Oenothera humifusa |
Oenothera glaucifolia |
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seabeach evening-primrose |
false gaura |
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Habit | Herbs annual or short-lived perennial, densely strigillose, sometimes also villous, also becoming glandular puberulent distally. | Herbs probably biennial, glabrous, becoming sparsely to densely glandular puberulent and short-villous distally, glaucous at least in proximal parts; from stout roots. |
Stems | erect to decumbent, much branched, 10–50(–90) cm. |
erect, branched or unbranched, 30–300 cm. |
Leaves | in a basal rosette and cauline, basal 4–8 × 0.7–1 cm, cauline 1–7 × 0.3–1.5 cm; blade usually grayish green, narrowly oblong to narrowly elliptic or narrowly obovate, margins remotely shallowly dentate to subentire; bracts spreading, flat. |
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. |
Inflorescences | long, wandlike, unbranched or branched. |
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Flowers | usually 1 opening per day near sunset; buds erect, with free tips erect and appressed or slightly spreading, 0.5–2 mm; floral tube 15–35 mm; sepals3–11 mm; petals yellow, very broadly obovate or obcordate, 4.5–16 mm; filaments 4–11 mm, anthers 2–5.5 mm, pollen ca. 50% fertile; style 23–45 mm, stigma surrounded by anthers at anthesis. |
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. |
Capsules | cylindrical, sometimes slightly enlarged toward apex, 15–45 × 2–3 mm. |
ovoid, 4-angled, somewhat flattened, 3–4 × 1.5–2.3 mm, valves with raised midrib and conspicuous lateral veins; sessile. |
Seeds | usually ellipsoid to broadly ellipsoid, rarely subglobose, 1–2 × 0.5–0.9 mm. |
1, pale yellow, oblanceoloid, 2.4–2.6 × 1–1.5 mm. |
2n | = 14. |
= 14. |
Oenothera humifusa |
Oenothera glaucifolia |
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Phenology | Flowering Apr–Nov. | Flowering May–Oct(–Nov). |
Habitat | Dunes, open sandy places along or near Atlantic coast. | Rocky prairie slopes and outcrops or bluffs, along streams, roadsides, usuallyon limestone. |
Elevation | 0–10 m. (0–0 ft.) | 200–1300 m. (700–4300 ft.) |
Distribution |
AL; DE; FL; GA; LA; MD; MS; NC; NJ; PA; SC; VA; Dunes; open sandy places along or near Atlantic coast; West Indies (Cuba); Bermuda
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AR; CO; KS; MO; NE; NM; OK; TX; WY
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Discussion | Oenothera humifusa is a PTH species and forms a ring of 14 chromosomes in meiosis, and is self-compatible and autogamous (W. Dietrich and W. L. Wagner 1988). The inland collection from Iredell County, North Carolina, presumably represents an introduction. There are two geographically separated morphological forms of O. humifusa. Plants of one form are somewhat decumbent, with subentire cauline leaves and bracts; this form occurs in the southern part of the range. The other form is more upright, with more deeply divided leaves; it occurs from North Carolina northward. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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.) |
Source | FNA vol. 10. | FNA vol. 10. |
Parent taxa | Onagraceae > subfam. Onagroideae > tribe Onagreae > Oenothera > sect. Oenothera > subsect. Raimannia | Onagraceae > subfam. Onagroideae > tribe Onagreae > Oenothera > sect. Gaura > subsect. Stenosiphon |
Sibling taxa | ||
Synonyms | O. niveifolia, O. sinuata var. humifusa, Raimannia humifusa | Gaura linifolia, Stenosiphon linifolius |
Name authority | Nuttall: Gen. N. Amer. Pl. 1: 245. (1818) | W. L. Wagner & Hoch: Syst. Bot. Monogr. 83: 212. (2007) |
Web links |