The composition and change of the weed flora in herbage seed

agentes nocivos crops cultivos dicotiledoneas dicotyledons economic plants economic sectors escandinavia europa europe facteur nuisible feed crops feed grasses feed legumes festuca festuca pratensis festuca rubra glumiflorae gramineae gramineas graminee grasses industria industria de semillas industrie industrie des semences industry injurious factors lawn grasses legumes leguminosae leguminosas leguminosas forrajeras lolium lolium perenne malezas mauvaise herbe monocotyledons ornamental plants papilionoideae phleum phleum pratense plantas plantas forrajeras plantas ornamentales plante plante de culture plante ornementale plants poa poa pratensis production de semences propagation materials rosales scandinavia scandinavie secondary sector secteur secondaire sector secundario seed seed industry seed production semence semillas suecia sweden trifolium trifolium hybridum trifolium pratense trifolium repens weeds