Vascular Flora of Ketona Dolomite Outcrops in Bibb County, Alabama

Explorations since 1992 in Bibb County, Alabama, have revealed an extraordinary, undescribed glade community developed over the Ketona Formation, an unusually pure dolomite. Eight new endemic taxa were found: Castilleja kraliana, Coreopsis grandiflora var. inclinata, Dalea cahaba, Erigeron strigosus var. dolomiticola, Liatris oligocephala, Onosmodium decipiens, Silphium glutinosum, and Spigelia gentianoides var. alabamensis. In assessing systematic relationships of the Erigeron and Silphium, two additional undescribed taxa, not of Bibb County, were discerned, E. strigosus var. calcicola and S. perplexum. Seven state records were discovered: Solanum pumilum, last collected in 1837 and presumed extinct; Astrolepis integerrima, disjunct from Texas; Paronychia virginica, bridging a gap between Arkansas and Virginia; Baptisia australis var. australis, Rhynchospora capillacea, R. thornei and Spiranthes lucida. More than 60 plant taxa of conservation concern occur on or near these glades, marking them as one of the most significant reservoirs of botanical diversity in the eastern United States.