Characteristics of Weed Flora in Pasture of the Jeju Island

This study was conducted to determine dynamics of weed flora in pasture of the Jeju island in Korea, carried out by the National Institute of Agricultural Science and Technology in 2004. Weeds occurred in pasture were 55 species belonging to 24 families in May and 68 species of 30 families in September. In total, weed observed in pasture were 94 species belonging to 33 families. Dominant weed species were Rumex acetosella, Artemisia princeps and Veronica tenella etc. in May and Digitaria ciliaris, Cyperus iria and Potentila anemonefolia etc. in September. Among 55 families, Asteraceae (20.0%) including 11 weed species was the biggest family, followed by Caryophyllaceae of 6 species (11.0%), and Polygonaceae, Scrophulariaceae and Rosaceae of 4 species (1.5%), respectively in May. Among 30 families, Asteraceae (17.6%) including 12 weed species was the biggest family, followed by Poaceae of 10 species (14.7%) and Polygonaceae of 4 species (5.9%), respectively in September. These weeds were composed of 33 annual species, 17 biennial species and 44 perennial species. Exotic weeds occurred in pasture of the Jeju island were 18 species belong to 10 families, dominated weeds were Rumex acetosella and R. obtusifolius.