Oenothera nuttallii |
Oenothera humifusa |
|
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Nuttall's evening primrose |
seabeach evening-primrose |
|
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 annual or short-lived perennial, densely strigillose, sometimes also villous, also becoming glandular puberulent distally. |
Stems | erect, often branched, 30–100 cm. |
erect to decumbent, much branched, 10–50(–90) 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 4–8 × 0.7–1 cm, cauline 1–7 × 0.3–1.5 cm; blade usually grayish green, narrowly oblong to narrowly elliptic or narrowly obovate, margins remotely shallowly dentate to subentire; bracts spreading, flat. |
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. |
usually 1 opening per day near sunset; buds erect, with free tips erect and appressed or slightly spreading, 0.5–2 mm; floral tube 15–35 mm; sepals3–11 mm; petals yellow, very broadly obovate or obcordate, 4.5–16 mm; filaments 4–11 mm, anthers 2–5.5 mm, pollen ca. 50% fertile; style 23–45 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. |
cylindrical, sometimes slightly enlarged toward apex, 15–45 × 2–3 mm. |
Seeds | numerous, in 1 row per locule, reddish dark brown, narrowly obovoid, 1.5–2.3 mm. |
usually ellipsoid to broadly ellipsoid, rarely subglobose, 1–2 × 0.5–0.9 mm. |
2n | = 14, 28. |
= 14. |
Oenothera nuttallii |
Oenothera humifusa |
|
Phenology | Flowering Jun–Sep. | Flowering Apr–Nov. |
Habitat | Dry, sandy or rocky prairies, open wooded hillsides, disturbed areas, roadsides. | Dunes, open sandy places along or near Atlantic coast. |
Elevation | 500–2200(–2900) m. (1600–7200(–9500) ft.) | 0–10 m. (0–0 ft.) |
Distribution |
CO; IL; MI; MN; MT; ND; NE; SD; WI; WY; AB; MB; SK
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AL; DE; FL; GA; LA; MD; MS; NC; NJ; PA; SC; VA; Dunes; open sandy places along or near Atlantic coast; West Indies (Cuba); Bermuda
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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 humifusa 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). The inland collection from Iredell County, North Carolina, presumably represents an introduction. There are two geographically separated morphological forms of O. humifusa. Plants of one form are somewhat decumbent, with subentire cauline leaves and bracts; this form occurs in the southern part of the range. The other form is more upright, with more deeply divided leaves; it occurs from North Carolina northward. (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. Raimannia |
Sibling taxa | ||
Synonyms | O. albicaulis, O. albicaulis var. nuttallii | O. niveifolia, O. sinuata var. humifusa, Raimannia humifusa |
Name authority | Sweet: Hort. Brit. ed. 2, 199. (1830) | Nuttall: Gen. N. Amer. Pl. 1: 245. (1818) |
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