This species is widespread in mesic woods of eastern states; see also under var. laphamii. P. divaricata (of woodlands) and P. pilosa (of grasslands) are both highly variable species that have probably hybridized in some regions. In central Kentucky, pilosa generally flowers 2-3 weeks later than divaricata (mostly in early May versus mid-late April) but there is often some overlap. Compared to divaricata (F, W, Y), pilosa lacks stoloniferous overwintering shoots; stems have more nodes (mostly 6-17 versus 4-6); leaves are narrower (with L/W mostly 7-10 versus 4-6); calices are sometimes glandless (versus consistently glandular); and corollas are generally more reddish (pink to purple versus pale blue to light purple).