Ivesia muirii |
Ivesia arizonica |
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granite mousetail, Muir's ivesia |
purpusia, rock whitefeather |
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Habit | Plants silvery, usually ± rosetted; taproot stout, sometimes fleshy. | Plants green, ± tufted, often forming hanging clumps, sometimes rosetted. | ||||
Stems | usually ± erect, sometimes nearly prostrate, 0.5–1.5(–2) dm. |
pendent or prostrate to ascending, (0.2–)0.5–1.6(–3) dm. |
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Basal leaves | 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. |
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. |
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Cauline leaves | (0–)1–2, paired if 2. |
1–3; blade well developed. |
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Inflorescences | 10–30-flowered, 1–2(–3.5) cm diam.; glomerules usually 1. |
(1–)5–30(–150)-flowered, open, 0.5–14 cm diam. |
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Pedicels | 0.3–2(–3.5) mm. |
5–30 mm. |
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Flowers | 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. |
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. |
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Achenes | grayish brown, mottled with red, 1.6–2 mm. |
greenish white to light tan, 1.2–2 mm, faintly rugose, ± carunculate. |
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Ivesia muirii |
Ivesia arizonica |
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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 |
CA
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AZ; CA; NV; UT |
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Discussion | 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.) |
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.) |
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Key |
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Source | FNA vol. 9, p. 236. | FNA vol. 9, p. 224. | ||||
Parent taxa | Rosaceae > subfam. Rosoideae > tribe Potentilleae > Ivesia > sect. Ivesia | Rosaceae > subfam. Rosoideae > tribe Potentilleae > Ivesia > sect. Setosae | ||||
Sibling taxa | ||||||
Subordinate taxa | ||||||
Synonyms | Potentilla muirii | Purpusia arizonica | ||||
Name authority | A. Gray: Proc. Amer. Acad. Arts 8: 627. (1873) | (Eastwood ex J. T. Howell) Ertter: Syst. Bot. 14: 233. (1989) | ||||
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