Oenothera rosea
Oenothera rhombipetala
pink evening primrose, rose evening-primrose
fourpoint evening primrose
1–several, ascending to decumbent, 7–65 cm.
sometimes with lateral branches arising obliquely from rosette, 30–100(–150) cm.
in a basal rosette and cauline, basal 1–6 × 0.3–2 cm, blade narrowly elliptic to elliptic or ovate, margins subentire, weakly serrulate, or sinuate-pinnatifid;
cauline 1–6 × 0.3–2 cm, blade narrowly elliptic to narrowly ovate, margins subentire or weakly serrulate, proximal ones sinuate-pinnatifid.
in a basal rosette and cauline, basal 6–20 × 0.6–2 cm, cauline 3–15 × 0.8–2.5 cm;
blade narrowly oblanceolate, gradually narrowly elliptic to narrowly lanceolate, oblanceolate, or ovate distally, margins lobed to remotely dentate or subentire;
bracts slightly longer than capsule they subtend.
erect.
dense, usually without lateral branches, mature buds usually not overtopping spike apex.
1–3 opening per day near sunrise;
buds with free tips 0.1–1 mm;
floral tube 4–8 mm;
sepals 6–12 mm;
petals rose purple, fading darker, 4–12 mm;
filaments 4–6 mm, anthers 2–3.5 mm, pollen 35–65% fertile;
style 7–13.5 mm, stigma surrounded by anthers at anthesis.
2–several per spike opening per day near sunset;
buds erect, with free tips erect, 0.5–3 mm;
floral tube slightly curved upward to ± straight, 30–45 mm;
sepals 15–30 mm;
petals yellow, broadly elliptic to rhombic-elliptic, 15–35 mm;
filaments 13–25 mm, anthers 3–8 mm, pollen 85–100% fertile;
style 25–50 mm, stigma exserted beyond anthers at anthesis.
narrowly obovoid, 4–12 × 2–4 mm, apex attenuate to a sterile beak, proximal stipe 5–20 mm, gradually tapering to base, valve midrib prominent in distal part;
sessile.
narrowly lanceoloid, 13–25 × 2.5–3 mm.
narrowly obovoid, 0.5–0.9 × 0.3–0.5 mm.
brown, sometimes flecked with dark red spots, ellipsoid, 1–1.7 × 0.4–0.7 mm.
= 14.
= 14.
Oenothera rosea
Oenothera rhombipetala
Oenothera rosea is a PTH species, forming a ring of 14 chromosomes in meiosis, and is self-compatible and autogamous. In the flora area, it is known from Cochise, Pima, and Santa Cruz counties in Arizona, Alameda, Los Angeles, Riverside, San Bernardino, San Diego, San Francisco, and Santa Barbara counties in California (primarily in urban areas), and from southern Texas. It is clearly of North American origin, since all of its close relatives are confined to North America, and has spread south along the Andes. It occurs at 500–3700 m in South America but generally at lower elevations in most areas.
The name Hartmannia affinis Spach is illegitimate, being based on Oenothera virgata; H. gauroides Spach is also illegitimate, being based on O. rosea; O. purpurea Lamarck is a later homonym; these three names pertain here.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Oenothera rhombipetala is primarily a central plains species that has scattered localities in the Midwest to Illinois, Michigan, and Wisconsin, and barely entering the easternmost parts of Colorado and New Mexico.
Oenothera rhombipetala had a broader delimitation (P. A. Munz 1965) until W. Dietrich and W. L. Wagner (1988) divided it into three species (O. clelandii, O. curtissii, and O. rhombipetala), with both of the split-off species being PTH. Evidence gathered by Dietrich and Wagner showed that these PTH species are geographically separated populations of small-flowered plants, and although they are very close morphologically, their distributions and morphological differences suggest that they were each derived independently from O. rhombipetala. Oenothera rhombipetala is self-incompatible.
Oenothera pyramidalis H. Léveillé is a superfluous name and pertains here.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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