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Engelmann's evening-primrose

Habit Herbs perennial or sometimes annual, glabrate to strigillose throughout; from a stout taproot. Herbs winter-annual, conspicuously villous throughout, also strigillose on leaves and distal parts; from a taproot.
Stems

1–several, ascending to erect, unbranched to densely branched, 15–70 cm.

erect, unbranched or with few, spreading branches, 30–50(–80) cm.

Leaves

1–3.5 × 0.1–0.7 cm, fascicles of small leaves 0.2–2.5 cm present in non-flowering axils;

petiole 0 cm;

blade narrowly lanceolate, base acute-attenuate, margins entire or obscurely and sparsely serrulate, not undulate, apex acute.

in a basal rosette and cauline, rosette weakly developed or absent, at least during flowering, (1–)2–6(–8) × 1–2(–3) cm;

sessile;

blade lanceolate to oblong lanceolate, proximal ones sometimes oblanceolate, margins coarsely repand-dentate or -pinnatifid.

Flowers

usually 1 per stem opening per day at sunset;

buds with free tips 2–9(–12) mm;

floral tube (15–)30–60(–70) mm, funnelform in distal 1/2 or less;

sepals 10–25 mm;

petals yellow, fading pale pink or pale purple, 10–20 mm;

filaments 4–12 mm, anthers 6–10 mm, pollen 85–100% fertile;

style 35–70(–80) mm, stigma yellow, quadrangular, usually exserted beyond anthers.

1–several opening per day near sunset;

buds nodding, weakly quadrangular, without free tips;

floral tube 20–30 mm;

sepals 13–21 mm, not spotted or with scattered small, maroon spots;

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

filaments 14–16 mm, anthers 6–8 mm;

style 40–50 mm, stigma exserted beyond anthers at anthesis.

Capsules

10–50 × 1.5–4 mm, somewhat papery, promptly dehiscent in distal 1/2.

widely spreading, woody in age, straight or slightly curved, cylindrical, obtusely 4-angled, especially toward base, tapering gradually from base to apex, 30–60 × 2–3 mm;

sessile.

Seeds

obovoid, 2–3 mm.

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

2n

= 14.

= 14.

Oenothera toumeyi

Oenothera engelmannii

Phenology Flowering (May–)Jul–Oct. Flowering Apr–Aug(–Sep).
Habitat Local and uncommon on shaded, rocky slopes or disturbed areas, pine-oak forests. Sandy prairies, dunes, disturbed areas, roadsides.
Elevation 1500–2600 m. (4900–8500 ft.) 500–1300 m. (1600–4300 ft.)
Distribution
from FNA
AZ; NM; Mexico (Chihuahua, Sonora)
[BONAP county map]
from FNA
CO; KS; NM; OK; TX
[WildflowerSearch map]
[BONAP county map]
Discussion

Oenothera toumeyi occurs locally from the Chiricahua, Huachuca, and Santa Rita mountains in Cochise and Santa Cruz counties, Arizona, and the Mogollon Mountains in southern Catron County, New Mexico, south through northeastern Sonora in the Sierra Madre Occidental to west-central Chihuahua. H. F. Towner (1977) found that O. toumeyi is self-incompatible and vespertine.

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

Oenothera engelmannii is self-incompatible (W. L. Wagner et al. 2007; K. E. Theiss et al. 2010). It has a relatively narrow distribution in sandy areas of eastern New Mexico and western Texas, extending to southeastern Colorado, western Oklahoma, and southwestern Kansas. The flower size seems to vary, with larger flowers in eastern New Mexico and considerably smaller flowers in the eastern part of its range.

(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. Calylophus > subsect. Salpingia 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. 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. 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. 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 Galpinsia toumeyi, Calylophus hartwegii subsp. toumeyi, C. hartwegii var. toumeyi, C. toumeyi, O. hartwegii var. toumeyi Anogra pallida var. engelmannii, A. engelmannii
Name authority (Small) Tidestrom: Proc. Biol. Soc. Wash. 48: 41. (1935) (Small) Munz: Amer. J. Bot. 18: 316. (1931) — (as engelmanni)
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