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large-flower evening-primrose

white-stem evening-primrose, whitest evening primrose, whitish evening primrose

Habit Herbs biennial, often appearing glabrous to naked eye, usually sparsely to moderately strigillose and villous with pustulate, translucent hairs proximal to inflorescence, pustules not red (in fresh material), inflorescence glabrous, glandular puberulent, or strigillose and glandular puberulent. Herbs winter-annual, densely strigillose, also sparsely villous; from a taproot.
Stems

erect, red on proximal parts, usually green on distal ones, rarely red throughout, unbranched or with branches obliquely arising from rosette and secondary branches arising from main stem, 100–300(–400) cm.

ascending to decumbent, 1–several from base, sometimes unbranched, erect or ascending, 5–30 cm.

Leaves

in a basal rosette and cauline, basal 18–32 × (2–)3–6.5 cm, cauline 6–20 × 1.5–6.5 cm;

blade soft and thin, bright green, usually flat, rarely undulate, narrowly oblanceolate to narrowly obovate, or narrowly elliptic to elliptic, sometimes narrowly ovate distally, margins bluntly dentate or subentire, teeth widely spaced, sometimes sinuate-dentate proximally or lobed;

bracts usually caducous.

in a basal rosette and cauline, 1.5–10 × 0.3–2.5 cm;

blade oblanceolate to oblong, margins subentire or coarsely dentate or pinnatifid.

Inflorescences

erect, often with secondary or tertiary branches just proximal to main one.

Flowers

opening near sunset;

buds erect, 5–9 mm diam., with free tips terminal, erect, 2–9 mm;

floral tube 35–55 mm;

sepals yellowish green or flushed with red, 22–46 mm;

petals yellow to pale yellow, fading pale yellowish white, very broadly obcordate or obovate, (25–)30–45 mm;

filaments 18–27 mm, anthers 10–15 mm, pollen 90–100% fertile;

style 57–90 mm, stigma exserted beyond anthers at anthesis.

1–3 opening per day near sunset;

buds nodding, weakly quadrangular, without free tips;

floral tube 15–30 mm, mouth glabrous;

sepals 15–30 mm;

petals white, fading pink, usually obcordate, sometimes obovate, (15–)20–35(–40) mm;

filaments 11–17 mm, anthers 6–10 mm;

style 25–50 mm, stigma exserted beyond anthers at anthesis.

Capsules

erect or slightly spreading, dull green when dry, narrowly lanceoloid to narrowly ovoid, 15–35 × 3.5–5.5 mm, free tips of valves 0.5–2.5 mm.

ascending to erect, usually straight, sometimes curved, cylindrical, weakly 4-angled, 20–40 × 3–4 mm, dehiscent 1/2 their length;

sessile.

Seeds

1–1.7 × 0.6–1.2 mm.

in 2 rows per locule, ellipsoid to subglobose, 0.8–1.5 × 0.5–0.9 mm, surface regularly pitted, pits in longitudinal lines.

2n

= 14.

= 14.

Oenothera grandiflora

Oenothera albicaulis

Phenology Flowering Jul–Aug(–Sep). Flowering (Feb–)Mar–Jun(–Dec).
Habitat Scattered, presumably relictual populations on chalky bluffs, loose sand over limestone, along streams, marshes, ditches, roadsides. Dry, usually sandy flats and slopes.
Elevation 20–600 m. (100–2000 ft.) 1000–2300 m. (3300–7500 ft.)
Distribution
from FNA
AL; FL; MS; NC; SC; TN
[BONAP county map]
from FNA
AZ; CO; ID; KS; MT; ND; NE; NM; OK; SD; TX; UT; WY; Mexico (Chihuahua, Sonora)
[WildflowerSearch map]
[BONAP county map]
Discussion

Oenothera grandiflora has a scattered distribution, from the eastern half of Mississippi and Alabama, east to Tennessee (Franklin and Marion counties), North Carolina (Cherokee, Macon, Martin, Moore, New Hanover, Sampson, and Swain counties), South Carolina (Oconee, Spartanburg, and Sumter counties), and Florida (Alachua, Escambia, Franklin, Lake, Leon, Polk, Putnam, and Santa Rosa counties). Collections from southern Canada, New York, Pennsylvania, Vermont, and West Virginia almost certainly represent cultivated plants, garden escapes, or adventive populations, and the single locality from central Kentucky also may be an introduction; it is sometimes a colonizer in disturbed sites such as along roads.

Oenothera grandiflora has plastome III and a BB genome composition. As summarized by W. Dietrich et al. (1997), some populations of O. grandiflora seem to be entirely or mostly composed of self-incompatible individuals, whereas others consist of self-compatible plants. This is an extremely uncommon phenomenon within a single species of Oenothera; the only other species known to exhibit mixed populations of self-incompatible and self-compatible individuals is O. primiveris.

Oenothera grandiflora Lamarck 1798, being a later homonym of O. grandiflora L’Héritier 1789, pertains here.

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

Oenothera albicaulis is self-incompatible (W. L. Wagner et al. 2007; K. E. Theiss et al. 2010). Oenothera albicaulis has been reported from southern Nevada, but documentation is needed of its occurrence there.

Anogra pinnatifida Spach, Baumannia pinnatifida Spach, Oenothera pinnatifida Nuttall, O. purshiana Steudel, and O. purshii G. Don are illegitimate names that pertain here.

(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. Oenothera > subsect. Oenothera Onagraceae > subfam. Onagroideae > tribe Onagreae > Oenothera > sect. Kleinia
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. 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. 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. triangulata, O. triloba, O. tubicula, O. villosa, O. wolfii, O. xylocarpa
Synonyms O. biennis var. grandiflora, O. grandiflora var. glabra, O. grandiflora var. pubescens, O. lamarckiana, O. spectabilis Anogra albicaulis, A. bradburiana, A. buffumii, A. confusa, A. ctenophylla, A. perplexa, O. albicaulis var. xanthosperma, O. ctenophylla, O. sinuata var. bicolor
Name authority L’Héritier in W. Aiton: Hort. Kew. 2: 2. (1789) Pursh: Fl. Amer. Sept. 2: 733. (1813)
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