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El Paso evening primrose

threadleaf evening-primrose, threadleaf sundrop

Habit Herbs acaulescent or caulescent, densely strigillose and glandular puberulent distally; from a taproot. Herbs annual, caulescent, strigillose or glabrous, also often glandular puberulent, especially distally; from a sparsely branched taproot.
Stems

densely leafy, 4–20 cm.

unbranched or with many ascending branches arising near base, erect, 10–50 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 and cauline, basal 1–2(–4) × 0.2–0.6 cm, petiole 0.2–1(–1.5) cm, blade ovate to obovate or narrowly elliptic;

cauline 1–4 × less than 0.1 cm, sessile, blade linear or filiform.

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 1–3 opening per day near sunrise;

buds without free tips;

sepals 1.5–2 mm;

petals bright yellow, fading pink, obcordate to obovate, 3–5(–7) mm;

filaments 1–2 mm, anthers 0.5–1 mm;

style 1–2 mm, stigma surrounded by anthers at anthesis.

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.

ellipsoid-rhombic to subglobose, 4-angled, 4–6(–10) × 1.5–3 mm, stipe 0–4 mm, valve midrib raised at distal end, indehiscent or tardily dehiscent distally;

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.

clustered in each locule, ovoid, surface minutely papillose, 1 × 0.5 mm.

2n

= 42.

= 14.

Oenothera coryi

Oenothera linifolia

Phenology Flowering Apr–May. Flowering Apr–Jun(–Aug).
Habitat Open grasslands, disturbed areas. Prairies, open woodlands, open rocky and sandy sites, roadsides.
Elevation 300–1000 m. (1000–3300 ft.) 0–400 m. (0–1300 ft.)
Distribution
from FNA
TX
[BONAP county map]
from FNA
AL; AR; FL; GA; IL; KS; KY; LA; MO; MS; NC; OK; SC; TN; TX
[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.)

Kneiffia linearifolia Spach (1835) is an illegitimate name based on Oenothera linifolia.

(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. Peniophyllum
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. 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 Kneiffia linifolia, O. linifolia var. glandulosa, Peniophyllum linifolium
Name authority W. L. Wagner: Ann. Missouri Bot. Gard. 73: 475. (1986) Nuttall: J. Acad. Nat. Sci. Philadelphia 2: 120. (1821)
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