Oenothera nuttallii |
Oenothera clelandii |
|
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Nuttall's evening primrose |
Cleland's evening primrose |
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Habit | Herbs perennial, mostly glabrous, sometimes strigillose on leaves and/or glandular puberulent on distal parts, at least on floral tube; from a taproot, lateral roots producing adventitious shoots. | Herbs biennial, densely to sometimes sparsely strigillose, or also sparsely glandular puberulent distally. |
Stems | erect, often branched, 30–100 cm. |
sometimes with lateral branches arising obliquely from rosette, 20–70(–100) cm. |
Leaves | in a basal rosette and cauline, rosette weakly developed or absent, at least during flowering, 2–6(–10.5) × 0.3–0.6(–1) cm; petiole 0–2 cm; blade narrowly oblong to oblong-lanceolate, margins usually entire, sometimes remotely denticulate or repand-denticulate. |
in a basal rosette and cauline, basal 5–16 × 0.5–1.5 cm, cauline 2–12 × 0.5–2 cm; blade narrowly oblanceolate, gradually narrowly elliptic to narrowly lanceolate distally, margins lobed to remotely dentate or subentire; bracts slightly longer than capsule they subtend. |
Inflorescences | dense, without lateral branches, mature buds usually not overtopping spike apex. |
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Flowers | 1–several opening per day near sunset; buds nodding, weakly quadrangular, with free tips 1–2 mm; floral tube 15–40 mm; sepals 20–30 mm, not spotted; petals white, fading pink, broadly obovate or obcordate,15–30 mm; filaments 15–18 mm, anthers 8–10 mm; style 35–45 mm, stigma exserted beyond anthers at anthesis. |
2–several per spike opening per day near sunset; buds erect, with free tips erect, 0.5–2 mm; floral tube slightly curved upward to± straight, 15–40 mm; sepals 6–13 mm; petals yellow, broadly elliptic to rhombic-ovate, 5–16 mm; filaments 4–18 mm, anthers 2–3.5 mm, pollen ca. 50% fertile; style 20–40 mm, stigma surrounded by anthers at anthesis. |
Capsules | erect or ascending, woody in age, straight or slightly curved, cylindrical, obtusely 4-angled, especially toward base, tapering slightly from base to apex, 20–30 × 2–3 mm; sessile. |
narrowly lanceoloid, 10–20 ×2–3 mm. |
Seeds | numerous, in 1 row per locule, reddish dark brown, narrowly obovoid, 1.5–2.3 mm. |
brown, sometimes flecked with dark red spots, ellipsoid, 1–1.9 × 0.4–0.8 mm. |
2n | = 14, 28. |
= 14. |
Oenothera nuttallii |
Oenothera clelandii |
|
Phenology | Flowering Jun–Sep. | Flowering Jun–Aug(–Sep). |
Habitat | Dry, sandy or rocky prairies, open wooded hillsides, disturbed areas, roadsides. | Fields, prairies, sandy soil. |
Elevation | 500–2200(–2900) m. (1600–7200(–9500) ft.) | 150–300 m. (500–1000 ft.) |
Distribution |
CO; IL; MI; MN; MT; ND; NE; SD; WI; WY; AB; MB; SK
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AR; IA; IL; IN; KY; MI; MN; MO; NJ; NY; VA; WI; ON
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Discussion | Oenothera nuttallii had been assumed to be self-incompatible (W. L. Wagner et al. 2007), but K. E. Theiss et al. (2010) determined two plants to be self-compatible. Anogra nuttalliana Spach and Baumannia nuttalliana Spach are illegitimate names that pertain here. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Oenothera clelandii 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). Some localities in the easternmost states may represent introductions, primarily occurring in disturbed areas along roads and railroad lines. (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. Anogra | Onagraceae > subfam. Onagroideae > tribe Onagreae > Oenothera > sect. Oenothera > subsect. Candela |
Sibling taxa | ||
Synonyms | O. albicaulis, O. albicaulis var. nuttallii | |
Name authority | Sweet: Hort. Brit. ed. 2, 199. (1830) | W. Dietrich, P. H. Raven & W. L. Wagner: Ann. Missouri Bot. Gard. 70: 196. (1983) |
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