Oenothera capillifolia |
Oenothera arizonica |
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California evening primrose |
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Habit | Herbs perennial (short-lived or, sometimes, suffrutescent) or annual, glabrous or strigillose; from a stout taproot. | Herbs winter-annual, younger parts sparsely to densely strigillose and sparsely to densely hirsute, older stems glabrate; from a taproot. | ||||
Stems | 1–many, weakly decumbent to ascending or erect, unbranched to moderately branched, (10–)25–80 cm. |
ascending to erect, with decumbent branches, thickened at base, tapering toward apex, 10–35(–60) 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 5–10(–26) × 0.6–1.5(–3.5) cm, cauline 5–8(–15.5) × 1–2 cm; petiole 0–12 cm; blade lanceolate to oblanceolate, margins pinnatifid or sometimes coarsely serrate. |
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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–several opening per day near sunset; buds nodding, weakly quadrangular, without free tips; floral tube 26–31 mm; sepals 19–26 mm, conspicuously maroon-spotted, each spot at base of a long hair; petals white, fading pink to deep pink, broadly obovate or obcordate, 16–26(–36) mm; filaments 9–15 mm, anthers 7–9 mm; style 45–50 mm, stigma 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. |
spreading, woody in age, curved upward, or distal end recurved, cylindrical, obtusely 4-angled, especially toward base, tapering gradually from base to apex, 30–80 × 2.5–3.5 mm; sessile. |
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Seeds | obovoid, 1–1.8 mm, sharply angled, apex truncate. |
numerous, in 1 row per locule, light brown to yellowish brown with dark purple splotches, obovoid, 1.6–2 mm. |
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2n | = 14. |
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Oenothera capillifolia |
Oenothera arizonica |
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Phenology | Flowering (Oct–)Feb–May. | |||||
Habitat | Gravelly or sandy soil, along watercourses, disturbed sites. | |||||
Elevation | 200–1400 m. (700–4600 ft.) | |||||
Distribution | c United States; sc United States; n Mexico |
AZ; Mexico (Sonora) |
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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 arizonica occurs in southern Arizona from Maricopa and Yuma counties to Cochise County, and from scattered localities in northern Sonora, Mexico, including Cerro Tepopa, Puerto Libertad, and Tastiota. The populations from southwestern Arizona (Yuma County) southward to Sonora often grow on low dunes. Populations from sand dunes in Yuma County, Cabeza Prieta National Wildlife Refuge, appear to be a large phenotype of Oenothera arizonica that differ from all other specimens in the size of vegetative parts and flowers, and comprise all of the atypical measurements given in the description. Oenothera arizonica typically grows on dunes in Sonora, but rarely so in Arizona. Populations growing on dunes should be studied further and compared to non-dune populations in the northern and eastern portion of the range. Oenothera arizonica is self-compatible (W. L. Wagner et al. 2007; K. E. Theiss et al. 2010). (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. Anogra | ||||
Sibling taxa | ||||||
Subordinate taxa | ||||||
Synonyms | Meriolix capillifolia | O. deltoides var. arizonica, O. avita subsp. arizonica, O. californica subsp. arizonica | ||||
Name authority | Scheele: Linnaea 21: 576. (1848) | (Munz) W. L. Wagner: Novon 8: 308. (1998) | ||||
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