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false gaura

variableleaf evening primrose

Habit Herbs probably biennial, glabrous, becoming sparsely to densely glandular puberulent and short-villous distally, glaucous at least in proximal parts; from stout roots. Herbs annual or short-lived perennial, sparsely to densely strigillose, inflorescence sometimes also sparsely glandular puberulent, villous, or sparsely hirsute with spreading, pustulate-based hairs, or sometimes glabrate.
Stems

erect, branched or unbranched, 30–300 cm.

unbranched or branched mainly in distal part, 25–70 cm.

Leaves

in a basal rosette and cauline, basal 3–7 × 0.5–2 cm, sessile, blade oblong to oblong-lanceolate, base usually ± auriculate, margins entire;

cauline 3–8(–10) × 0.4–1.8 cm, blade lanceolate to oblong-lanceolate, gradually smaller, becoming linear-subulate distally.

in a basal rosette and cauline, basal 7–15 × 1–2.5 cm, cauline 3–13 ×0.4–2.3 cm;

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

bracts longer than capsule they subtend, 1–3 cm.

Inflorescences

long, wandlike, unbranched or branched.

dense, often with several lateral branches, mature buds usually overtopping spike apex.

Flowers

4-merous, nearly actinomorphic, opening near sunrise;

floral tube 6–17 mm;

sepals 4–6 mm;

petals white, fading off-white or tinged pink, slightly unequal, rhombic, 4–6 mm, abruptly clawed;

filaments 5–8 mm, anthers 1.5–2 mm, pollen 85–100% fertile;

style 6–10, stigma exserted beyond anthers at anthesis.

2–several per spike opening per day near sunset;

buds erect, with free tips erect or spreading, 1–6 mm;

floral tube nearly straight, 25–47 mm;

sepals 15–30 mm;

petals yellow, broadly elliptic to nearly rhombic, 18–35 mm;

filaments 15–30 mm, anthers 3–8 mm, pollen 85–100% fertile;

style 45–75 mm, stigma usually exserted beyond anthers at anthesis.

Capsules

ovoid, 4-angled, somewhat flattened, 3–4 × 1.5–2.3 mm, valves with raised midrib and conspicuous lateral veins;

sessile.

lanceoloid, 13–25 × 2.5–4 mm.

Seeds

1, pale yellow, oblanceoloid, 2.4–2.6 × 1–1.5 mm.

brown, often flecked with darker spots, ellipsoid to broadly ellipsoid, 1.1–1.8 × 0.4–0.8 mm.

2n

= 14.

Oenothera glaucifolia

Oenothera heterophylla

Phenology Flowering May–Oct(–Nov).
Habitat Rocky prairie slopes and outcrops or bluffs, along streams, roadsides, usuallyon limestone.
Elevation 200–1300 m. (700–4300 ft.)
Distribution
from FNA
AR; CO; KS; MO; NE; NM; OK; TX; WY
[WildflowerSearch map]
[BONAP county map]
from USDA
s United States
[BONAP county map]
Discussion

Oenothera glaucifolia is self-incompatible, the flowers diurnal, pollinated primarily by wasps (R. Clinebell, unpubl.), as well as bees, flies, butterflies, and occasionally beetles (summarized by W. L. Wagner et al. 2007). It was collected once in 1988 in Indiana at Miller Woods Visitor Center (Lake County), Dritz 596 (MOR); it seems likely that it was introduced, and has not been collected there since.

Stenosiphon virgatus Spach is a superfluous name and pertains here.

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

Subspecies 2 (2 in the flora).

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

Key
1. Herbs densely to sparsely strigillose, also at least parts of inflorescence sparsely hirsute with spreading, pustulate-based hairs, and often glandular puberulent and villous; flower buds with free tips spreading, 2–6 mm.
subsp. heterophylla
1. Herbs densely to sparsely strigillose, also at least part of inflorescence glabrate or glandular puberulent; flower buds with free tips erect, 1–3 mm.
subsp. orientalis
Source FNA vol. 10. FNA vol. 10.
Parent taxa Onagraceae > subfam. Onagroideae > tribe Onagreae > Oenothera > sect. Gaura > subsect. Stenosiphon 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. 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. 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
Subordinate taxa
O. heterophylla subsp. heterophylla, O. heterophylla subsp. orientalis
Synonyms Gaura linifolia, Stenosiphon linifolius Raimannia heterophylla
Name authority W. L. Wagner & Hoch: Syst. Bot. Monogr. 83: 212. (2007) Spach: Nouv. Ann. Mus. Hist. Nat. 4: 348. (1836)
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