Oenothera capillifolia |
Oenothera cordata |
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heartleaf evening primrose |
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Habit | Herbs perennial (short-lived or, sometimes, suffrutescent) or annual, glabrous or strigillose; from a stout taproot. | Herbs annual or biennial, densely to sparsely strigillose, glandular puberulent or sometimes also sparsely villous distally. | ||||
Stems | 1–many, weakly decumbent to ascending or erect, unbranched to moderately branched, (10–)25–80 cm. |
unbranched or branched primarily distally, 25–70 cm. |
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Leaves | 1–9 × (0.1–)0.3–1 cm, sometimes fascicles of small leaves to 2 cm present in non-flowering axils; petiole 0–0.6 cm; blade linear to narrowly lanceolate or oblanceolate, often folded lengthwise, usually not much reduced distally, proximalmost leaves sometimes spatulate, base attenuate, margins subentire or serrulate or spinulose-serrate, apex acute. |
in a basal rosette and cauline, basal 6–12 × 0.7–2 cm, cauline 2–10 ×0.5–3 cm; subsessile; blade narrowly elliptic to oblanceolate, gradually narrowly lanceolate to lanceolate, elliptic, or ovate distally, margins lobed to remotely dentate or subentire; bracts shorter than capsule they subtend, 0.5–1.7 cm. |
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Inflorescences | open, lax, usually unbranched, mature buds usually overtopping spike apex. |
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Flowers | opening at sunrise; buds with free tips 0–4 mm; floral tube 5–20 mm; sepals 4–12 mm, midribs keeled; petals yellow, fading orangish to purplish, 6–25 mm; antisepalous filaments 2–8 mm, antipetalous filaments 1–4 mm, anthers 2–7 mm, pollen 90–100% fertile; style 9–30 mm, stigma sometimes blue-black, discoid to quadrangular, exserted beyond anthers. |
1–few per spike opening per day near sunset; buds erect, with free tips erect, 1–3 mm; floral tube nearly straight, 20–40 mm; sepals 15–25 mm; petals yellow, broadly elliptic to rhombic-ovate, 20–30 mm; filaments 17–22 mm, anthers 4–7 mm, pollen 85–100% fertile; style 50–65 mm, stigma usually exserted beyond anthers at anthesis. |
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Capsules | 10–35 × 1–2 mm, hard, dehiscent 1/2 their length, often tardily dehiscent throughout their length. |
narrowly lanceoloid, 15–33 × 2–3 mm. |
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Seeds | obovoid, 1–1.8 mm, sharply angled, apex truncate. |
dark brown, ellipsoid, 1–1.4 ×0.4–0.6 mm. |
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2n | = 14. |
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Oenothera capillifolia |
Oenothera cordata |
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Phenology | Flowering Apr–Jul. | |||||
Habitat | Sandy, open places in oak woodlands. | |||||
Elevation | 30–200 m. (100–700 ft.) | |||||
Distribution | c United States; sc United States; n Mexico |
TX |
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Discussion | Subspecies 2 (2 in the flora). Oenothera capillifolia is self-incompatible (H. F. Towner 1977). Oenothera berlandieri (Spach) Steudel 1841, not D. Dietrich 1840, is superfluous and cannot be used in Oenothera when transferred from Calylophus, and pertains here. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Oenothera cordata is self-incompatible. It occurs in a narrow range in eastern Texas (Austin, Bastrop, Colorado, Fayette, Guadalupe, Goliad, Matagorda, San Patricio, Victoria, Waller, and Wilson). It apparently occasionally hybridizes with O. heterophylla subsp. heterophylla where their ranges come together. Oenothera bifrons D. Don 1838 (not Lindley 1831) pertains here. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 10. | FNA vol. 10. | ||||
Parent taxa | Onagraceae > subfam. Onagroideae > tribe Onagreae > Oenothera > sect. Calylophus > subsect. Calylophus | Onagraceae > subfam. Onagroideae > tribe Onagreae > Oenothera > sect. Oenothera > subsect. Candela | ||||
Sibling taxa | ||||||
Subordinate taxa | ||||||
Synonyms | Meriolix capillifolia | |||||
Name authority | Scheele: Linnaea 21: 576. (1848) | J. W. Loudon: Ladies’ Flower-gard. Ornam. Perenn. 1: 167. (1843) | ||||
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