Oenothera glaucifolia |
Oenothera engelmannii |
|
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false gaura |
Engelmann's 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, conspicuously villous throughout, also strigillose on leaves and distal parts; from a taproot. |
Stems | erect, branched or unbranched, 30–300 cm. |
erect, unbranched or with few, spreading branches, 30–50(–80) 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, rosette weakly developed or absent, at least during flowering, (1–)2–6(–8) × 1–2(–3) cm; sessile; blade lanceolate to oblong lanceolate, proximal ones sometimes oblanceolate, margins coarsely repand-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–several opening per day near sunset; buds nodding, weakly quadrangular, without free tips; floral tube 20–30 mm; sepals 13–21 mm, not spotted or with scattered small, maroon spots; petals white, fading pink, broadly obovate or obcordate, 15–30 mm; filaments 14–16 mm, anthers 6–8 mm; style 40–50 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. |
widely spreading, woody in age, straight or slightly curved, cylindrical, obtusely 4-angled, especially toward base, tapering gradually from base to apex, 30–60 × 2–3 mm; sessile. |
Seeds | 1, pale yellow, oblanceoloid, 2.4–2.6 × 1–1.5 mm. |
numerous, in 1 row per locule, brown, narrowly obovoid, 1–1.5 mm. |
2n | = 14. |
= 14. |
Oenothera glaucifolia |
Oenothera engelmannii |
|
Phenology | Flowering May–Oct(–Nov). | Flowering Apr–Aug(–Sep). |
Habitat | Rocky prairie slopes and outcrops or bluffs, along streams, roadsides, usuallyon limestone. | Sandy prairies, dunes, disturbed areas, roadsides. |
Elevation | 200–1300 m. (700–4300 ft.) | 500–1300 m. (1600–4300 ft.) |
Distribution |
AR; CO; KS; MO; NE; NM; OK; TX; WY
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CO; KS; NM; OK; TX
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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 engelmannii is self-incompatible (W. L. Wagner et al. 2007; K. E. Theiss et al. 2010). It has a relatively narrow distribution in sandy areas of eastern New Mexico and western Texas, extending to southeastern Colorado, western Oklahoma, and southwestern Kansas. The flower size seems to vary, with larger flowers in eastern New Mexico and considerably smaller flowers in the eastern part of its range. (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. Anogra |
Sibling taxa | ||
Synonyms | Gaura linifolia, Stenosiphon linifolius | Anogra pallida var. engelmannii, A. engelmannii |
Name authority | W. L. Wagner & Hoch: Syst. Bot. Monogr. 83: 212. (2007) | (Small) Munz: Amer. J. Bot. 18: 316. (1931) — (as engelmanni) |
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