Ivesia arizonica |
Ivesia muirii |
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purpusia, rock whitefeather |
granite mousetail, Muir's ivesia |
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Habit | Plants green, ± tufted, often forming hanging clumps, sometimes rosetted. | Plants silvery, usually ± rosetted; taproot stout, sometimes fleshy. | ||||
Stems | pendent or prostrate to ascending, (0.2–)0.5–1.6(–3) dm. |
usually ± erect, sometimes nearly prostrate, 0.5–1.5(–2) dm. |
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Basal leaves | planar, 2–15(–20) cm; sheathing base usually not strigose abaxially; petiole 3–10 cm; lateral leaflets (2–)3–4(–5) per side, separate, broadly ovate or obovate to orbiculate, (2–)5–15(–18) mm, incised 1/4–3/4 to base into (3–)7–11 ± ovate teeth, apex not setose, surfaces ± sparsely short-pilose, ± glandular; terminal leaflets ± distinct. |
very tightly cylindric (mousetail-like, with individual leaflets scarcely distinguishable), 2–5(–10) cm; sheathing base densely strigose abaxially; petiole 0.2–0.8(–1) cm, hairs 0.5–1.5 mm; leaflets 25–40 per side, 0.4–1 mm, densely sericeous, glands obscured, lobes 2–5, obovate or oval to orbiculate, apex not setose. |
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Cauline leaves | 1–3; blade well developed. |
(0–)1–2, paired if 2. |
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Inflorescences | (1–)5–30(–150)-flowered, open, 0.5–14 cm diam. |
10–30-flowered, 1–2(–3.5) cm diam.; glomerules usually 1. |
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Pedicels | 5–30 mm. |
0.3–2(–3.5) mm. |
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Flowers | 6–12 mm diam.; epicalyx bractlets 0(–3), lanceolate, 0.9–1.8 mm; hypanthium turbinate or campanulate, 1.5–3(–5) × 1–3(–4) mm; sepals 2–4(–5) mm, acute; petals yellow or white, oblanceolate to elliptic or obovate, (1.6–)2–4 mm; stamens 5, filaments 0.8–1.3 mm, anthers ± yellow, oblong to narrowly ovate, 0.6–1.5 mm; carpels (2–)6–10(–13), atop a stipelike torus, styles 0.9–1.8 mm. |
5–6 mm diam.; epicalyx bractlets oblong to obovate, 0.5–1 mm; hypanthium shallowly cupulate, 0.5–1(–1.5) × 1.5–2.5 mm; sepals (1–)1.5–2.5 mm, acute; petals yellow, linear to oblanceolate or narrowly oblong, 1–2 mm; stamens 5, filaments 0.3–0.6 mm, anthers yellow, 0.4–0.6 mm; carpels 1–4, styles 0.7–1.2 mm. |
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Achenes | greenish white to light tan, 1.2–2 mm, faintly rugose, ± carunculate. |
grayish brown, mottled with red, 1.6–2 mm. |
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Ivesia arizonica |
Ivesia muirii |
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Phenology | Flowering summer. | |||||
Habitat | Dry rocky slopes, fellfields, mostly in alpine conifer woodlands and tundra | |||||
Elevation | 2900–4000 m (9500–13100 ft) | |||||
Distribution |
AZ; CA; NV; UT |
CA
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Discussion | Varieties 2 (2 in the flora). Because the epithet saxosa was retained for Potentilla saxosa upon transfer to Ivesia, a different epithet (arizonica) was needed when Purpusia was likewise transferred in the same publication (B. Ertter 1989). The correct name for this species in Potentilla is P. osterhoutii (A. Nelson) J. T. Howell, due to the existence of P. arizonica. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Ivesia muirii is known from alpine areas in the Sierra Nevada. It is one of the more distinctive species of the genus, in its silvery mousetail-like leaves and usually tightly capitate inflorescences. Putative hybrids are known with I. lycopodioides (D. D. Keck 1938) and I. pygmaea (Center Basin area of Tulare County). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 9, p. 224. | FNA vol. 9, p. 236. | ||||
Parent taxa | ||||||
Sibling taxa | ||||||
Subordinate taxa | ||||||
Synonyms | Purpusia arizonica | Potentilla muirii | ||||
Name authority | (Eastwood ex J. T. Howell) Ertter: Syst. Bot. 14: 233. (1989) | A. Gray: Proc. Amer. Acad. Arts 8: 627. (1873) | ||||
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