Oenothera macrocarpa |
Oenothera macrocarpa subsp. fremontii |
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bigfruit evening primrose, Missouri evening primrose, Ozark sundrop |
Fremont's evening primrose |
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Habit | Herbs caulescent, strigillose or glabrous, sometimes glandular puberulent distally; from a stout taproot, sometimes lateral roots producing adventitious shoots. | Herbs densely strigillose. | ||||||||||||||||
Stems | moderately leafy, (1–)4–40(–60) cm. |
numerous, with numerous short secondary branches, 3–30 cm. |
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Leaves | cauline, (2.8–)3.7–12.5(–17) × (0.1–)0.4–3(–4.5) cm; petiole (0.4–)1–4(–6) cm; blade linear, lanceolate-elliptic, elliptic to oblanceolate or suborbiculate, margins entire or conspicuously or inconspicuously denticulate or serrulate, sometimes undulate, apex usually acute, sometimes obtuse or retuse (subsp. incana). |
gray, (2.8–)3.7–11 × 0.1–0.6(–1.5) cm; blade linear to narrowly elliptic to narrowly elliptic-lanceolate or narrowly oblanceolate, margins flat, entire or inconspicuously denticulate, apex acute. |
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Flowers | usually 1 or 2, rarely more, opening per day near sunset, fading next morning, sometimes (subspp. |
buds with unequal free tips 1–2(–5) mm; floral tube (21–)35–65(–80) mm; sepals (20–)25–30(–37) mm; petals (17–)25–33(–37) mm; filaments 13–18 mm, anthers 10–12 mm; style (45–)55–80(–98) mm. |
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Capsules | papery in age, narrowly ellipsoid to lanceoloid, sometimes twisted (subsp. fremontii), winged, wings (2–)10–28(–34) mm wide, body (13–)25–70(–115) × 2–9 mm, dehiscent 1/4–1/3 their length; pedicel 1–12(–25) mm. |
ellipsoid to narrowly ellipsoid, often twisted, wings 2–5(–9) mm wide, body 13–30(–65) × 2–6 mm. |
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Seeds | numerous, rarely as few as 8, in 1 row per locule, obovoid, (2–)3–5 × 1–2.3 mm. |
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Macrocarpa | and oklahomensis) lasting for 2 days, weakly scented; buds with unequal free tips 1–11(–15) mm; floral tube (21–)35–140(–160) mm; sepals (20–)25–65(–75) mm; petals bright yellow, fading orange, reddish orange or mostly unchanged, obovate to very broadly obovate, (17–)25–65(–68) mm, usually with terminal notch and/or tooth, margin sometimes erose; filaments 13–40(–44) mm, anthers 10–24(–25) mm; style (45–)55–192 mm, stigma usually exserted beyond anthers at anthesis. |
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2n | = 14. |
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Oenothera macrocarpa |
Oenothera macrocarpa subsp. fremontii |
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Phenology | Flowering May–Aug. | |||||||||||||||||
Habitat | Rocky soil derived from fine-textured sandstone, shale or chalk on rocky hillsides, bluffs, badlands. | |||||||||||||||||
Elevation | 400–900 m. (1300–3000 ft.) | |||||||||||||||||
Distribution |
c United States; n Mexico; s United States
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KS; NE |
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Discussion | Subspecies 5 (4 in the flora). Oenotheramacrocarpa is variable and has differentiated extensively in the Great Plains region. Each of the five distinctive subspecies occupies a different geographical and ecological situation. Only subsp. mexicana W. L. Wagner from Coahuila, Mexico, occurs outside of the flora area. In general, the subspecies are sharply distinct and each is characterized by a number of features, including pubescence, leaf features, flower and floral tube size, and size and morphology of the capsules and seeds. The five entities are treated as subspecies primarily because of their complete interfertility and extensive intergradation in any area of marginal contact. Intermediates are known between subsp. macrocarpa and subspp. fremontii and oklahomensis and between subspp. incana and oklahomensis. There is also some evidence that suggests past hybridization between subspp. fremontii and incana although there is no present contact between them. All subspecies are self-incompatible. Oenothera alata Nuttall (1818) is an illegitimate name based on O. macrocarpa and pertains here. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Subspecies fremontii occurs from Franklin and Webster counties in south-central Nebraska south into Kansas to Ellsworth, Hodgeman, and Logan counties; also with disjunct locations in Antelope and Cedar counties in northeastern Nebraska, and Barber County in south-central Kansas. Some specimens from the eastern part of the range, where subsp. fremontii and subsp. macrocarpa are sympatric, appear intermediate between the two subspecies and are difficult to assign. (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. Megapterium | Onagraceae > subfam. Onagroideae > tribe Onagreae > Oenothera > sect. Megapterium > Oenothera macrocarpa | ||||||||||||||||
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Subordinate taxa | ||||||||||||||||||
Synonyms | Megapterium macrocarpum, M. nuttallianum | O. fremontii, Megapterium fremontii | ||||||||||||||||
Name authority | Nuttall: Cat. Pl. Upper Louisiana, no. 56. (1813) | (S. Watson) W. L. Wagner: Ann. Missouri Bot. Gard. 70: 194. (1983) | ||||||||||||||||
Web links |