Oenothera glaucifolia |
Oenothera albicaulis |
|
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false gaura |
white-stem evening-primrose, whitest evening primrose, whitish 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 winter-annual, densely strigillose, also sparsely villous; from a taproot. |
Stems | erect, branched or unbranched, 30–300 cm. |
ascending to decumbent, 1–several from base, sometimes unbranched, erect or ascending, 5–30 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, 1.5–10 × 0.3–2.5 cm; blade oblanceolate to oblong, margins subentire or coarsely dentate or pinnatifid. |
Inflorescences | long, wandlike, unbranched or branched. |
|
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. |
1–3 opening per day near sunset; buds nodding, weakly quadrangular, without free tips; floral tube 15–30 mm, mouth glabrous; sepals 15–30 mm; petals white, fading pink, usually obcordate, sometimes obovate, (15–)20–35(–40) mm; filaments 11–17 mm, anthers 6–10 mm; style 25–50 mm, stigma 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. |
ascending to erect, usually straight, sometimes curved, cylindrical, weakly 4-angled, 20–40 × 3–4 mm, dehiscent 1/2 their length; sessile. |
Seeds | 1, pale yellow, oblanceoloid, 2.4–2.6 × 1–1.5 mm. |
in 2 rows per locule, ellipsoid to subglobose, 0.8–1.5 × 0.5–0.9 mm, surface regularly pitted, pits in longitudinal lines. |
2n | = 14. |
= 14. |
Oenothera glaucifolia |
Oenothera albicaulis |
|
Phenology | Flowering May–Oct(–Nov). | Flowering (Feb–)Mar–Jun(–Dec). |
Habitat | Rocky prairie slopes and outcrops or bluffs, along streams, roadsides, usuallyon limestone. | Dry, usually sandy flats and slopes. |
Elevation | 200–1300 m. (700–4300 ft.) | 1000–2300 m. (3300–7500 ft.) |
Distribution |
AR; CO; KS; MO; NE; NM; OK; TX; WY
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AZ; CO; ID; KS; MT; ND; NE; NM; OK; SD; TX; UT; WY; Mexico (Chihuahua, Sonora)
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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.) |
Oenothera albicaulis is self-incompatible (W. L. Wagner et al. 2007; K. E. Theiss et al. 2010). Oenothera albicaulis has been reported from southern Nevada, but documentation is needed of its occurrence there. Anogra pinnatifida Spach, Baumannia pinnatifida Spach, Oenothera pinnatifida Nuttall, O. purshiana Steudel, and O. purshii G. Don are illegitimate names that pertain here. (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. Gaura > subsect. Stenosiphon | Onagraceae > subfam. Onagroideae > tribe Onagreae > Oenothera > sect. Kleinia |
Sibling taxa | ||
Synonyms | Gaura linifolia, Stenosiphon linifolius | Anogra albicaulis, A. bradburiana, A. buffumii, A. confusa, A. ctenophylla, A. perplexa, O. albicaulis var. xanthosperma, O. ctenophylla, O. sinuata var. bicolor |
Name authority | W. L. Wagner & Hoch: Syst. Bot. Monogr. 83: 212. (2007) | Pursh: Fl. Amer. Sept. 2: 733. (1813) |
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