Add to ORKGThe combined vascular flora of Lyon and Sioux counties, Iowa, based upon field and herbarium study, is composed of 612 species, of which 454 species (74%) occur in both counties. The Lyon County vascular flora consists of 561 species, including 13 state endangered, 9 state threatened species, and 102 non-native species. The Sioux County vascular flora consists of 506 species, including 2 state threatened species and 106 non-native species. The floras are most notable for the presence of plants with floristic affinities to the Great Plains to the west of Iowa. They also have a very high percentage (18%-20%) of their floras comprised of non-native species, reflecting the intensity of human activities on the landscape