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Oenothera clelandii W.Dietrich, P.H.Raven & W.L.Wagner
Family: Onagraceae
Cleland's evening-primrose
Oenothera clelandii image
Peter Gorman  
Erect or ascending biennial 4-10 dm; lvs linear to narrowly lanceolate or linear-oblong, 3-8 cm, entire or remotely and obscurely denticulate, short- hairy on both sides; fls autogamous, numerous, crowded in a terminal, leafy-bracteate spike 1-3 dm; hypanthium 1.5-3 cm, sparsely strigose; sep linear, 0.5-1.5 cm, reflexed separately or ┬▒connivent; pet yellow, 0.5-1.5(-2) cm, broadly elliptic or ovate, usually acute; fr linear, 10-18 mm, usually curved; seeds dark brown, obovoid or fusiform, obscurely pitted; 2n=14, a complex heterozygote. Fields and prairies in sandy soil; Mich. to Minn., Io., Ill., and Ind., and irregularly to Ark., Ky., N.J., and N.Y. June-Sept. (O. rhombipetala, in part)

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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From Flora of Indiana (1940) by Charles C. Deam
In very sandy soil along roadsides and in fallow fields and in the dune area in open woodland, along roadsides, and in waste places, becoming plentiful where conditions permit it to spread.