Oenothera pilosella
Oenothera nealleyi
meadow evening-primrose
spreading or ascending, unbranched or few-branched distally, 20–80 cm.
usually well-branched, 20–70(–100) cm.
in a basal rosette and cauline, basal 4–8 × 2–5 cm, petiole (0.5–)1–3(–4) cm, blade oblanceolate to ovate, margins entire;
cauline 3–10(–13) × 1–2(–4) cm, petiole 0–0.5(–2) cm, blade lanceolate to ovate, abruptly narrowed to base, margins subentire or coarsely dentate.
in a basal rosette and cauline, basal 3.5–9 × 0.5–1.5 cm, blade lyrate;
cauline 1.5–7 × 0.1–0.6 cm, blade narrowly lanceolate to linear, margins sinuate-dentate, undulate.
erect, flowers in axils of distalmost few nodes.
opening near sunrise;
buds with free tips 1–3 mm, spreading;
floral tube 10–25 mm;
sepals 10–20 mm;
petals bright yellow, fading pale pink or pale yellow, 15–30 mm;
filaments 7–15 mm, anthers 4–8 mm, pollen 85–100% fertile;
style 10–20 mm, stigma exserted beyond anthers at anthesis.
4-merous, zygomorphic, opening at sunset;
floral tube 10–20 mm;
sepals 11–21 mm;
petals white, fading pink to red, elliptic to elliptic-obovate, 10–15 mm;
filaments 8–13 mm, anthers 2–6 mm, pollen 90–100% fertile;
style 22–36 mm, stigma exserted beyond anthers at anthesis.
usually oblong-clavate to oblong-ellipsoid or ellipsoid, 4-angled or weakly 4-winged, (5–)10–15(–28) × 2–4(–5) mm, stipe (1–)3–5(–9) mm;
sessile.
ellipsoid or ovoid, narrowly 4-winged, furrowed between angles, 4.5–8 × 2–5 mm, stipe 0.2–2.2 mm;
sessile.
1 × 0.5 mm.
3 or 4 (or 5), yellowish to light brown, 2–3(–4) × 1 mm.
= 56.
= 14.
Oenothera pilosella
Oenothera nealleyi
Oenothera pilosella is widespread in cultivation in gardens and frequently escapes and becomes naturalized; the northern and eastern natural limits of O. pilosella are not clear. According to G. B. Straley (1977) the natural limits are from Wayne County, West Virginia, along the Ohio River and Erie County, New York, for the eastern limits, and Tuscola County, Michigan, and Manitowoc County, Wisconsin, for the northern limits. K. N. Krakos (2014), based on new field studies and phylogenetic data, found that O. pilosella does not form a monophyletic group with plants previously treated by Straley as O. pilosella subsp. sessilis in molecular analyses, and thus is here reinstated as the distinct species O. sessilis. Straley determined that O. pilosella is self-incompatible and an octoploid, one of the few in the genus.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Oenothera nealleyi is restricted to an area from trans-Pecos Texas and northern Coahuila, Mexico, north to Bernalillo and Torrance counties, New Mexico. P. H. Raven and D. P. Gregory (1972[1973]) considered O. nealleyi to represent an unevenly intergrading entity with O. suffulta based on merging of distinguishing characteristics. The known intermediates occur in Terrell County, Texas, and were previously described as Gaura suffulta var. terrellensis Munz, but until new data on its status are available, we include this name with O. nealleyi. The molecular data (K. N. Krakos, unpubl.) suggest that O. nealleyi is not as closely related to O. suffulta as suggested by Raven and Gregory, given the placement in the phylogeny and the difference in scent profiles for these two taxa. Oenothera suffulta is a member of a strongly supported clade that also includes O. patriciae and O. triangulata, while O. nealleyi is a member of a polytomy that consists of other species of subsect. Gaura, with the O. suffulta—O. triangulata—O. patriciae clade sister to it (W. L. Wagner et al. 2013). Oenothera nealleyi has a strong sweet scent, whereas O. suffulta does not have a discernible scent (Wagner et al.). Raven and Gregory determined O. nealleyi to be self-incompatible.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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