Supplement 1 makes the following changes to the original guide, which was published in 2004. Replaces the title page. Corrects and clarifies information in the original guide for two species: Microstegium vimineum(Japanese stiltgrass) and Rosa multiflora (multiflora rose). Replaces the Species List. Adds descriptions with photos for five new species. These species are among a long list of priority species and were selected over others for one key reason. Literature and research on them currently are relatively abundant.