Chaenactis douglasii |
Chaenactis artemisiifolia |
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chaenactis, Douglas' dusty maidens, Douglas' dustymaiden, hoary chaenactis, hoary false-yarrow, hoary pincushion |
artemisia leaf chaenactis, white pincushion |
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Habit | Biennials or perennials, (2–)5–50(–60) cm (rarely slightly woody or flowering first year, sometimes cespitose or ± matted); proximal indument thinning with age, grayish, mostly arachnoid-sericeous to thinly lanuginose. | Plants (15–)25–90(–200) cm. | ||||
Stems | 1–25+, erect to spreading. |
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Leaves | basal, or basal (sometimes withering) and ± cauline, (1–)2–12(–15) cm; largest blades ± elliptic or slightly lanceolate to ovate, ± 3-dimensional, usually 2-pinnately lobed; primary lobes (4–)5–9(–12) pairs, ± congested, scarcely imbricate, ultimate lobes ± involute and/or twisted. |
basal (withering) and cauline, 3–15(–20) cm; largest blades ± plane, not succulent; primary lobes mostly 5–10 pairs, ultimate lobes ± crowded, antrorse, lanceolate to elliptic, plane. |
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Peduncles | mostly ascending to erect, 1–10 cm. |
1.5–6 cm. |
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Involucres | obconic to ± hemispheric. |
± hemispheric, mostly 10–15 mm diam. |
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Receptacles | paleae 0. |
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Corollas | 5–8 mm. |
5–7 mm. |
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Phyllaries | longest 9–15(–17) mm; outer usually stipitate-glandular (sometimes sparsely or obscurely, rarely eglandular) and, often, arachnoid to lanuginose and, sometimes, sparsely villous, apices usually ± squarrose, pliant. |
longest 7–10(–12) mm, ± densely villous, not or sparsely glandular; apices (all) erect, ± green, acute or scarcely acuminate, not aristate, ± plane. |
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Heads | 1–25+ per stem. |
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Cypselae | 5–8 mm (usually sparsely glandular amidst other indument); pappi: longest scales 3–6 mm. |
compressed, 4–7 mm; pappi 0 or coroniform (of ± 10 scales, longest 0.1–0.5 mm). |
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2n | = 16. |
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Chaenactis douglasii |
Chaenactis artemisiifolia |
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Phenology | Flowering Apr–early Jul. | |||||
Habitat | Dry canyons, open slopes, often over granitoid rocks, locally abundant in chaparral burns or other recovering disturbances | |||||
Elevation | 80–1600 m (300–5200 ft) | |||||
Distribution |
AZ; CA; CO; ID; MT; ND; NM; NV; OR; SD; UT; WA; WY; AB; BC
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CA; Mexico (Baja California)
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Discussion | Varieties 2 (2 in the flora). Chaenactis douglasii is widespread and variable (see discussion under var. douglasii). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
In the flora area, Chaenactis artemisiifolia is known from the Transverse and Peninsular ranges and seaward valleys of southwestern California. It is fire-adapted; its germination is significantly enhanced by exposure to biomass smoke (J. E. Keeley and C. J. Fotheringham 1998). Chaenactis lacera Greene, the eighteenth species of the genus, is known from coastal portions (including islands) of the western Vizcaíno Desert in Baja California and Baja California Sur, Mexico. Forms of C. artemisiifolia sometimes resemble C. lacera in coastal southern California (P. Stockwell 1940), where C. lacera could eventually be introduced. Besides the key characteristics above, C. lacera differs from C. artemisiifolia by its largest leaf blades broadly ± elliptic, 2–3-pinnately lobed, ultimate lobes remote, recurved to retrorse, ± linear, involute (leaf blades appearing ± skeletal). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 21, p. 405. | FNA vol. 21, p. 402. | ||||
Parent taxa | Asteraceae > tribe Heliantheae > subtribe Chaenactidinae > Chaenactis > sect. Macrocarphus | Asteraceae > tribe Heliantheae > subtribe Chaenactidinae > Chaenactis > sect. Acarphaea | ||||
Sibling taxa | ||||||
Subordinate taxa | ||||||
Synonyms | Hymenopappus douglasii, Macrocarphus douglasii | Acarphaea artemisiifolia | ||||
Name authority | (Hooker) Hooker & Arnott: Bot. Beechey Voy., 354. (1839) | (Harvey & A. Gray) A. Gray: Proc. Amer. Acad. Arts 10: 74. (1874) | ||||
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