Oenothera hartwegii |
Oenothera gayleana |
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Fendler evening primrose, Hartweg's sundrops |
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Habit | Herbs perennial, sometimes suffrutescent, strigillose, glandular puberulent, glabrous, hirtellous, or short-pilose; from a stout taproot. | Herbs perennial, sometimes suffrutescent, usually strigillose, sometimes glabrous; from a stout taproot. | ||||||||||||||||
Stems | 1–many, erect to ascending, unbranched to densely branched, 4–60 cm. |
many, ascending to erect, branched from base, 15–30(–40) cm. |
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Leaves | 0.3–6.5 × 0.04–1.2 cm, sometimes fascicles of small leaves 0.1–1.5 cm present in non-flowering axils; petiole 0–0.2 cm; blade elliptic, lanceolate, linear, or filiform to ovate or oblanceolate, usually not much reduced distally, proximalmost leaves sometimes obovate to spatulate, base attenuate to obtuse, truncate, or subcordate, sometimes clasping, margins entire or serrate, often undulate, apex acute. |
2.5–3.5 × 0.1–0.2 cm, rarely fascicles of small leaves present in non-flowering axils; petiole 0–0.1 cm; blade linear to narrowly linear-lanceolate, folded lengthwise, base long-attenuate, margins subentire or serrulate, apex acute. |
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Flowers | usually 1 per stem opening per day in afternoon or near sunset; buds with free tips 0.5–6 mm; floral tube 16–50(–60) mm, funnelform in distal 1/2 or less; sepals 7–28 mm; petals yellow, fading pale pinkish or pale purple, 10–35 mm; filaments 4–13 mm, anthers 5–13 mm, pollen 85–100% fertile; style 25–65(–75) mm, stigma yellow, quadrangular, usually exserted beyond anthers. |
opening near sunrise; buds with free tips 0–0.5 mm; floral tube 7 mm; sepals 4–6 mm, midribs keeled; petals yellow, fading yellow to orange, 15–20 mm; antisepalous filaments 5 mm, antipetalous filaments 2 mm, anthers 3–4 mm, pollen 90–100% fertile; style 10 mm, stigma discoid to quadrangular, exserted beyond anthers at anthesis. |
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Capsules | 6–40 × 2–4 mm, hard, promptly dehiscent throughout their length. |
18–20 × 2 mm, hard, dehiscent 1/2 their length, often tardily dehiscent throughout their length. |
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Seeds | obovoid, 1–2.5 mm. |
oblanceoloid, 1–1.8 mm, sharply angled, apex truncate. |
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2n | = 14, 28. |
= 14. |
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Oenothera hartwegii |
Oenothera gayleana |
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Phenology | Flowering May–Sep. | |||||||||||||||||
Habitat | Gypsum outcrops. | |||||||||||||||||
Elevation | 500–1400 m. (1600–4600 ft.) | |||||||||||||||||
Distribution |
c United States; sw United States; n Mexico
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NM; TX |
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Discussion | Subspecies 5 (5 in the flora). Oenothera hartwegii consists of five intergrading subspecies, which are generally locally common on rocky, sandy, gypsum, or limestone soil in arid to relatively mesic open areas, in southeastern Colorado, southwestern Kansas, western Oklahoma, Texas (except eastern part), New Mexico, southeastern and east-central Arizona, and in Mexico from Chihuahua, northern Coahuila, and northwestern Tamaulipas south to Aguascalientes. H. F. Towner (1977) found that O. hartwegii is self-incompatible and usually vespertine; two of the subspecies (filifolia and maccartii) open early in the afternoon and are pollinated both day and evening. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Oenothera gayleana is a recently discovered gypsum endemic known only from scattered outcrops from De Baca and Eddy counties in New Mexico, and Culberson County in Texas. When published, the delimitation of O. gayleana included populations in Collinsworth and Dickens counties in the Texas panhandle, and adjacent Harmon County in Oklahoma. Subsequent study (B. Cooper et al., unpubl.) has determined they are actually O. serrulata. (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 | ||||||||||||||||||
Sibling taxa | ||||||||||||||||||
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Synonyms | Calylophus hartwegii, Galpinsia hartwegii, Salpingia hartwegii | |||||||||||||||||
Name authority | Bentham: Pl. Hartw., 5. (1839) — (as hartwegi) | B. L. Turner & M. J. Moore: Phytologia 96: 200, figs. 1, 2. (2014) | ||||||||||||||||
Web links |