Oenothera speciosa Nuttall. Phen: (Feb-) Apr-Jul (-Oct). Hab: Grasslands, prairies, glades, roadsides and fields, also cultivated as an ornamental. Dist: The original distribution obscured by subsequent cultivation and spread, but apparently something like IA and NE south to LA, TX, NM, and Mexico (BCS, CHH, COA, DGO, MOR, NLE, SLP, SON, TAM, ZAC).
Origin/Endemic status: Native
Taxonomy Comments: Substantial variation in ploidy (n= 7, 14, 21), color (white, pink), and flower-opening time (morning, evening) is here included uncomfortably in one taxon. Great Plains Flora Association (1986) discussed "Most of our plants are diploid, with white flowers that open in the evening. In se. KS rare roadside colonies are tetraploid, with rose-purple flowers that open in the morning".
Synonymy: = Ar, C, F, Fl4, FNA10, G, GrPl, Il, K1, K3, K4, NcTx, Pa, RAB, Tn, Tx, Va, W, WH3, Munz (1965), Wagner, Hoch, & Raven (2007); = Hartmannia speciosa (Nutt.) Small – S; > Oenothera delessertiana Steud.