Eremothera |
Eremothera refracta |
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evening primrose, mooncup |
narrow leaf primrose, narrowleaf suncup |
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Habit | Herbs, annual, caulescent; with a taproot. | Herbs sparsely strigillose, sometimes also glandular puberulent, especially in inflorescence. | ||||||||||||||||||||||||
Stems | usually erect, sometimes ascending, usually well-branched from base, sometimes also distally, with white or reddish green exfoliating epidermis. |
usually well branched from base and distally, 6–45 cm, flowering only distally. |
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Leaves | cauline, proximal ones often clustered near base, alternate; stipules absent; petiolate, often subsessile distally; blade margins denticulate, crenate-dentate, serrulate, sinuate-toothed, or entire. |
cauline, with lower ones clustered near base and these often withered by flowering, 2–6(–8) × 0.1–0.8 cm; petiole 0–2 cm; blade narrowly lanceolate to narrowly elliptic-lanceolate or narrowly oblanceolate, those distally on stems usually linear to linear-lanceolate, margins usually sparsely and weakly denticulate, sometimes sinuate-toothed. |
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Inflorescences | spikes, erect or nodding at anthesis, or flowers also in proximal leaf axils in some taxa. |
nodding. |
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Flowers | bisexual, actinomorphic, buds erect; floral tube deciduous (with sepals, petals, and stamens) after anthesis, with basal nectary; sepals 4, reflexed singly or in pairs; petals 4, usually white, rarely red or tinged red, without spots, fading pink or red; stamens 8 in 2 unequal series, episepalous ones rarely abortive (E. minor), anthers versatile, pollen shed singly; ovary 4-locular, without apical projection, style villous near base, strigillose, or glabrous, stigma entire, subglobose, surface unknown, probably wet and non-papillate. |
opening at sunset; floral tube 4–7 mm, villous in proximal 1/2 inside; sepals 4–6 mm; petals white, fading pinkish, 3.5–10 mm; episepalous filaments 2–4.5 mm, epipetalous filaments slightly shorter, anthers 1.5–2.5 mm; style 9–13 mm, villous proximally, stigma 1–1.5 mm diam., exserted beyond anthers at anthesis. |
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Fruit | a capsule, straight or much contorted, narrowly cylindrical throughout or thickened proximally, terete or 4-angled, regularly but tardily loculicidal; sessile. |
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Capsules | narrowly cylindrical throughout, spreading or reflexed, straight to ± contorted, terete, 20–50 × 0.7–1 mm, regularly but tardily dehiscent. |
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Seeds | numerous, in 1 row per locule, usually monomorphic and narrowly obovoid to oblanceoloid, sometimes dimorphic, with seeds near base of capsule sharply angular and truncate-ellipsoid, finely reticulate, or seeds near base of capsule coarsely papillose. |
monomorphic, gray, 0.9–1.5 × 0.4–0.5 mm, finely reticulate. |
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x |
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2n | = 14. |
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Eremothera |
Eremothera refracta |
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Phenology | Flowering Mar–May. | |||||||||||||||||||||||||
Habitat | Sandy desert slopes and flats. | |||||||||||||||||||||||||
Elevation | -30–1700 m. (-100–5600 ft.) | |||||||||||||||||||||||||
Distribution | w United States; sc United States; nw Mexico |
AZ; CA; NM; NV; UT
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Discussion | Species 7 (7 in the flora). Species of Eremothera are found mainly in the interior deserts and bordering areas of the western United States. R. A. Levin et al. (2004) found strong molecular support for paraphyly in the broadly delimited Camissonia of P. H. Raven (1969). There was some support for a clade of Camissonia and Eremothera and another clade of Camissoniopsis, Neoholmgrenia, and Tetrapteron (Levin et al.), but without morphological features linking the members of these two clades. The monophyletic subclades of these two clades were recognized as genera by W. L. Wagner et al. (2007) whereas they were all treated by Raven as clearly distinguishable sections. Raven recognized four distinct groups within Eremothera (as Camissonia sect. Eremothera): E. refracta and its autogamous derivative, E. chamaenerioides; the very diverse E. boothii (with six subspecies) and two rare autogamous derivatives, E. gouldii and E. pygmaea; the local clay endemic E. nevadensis; and the widespread autogamous and often cleistogamous E. minor. Levin et al. included one species from each of these four groups in their molecular analyses and found strong support for Eremothera as circumscribed by Raven and maintained by Wagner et al. Eremothera is well defined by white petals that open in the evening and an entire, subglobose stigma; some species are visited by moths at anthesis and by bees the following morning (Raven). Reproductive features include: self-incompatible (E. boothii, E. refracta, and, possibly, E. nevadensis) or self-compatible; flowers vespertine; outcrossing and pollinated in the evening by small moths and the following morning by bees, in E. boothii subsp. decorticans by large oligolectic andrenid bees (E. G. Linsley et al. 1963, 1964, 1973), or autogamous, rarely cleistogamous (Raven). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Eremothera refracta is known from Esmeralda, southern Nye, and Clark counties in Nevada, Washington County in Utah, south throughout the Mojave and Colorado deserts of Inyo, San Bernardino, Imperial, central and eastern Riverside, and eastern Kern and San Diego counties in California, Mohave, Yuma, and western Pima counties in Arizona, and a single collection well east of normal range has been seen from Hidalgo County in New Mexico (east of Lordsburg, Jones in 1930, POM). P. H. Raven (1969) determined E. refracta to be self-incompatible. (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 | ||||||||||||||||||||||||||
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Synonyms | Camissonia section eremothera, Oenothera section eremothera | Oenothera refracta, Camissonia refracta, O. deserti, Sphaerostigma deserti, S. refractum | ||||||||||||||||||||||||
Name authority | (P. H. Raven) W. L. Wagner & Hoch: Syst. Bot. Monogr. 83: 125. (2007) | (S. Watson) W. L. Wagner & Hoch: Syst. Bot. Monogr. 83: 210. (2007) | ||||||||||||||||||||||||
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