Oenothera perennis L.
Family: Onagraceae
Small Evening-Primrose,  more...
[Kneiffia perennis (L.) Pennell,  more...]
Oenothera perennis image
From Flora of Indiana (1940) by Charles C. Deam

Our specimens from southern Indiana were found in hard, white clay soil and those from the northern part were in a wet, prairie habitat.

Fibrous-rooted perennial (1-)2-6 dm, usually simple; principal lvs oblanceolate to elliptic, (1-)3-6 cm, obtuse, narrowed to a petiolar base, the bracteal shorter and proportionately narrower, but still well developed and generally exceeding the ovary; infl nodding, the axis straightening during anthesis, the fls becoming erect and opening singly, autogamous, diurnal; hypanthium 3-10 mm; pet 5-10 mm, obcordately notched; filaments 3-4 mm, alternately unequal; anthers 1.5-2.5 mm; style 3-10 mm, about equaling the anthers; fr ellipsoid-clavate or oblong, glandular puberulent (or glabrate in age), the body 4-10 mm, tapering to a short pedicel-like base; 2n=14, a complex heterozygote. Moist or dry soil, fields, meadows, and open woods; Nf., and Que. to s. Man., s. to Va., and Mo., and in the mts. to N.C. and S.C. June-Aug. (O. pumila; Kneiffia pumila; K. perennis)

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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