Nova Scotia is unique in northeastern North America for the extent of sites having gypsum bedrock at or near the soil surface.
The distinctive set of plants associated with these gypsum exposures includes Packera paupercula (Balsam groundsel), Carex eburnea (Ebony sedge), Erigeron hyssopifolius (Hyssop-leaved fleabane), Cypripedium parviflorum (Small yellow lady’s-slipper).
Some of these species appear to be associated with sunny clearings created by natural erosion from gypsum cliffs, which provides a distinctive sunny and calcareous habitat within landscapes that are otherwise forested.
[2] Many of these sites are threatened by gypsum mining and logging.
Gypsum floras are well-documented in other parts of the world, but are sufficiently rare in eastern North America that they are not mapped in a recent world-wide review on the topic.