Clarkia exilis |
Onagraceae tribe Onagreae |
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Kern River clarkia, Kern River or slender clarkia, slender clarkia |
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Habit | Herbs (annual or perennial), [shrubs]. | |
Stems | erect, 30–100 cm, glabrous, glaucous. |
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Leaves | petiole 0–5 mm; blade bright green, lanceolate to narrowly elliptic, 1–6 cm, surfaces not glaucous, glabrous. |
alternate or basal; stipules absent. |
Inflorescences | open racemes, axis erect; buds pendent. |
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Flowers | floral tube 1–3 mm; sepals reflexed together to 1 side, usually green, sparsely to densely puberulent inside, without longer, spreading hairs; corolla rotate, petals lavender-pink or white, often with dark purplish spot, usually diamond-shaped, 5–15 mm, claw slender, equal to or longer than blade, entire; stamens 8, unequal, outer anthers red, inner smaller, paler; ovary with hairs as on sepals; stigma subequal to anthers. |
usually actinomorphic, rarely slightly zygomorphic (in Oenothera), (3 or)4-merous; stamens 2 times as many, or rarely as many, as sepals; pollen usually shed in monads, rarely tetrads (Chylismia sect. Lignothera). |
Fruit | a dry capsule, usually dehiscent, sometimes indehiscent. |
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Capsules | 10–30 mm. |
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Seeds | brown, 1 mm, tuberculate, crest inconspicuous. |
few to numerous, without hairs or wings, [very rarely with asymmetrical dry wing (Xylonagra)], or with dry (Oenothera), erose or smooth wing, or with thick, papillate wings (Chylismiella). |
2n | = 18. |
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Clarkia exilis |
Onagraceae tribe Onagreae |
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Phenology | Flowering Apr–May. | |
Habitat | Woodlands | |
Elevation | 0–1000 m. (0–3300 ft.) | |
Distribution |
CA |
North America; Mexico; Central America; South America; West Indies |
Discussion | Clarkia exilis is of limited distribution, known primarily from the southern Sierra Nevada Foothills and Tehachapi Mountain area in Kern and Tulare counties, with unverified reports from Fresno, San Luis Obispo, and Ventura counties. It is listed as rare by the California Native Plant Society. Clarkia exilis is derived from C. unguiculata and is closely related to C. springvillensis and C. tembloriensis. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Genera 13, species 265 (12 genera, 199 species in the flora). Onagreae account for more than half the total genera in Onagraceae and diversified from a center in southwestern North America (L. Katinas et al. 2004). Delimitation of the tribe by W. L. Wagner et al. (2007) differs from previous ones by the exclusion of Gongylocarpus, now in its own tribe, by the segregation of eight genera (Camissoniopsis, Chylismia, Chylismiella, Eremothera, Eulobus, Neoholmgrenia, Taraxia, and Tetrapteron) from Camissonia, and by the inclusion of three previously separate genera (Calylophus, Gaura, and Stenosiphon) in Oenothera. Within the branch of the family that lacks stipules (Gongylocarpeae, Epilobieae, and Onagreae), the last two tribes form a clade that has very strong molecular support (R. A. Levin et al. 2003, 2004), but no obvious morphological synapomorphy. The clade may be defined by a cytogenetic change from the base chromosome number of x = 11 found in Circaeeae, Gongylocarpeae, and Lopezieae, to x = 18 in Epilobieae, and x = 7 in Onagreae; however, these changes could also have occurred independently. Other than the new chromosome number x = 7, the only apparent morphological synapomorphy for Onagreae alone is pollen with prominent apertural protrusions (J. Praglowski et al. 1987, 1989), a character state also found in Circaeeae (Praglowski et al. 1994). The monophyly of Onagreae has moderate (Levin et al. 2004) to strong support (V. S. Ford and L. D. Gottlieb 2007). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 10. | FNA vol. 10. |
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Name authority | H. Lewis & Vasek: Madroño 12: 211. (1954) | Dumortier: Fl. Belg., 89. (1827) |
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