Oenothera triloba
Oenothera grandis
stemless evening-primrose
largeflower eveningprimrose, showy evening-primrose
(when present) ascending, 1–several, densely leafy, 0–20 cm.
erect to ascending, often with ascending lateral branches, 15–60(–100) cm.
in a basal rosette, sometimes also cauline, (2.5–)6–25(–32) × (0.6–)1.5–4(–5) cm, thin;
petiole (0.5–)1–8 cm;
blade oblanceolate to elliptic, margins irregularly pinnatifid, sometimes subentire, apex acute to obtuse or rounded.
in a basal rosette and cauline, basal 5–13 × 1–3 cm, cauline 3–10 × 1.5–3.5 cm;
blade green, narrowly oblanceolate to narrowly elliptic, margins lobed or dentate, lobes often dentate;
bracts spreading, flat.
1–4 opening per day near sunset, without noticeable scent;
buds with subequal free tips 2–7 mm;
floral tube (20–)28–95(–138) mm;
sepals (6–)10–30(–35) mm;
petals pale yellow, fading pale orange, drying lavender, (10–)12–30(–38) mm;
filaments (5–)8–15(–18) mm, anthers (3.5–)4–11 mm;
style (3.4–)4.2–11.5(–16.3) mm, stigma usually surrounded by anthers, sometimes (especially in some Texas populations) exserted beyond anthers.
1–few opening per day near sunset;
buds erect, with free tips terminal, erect or hornlike, 1.5–5 mm;
floral tube 25–45 mm;
sepals 15–30 mm;
petals yellow, very broadly obovate or shallowly obcordate, 25–40 mm;
filaments 12–22 mm, anthers 4–11 mm, pollen 85–100% fertile;
style 40–75 mm, stigma exserted beyond anthers at anthesis.
woody in age, rhombic-obovoid, winged, wings broadly triangular, 5–10 mm wide, often terminating in a hooked tooth, (10–)15–25(–28) × 4–8 mm (excluding wings), valve surface reticulate, dehiscent 1/8–1/3 their length.
cylindrical, sometimes slightly enlarged toward apex, 25–50 ×2–3 mm.
asymmetrically cuneiform, (2.1–)2.5–3(–3.3) mm.
broadly ellipsoid to subglobose, 0.8–1.5 × 0.5–0.9 mm.
= 14.
= 14.
Oenothera triloba
Oenothera grandis
Oenotheratriloba is primarily a species of the high plains from eastern Socorro County, New Mexico, east through all but eastern Texas, Oklahoma, to southern Kansas, east of Meade and Pawnee counties and south of Douglas and Saline counties. It becomes more sporadic eastward into Missouri south of the Missouri River, northwestern and north-central Arkansas, central and eastern Tennessee, northern Alabama, and Logan and Warren counties, Kentucky; also known from disjunct sites in northern Mexico from Nuevo León, Chihuahua, and Baja California, Mexico; and, introduced in Illinois, Indiana, Ohio, Kentucky (Campbell and Fayette counties), Pennsylvania, Virginia, Maryland, and the District of Columbia. Areas where it was introduced are represented by old collections; no current information indicates their continued presence in any of these areas. It was recently collected in Baca County, Colorado.
Capsules of dead plants sometimes form pineconelike clusters of ten to 100 or more capsules.
The illegitimate names Lavauxia nuttalliana Spach and L. triloba (Nuttall) Spach var. watsonii Britton pertain here.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Oenothera grandis is probably native to eastern New Mexico and Colorado, Arkansas, Kansas, Louisiana, Missouri, Nebraska, Oklahoma, and Texas, and northeastern Tamaulipas, Mexico. Scattered collections made in other states probably represent introductions (W. Dietrich and W. L. Wagner 1988).
Oenothera grandis is self-incompatible (W. Dietrich and W. L. Wagner 1988).
Oenothera laciniata Hill var. occidentalis Small and O. laciniata var. grandis Britton are illegitimate superfluous names based on O. sinuata Linnaeus var. grandiflora S. Watson and pertain here.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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