Oenothera canescens |
Oenothera rhombipetala |
|
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beakpod evening primrose, spotted evening-primrose |
fourpoint evening primrose |
|
Habit | Herbs low, forming clumps 10–50 cm diam., densely strigillose throughout; from a taproot, lateral roots producing adventitious shoots. | Herbs biennial, densely to sparsely strigillose, sometimes also sparsely glandular puberulent distally. |
Stems | many-branched from base, leafy, (10–)15–25(–38) cm. |
sometimes with lateral branches arising obliquely from rosette, 30–100(–150) cm. |
Leaves | cauline, (0.3–)0.6–1.5(–2.5) × (0.05–)0.15–0.4(–0.6) cm, fascicles of small leaves 0.2–0.6 cm often present in non-flowering axils; petiole 0–0.1 cm; blade lanceolate to linear, base cuneate, apex acute. |
in a basal rosette and cauline, basal 6–20 × 0.6–2 cm, cauline 3–15 × 0.8–2.5 cm; blade narrowly oblanceolate, gradually narrowly elliptic to narrowly lanceolate, oblanceolate, or ovate distally, margins lobed to remotely dentate or subentire; bracts slightly longer than capsule they subtend. |
Inflorescences | dense, usually without lateral branches, mature buds usually not overtopping spike apex. |
|
Flowers | several opening per day near sunset; buds usually without free tips, rarely free tips 0.2–0.3 mm; sepals (7–)8–12 mm; petals pink, rarely white, streaked or flecked with red, fading bright purple, (8–)10–17 mm; filaments 6–8 mm, anthers often with red longitudinal stripe, 3–6 mm; style (16–)22–27 mm, stigma exserted beyond anthers at anthesis. |
2–several per spike opening per day near sunset; buds erect, with free tips erect, 0.5–3 mm; floral tube slightly curved upward to ± straight, 30–45 mm; sepals 15–30 mm; petals yellow, broadly elliptic to rhombic-elliptic, 15–35 mm; filaments 13–25 mm, anthers 3–8 mm, pollen 85–100% fertile; style 25–50 mm, stigma exserted beyond anthers at anthesis. |
Capsules | woody, ovoid, narrowly winged, wings 0.8–1.5 mm wide, (7–)9–12(–14) × 2–4 mm (excluding wings), abruptly constricted to a conspicuous, sterile beak, (2–)3–4.5 mm, indehiscent; sessile. |
narrowly lanceoloid, 13–25 × 2.5–3 mm. |
Seeds | asymmetrically cuneiform or oblanceoloid, 1.2–1.5 × 0.4–0.5 mm. |
brown, sometimes flecked with dark red spots, ellipsoid, 1–1.7 × 0.4–0.7 mm. |
2n | = 14. |
= 14. |
Oenothera canescens |
Oenothera rhombipetala |
|
Phenology | Flowering May–Aug. | Flowering May–Oct. |
Habitat | Prairie depressions, playas, margins of ditches, temporary wet areas. | Fields, prairies, sandy soil. |
Elevation | (400–)700–1800 m. ((1300–)2300–5900 ft.) | 60–600(–1300) m. (200–2000(–4300) ft.) |
Distribution |
CO; KS; NE; NM; OK; TX; WY
|
AR; CO; IL; KS; MI; MN; MO; NE; NM; OK; SD; TX; WI
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Discussion | Oenothera canescens is restricted to prairie depressions, playas, ditch margins, and other places of temporary water in the High Plains of the western United States from Goshen County, Wyoming, southeast to Hayes County, Nebraska, south through eastern Colorado, the eastern tier of counties in New Mexico, western Kansas, and to Garza and Dawson counties in the Texas Panhandle; also disjunct populations from Chautauqua, Sedgwick, and Stafford counties, Kansas. The illegitimate names Gaurella guttulata (Geyer ex Hooker) Small, G. canescens (Torrey & Frémont) Cockerell, and Gauropsis guttulata (Geyer ex Hooker) Cockerell pertain here. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Oenothera rhombipetala is primarily a central plains species that has scattered localities in the Midwest to Illinois, Michigan, and Wisconsin, and barely entering the easternmost parts of Colorado and New Mexico. Oenothera rhombipetala had a broader delimitation (P. A. Munz 1965) until W. Dietrich and W. L. Wagner (1988) divided it into three species (O. clelandii, O. curtissii, and O. rhombipetala), with both of the split-off species being PTH. Evidence gathered by Dietrich and Wagner showed that these PTH species are geographically separated populations of small-flowered plants, and although they are very close morphologically, their distributions and morphological differences suggest that they were each derived independently from O. rhombipetala. Oenothera rhombipetala is self-incompatible. Oenothera pyramidalis H. Léveillé is a superfluous name and pertains here. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 10. | FNA vol. 10. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | Gaurella canescens, Megapterium canescens, O. guttulata | O. heterophylla var. rhombipetala, O. leona, Raimannia rhombipetala |
Name authority | Torrey & Frémont in J. C. Fremont: Rep. Exped. Rocky Mts., 315. (1845) | Nuttall ex Torrey & A. Gray: Fl. N. Amer. 1: 493. (1840) |
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