About Isoetes butleri Engelm.
Isoetes butleri, commonly called limestone quillwort, is a plant species in the quillwort family, and it belongs to the group of lycophytes. It is native to the eastern United States, where it occurs in scattered, local populations. It grows almost exclusively on seasonally wet alkaline soils. Its common habitats include rocky prairies and glades, most frequently located over limestone deposits. This species is inconspicuous and easily overlooked because it looks very similar to vegetative grass or sedge on the surface. The leaves of Isoetes butleri die back by the end of spring, when its habitat becomes hot and dry. After leaf dieback, only the underground corm of the plant remains.
