Oenothera triloba
Oenothera howardii
stemless evening-primrose
Howard's evening-primrose
(when present) ascending, 1–several, densely leafy, 0–20 cm.
(when present) ascending, longer ones becoming decumbent, leafy, sometimes densely so, 0–10(–30) 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, sometimes also cauline, (6–)8.5–17(–23) × (0.5–)1–2(–3) cm;
petiole 2–7.5 cm;
blade usually oblanceolate, elliptic to narrowly oblong, rarely lanceolate, margins often undulate, entire or remotely and irregularly pinnately lobed mostly in proximal 1/2, rarely more regularly pinnately lobed and lobing extending to distal 1/2, sinuses usually extending less than 1/2 to midrib, lobes triangular to oblong or linear, (1–)4–9(–13) mm, apex acute to obtuse.
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.
usually 1 or 2, rarely more, opening per day near sunset, strongly and sweetly scented;
buds with unequal free tips 1–3(–4) mm;
floral tube (43–)60–110(–125) mm;
sepals (30–)35–60(–80) mm;
petals brilliant yellow, fading deep red, drying deep reddish purple to reddish brown, usually broadly obovate, rarely subrhombic, (30–)40–60(–73) mm, sometimes with a terminal tooth;
filaments (19–)25–38 mm, anthers 10–17 mm;
style(90–)110–145(–165) 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.
leathery, ovoid, narrowly ovoid, or narrowly lanceoloid to broadly ellipsoid, winged, wings (2–)4–7(–11) mm wide, body (20–)25–50(–80) × 4–6 mm, dehiscent 1/4–1/3 their length;
pedicel 2–6 mm.
asymmetrically cuneiform, (2.1–)2.5–3(–3.3) mm.
numerous, usually in 1 row per locule, rarely in 2 rows toward base, obovoid to subcuboid, 3–8 × 2.5–3.5 mm.
= 14.
= 28, 42, 56.
Oenothera triloba
Oenothera howardii
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.)
Oenotherahowardii is known from three disjunct areas: three collections on the High Plains (Baca and Otero counties, Colorado, and Hamilton County, Kansas); open yucca-juniper grassland, rocky slopes or disturbed areas on shale substrates along the Colorado counties of Boulder, Denver, Jefferson, and Larimer, and just over the state line in Wyoming; and, common to scattered, mostly on rocky slopes but also in shaded canyon sites on fine-textured red sandstones, clays, gypsum, chalky white degraded limestone or limestone in pinyon-juniper woodland to ponderosa pine-Douglas fir forest in southern Utah and eastern Nevada.
A. Nelson intended to publish Lavauxia howardii as a new combination and base it on Oenothera howardii M. E. Jones (1893), which was not validly published at the time, but inadvertently published L. howardii as a new species. Oenothera howardii (A. Nelson) W. L. Wagner is an isonym.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
IL Wildflowers
KS Wildflowers
MD Biodiversity
MO Plants
WildflowerSearch
iNaturalist
USDA Plants Database
CalFlora
