This is a widespread variable species of central North America, but extending locally to both Pacific and Atlantic coasts; 2n = 36/38 and 72 (FNA 25). It usually occurs on dry sandy soils. In Ky. it appears native and locally abundant on high sandy banks of the Mississippi Rv. and lower Ohio Rv. The coll. from CAMP (KNK) is presumably from an adventive plant, found by Budell & Thieret in a railroad yard at Silver Grove. The related southeastern species, S. junceus (P. Beauv.) Kunth, is known from banks of the Obed Rv. in e. Tenn. (Schmalzer et al. 1985). It may be expected along the Big South Fk. of Cumberland Rv.