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Texas evening primrose

prairie beeblossom

Habit Herbs perennial, caulescent, strigillose and also sparsely hirsute; from slender taproot. Herbs annual, villous proximally, sparsely villous along veins and on margins, usually glabrate, sometimes strigillose distally; from taproot.
Stems

several–many, ascending, unbranched or branched, 25–50 cm.

ascending, usually well-branched from base and distally, rarely unbranched, 15–60 cm.

Leaves

in a basal rosette and cauline, basal (1–)2.5–6.5 × 0.6–2.3 cm, blade narrowly elliptic to narrowly ovate or ovate, margins weakly serrulate to sinuate-pinnatifid;

cauline 1–5.5 × 0.6–2 cm, blade narrowly elliptic to narrowly ovate, margins weakly serrulate.

in a basal rosette and cauline, 1.5–8 × 0.2–0.6(–1.5) cm, blade very narrowly elliptic to oblanceolate or oblong-elliptic, margins entire or weakly sinuate-dentate.

Inflorescences

erect.

Flowers

1–3 opening per day near sunrise;

buds with free tips 0–1 mm;

floral tube 15–26 mm;

sepals 15–23 mm;

petals rose purple, fading darker, 12–25(–30) mm;

filaments 9–13 mm, anthers 3.5–6mm, pollen 85–100% fertile;

style 26–36 mm, stigma exserted beyond anthers at anthesis.

3(or 4)-merous, zygomorphic, opening at sunset;

floral tube 4–5.5 mm;

sepals 4.5–6 mm;

petals white, fading pink, elliptic-obovate, 3.5–5 mm;

filaments 2–3.5 mm, anthers 1.5–3 mm, pollen 35–65% fertile;

style 9–10 mm, stigma surrounded by anthers.

Capsules

clavate or narrowly obovoid, 9–15 × 3.5–6 mm, apex attenuate to a sterile beak, valve midrib prominent in distal part, proximal stipe 7–12(–28) mm, gradually taperingto base;

sessile.

narrowly obovoid, 3(or 4)-winged, furrowed between wings, 7–9 × 3–5 mm, narrowed at base;

sessile.

Seeds

narrowly obovoid, 0.8–1 × 0.2–0.4 mm.

(1 or)2–5, yellowishto light brown, 1.5–3.5 × 1–1.5 mm.

2n

= 14.

= 14.

Oenothera texensis

Oenothera triangulata

Phenology Flowering May–Sep. Flowering Apr–Jul.
Habitat Sandy and gravel bars of streambeds and along streams. Open, sandy sites.
Elevation 900–2500 m. (3000–8200 ft.) 200–600 m. (700–2000 ft.)
Distribution
from FNA
TX; Mexico (Coahuila, Tamaulipas)
[BONAP county map]
from FNA
OK; TX
[BONAP county map]
Discussion

In the flora area, Oenothera texensis is known only from Jeff Davis County.

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

Oenothera triangulata is a PTH species and forms a ring of 14 chromosomes in meiosis. The species is self-compatible and autogamous (P. H. Raven and D. P. Gregory 1972[1973]). It may have been derived from hybridization between O. patriciae and O. suffulta. The species has a relatively narrow distribution across south-central Oklahoma and north-central Texas (Oklahoma in Cleveland, Comanche, Cotton, Grady, Oklahoma, Rogers, Stephens, and Tulsa counties; Texas in Archer, Baylor, Callahan, Clay, Coleman, Crosby, Eastland, Erath, Jones, Montague, Taylor, Throckmorton, Tom Greene, Wichita, Wilbarger, and Young counties).

(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. Hartmannia Onagraceae > subfam. Onagroideae > tribe Onagreae > Oenothera > sect. Gaura > subsect. Gaura
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. 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. 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. 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. triloba, O. tubicula, O. villosa, O. wolfii, O. xylocarpa
Synonyms Gaura triangulata, G. hexandra var. triangulata, G. tripetala var. triangulata
Name authority P. H. Raven & D. R. Parnell: Madroño 20: 247. (1970) (Buckley) W. L. Wagner & Hoch: Syst. Bot. Monogr. 83: 214. (2007)
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