. The standing crop and net production of this district were estimated as 3059140T and 699470T/Year.