Xanthisma junceum |
Xanthisma grindelioides |
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rush bristleweed, rush-like bristleweed |
goldenweed, gumweed aster, rayless tansyaster |
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Habit | Subshrubs, 25–100 cm; caudices branched, taproots 2–10+ cm. | Subshrubs, 3–35 cm (tufted or densely cespitose, often mound-forming); caudices much branched, taproot 2–20+ cm. | ||||
Stems | 3–15+, branched in distal 1/2, slender and wiry, glabrous. |
10–30+, simple or branched in distal 1/3, moderately stout to stout, not wiry, hairy or minutely stipitate-glandular. |
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Leaves | basal often withering by flowering, 20–35 × 6–12 mm, pinnatifid; cauline evenly spaced, blades oblong to linear, scalelike, 4–6 × 1–2 mm (except proximalmost), markedly reduced distally, margins usually entire, faces glabrous. |
basal often persistent; cauline evenly spaced, blades oblong, obovate, lanceolate to spatulate or narrowly ovate to obovate, 7–60 × 2–13 mm, gradually reduced distally, margins usually evenly coarsely serrate to serrulate, teeth 4–16 per side, each tipped with white bristle 0.5–4 mm, faces sparsely to densely hairy (hairs subappressed), often minutely stipitate-glandular. |
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Peduncles | minutely glandular, if stipitate, then minutely so; bracts 5–25, imbricate, grading into phyllaries. |
sparsely to densely hairy, often stipitate-glandular; sometimes bracteate. |
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Involucres | hemispheric (narrowed at bases), 0.5–0.8 × 1–1.2 cm. |
hemispheric to campanulate, 0.5–1 × 0.6–1.5 cm. |
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Ray florets | 15–25; corollas yellow, tubes 3.5–4 mm, laminae 5–6 × 1.5–2.5 mm. |
0. |
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Disc florets | 25–40+; corollas 4.8–6.3 mm. |
15–50+; corollas 5–8.5 mm. |
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Phyllaries | in 5–6 series, oblong to linear-oblanceolate, 1.5–6.5 mm, apices acute, tipped by white bristle, faces minutely stipitate-glandular. |
in 3–5 series, oblong to broadly lanceolate, 2–9 mm, apices obtuse to acute, tipped by white seta, faces usually densely stipitate-glandular. |
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Heads | 1–10+. |
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Cypselae | narrowly obovoid to oblanceoloid, 1.5–2.5 mm, nerves 12–18, moderately tawny hairy; pappi tawny, 3.5–6 mm, a few abaxial bristles to 1/3 of longest. |
oblong to narrowly obovoid, 2–3.5 mm, ribs 12–24, densely whitish to tawny hairy; pappi whitish to tawny, 3–7 mm, a few abaxial bristles to 1/3 of longest. |
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2n | = 8, 16. |
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Xanthisma junceum |
Xanthisma grindelioides |
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Phenology | Flowering summer–fall. | |||||
Habitat | Rocky, dry slopes | |||||
Elevation | 100–1000 m (300–3300 ft) | |||||
Distribution |
CA; Mexico (Baja California, Sonora)
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AZ; CO; ID; MT; ND; NE; NM; NV; SD; UT; WY; AB; SK
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Discussion | Xanthisma junceum is reported from Arizona, but no specimen has been seen; as it is coastal in distribution, the report is likely based on a misidentified specimen. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Varieties 2 (2 in the flora). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 20, p. 390. | FNA vol. 20, p. 387. | ||||
Parent taxa | Asteraceae > tribe Astereae > Xanthisma > sect. Sideranthus | Asteraceae > tribe Astereae > Xanthisma > sect. Blepharodon | ||||
Sibling taxa | ||||||
Subordinate taxa | ||||||
Synonyms | Haplopappus junceus, Machaeranthera juncea | Eriocarpum grindelioides, Haplopappus nuttallii, Machaeranthera grindelioides | ||||
Name authority | (Greene) D. R. Morgan & R. L. Hartman: Sida 20: 1406. (2003) | (Nuttall) D. R. Morgan & R. L. Hartman: Sida 20: 1403. (2003) | ||||
Web links |
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