Oenothera triloba |
Oenothera curtissii |
|
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stemless evening-primrose |
Curtiss' evening primrose |
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Habit | Herbs winter-annual, sometimes biennial, acaulescent or very short-caulescent, sparsely to moderately strigillose and glandular puberulent, sometimes one hair type predominant, rarely glabrate, sometimes also very sparsely hirsute, especially on leaf veins; from a slender or, sometimes, stout taproot. | Herbs biennial or short-lived perennial, densely to sparsely strigillose, sometimes also sparsely glandular puberulent distally. |
Stems | (when present) ascending, 1–several, densely leafy, 0–20 cm. |
sometimes with lateral branches arisingobliquely from rosette, 30–80 cm. |
Leaves | in a basal rosette, sometimes also cauline, (2.5–)6–25(–32) × (0.6–)1.5–4(–5) cm, thin; petiole (0.5–)1–8 cm; blade oblanceolate to elliptic, margins irregularly pinnatifid, sometimes subentire, apex acute to obtuse or rounded. |
in a basal rosette and cauline, basal 7–17 × 0.5–1.5 cm, cauline 2–8 × 0.5–1.5 cm; blade narrowly oblanceolate, gradually narrowly elliptic to narrowly oblong distally, margins lobed to remotely dentate or subentire; bracts slightly longer than capsule they subtend. |
Inflorescences | open, lax, without lateral branches, mature buds usually not overtopping spike apex. |
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Flowers | 1–4 opening per day near sunset, without noticeable scent; buds with subequal free tips 2–7 mm; floral tube (20–)28–95(–138) mm; sepals (6–)10–30(–35) mm; petals pale yellow, fading pale orange, drying lavender, (10–)12–30(–38) mm; filaments (5–)8–15(–18) mm, anthers (3.5–)4–11 mm; style (3.4–)4.2–11.5(–16.3) mm, stigma usually surrounded by anthers, sometimes (especially in some Texas populations) exserted beyond anthers. |
1 or 2 per spike opening per day near sunset; buds erect, with free tips erect to spreading, 0.3–0.8 mm; floral tube slightly curved upward to straight, 23–37 mm; sepals 7–13 mm; petals yellow, broadly elliptic to rhombic-ovate, 8–17 mm; filaments 6–10 mm, anthers 1.5–4 mm, pollen ca. 50% fertile; style 30–45 mm, stigma surrounded by anthers at anthesis. |
Capsules | woody in age, rhombic-obovoid, winged, wings broadly triangular, 5–10 mm wide, often terminating in a hooked tooth, (10–)15–25(–28) × 4–8 mm (excluding wings), valve surface reticulate, dehiscent 1/8–1/3 their length. |
narrowly lanceoloid, 10–25 ×2–3 mm. |
Seeds | asymmetrically cuneiform, (2.1–)2.5–3(–3.3) mm. |
brown, sometimes flecked with darkred spots, ellipsoid, 1–1.3 × 0.5–0.7 mm. |
2n | = 14. |
= 14. |
Oenothera triloba |
Oenothera curtissii |
|
Phenology | Flowering (Feb–)Mar–May(–Jul). | Flowering Jun–Sep. |
Habitat | Scattered to common in clay, sandy or rocky soil, playas, floodplains, creek beds, slopes and flats, moist sites, disturbed sites, roadsides, old fields, in Larrea deserts, prairies, glades. | Dry places, pine-oak woods, fields, roadsides, sandy soil. |
Elevation | 300–1900 m. (1000–6200 ft.) | 0–60 m. (0–200 ft.) |
Distribution |
AL; AR; CO; DC; IL; IN; KS; KY; MD; MO; NM; OH; OK; PA; TN; TX; VA; Mexico (Baja California, Chihuahua, Nuevo León)
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AL; FL; GA; SC |
Discussion | Oenotheratriloba is primarily a species of the high plains from eastern Socorro County, New Mexico, east through all but eastern Texas, Oklahoma, to southern Kansas, east of Meade and Pawnee counties and south of Douglas and Saline counties. It becomes more sporadic eastward into Missouri south of the Missouri River, northwestern and north-central Arkansas, central and eastern Tennessee, northern Alabama, and Logan and Warren counties, Kentucky; also known from disjunct sites in northern Mexico from Nuevo León, Chihuahua, and Baja California, Mexico; and, introduced in Illinois, Indiana, Ohio, Kentucky (Campbell and Fayette counties), Pennsylvania, Virginia, Maryland, and the District of Columbia. Areas where it was introduced are represented by old collections; no current information indicates their continued presence in any of these areas. It was recently collected in Baca County, Colorado. Capsules of dead plants sometimes form pineconelike clusters of ten to 100 or more capsules. The illegitimate names Lavauxia nuttalliana Spach and L. triloba (Nuttall) Spach var. watsonii Britton pertain here. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Oenothera curtissii is a PTH species and forms a ring of 14 chromosomes in meiosis, and is self-compatible and autogamous (W. Dietrich and W. L. Wagner 1988). It is known only from northern Florida, adjacent southern Georgia and southeastern Alabama, and one disjunct locality in South Carolina (Allendale County). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 10. | FNA vol. 10. |
Parent taxa | Onagraceae > subfam. Onagroideae > tribe Onagreae > Oenothera > sect. Lavauxia > subsect. Lavauxia | Onagraceae > subfam. Onagroideae > tribe Onagreae > Oenothera > sect. Oenothera > subsect. Candela |
Sibling taxa | ||
Synonyms | Lavauxiahamata wooton, L. triloba, L. watsonii, O. hamata, O. rhizocarpa, O. roemeriana, O. triloba var. parviflora, O. triloba | O. heterophylla var. curtissii |
Name authority | Nuttall: J. Acad. Nat. Sci. Philadelphia 2: 118. (1821) | Small: Fl. S.E. U.S. ed. 2, 1353. (1913) |
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