ASTERACEAE (BOTANIK); ADVENTIVPFLANZEN (GEOBOTANIK); INVASION UND KOLONISATION VON ÖKOSYSTEMEN (BIOGEOGRAPHIE); CHOROLOGIE (GEOBOTANIK); SUBALPINE VEGETATION + MONTANE VEGETATION + KOLLINE VEGETATION (PFLANZENÖKOLOGIE); KANTON WALLIS (SCHWEIZ); OREGON, BUNDESSTAAT (USA); ASTERACEAE (BOTANY); ADVENTIVE PLANTS (GEOBOTANY); BIOLOGICAL INVASION AND COLONIZATION OF ECOSYSTEMS (BIOGEOGRAPHY); CHOROLOGY (GEOBOTANY); SUBALPINE VEGETATION + MONTANE VEGETATION + COLLINE VEGETATION (PLANT ECOLOGY); CANTON OF VALAIS (SWITZERLAND); OREGON, STATE (USA)