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Engelmann's evening-primrose

largeflower eveningprimrose, showy evening-primrose

Habit Herbs winter-annual, conspicuously villous throughout, also strigillose on leaves and distal parts; from a taproot. Herbs annual, strigillose and sparsely villous, also glandular puberulent distally.
Stems

erect, unbranched or with few, spreading branches, 30–50(–80) cm.

erect to ascending, often with ascending lateral branches, 15–60(–100) cm.

Leaves

in a basal rosette and cauline, rosette weakly developed or absent, at least during flowering, (1–)2–6(–8) × 1–2(–3) cm;

sessile;

blade lanceolate to oblong lanceolate, proximal ones sometimes oblanceolate, margins coarsely repand-dentate or -pinnatifid.

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.

Flowers

1–several opening per day near sunset;

buds nodding, weakly quadrangular, without free tips;

floral tube 20–30 mm;

sepals 13–21 mm, not spotted or with scattered small, maroon spots;

petals white, fading pink, broadly obovate or obcordate, 15–30 mm;

filaments 14–16 mm, anthers 6–8 mm;

style 40–50 mm, stigma exserted beyond anthers at anthesis.

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.

Capsules

widely spreading, woody in age, straight or slightly curved, cylindrical, obtusely 4-angled, especially toward base, tapering gradually from base to apex, 30–60 × 2–3 mm;

sessile.

cylindrical, sometimes slightly enlarged toward apex, 25–50 ×2–3 mm.

Seeds

numerous, in 1 row per locule, brown, narrowly obovoid, 1–1.5 mm.

broadly ellipsoid to subglobose, 0.8–1.5 × 0.5–0.9 mm.

2n

= 14.

= 14.

Oenothera engelmannii

Oenothera grandis

Phenology Flowering Apr–Aug(–Sep). Flowering Mar–Sep.
Habitat Sandy prairies, dunes, disturbed areas, roadsides. Open, sandy sites.
Elevation 500–1300 m. (1600–4300 ft.) 0–1500(–2200) m. (0–4900(–7200) ft.)
Distribution
from FNA
CO; KS; NM; OK; TX
[WildflowerSearch map]
[BONAP county map]
from FNA
AL; AR; CO; CT; FL; IL; IN; KS; LA; MD; MI; MO; NC; NE; NJ; NM; TX; Mexico (Tamaulipas)
[WildflowerSearch map]
[BONAP county map]
Discussion

Oenothera engelmannii is self-incompatible (W. L. Wagner et al. 2007; K. E. Theiss et al. 2010). It has a relatively narrow distribution in sandy areas of eastern New Mexico and western Texas, extending to southeastern Colorado, western Oklahoma, and southwestern Kansas. The flower size seems to vary, with larger flowers in eastern New Mexico and considerably smaller flowers in the eastern part of its range.

(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.)

Source FNA vol. 10. FNA vol. 10.
Parent taxa Onagraceae > subfam. Onagroideae > tribe Onagreae > Oenothera > sect. Anogra Onagraceae > subfam. Onagroideae > tribe Onagreae > Oenothera > sect. Oenothera > subsect. Raimannia
Sibling taxa
O. acutissima, O. albicaulis, O. argillicola, O. arida, O. arizonica, O. biennis, O. boquillensis, O. brachycarpa, O. calcicola, O. californica, O. canescens, O. capillifolia, O. cavernae, O. cespitosa, O. cinerea, O. clelandii, O. coloradensis, O. cordata, O. coronopifolia, O. coryi, O. curtiflora, O. curtissii, O. deltoides, O. demareei, O. dodgeniana, O. drummondii, O. elata, O. falfurriae, O. filiformis, O. filipes, O. flava, O. fruticosa, O. gaura, O. gayleana, O. glaucifolia, O. glazioviana, O. grandiflora, O. grandis, O. harringtonii, O. hartwegii, O. havardii, O. heterophylla, O. hispida, O. howardii, O. humifusa, O. jamesii, O. kunthiana, O. laciniata, O. lavandulifolia, O. lindheimeri, O. linifolia, O. longissima, O. macrocarpa, O. mckelveyae, O. mexicana, O. nealleyi, O. neomexicana, O. nutans, O. nuttallii, O. oakesiana, O. organensis, O. pallida, O. parviflora, O. patriciae, O. perennis, O. pilosella, O. platanorum, O. podocarpa, O. primiveris, O. psammophila, O. pubescens, O. rhombipetala, O. riparia, O. rosea, O. serrulata, O. sessilis, O. simulans, O. sinuosa, O. spachiana, O. speciosa, O. stricta, O. suffrutescens, O. suffulta, O. tetraptera, O. texensis, O. toumeyi, O. triangulata, O. triloba, O. tubicula, O. villosa, O. wolfii, O. xylocarpa
O. acutissima, O. albicaulis, O. argillicola, O. arida, O. arizonica, O. biennis, O. boquillensis, O. brachycarpa, O. calcicola, O. californica, O. canescens, O. capillifolia, O. cavernae, O. cespitosa, O. cinerea, O. clelandii, O. coloradensis, O. cordata, O. coronopifolia, O. coryi, O. curtiflora, O. curtissii, O. deltoides, O. demareei, O. dodgeniana, O. drummondii, O. elata, O. engelmannii, O. falfurriae, O. filiformis, O. filipes, O. flava, O. fruticosa, O. gaura, O. gayleana, O. glaucifolia, O. glazioviana, O. grandiflora, O. harringtonii, O. hartwegii, O. havardii, O. heterophylla, O. hispida, O. howardii, O. humifusa, O. jamesii, O. kunthiana, O. laciniata, O. lavandulifolia, O. lindheimeri, O. linifolia, O. longissima, O. macrocarpa, O. mckelveyae, O. mexicana, O. nealleyi, O. neomexicana, O. nutans, O. nuttallii, O. oakesiana, O. organensis, O. pallida, O. parviflora, O. patriciae, O. perennis, O. pilosella, O. platanorum, O. podocarpa, O. primiveris, O. psammophila, O. pubescens, O. rhombipetala, O. riparia, O. rosea, O. serrulata, O. sessilis, O. simulans, O. sinuosa, O. spachiana, O. speciosa, O. stricta, O. suffrutescens, O. suffulta, O. tetraptera, O. texensis, O. toumeyi, O. triangulata, O. triloba, O. tubicula, O. villosa, O. wolfii, O. xylocarpa
Synonyms Anogra pallida var. engelmannii, A. engelmannii O. laciniata var. grandiflora, O. sinuata var. grandiflora, Raimannia grandis
Name authority (Small) Munz: Amer. J. Bot. 18: 316. (1931) — (as engelmanni) Smyth: Trans. Kansas Acad. Sci. 16: 160. (1899)
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