This largely Appalachian species includes complex natural variation; also diverse hybrids and cultivars have been widely planted. Wild plants are mostly diploids (2n = 14), but mixed in some regions (especially further north) with tetraploids and rarely hexaploids (Zale et al. 2016). Var. australis is known only along western margins of the Appalachian Plateaus in Ohio and Ky., and from disjunct central Appalachian regions further east. It is sometimes combined with Wherry;s (1951, 1955) var. brittonii (an Alleghanian tetraploid with bluish or violet versus lavendar or purplish flowers) and with var. setacea (a Linnaean type of uncertain disposition); see also Cr. Similar distribution patterns to var. australis are found in Paxistima canbyi and Solidago harrisii (Campbell et al. 1993); see also Draba ramosissima. Var. subulata is more northern; it may extend west to w. Ind.or perhaps confused there with "var. setacea" (S. Nemestnik, pers. comm.).Var. australis reportedly differs from var. subulata as follows (Wherry 1951, 1955; F, Cr): inflorescence with mostly glandular hairs (versus eglandular); corolla lobes 4-9 x 2-6 mm (versus 8-12 x 4.5-12.5 mm); calices mostly 4-7 mm long (versus 6-9.5 mm); leaves mostly 5-10 mm long (versus 8-20 mm). Records mapped here are from plants that appear native, excluding the more robust cultivars that occasionally persist along roadside banks. These cultivars include hybrids with bifida, some of which are known as "Stellaria" (Wherry 1955). P. subulata is distinguished from bifida as follows (W): larger leaves ca. 1.5-2.5 cm long (versus 3-4 cm); nodes usually 6-8, more crowded (versus 4-5); petals with notch 0.5-3 mm deep (versus 1.5-5 mm), usually in Ky. rose-prplish to pink (versus sky blue to almost white). Hybrids of subulata with P. nivalis Lodd. ("Frondosa") and P. stolonifera Sims ("Amoena") may also be cultivated.