More research is needed. Plants of the pilosa complex on the Coastal Plain and western Highland Rim in Ky. and Tenn. are particularly variable in overall robustness (including possible tetraploids), phenology (with some plants extending into early July), pubescence, flower size, shape and color (white to deep purple). Most or all of the plants in this region have long largely eglandular hairs and may be referable to var. amplexicaulis (Raf.) Wherry, which is recorded from the lower Mississippi Valley and west to Texas. These plants may be close to (or combind with) ssp. pulcherrima (Lundell) Wherry, which is a robust tetraploid recorded mostly in La. and Tex. (treated as a species in W). They have also been confused or combined with deamii in some cases; see Zale (2014) for review.