Rare vascular plants and associate plant communities from the Sand Creek Chalk Bluffs, Oktibbeha County, Mississippi

New stations for 12 species of vascular plants considered rare, imperiled, or critically imperiled in Mississippi were discovered during collecting trips made from 1984-1989. The study area included two chalk outcrops and barrens, a mesic calcareous bluff, and a small stream bottom at the base of the bluffs along a transition area between the Pontotoc Ridge and Black Prairie physiographic regions for a distance of approximately 2.5 km. All sites are in Oktibbeha County, Mississippi, in the northeastern quarter of the state. The rare, imperiled, or critically imperiled species reported herein, which are usually associated with calcareous soils in Mississippi, are Apios priceana, Carex gracilescens, C. meadii, Carya laciniosa, Dodecatheon meadia, Euonymus atropurpureus, Fraxinus quadrangulata, Menispermum canadense, Nemastylis geminiflora, Panax quinquefolium, Penstemon tenuiflorus, and Swertia caroliniensis.