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prairie beeblossom

Mexican evening primrose

Habit Herbs annual, villous proximally, sparsely villous along veins and on margins, usually glabrate, sometimes strigillose distally; from taproot. Herbs annual, moderately to sparsely strigillose and densely long-villous, sometimes also becoming glandular puberulent distally.
Stems

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

erect to ascending, usually unbranched, or with arcuate lateral branches arising from rosette, 15–40(–60) cm.

Leaves

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.

in a basal rosette and cauline, basal 6–10 × 1–2.5 cm, cauline 3–7.5 × 0.8–2 cm;

blade usually grayish green, narrowly oblanceolate to narrowly oblanceolate, margins deeply lobed, lobes usually dentate;

bracts distalmost erect, revolute.

Flowers

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.

usually 1 opening per day near sunset;

buds erect, with free tips erect or appressed, 0.5–2.5 mm;

floral tube 23–28 mm;

sepals 5–12 mm;

petals yellow, fading orange, broadly obovate or shallowly obcordate, 6–15 mm;

filaments 4–12 mm, anthers 3–4 mm, pollen 85–100% fertile;

style 27–40 mm, stigma surrounded by anthers at anthesis.

Capsules

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

sessile.

cylindrical, sometimes slightly enlarged toward apex, 25–45 × 2.5–3 mm.

Seeds

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

ellipsoid to subglobose, 0.8–1.2 × 0.3–0.5 mm.

2n

= 14.

= 14.

Oenothera triangulata

Oenothera mexicana

Phenology Flowering Apr–Jul. Flowering Apr–May.
Habitat Open, sandy sites. Open, sandy sites.
Elevation 200–600 m. (700–2000 ft.) 30–200 m. (100–700 ft.)
Distribution
from FNA
OK; TX
[BONAP county map]
from FNA
TX
[BONAP county map]
Discussion

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.)

Oenothera mexicana is known only from southeastern Texas (Atascosa, Aransas, Bexar, Brooks, Burleson, De Witt, Frio, Gonzales, Kenedy, Medina, Newton, Refugio, San Patricio, Waller, and Washington counties). It is self-compatible and autogamous, but not a PTH species.

(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. Gaura > subsect. Gaura 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. 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
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. 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 Gaura triangulata, G. hexandra var. triangulata, G. tripetala var. triangulata O. laciniata var. mexicana, O. sinuata var. hirsuta, Raimannia mexicana
Name authority (Buckley) W. L. Wagner & Hoch: Syst. Bot. Monogr. 83: 214. (2007) Spach: Nouv. Ann. Mus. Hist. Nat. 4: 347. (1836)
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