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Colorado Springs evening primrose

long-tubed evening primrose, yellow evening primrose

Habit Herbs robust spring annual or, rarely, surviving a second year, caulescent, hirtellous, also glandular puberulent; from stout taproot. Herbs perennial, rarely short-lived, acaulescent or very short-caulescent, glabrate to moderately strigillose, usually also glandular puberulent, sometimes sparsely hirsute distally; from a taproot.
Stems

ascending to erect, stout, unbranched or with lateral stems from basal rosette, densely leafy, 15–30 cm.

(when present) ascending, 1–several, usually densely leafy, 0–2 cm.

Leaves

10–14(–14.5) × 1.5–2.3(–3) cm;

petiole 4.3–6.6 cm;

blade narrowly oblanceolate, margins irregularly and coarsely dentate, apex acute.

primarily in a basal rosette, (3.4–)6–30(–36) × (0.5–)1.5–5(–7) cm, flexible, sometimes ± fleshy;

petiole (0.2–)2–7(–10) cm;

blade oblanceolate to linear, margins usually irregularly and coarsely pinnately lobed, rarely subentire, apex acute.

Flowers

usually 5–10 per stem opening per day near sunset, with heavy, sweet scent;

buds erect;

floral tube 31–60 mm;

sepals 17–26 mm;

petals white, fading pale pink, 20–26 mm;

filaments 11–16 mm, anthers 8–11 mm;

style 65–96 mm, stigma exserted beyond anthers at anthesis.

1–4 opening per day near sunset;

buds with free tips (1–)2–10(–12) mm;

floral tube (24–)40–200(–265) mm;

sepals (8–)11–40(–42) mm;

petals bright yellow, sometimes paler (in smaller-flowered plants), fading pale orange, drying purple, (7–)10–45(–50) mm;

filaments (5–)8–23(–26) mm, anthers (2–)3–13(–16) mm;

style (40–)50–250(–290) mm, stigma exserted beyond or surrounded by ring of anthers.

Capsules

straight, lanceoloid, obtusely 4-angled, (21–)25–30(–35) × (5–)6–8 mm, tapering to a sterile beak 6–8 mm, dehiscent 1/2–2/3 their length, valve margins with 5–8 conspicuous, irregular tubercles, sometimes 2 or more coalesced into a sinuate ridge, also with conspicuous medial ridge throughout;

pedicel 0.5–1 mm.

leathery in age, surface usually conspicuously reticulate, usually narrowly ovoid or ellipsoid, sometimes ovoid or lanceoloid, winged, wings narrowly oblong, (2–)3–5(–6) mm wide, confined to distal 2/3 of capsule, (10–)20–35(–43) × 4–8 mm (excluding wings), gradually constricted to a short beak, dehiscent 1/4–1/2 their length, valve surface usually conspicuously reticulate;

sessile.

Seeds

numerous, usually in 2 distinct rows per locule, sometimes rows partially overlapping, narrowly obovoid, 2.1–2.3 × 1–1.3 mm, embryo slightly less than 1/2 seed volume, surface appearing finely striate but papillose under magnification;

seed collar with membrane intact at maturity, membrane rarely splitting and separating from collar, margin entire.

asymmetrically cuneiform, 1.8–2.2(–2.6) mm.2n = 14.

2n

= 14.

Oenothera harringtonii

Oenothera flava

Phenology Flowering May–Jun. Flowering Mar–Aug(–Oct).
Habitat On compacted, silty clay to looser rocky and sandy soil in open grassland. Local and colonial, sometimes abundant in wet (at least seasonally moist) clay to gravelly sand of swales, desiccating flats and ponds, montane meadows, margins of permanent or seasonal watercourses, open sites.
Elevation 1400–1900 m. (4600–6200 ft.) 300–3200 m. (1000–10500 ft.)
Distribution
from FNA
CO
[BONAP county map]
from FNA
AZ; CA; CO; ID; MT; ND; NE; NM; NV; OR; SD; UT; WA; WY; AB; MB; SK; Mexico (Chihuahua, Durango, Guanajuato, Hidalgo, Jalisco, Sonora)
[WildflowerSearch map]
[BONAP county map]
Discussion

Oenothera harringtonii is known only from southeastern Colorado from western El Paso and eastern Fremont counties, southeast through Pueblo to Otero counties, and south to Las Animas County; it may also occur in adjacent Colfax and Union counties in New Mexico but has not been collected there. Oenothera harringtonii is self-incompatible (W. L. Wagner et al. 1985; Wagner 2005).

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

Petals in Oenothera flava typically range from 7–32 mm with floral tubes 24–100 mm; however, plants from three disjunct areas: the Mogollon Plateau in Arizona to Catron County, New Mexico; Sacramento Mountains and Sierra Blanca, Lincoln and Otero counties, New Mexico; and the Sierra Madre Occidental from northern Chihuahua south to Durango, have much larger petals (30–55 mm) and longer floral tubes (80–265 mm). They were originally recognized as a distinct species or most recently as a subspecies (O. flava subsp. taraxacoides), but detailed study of the variation pattern suggests that the larger flowers occur in areas of high hawkmoth species diversity and higher rates of outcrossing, similar to the pattern discussed in detail by D. P. Gregory (1963, 1964). R. A. Raguso et al. (2007) and H. E. Summers et al. (2015) came to the same conclusion in an independent study of floral biology of sect. Lavauxia. Because populations from the three disjunct areas appear to have diverged independently from lower-elevation source populations, it seems best to treat the complex as one variable species without any formal subdivision.

(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. Pachylophus Onagraceae > subfam. Onagroideae > tribe Onagreae > Oenothera > sect. Lavauxia > subsect. Lavauxia
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. 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. 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. 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 Lavauxiaflava a., L. palustris, L. taraxacoides, O. flava subsp. taraxacoides, O. murdockii, O. taraxacoides, O. triloba var. ecristata
Name authority W. L. Wagner, Stockhouse & W. M. Klein: Ann. Missouri Bot. Gard. 70: 195. (1983) (A. Nelson) Garrett: Spring Fl. Wasatch ed. 4, 106. (1927)
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