This alien is widely scattered across eastern North America, and it has probably been present in Ky. since early after settlement (Short 1840; Gm). However, it has remained rather uncommon and largely restricted to less fertile soils, especially in marginal pastures and old fields. S. graminea is a variable species that has sometimes been confused with longifolia, but it has more diffuse, many-flowered inflorescences; larger, strongly-nerved sepals; and larger, more tuberculate seeds; 2n = 26 or 39 versus just 26 (Cr, FNA 4, W).