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evening primrose

evening primrose, Hooker's evening-primrose, western evening primrose

Habit Herbs strigillose, usually also villous, with appressed or spreading hairs, sometimes these with red-pustulate bases, distally sometimes also glandular puberulent. Herbs biennial or short-lived perennial, densely strigillose and either sparsely or moderately villous, with appressed or spreading hairs (sometimes with red-pustulate bases), distally sometimes also glandular puberulent.
Stems

erect, green, flushed with red proximally or red throughout, unbranched or branches obliquely arising from rosette and secondary branches arising from main stem, 30–250 cm.

Leaves

in a basal rosette and cauline, basal 10–43 × 1.2–4(–6) cm, cauline 4–25 × 1–2.5(–4) cm;

blade dull green to grayish green, rarely red, narrowly oblanceolate or oblanceolate to narrowly elliptic or narrowly lanceolate, margins usually flat, rarely undulate, bluntly dentate or subentire, teeth sometimes widely spaced, proximal blades sometimes sinuate-dentate toward base;

bracts persistent.

Inflorescences

erect, unbranched.

Flowers

buds green to yellowish green, red-striped, or sometimes red throughout, with free tips 2–7 mm;

petals 30–47(–55) mm;

anthers 8–15(–22) mm.

opening near sunset;

buds erect, 6–10 mm diam., with free tips terminal, erect, 1–7 mm;

floral tube (20–)30–45(–50) mm;

sepals yellowish green, red-striped or strongly flushed with red, 27–50 mm;

petals yellow to pale yellow, fading orange or pale yellow, very broadly obcordate, (25–)30–47(–55) mm;

filaments 17–25 mm, anthers 8–23 mm, pollen 90–100% fertile;

style 50–90 mm, stigma exserted beyond anthers at anthesis.

Capsules

erect or slightly spreading, dull green or gray-green when dry, narrowly lanceoloid, 20–65 × 4–7 mm, free tips of valves 0.5–2.5 mm.

Seeds

1–1.9 × 0.6–1.2 mm.

2n

= 14.

Oenothera elata subsp. hirsutissima

Oenothera elata

Phenology Flowering (Apr–)Jul–Sep(–Oct).
Habitat Montane sites along streams, mesic meadows, roadsides, near permanent or seasonally wet sites, ditch banks, riverbanks, flood plains, fallow agricultural land.
Elevation 10–3000 m. (0–9800 ft.)
Distribution
from FNA
AZ; CA; CO; ID; KS; NM; NV; OK; OR; TX; UT; WA; Mexico (n Baja California, Chihuahua, Coahuila, Durango, Sinaloa, Sonora)
[BONAP county map]
from USDA
w United States; c United States; Mexico; Central America
[WildflowerSearch map]
[BONAP county map]
Discussion

Subspecies hirsutissima occurs throughout much of the western United States, but with only scattered populations in Oklahoma (Custer, Logan, and McCurtain counties) and in eastern Texas (Anderson, Brazos, and Leon counties) and western Texas (Brewster, Culberson, Jeff Davis, and Presidio counties).

Onagra spectabilis Spach is an illegitimate name as is Oenothera corymbosa Sims 1818, not Lamarck 1798, and both pertain here.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Subspecies 3 (2 in the flora).

Subspecies elata differs in anthers 7–12 mm, fewer or no pustulate-based hairs, and generally smaller flowers and habit. It ranges from the highlands of central Mexico, including Guanajuato, Hidalgo, México, Michoacán, Puebla, Querétaro, and Veracruz, south to Guatemala, El Salvador, Costa Rica, and Panama.

Oenothera elata has plastome I and a AA genome composition. Onagra kunthiana Spach is a superfluous name that pertains here.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Key
1. Plants strigillose, usually also villous, with appressed or spreading hairs, sometimes these with red-pustulate bases, distally sometimes also glandular puberulent; buds green to yellowish green, red-striped, or sometimes red throughout; anthers 8–15(–20) mm.
subsp. hirsutissima
1. Plants strigillose, also villous with appressed or spreading hairs, usually these with conspicuous red-pustulate bases, also glandular puberulent; buds flushed with red; anthers 12–23 mm.
subsp. hookeri
Source FNA vol. 10. FNA vol. 10.
Parent taxa Onagraceae > subfam. Onagroideae > tribe Onagreae > Oenothera > sect. Oenothera > subsect. Oenothera > Oenothera elata Onagraceae > subfam. Onagroideae > tribe Onagreae > Oenothera > sect. Oenothera > subsect. Oenothera
Sibling taxa
O. elata subsp. hookeri
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. engelmannii, 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
Subordinate taxa
O. elata subsp. hirsutissima, O. elata subsp. hookeri
Synonyms O. biennis var. hirsutissima, O. elata var. hirsutissima, O. elata subsp. texensis, O. grisea, O. hewettii, O. hirsutissima, O. hookeri subsp. angustifolia, O. hookeri var. angustifolia, O. hookeri subsp. grisea, O. hookeri var. grisea, O. hookeri subsp. hewettii, O. hookeri var. hewettii, O. hookeri subsp. hirsutissima, O. hookeri var. hirsutissima, O. hookeri var. irrigua, O. hookeri subsp. ornata, O. hookeri var. ornata, O. hookeri var. semiglabra, O. hookeri var. simsiana, O. hookeri subsp. venusta, O. hookeri var. venusta, O. irrigua, O. jepsonii, O. macbrideae, O. ornata, O. simsiana, O. venusta, O. venusta var. grisea, Onagra macbrideae, O. ornata
Name authority (A. Gray ex S. Watson) W. Dietrich: Ann. Missouri Bot. Gard. 70: 195. (1983) Kunth in A. von Humboldt et al.: Nov. Gen. Sp. 6(fol.): 72; 6(qto.): 90. (1823)
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