We have investigated the flora of Yeongheungdo Island in Ongjin-gun, Incheon. A total of 13 separate field trips were carried out from March 2012 to October 2013. As a result, 302 taxa including 80 families, 211 genera, 261 species, 6 subspecies, 31 varieties and 4 forms were identified. These include the following: 1 taxon protected under the Act on the Protection and Management of Wildlife, 3 Korean endemic taxa, 8 floristic indicator species including 2 taxa of grade V, 3 of grade II and 3 of grade I, 33 naturalized taxa with the naturalization rate of 10.9% and 1 northern taxon vulnerable to climate change.

This study intended to investigate environmental factors including soil and vegetation in order to understand the environmental and ecological characteristics of 12 different habitats of Iris odaesanensis. These habitats, according to investigations, are mostly located at elevation of 280 m to 1,555 m with angles of inclination ranging from 2 degree to 30 degrees. A total of 273 vascular plants are identified in 23 quadrates of 12 habitats. Dominant species of woody plants in 12 habitats are represented as Quercus mongolica in the tree layer (T1) and the subtree (T2) layer, and Lespedeza maximowiczii, Lindera obtusiloba, Rhododendron schlippenbachii in the shrub (S) layer. The importance value of Iris odaesanensis is 9.65%, as regards the herbaceous layer, and 6 highly ranked species such as Carex siderosticta (3.92%), Meehania urticifolia (2.67%), Spodiopogon cotulifer (2.58%), Aconitum pseudolaeve (2.51%), Carex bostrychostigma (2.28%) and Disporum smilacinum (2.09%) are considered to be an affinity with Iris odaesanensis in their habitats. The degree of their average species diversity is 1.32, and that of dominance and evenness are 0.08 and 0.89, respectively. The type of soil is sandy loam and loam, and the average field capacity of soil is 28.31%. Their average organic matter is 16.71%, soil pH 5.29, and available phosphorus is 9.29%. Correlation coefficients analysis based on environmental factors, vegetation and soil analysis shows that the coverage of Iris odaesanensis is correlated with pH and dominance, and species richness is positive related with species diversity.

화천 일산에 대한 관속식물 분포와 용도를 파악하기 위하여 2008년 4월부터 10월까지 6회에 걸쳐 조사하였다. 그 결과 확인된 관속식물은 총 91과 295속 422종 1아종 58변종 15품종 등 총 496분류군이었다. 조사된 496종류 중에는 한국특산식물 17분류군, 희귀식물 9분류군과 멸종위기 식물인 백부자가 포함되어있다. 식물구계학적 특정식물종은 금강초롱꽃과 백부자를 포함하여 총 68분류군으로 나타났다. 귀화식물은 27분류군이었으며 귀화율은 5.4%, 도시화지수는 9.4%로 나타났다. 용도는 식용이 201종류(40.5%)로 가장 높게 나타났으며, 약용이 168종류(33.9%), 목초용이 69종류(13.9%), 관상용이 61종류(12.3%), 목재용이 17종류(3.4%), 섬유용이 16종류(3.2%), 그리고 공업용이 4종류(0.8%)로 나타났다.