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pink evening primrose, rose evening-primrose

bee-blossom, longflower beeblossom

Habit Herbs perennial, caulescent, strigillose and often also sparsely hirsute; from slender taproot. Herbs usually robust winter-annual, sometimes biennial, moderately to densely strigillose, sometimes also glandular puberulent, villous and/or short-hirtellous; from fleshy taproot.
Stems

1–several, ascending to decumbent, 7–65 cm.

usually well-branched distal to base, (50–)100–400 cm.

Leaves

in a basal rosette and cauline, basal 1–6 × 0.3–2 cm, blade narrowly elliptic to elliptic or ovate, margins subentire, weakly serrulate, or sinuate-pinnatifid;

cauline 1–6 × 0.3–2 cm, blade narrowly elliptic to narrowly ovate, margins subentire or weakly serrulate, proximal ones sinuate-pinnatifid.

in a basal rosette and cauline, basal 8–15(–40) × 1.5–3.6 cm, blade lyrate, margins irregularly toothed to lobed;

cauline 1.5–13 × 0.5–3 cm, blade narrowly elliptic to elliptic or lanceolate, margins subentire or shallowly undulate-denticulate.

Inflorescences

erect.

Flowers

1–3 opening per day near sunrise;

buds with free tips 0.1–1 mm;

floral tube 4–8 mm;

sepals 6–12 mm;

petals rose purple, fading darker, 4–12 mm;

filaments 4–6 mm, anthers 2–3.5 mm, pollen 35–65% fertile;

style 7–13.5 mm, stigma surrounded by anthers at anthesis.

4-merous, zygomorphic, opening at sunset;

floral tube 4–13(–15) mm;

sepals 7–18 mm;

petals white, fading pink, elliptic to elliptic-obovate, 7–15 mm;

filaments 5–13 mm, anthers 1.5–5 mm, pollen 90–100% fertile;

style 12–34 mm, stigma exserted beyond anthers at anthesis.

Capsules

narrowly obovoid, 4–12 × 2–4 mm, apex attenuate to a sterile beak, proximal stipe 5–20 mm, gradually tapering to base, valve midrib prominent in distal part;

sessile.

ellipsoid or ovoid, sharply 4-angled, 4.5–7 × 1.5–2.5 mm;

sessile.

Seeds

narrowly obovoid, 0.5–0.9 × 0.3–0.5 mm.

2–4, yellowish to reddish brown, 1.3–3 × 0.7–1.3 mm.

2n

= 14.

= 14.

Oenothera rosea

Oenothera filiformis

Phenology Flowering Mar–Sep. Flowering (Jun–)Jul–Oct(–Nov).
Habitat tropical areas.. Open woods, fields, along streams, sandy soil, disturbed sites, ditch banks, roadsides, railway embankments.
Elevation 10–600 m. (0–2000 ft.) 10–500 m. (0–1600 ft.)
Distribution
from FNA
AZ; CA; TX; Mexico; Central America; West Indies; tropical areas [Introduced in South America (Argentina), Europe, Asia, s Africa, Atlantic Islands (Azores, Canary Islands)]
[WildflowerSearch map]
[BONAP county map]
from FNA
AL; AR; CO; CT; IA; IL; IN; KS; KY; LA; MA; MD; MI; MO; MS; NE; OH; OK; PA; TN; TX; WI; ON
[WildflowerSearch map]
[BONAP county map]
Discussion

Oenothera rosea is a PTH species, forming a ring of 14 chromosomes in meiosis, and is self-compatible and autogamous. In the flora area, it is known from Cochise, Pima, and Santa Cruz counties in Arizona, Alameda, Los Angeles, Riverside, San Bernardino, San Diego, San Francisco, and Santa Barbara counties in California (primarily in urban areas), and from southern Texas. It is clearly of North American origin, since all of its close relatives are confined to North America, and has spread south along the Andes. It occurs at 500–3700 m in South America but generally at lower elevations in most areas.

The name Hartmannia affinis Spach is illegitimate, being based on Oenothera virgata; H. gauroides Spach is also illegitimate, being based on O. rosea; O. purpurea Lamarck is a later homonym; these three names pertain here.

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

P. H. Raven and D. P. Gregory (1972[1973]) found various levels of hybridization and intergradation between Oenothera filiformis and O. lindheimeri to occur where their ranges overlap. In the region of geographical overlap, most populations of O. filiformis are strigillose in the inflorescences and have evening-opening flowers, while O. lindheimeri is villous in the inflorescences, and has large morning-opening flowers. Moreover, O. lindheimeri occurs only on black clay prairie soil, while O. filiformis occurs in light, sandy soil, as it does throughout its range, and in more disturbed areas. Despite these differences, Raven and Gregory found hybridization between these species scattered across an area from eastern Texas across Louisiana to Alabama. At some locations there is apparently no hybridization, while at others hybrids were uncommon to relatively common. Intermediate morning-blooming plants in Alabama appear to represent evidence of past hybridization since O. lindheimeri does not occur there. Many of the individuals they tested had somewhat reduced pollen fertility (40–70% fertile). They suspected that habitat disturbance was primarily responsible in many cases, but they also detected what may have been intergradation resulting from past hybridization outside of the current distribution of O. lindheimeri. Many of these individual cases deserve further investigation to better understand the dynamics of the interactions between these species and if any of the interactions have led to stabilization of novel populations that might be recognized taxonomically.

Very few collections have been made from areas on the periphery of the range of Oenothera filiformis (southern Ontario, Connecticut, Maryland, Massachusetts, Pennsylvania), and populations in these areas probably represent recent human-based introductions. P. H. Raven and D. P. Gregory (1972[1973]) determined O. filiformis to be self-incompatible.

(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. Hartmannia Onagraceae > subfam. Onagroideae > tribe Onagreae > Oenothera > sect. Gaura > subsect. Gaura
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. 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. 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 Gaura epilobia, Godetia heuckii, Hartmannia rosea, H. rosea var. parvifolia, H. virgata, O. psycrophila, O. rosea var. parvifolia, O. rubra, O. virgata, Xylopleurum roseum Gaura filiformis, G. biennis var. pitcheri, G. filiformis var. kearneyi, G. longiflora
Name authority L’Héritier ex Aiton: Hort. Kew. 2: 3. (1789) (Small) W. L. Wagner & Hoch: Syst. Bot. Monogr. 83: 212. (2007)
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