Occurrence Characteristics of Weed Flora in Upland Field in Korea

National Institute Agricultural and Science Technology, National Crop Experiment Station, National Honam Agricultural Experiment Station and National Yeongnam Agricultural Experiment Station did upland weed survey at 2002. Weed family occurred in upland field were 112 species belonged to 33 families. Among 33 families, 25 weed species belonged to Asteraceae were the biggest family, Poaceae were 14 species, Polygonaceae were 9 species, respectively. Main weed in Poaceae were Erigeron annuus (L.) Pers., Conyza canadensis (L.) Cronq. var. canadensis, Taraxacum officinale G. H. Weber ex Wiggers, Artemisia princeps Pamp. and Youngia sonchifolia (Bunge) Maxim. Weed species of Poaceae were Digitaria ciliaris (Retz.) Koel., Echinochloa crus- galli (L.) Beauv., Setaria viridis (L.) Beauv. and Eleusine indica Gaertn. In Polygonaceae were mainly occurred annual weeds, Persicaria hydropiper (L.) Spach, Rumex crispus L. and Rumex japonicus Houtt. In Convolvulaceae were Calystegia sepium (L.) R. Br., Calystegia japonica Choysi and Calystegia hederacea Wallich and mainly occurred weed in Cyperaceae were Cyperus microiria Stend., Cyperus amuricus Max. and Cyperus nipponicus Franch. et Sav. Weed occurrence character- istics from this survey were increasing exotic weed, Amaranthus hybridus L. in Amaranthaceae, Ambrosia trifida L. in Asteraceae and Chelidonium majus L. var. asiaticum (Hara) Ohwi in Papaveraceae in upland field