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Nuttall's evening primrose

Cleland's evening primrose

Habit 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. Herbs biennial, densely to sometimes sparsely strigillose, or also sparsely glandular puberulent distally.
Stems

erect, often branched, 30–100 cm.

sometimes with lateral branches arising obliquely from rosette, 20–70(–100) cm.

Leaves

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.

in a basal rosette and cauline, basal 5–16 × 0.5–1.5 cm, cauline 2–12 × 0.5–2 cm;

blade narrowly oblanceolate, gradually narrowly elliptic to narrowly lanceolate distally, margins lobed to remotely dentate or subentire;

bracts slightly longer than capsule they subtend.

Inflorescences

dense, without lateral branches, mature buds usually not overtopping spike apex.

Flowers

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.

2–several per spike opening per day near sunset;

buds erect, with free tips erect, 0.5–2 mm;

floral tube slightly curved upward to± straight, 15–40 mm;

sepals 6–13 mm;

petals yellow, broadly elliptic to rhombic-ovate, 5–16 mm;

filaments 4–18 mm, anthers 2–3.5 mm, pollen ca. 50% fertile;

style 20–40 mm, stigma surrounded by anthers at anthesis.

Capsules

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.

narrowly lanceoloid, 10–20 ×2–3 mm.

Seeds

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

brown, sometimes flecked with dark red spots, ellipsoid, 1–1.9 × 0.4–0.8 mm.

2n

= 14, 28.

= 14.

Oenothera nuttallii

Oenothera clelandii

Phenology Flowering Jun–Sep. Flowering Jun–Aug(–Sep).
Habitat Dry, sandy or rocky prairies, open wooded hillsides, disturbed areas, roadsides. Fields, prairies, sandy soil.
Elevation 500–2200(–2900) m. (1600–7200(–9500) ft.) 150–300 m. (500–1000 ft.)
Distribution
from FNA
CO; IL; MI; MN; MT; ND; NE; SD; WI; WY; AB; MB; SK
[WildflowerSearch map]
[BONAP county map]
from FNA
AR; IA; IL; IN; KY; MI; MN; MO; NJ; NY; VA; WI; ON
[WildflowerSearch map]
[BONAP county map]
Discussion

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.)

Oenothera clelandii is a PTH species and forms a ring of 14 chromosomes in meiosis, and is self-compatible and autogamous (W. Dietrich and W. L. Wagner 1988). Some localities in the easternmost states may represent introductions, primarily occurring in disturbed areas along roads and railroad lines.

(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. Anogra Onagraceae > subfam. Onagroideae > tribe Onagreae > Oenothera > sect. Oenothera > subsect. Candela
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. 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. 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. albicaulis, O. albicaulis var. nuttallii
Name authority Sweet: Hort. Brit. ed. 2, 199. (1830) W. Dietrich, P. H. Raven & W. L. Wagner: Ann. Missouri Bot. Gard. 70: 196. (1983)
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