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Oakes' evening-primrose

Nuttall's evening primrose

Habit Herbs biennial, densely silky-strigillose, at least proximally, also sparsely villous with long, appressed hairs, sometimes also villous with spreading, pustulate hairs and/or glandular puberulent distally. Herbs perennial, mostly glabrous, sometimes strigillose on leaves and/or glandular puberulent on distal parts, at least on floral tube; from a taproot, lateral roots producing adventitious shoots.
Stems

erect to decumbent, green or flushed with red on proximal parts or throughout, unbranched or bushy and branched from base, with side branches arising obliquely or arcuately from rosette, 10–60 cm.

erect, often branched, 30–100 cm.

Leaves

in a basal rosette and cauline, basal 8–30 × 0.5–3 cm, cauline 3.5–20 ×0.5–2.7 cm;

blade grayish green to dull green, very narrowly oblanceolate to narrowly oblanceolate or narrowly elliptic, margins flat, subentire or remotely dentate, teeth sometimes blunt, sometimes sinuate-dentate proximally;

bracts persistent.

in a basal rosette and cauline, rosette weakly developed or absent, at least during flowering, 2–6(–10.5) × 0.3–0.6(–1) cm;

petiole 0–2 cm;

blade narrowly oblong to oblong-lanceolate, margins usually entire, sometimes remotely denticulate or repand-denticulate.

Inflorescences

usually recurved with ascending tip distally, rarely suberect, unbranched.

Flowers

opening near sunset;

buds erect, 3–5 mm diam., with free tips subterminal, spreading to erect, 2.5–4 mm;

floral tube 15–40 mm;

sepals green to yellow, flushed with red and dark red flecked or red-striped, 9–17 mm;

petals yellow to pale yellow, fading yellowish white to pale yellowish orange, very broadly obcordate, 7–20 mm;

filaments 6–15 mm, anthers 3–7 mm, pollen ca. 50% fertile;

style 20–45 mm, stigma surrounded by anthers at anthesis.

1–several opening per day near sunset;

buds nodding, weakly quadrangular, with free tips 1–2 mm;

floral tube 15–40 mm;

sepals 20–30 mm, not spotted;

petals white, fading pink, broadly obovate or obcordate,15–30 mm;

filaments 15–18 mm, anthers 8–10 mm;

style 35–45 mm, stigma exserted beyond anthers at anthesis.

Capsules

erect or slightly spreading, usually rusty brown when dry, narrowly lanceoloid to lanceoloid, 15–40 × 4–8 mm, free tips of valves 0.5 mm.

erect or ascending, woody in age, straight or slightly curved, cylindrical, obtusely 4-angled, especially toward base, tapering slightly from base to apex, 20–30 × 2–3 mm;

sessile.

Seeds

1.1–1.2 ×0.8–1 mm.

numerous, in 1 row per locule, reddish dark brown, narrowly obovoid, 1.5–2.3 mm.

2n

= 14.

= 14, 28.

Oenothera oakesiana

Oenothera nuttallii

Phenology Flowering Jun–Aug. Flowering Jun–Sep.
Habitat Sandy coastal meadows and dunes, gravelly or rocky sites along rivers, disturbed sites, roadsides. Dry, sandy or rocky prairies, open wooded hillsides, disturbed areas, roadsides.
Elevation 0–50(–500) m. (0–200(–1600) ft.) 500–2200(–2900) m. (1600–7200(–9500) ft.)
Distribution
from FNA
CT; DC; DE; IL; IN; MA; MD; ME; MI; MN; NH; NJ; NY; OH; PA; RI; VA; VT; WI; MB; NB; NF; NS; ON; PE; QC [Introduced in Europe, Asia]
[WildflowerSearch map]
[BONAP county map]
from FNA
CO; IL; MI; MN; MT; ND; NE; SD; WI; WY; AB; MB; SK
[WildflowerSearch map]
[BONAP county map]
Discussion

Oenothera oakesiana is a PTH species and forms a ring of 14 chromosomes or a ring of 12 and 1 bivalent in meiosis, and is self-compatible and autogamous (W. Dietrich et al. 1997). It has plastome IV and a AC genome composition.

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

Oenothera nuttallii had been assumed to be self-incompatible (W. L. Wagner et al. 2007), but K. E. Theiss et al. (2010) determined two plants to be self-compatible.

Anogra nuttalliana Spach and Baumannia nuttalliana Spach 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. Anogra
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. 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. 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. oakesiana, O. ammophila, O. ammophiloides, O. ammophiloides var. angustifolia, O. ammophiloides var. laurensis, O. atrovirens var. ostreae, O. canovirens var. cymatilis, O. cruciata var. stenopetala, O. cymatilis, O. deflexa var. bracteata, O. disjuncta, O. eriensis, O. eriensis var. niagarensis, O. eriensis var. repandodentata, O. germanica, O. insignis, O. laevigata var. rubripunctata, O. leucophylla, O. litorea, O. magdalena, O. millersii, O. muricata var. parviflora, O. niagarensis, O. nobska, O. oakesiana var. nobska, O. oakesiana var. tidestromii, O. ostreae, O. parviflora var. oakesiana, O. perangusta, O. perangusta var. rubricalyx, O. repandodentata, O. rubescens, O. stenopetala, O. tidestromii, Onagra oakesiana O. albicaulis, O. albicaulis var. nuttallii
Name authority (A. Gray) J. W. Robbins ex S. Watson & J. M. Coulter in A. Gray et al.: Manual ed. 6, 190. (1890) Sweet: Hort. Brit. ed. 2, 199. (1830)
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