The green links below add additional plants to the comparison table. Blue links lead to other Web sites.
enable glossary links

basket evening-primrose, birdcage evening primrose, desert lantern, devil's lantern, dune primrose, hairy evening primrose, lion-in-a-cage

Habit Herbs usually winter-annual, sometimes perennial, glabrous, glandular puberulent, strigillose, and/or villous, sometimes more villous distally, hairs sometimes very curly, especially on flower parts; from a taproot or relatively long, fleshy roots. Herbs perennial, sparsely strigillose, becoming glabrate distally, usually also glandular puberulent distally; from a somewhat fleshy rootstock, forming adventitious roots where submerged.
Stems

central stem usually erect, usually thickened at base and spongy, branched or unbranched, branches few–several, slender, decumbent to ascending, from base, usually encircling central stem in older plants, 10–40(–100) cm.

erect or ascending, usually many-branched throughout, proximal branches often somewhat spongy, 50–120 cm.

Leaves

in a basal rosette and cauline, rosette usually well developed (except subsp. howellii), basal 5–25 × 1–5 cm, cauline 4–12(–18) × 0.5–4 cm;

petiole 1.5–8 cm;

blade rhombic-obovate, lanceolate, or oblanceolate, margins subentire, dentate, or pinnatifid.

in a basal rosette and cauline, softly succulent, 4–13.5 × 0.8–2.1 cm, petiole 0–1.5 cm, blade lanceolate to elliptic-lanceolate, margins remotely denticulate.

Inflorescences

erect, flowers in axils of distalmost few nodes.

Flowers

1–several opening per day near sunset;

buds nodding, weakly or strongly quadrangular or fluted in distal 1/2, with free tips 0–9 mm;

floral tube 20–40 mm;

sepals (13–)15–35 mm, not spotted;

petals white, fading pink to deep pink, broadly obovate or obcordate, 15–44 mm;

filaments 8–15 mm, anthers 5–14 mm;

style 35–60 mm, stigma exserted beyond anthers at anthesis.

opening near sunrise;

buds with free tips 0.5–2(–5) mm, erect to spreading;

floral tube 14–20 mm;

sepals 20–30 mm;

petals bright yellow, fading pale pink or lavender, 16–27 mm;

filaments 10–15 mm, anthers 7–8 mm, pollen 85–100% fertile;

style 15–30 mm, stigma exserted beyond anthers at anthesis.

Capsules

spreading, straight to curved, becoming somewhat woody in age, cylindrical to slightly 4-angled, widest toward base, tapering from base to apex, (15–)30–80 × 1.5–5 mm;

sessile.

oblong-clavate to oblong-ellipsoid, 4-angled or 4-winged, and wings 0.1–0.2 mm, 7–15 × 4–6 mm, stipe 2–5 mm;

sessile.

Seeds

numerous, in 1 row per locule, buff with dark spots or black, narrowly obovoid, 1.5–2.8 mm.

0.8 × 0.4 mm.

2n

= 56.

Oenothera deltoides

Oenothera riparia

Phenology Flowering May–Jul.
Habitat Isolated colonies in or at edge of water in marshes or slow-running rivers, apparently with at least some tidal influence.
Elevation 0–10 m. (0–0 ft.)
Distribution
from USDA
w United States; nw Mexico
[WildflowerSearch map]
[BONAP county map]
from FNA
GA; NC; SC; VA
Discussion

Subspecies 5 (5 in the flora).

Oenothera deltoides is self-incompatible or self-compatible (W. M. Klein 1964; W. L. Wagner et al. 2007; K. E. Theiss et al. 2010).

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

Oenothera riparia has not been accepted as a distinct species for a long time. The conservative approach used by G. B. Straley (1977) is here followed in recognizing a broadly delimited O. fruticosa, except that the very distinctive coastal tidal-freshwater semi-aquatic octoploid populations (Straley 1982) are recognized as O. riparia. Plants of these coastal populations, which occur from southern Virginia to North Carolina, are more robust, more branched, and less pubescent than those of the two subspecies of O. fruticosa, and have slightly succulent leaves and more prominent adventitious roots (Straley 1982; D. Boufford, pers. comm.). Further field studies and cytological analyses are needed to fully understand the geographical and ecological limits of O. riparia and confirm that it is strictly an octoploid species. K. N. Krakos et al. (2014) determined that Oenothera riparia is self-incompatible and is pollinated by bees (Bombus, Lassioglossum, Megachile, Parallelia, Xylocopa, and Zale).

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

Key
1. Herbs perennial, from long, fleshy roots; stems not thickened at base, branches erect or ascending, not encircling stems in older plants.
subsp. howellii
1. Herbs annual or short-lived perennial from a taproot; stems usually thickened at base, branches ascending or decumbent, often encircling stems in older plants.
→ 2
2. Flower buds fluted or strongly quadrangular in distal 1/2, without free tips, villous with curly hairs, sometimes glabrous; leaf blade margins sinuate-dentate to pinnatifid; petals 15–25(–30) mm; capsules 15–25(–30) mm.
subsp. piperi
2. Flower buds weakly or strongly quadrangular in distal 1/2, with free tips 0–3 mm, strigillose, sparsely to moderately villous, or glabrous; leaf blade margins sinuate-dentate or subentire, rarely pinnatifid; petals 15–44 mm; capsules 40–80 mm.
→ 3
3. Flower buds with free tips 1–3 mm, quadrangular in distal 1/2; plants strigillose, especially distally.
subsp. ambigua
3. Flower buds with free tips 0–1.5 mm, weakly quadrangular in distal 1/2; plants glabrous, villous, or strigillose.
→ 4
4. Herbs annual, strigillose, sometimes also villous; capsules 2–3.5 mm diam.; flower buds with free tips 0–1.5 mm.
subsp. deltoides
4. Herbs short-lived perennial or some­times annual, glabrous or sparsely villous, rarely also strigillose; capsules 3–5 mm diam.; flower buds without free tips.
subsp. cognata
Source FNA vol. 10. FNA vol. 10.
Parent taxa Onagraceae > subfam. Onagroideae > tribe Onagreae > Oenothera > sect. Anogra Onagraceae > subfam. Onagroideae > tribe Onagreae > Oenothera > sect. Kneiffia
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. 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
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. 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
Subordinate taxa
O. deltoides subsp. ambigua, O. deltoides subsp. cognata, O. deltoides subsp. deltoides, O. deltoides subsp. howellii, O. deltoides subsp. piperi
Synonyms Anogra deltoides Kneiffia riparia, O. tetragona var. riparia
Name authority Torrey & Frémont in J. C. Frémont: Rep. Exped. Rocky Mts., 315. (1845) Nuttall: Gen. N. Amer. Pl. 1: 247. (1818)
Web links