All plants of this species in Ky. are probably ssp. calciphilum Warnock, which is virtually restricted to flat limestone glades of the southern Interior Low Plateaus in Ala., Ga., Ky. and Tenn. (Warnock 1995; FNA 3). However, there has been a tortuous taxonomic trail; other segregates have been reported, and some colls. should be rechecked (M). The name D. virescens Nutt. has been partly misapplied to ssp. calciphilum, but belongs with closely related plants of the Great Plains now treated as D. carolinianum ssp. virescens (Nutt.) Brooks (including ssp. penardii (Huth) Warnock). Ssp. carolinianum occurs mostly on the southeastern Coastal Plain and in Ozarkian regions, often on non-calcareous soils. [A somewhat parallel situation occurs with Viola egglestonii, V. pedatifida and V. septemloba, respectively.]