Oenothera rhombipetala Nutt.
Source: IPNI
Family: Onagraceae
Oenothera rhombipetala image
Much like no. 6 [Oenothera clelandii W. Dietr., P. H. Raven & W. L. Wagner], but an out crossing diploid with larger fls, the hypanthium 2-3.5 cm, the sep 1.5-2.5 cm, the pet 1.5-2.5(3) cm, often rhombic- obovate. Fields and prairies in sandy soil; Great Plains, from S.D. to Okla. and Tex., e. occasionally at least as far as se. Minn. June-Sept. (Raimannia r.)

Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.

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