Oenothera glaucifolia |
Oenothera linifolia |
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false gaura |
threadleaf evening-primrose, threadleaf sundrop |
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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, caulescent, strigillose or glabrous, also often glandular puberulent, especially distally; from a sparsely branched taproot. |
Stems | erect, branched or unbranched, 30–300 cm. |
unbranched or with many ascending branches arising near base, erect, 10–50 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 1–2(–4) × 0.2–0.6 cm, petiole 0.2–1(–1.5) cm, blade ovate to obovate or narrowly elliptic; cauline 1–4 × less than 0.1 cm, sessile, blade linear or filiform. |
Inflorescences | long, wandlike, unbranched or branched. |
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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. |
usually 1–3 opening per day near sunrise; buds without free tips; sepals 1.5–2 mm; petals bright yellow, fading pink, obcordate to obovate, 3–5(–7) mm; filaments 1–2 mm, anthers 0.5–1 mm; style 1–2 mm, stigma surrounded by 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. |
ellipsoid-rhombic to subglobose, 4-angled, 4–6(–10) × 1.5–3 mm, stipe 0–4 mm, valve midrib raised at distal end, indehiscent or tardily dehiscent distally; sessile. |
Seeds | 1, pale yellow, oblanceoloid, 2.4–2.6 × 1–1.5 mm. |
clustered in each locule, ovoid, surface minutely papillose, 1 × 0.5 mm. |
2n | = 14. |
= 14. |
Oenothera glaucifolia |
Oenothera linifolia |
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Phenology | Flowering May–Oct(–Nov). | Flowering Apr–Jun(–Aug). |
Habitat | Rocky prairie slopes and outcrops or bluffs, along streams, roadsides, usuallyon limestone. | Prairies, open woodlands, open rocky and sandy sites, roadsides. |
Elevation | 200–1300 m. (700–4300 ft.) | 0–400 m. (0–1300 ft.) |
Distribution |
AR; CO; KS; MO; NE; NM; OK; TX; WY
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AL; AR; FL; GA; IL; KS; KY; LA; MO; MS; NC; OK; SC; TN; 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.) |
Kneiffia linearifolia Spach (1835) is an illegitimate name based on Oenothera linifolia. (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. Peniophyllum |
Sibling taxa | ||
Synonyms | Gaura linifolia, Stenosiphon linifolius | Kneiffia linifolia, O. linifolia var. glandulosa, Peniophyllum linifolium |
Name authority | W. L. Wagner & Hoch: Syst. Bot. Monogr. 83: 212. (2007) | Nuttall: J. Acad. Nat. Sci. Philadelphia 2: 120. (1821) |
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