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El Paso evening primrose

desert evening primrose, yellow desert evening primrose

Habit Herbs acaulescent or caulescent, densely strigillose and glandular puberulent distally; from a taproot. Herbs winter-annual, caulescent to short-caulescent, long-hirsute, hairs often with reddish purple pustulate bases, especially proximally, also moderately strigillose, and glandular puberulent distally, often on leaves; from a weakly fleshy taproot.
Stems

densely leafy, 4–20 cm.

(when present) unbranched and erect or, sometimes, few branches from near base, in robust plants stems and caudex hollow and greatly enlarged, especially toward base, densely leafy, 5–35 cm.

Leaves

in a basal rosette, sometimes also cauline, 5–16 × (0.2–)0.3–0.5(–0.7) cm;

petiole 0.6–3.5 cm;

blade linear to narrowly lanceolate, margins entire or sometimes proximal 1/2 of blade remotely lobed, apex long-attenuate, acute to rounded.

in a basal rosette, sometimes also cauline, (1.4–)6–15(–28) × (0.2–)1–3.5(–5.6) cm;

petiole (0.9–)3.5–8(–14) cm;

blade oblanceolate to linear-oblanceolate, pinnatifid or 2-pinnatifid to shallowly pinnately lobed, margins sinuate-dentate or subentire, apex obtuse.

Flowers

usually 1–3, rarely more, opening per day near sunset, weakly scented;

buds with unequal free tips 0.7–1.2 mm;

floral tube (55–)75–100(–125) mm;

sepals 34–40 mm;

petals lemon-yellow, fading orange, drying lavender to purple, broadly obovate, 35–43 mm, sometimes with terminal tooth;

filaments 17–25 mm, anthers 14–17 mm;

style (85–)105–135(–143) mm, stigma exserted beyond anthers at anthesis.

usually 1–4, rarely more, opening per day, 1–2 hours before sunset;

sepals (7–)12–25(–30) mm;

petals yellow, fading reddish orange to purple, obcordate to obovate, (6–)13–35(–40) mm;

filaments 6–16 mm, anthers 3–10 mm;

style (32–)40–90(–100) mm, stigma exserted beyond anthers or surrounded by them.

Capsules

leathery, lanceoloid to ovoid, winged, wings 4–6 mm wide, body 25–30 × 8 mm, dehiscent 1/4–1/3 their length;

pedicel 1–2(–3) mm.

woody in age, sigmoid or curved to nearly straight, lanceoloid to ovoid, 4-angled, 10–45(–60) × 4–8 mm, beak 4–15 mm, dehiscent 1/4–2/3 their length;

sessile.

Seeds

numerous, usually in 2 distinct rows per locule, often reduced to 1 row near apex, rarely 1 row throughout, obovoid to subcuboid, 2.5–4 × 2.5–3.5 mm.

usually numerous, in 2 rows per locule, obovoid to oblanceoloid, 3–3.5 × 1–1.4 mm, surface thickened above raphe and at distal end into U-shaped structure.

2n

= 42.

= 14.

Oenothera coryi

Oenothera primiveris

Phenology Flowering Apr–May. Flowering Feb–May(–Jun).
Habitat Open grasslands, disturbed areas. Sandy soil on flats, low hills and margins of sand dunes, along arroyos, road­sides, in desert scrub, grasslands and oak-grasslands.
Elevation 300–1000 m. (1000–3300 ft.) 30–1600 m. (100–5200 ft.)
Distribution
from FNA
TX
[BONAP county map]
from FNA
AZ; CA; NM; NV; TX; UT; Mexico (Baja California, Chihuahua, Sonora)
[WildflowerSearch map]
[BONAP county map]
Discussion

Oenothera coryi is known only from Baylor, Callahan, Knox, Nolan, Taylor, and Throckmorton counties in north-central Texas and Crosby and Garza counties in the Texas Panhandle.

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

Oenothera primiveris has a complex variation pattern (W. L. Wagner 2005). In the western part of the range from southeastern California across southern Nevada to southern Utah counties of Emery, Kane, and Washington, and northwestern Mohave County, Arizona, plants generally have a gray appearance, with dense pubescence and larger flowers with widespread self-compatibility, but with scattered populations retaining self-incompatibility. Populations from southof the Mogollon Plateau to southern New Mexico, western Texas, Chihuahua, Sonora, and Baja California, Mexico, are greener in appearance with smaller to much smaller flowers, and are all self-compatible with occasional outcrossing or complete autogamy. The transitions between these two extremes are so extensive and more or less gradual that it is not possible to subdivide into two subspecies as has been done previously (Wagner).

(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. Megapterium Onagraceae > subfam. Onagroideae > tribe Onagreae > Oenothera > sect. Eremia
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. 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. 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. 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. 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 Lavauxia lobata, L. primiveris, O. bufonis, O. cespitosa var. primiveris, O. johnsonii, O. primiveris subsp. bufonis, O. primiveris var. bufonis, O. primiveris subsp. caulescens, O. primiveris var. caulescens, Pachylophus johnsonii
Name authority W. L. Wagner: Ann. Missouri Bot. Gard. 73: 475. (1986) A. Gray: Smithsonian Contr. Knowl. 5(6): 58. (1853)
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