Chylismia sect. Chylismia |
Chylismia multijuga |
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froststem suncup |
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Habit | Herbs usually annual, sometimes perennial, rarely biennial.Leaves basal and cauline, usually with well-developed basal rosette; blade usually pinnately or bipinnately lobed, sometimes with scattered, irregular lobes, sometimes lateral lobes greatly reduced or absent, terminal lobe elliptic, narrowly to broadly ovate to oblong, lanceolate, oblanceolate, cordate, or subcordate. | Herbs annual or biennial, villous, at least proximally, glabrous or even glaucous distally, rarely glandular puberulent. | ||||||||||||||||||||||||||||||||||||||||||||||||||||
Stems | virgate with numerous divergent branches, 20–150 cm. |
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Leaves | primarily in well-developed basal rosette, cauline reduced or absent, 6–30 × 1.4–6.5 cm; petiole 0.3–6 cm; blade pinnately or bipinnately lobed, terminal lobe ovate to elliptic, 2.5–6.5 × 1.5–3 cm, margins irregularly serrate, dark brown oil cells prominently lining veins abaxially. |
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Racemes | erect to nodding, elongating in bud. |
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Flowers | usually opening at sunrise, rarely at sunset; floral tube 0.4–9 mm; petals usually bright yellow, rarely white or cream, usually with red dots basally, or lavender to purple with white or yellow basally, sometimes with darker flecks near base, fading yellow, orange, reddish, or lavender; pollen shed singly. |
opening at sunrise; buds individually reflexed, with apical or slightly subapical free tips less than 1 mm; floral tube 1–3 mm, glabrous or villous inside proximally; sepals 3–8 mm; petals usually bright yellow, rarely cream, fading yellow to lavender, 4–9 mm; stamens unequal, filaments of antisepalous stamens 2.5–4 mm, those of antipetalous ones 1.3–3 mm, anthers 2–4 mm, ciliate; style 7–11 mm, stigma exserted beyond anthers at anthesis. |
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Capsules | usually spreading, rarely slightly reflexed, oblong-cylindrical, 10–52 mm; pedicel 7–20 mm. |
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Seeds | 1–1.3 mm. |
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2n | = 14. |
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Chylismia sect. Chylismia |
Chylismia multijuga |
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Phenology | Flowering Mar–Jun(–Sep). | |||||||||||||||||||||||||||||||||||||||||||||||||||||
Habitat | Forming colonies on rocky slopes and banks of eroded sedimentaries, on gypsum or limestone, on conglomerates, often with Juniperus and Pinus edulis, with Encelia farinosa and Larrea. | |||||||||||||||||||||||||||||||||||||||||||||||||||||
Elevation | 300–1100 m. (1000–3600 ft.) | |||||||||||||||||||||||||||||||||||||||||||||||||||||
Distribution | w United States; nw Mexico |
AZ; NV; UT
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Discussion | Species 14 (14 in the flora). Section Chylismia consists of 10 diploid (2n = 14) species, and two that are partly polyploid (2n = 14, 28) [C. scapoidea subsp. scapoidea and C. walkeri subsp. walkeri (only one tetraploid population)]; no chromosome counts are available for the remaining two species, C. atwoodii and C. confertiflora (P. H. Raven 1962, 1969). Species of sect. Chylismia usually occur on sandy desert slopes, flats, and washes, often in sagebrush shrubland in the northern part of its range, or on rock slides or cliffs, mainly in the Mojave and northwestern Sonoran deserts, the Great Basin, and the lower elevations of the surrounding Sierra Nevada and Rocky Mountains. The limits of this range stretch from southeastern Oregon, central and southern Idaho, and central Wyoming, south through Nevada and Utah to eastern and southeastern California, northern Baja California and northwestern Sonora, Mexico, Arizona, northwestern New Mexico, and western Colorado. Several species are rare; C. confertiflora and C. specicola are known only from the Grand Canyon in northwestern Arizona, C. megalantha only from the vicinity of the type locality in Nye County, Nevada, and C. atwoodii also only from a narrow area around its type locality in Kane County, Utah. Others are widespread, especially the very diverse C. claviformis (11 subspp.), C. scapoidea (4 subspp.), C. walkeri (2 subspp.), and C. brevipes (3 subspp.). Chylismia scapoidea is the only species in the genus to occur east of the continental divide, both in Colorado on the upper Arkansas River in Fremont and Pueblo counties, and much more widely in Wyoming. Chylismia does not occur west of the Cascade-Sierra Nevada axis. Because R. A. Levin et al. (2004) included only C. claviformis in their analysis, they did not test the monophyly of sect. Chylismia; however, this section is both geographically distinct and morphologically set apart by the characteristic pinnate leaves (modified in some species, which have retained the entire apical lobe but do not have the smaller lateral lobes). Most species have bright yellow petals with red dots proximally and ultraviolet reflectance distally; some subspecies of C. claviformis have white petals; three species (C. atwoodii, C. heterochroma, and C. megalantha) have lavender or purple petals, often with lavender or purple flecks toward base, and white or yellow at the base and no reflectance, clearly a derived condition within the section (Raven 1962, 1969). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Chylismia multijuga is known from Washington County, Utah, and southern Lincoln County, Nevada, to northern Mohave County, Arizona. P. H. Raven (1962, 1969) determined this species to be self-incompatible. It hybridizes with C. brevipes subspp. brevipes and pallidula. (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. | ||||||||||||||||||||||||||||||||||||||||||||||||||||
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Synonyms | Camissonia section tetranthera, Oenothera section tetranthera | Oenothera multijuga, Camissonia multijuga, Chylisma hirta, C. parviflora, C. venosa, O. brevipes var. multijuga, O. brevipes var. parviflora, O. multijuga var. parviflora, O. phlebophylla, O. watsonii | ||||||||||||||||||||||||||||||||||||||||||||||||||||
Name authority | unknown | (S. Watson) Small: Bull. Torrey Bot. Club 23: 193. (1896) — (as Chylisma) | ||||||||||||||||||||||||||||||||||||||||||||||||||||
Web links |