Add to ORKGCharles and Anna Roggman Boreal Slopes is a 20 acre (8.1 ha) Nature Conservancy preserve situated on the floodplain and adjacent northfacing slope of a tributary of Buck Creek in Clayton County, northeastern Iowa. My study of the preserve in 1981 revealed a vascular flora of 160 species representing 59 families. Three plant communities were recognized: ash-elm on the floodplain, maple-basswood on the slope, and an unusual boreal slope community in areas of the slope with cold air drainage. The last contains several species with boreal American or circumboreal distributions which have probably persisted since the Pleistocene. Eleven species protected by state and federal laws inhabit the preserve. The most significant is Aconitum noveborac...