Oenothera humifusa |
Oenothera pallida |
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seabeach evening-primrose |
mountain evening primrose, pale evening-primrose, rockweed brush, white-stem evening primrose |
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Habit | Herbs annual or short-lived perennial, densely strigillose, sometimes also villous, also becoming glandular puberulent distally. | Herbs annual or perennial, glabrous, strigillose and/or villous, sometimes more villous distally, especially on flower parts; from a taproot, sometimes lateral roots producing adventitious shoots. | ||||||||||||
Stems | erect to decumbent, much branched, 10–50(–90) cm. |
erect or ascending, single to several from base, unbranched or many-branched throughout, 10–50(–70) cm. |
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Leaves | 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. |
cauline, rosette usually weakly developed or absent, at least during flowering, sometimes well developed, 1–5(–7.8) × 0.3–1(–1.5) cm; petiole 0–2(–4.5) cm; blade lanceolate, oblong, linear-lanceolate, or ovate, margins subentire or remotely denticulate, deeply sinuate-dentate, or pinnatifid, sometimes repand. |
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Flowers | 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. |
1–several opening per day near sunset; buds nodding, weakly quadrangular, with free tips 0–2 mm; floral tube 15–40 mm; sepals 10–30 mm, not spotted; petals white, fading pink to deep pink, broadly obovate or obcordate, (10–)15–25(–40) mm; filaments 9–15 mm, anthers 3–10 mm; style 25–55 mm, stigma exserted beyond anthers at anthesis. |
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Capsules | cylindrical, sometimes slightly enlarged toward apex, 15–45 × 2–3 mm. |
spreading to reflexed, straight to curved or contorted, cylindrical, obtusely 4-angled, tapering slightly from base to apex, 15–60 × 1.5–2.5 mm; sessile. |
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Seeds | usually ellipsoid to broadly ellipsoid, rarely subglobose, 1–2 × 0.5–0.9 mm. |
numerous, in 1 row per locule, brownish with dark spots or black, narrowly obovoid, 1.5–2.2 mm. |
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2n | = 14. |
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Oenothera humifusa |
Oenothera pallida |
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Phenology | Flowering Apr–Nov. | |||||||||||||
Habitat | Dunes, open sandy places along or near Atlantic coast. | |||||||||||||
Elevation | 0–10 m. (0–0 ft.) | |||||||||||||
Distribution |
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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w North America; n Mexico; c North America
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Discussion | 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.) |
Subspecies 4 (4 in the flora). Oenothera pallida is a poorly understood species currently subdivided into four subspecies (W. L. Wagner et al. 2007) that differ largely in aspect, leaf division, capsule configuration, and pubescence. The variation pattern is rather complex with almost no diagnostic character uniformly distinguishing any one of the subspecies. Instead, each of the subspecies, which are mostly geographically separated although there is some level of overlap, have diagnostic suites of characters that maintain their linkage some of the time, but break down across the geographic area of each so that no single character uniquely identifies it. Each subspecies is characterized by leaf, pubescence, and, often, habit features. The issues with the integrity and intergradations of the subspecies are discussed below. Oenothera pallida has been determined to be self-incompatible (W. L. Wagner et al. 2007), but K. E. Theiss et al. (2010) determined that although most populations of subsp. pallida are self-incompatible, one near Salt Lake City is self-compatible. (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. Oenothera > subsect. Raimannia | Onagraceae > subfam. Onagroideae > tribe Onagreae > Oenothera > sect. Anogra | ||||||||||||
Sibling taxa | ||||||||||||||
Subordinate taxa | ||||||||||||||
Synonyms | O. niveifolia, O. sinuata var. humifusa, Raimannia humifusa | Anogra pallida, O. albicaulis var. pallida | ||||||||||||
Name authority | Nuttall: Gen. N. Amer. Pl. 1: 245. (1818) | Lindley: Bot. Reg. 14: plate 1142. (1828) | ||||||||||||
Web links |