Canada’s estimated number of vascular plants varies between 4,000-4,150 species and makes up approximately only 1.5% of the world’s species plant diversity and roughly 17% relative to the continental flora of USA. In turn, Saskatchewan’s flora includes 120 families, 600 genera, and between 1380 and 1791 species, of which 414 (about 30% of the provincial flora) are rare, including 134 endangered and 11 endangered/extirpated? species (Harms, 2001). The relatively high number of rare plants in Saskatchewan is of concern and is, to some extent, the result of human activities including over-collecting. Because rare plant species exist in restricted geographic areas with characteristic habitats, have small populations, and may have a unique genetic make up, the assessment of rarity status at the specific level is relevant within the biodiversity and conservation contexts. Here, we have identified geographic areas with high concentrations of rare plants. Concentrations of rare plants in Saskatchewan are based on records of the W.P. Fraser Herbarium Rare Plants Database. The information has been plotted on a base map of Saskatchewan using ArcView GIS software. Preliminary data indicates that high numbers of rare species records occur in ecologically unique areas such as the Athabasca Sand Dunes on the S shore of Lake Athabasca in the NW corner; the Cypress Hills in the SW corner; the Pasquia, Porcupine, and Wildcat Hills areas near the eastern border. In the northern part of Saskatchewan, concentrations occur in conjunction with roads. Other northern concentrations occur near uranium mine sites such as Cluff Lake and Wollaston Lake. Concentrations along the provincial borders show up because those areas are at the edge of the ranges for some species rare in Saskatchewan. Additional information regarding the taxonomic groups and distribution of rare and endangered flora of Saskatchewan is provided.

Key words: Canada, endangered species, rare plants, Saskatchewan