Ivesia argyrocoma |
Ivesia muirii |
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silver-hair ivesia, silverhair mousetail |
granite mousetail, Muir's ivesia |
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Habit | Plants silvery, usually ± rosetted; taproot stout, sometimes fleshy. | |
Stems | usually ± erect, sometimes nearly prostrate, 0.5–1.5(–2) 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. |
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Cauline leaves | (0–)1–2, paired if 2. |
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Inflorescences | 10–30-flowered, 1–2(–3.5) cm diam.; glomerules usually 1. |
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Pedicels | 0.3–2(–3.5) 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. |
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Achenes | grayish brown, mottled with red, 1.6–2 mm. |
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Ivesia argyrocoma |
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 |
CA; nw Mexico
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CA
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Discussion | Varieties 2 (1 in the flora). Plants from the central Sierra San Pedro Mártir in northern Baja California belong to var. moranii Ertter & Reveal, which may be distinguished by its compact stature (to 0.5 dm), densely villous basal stipules 2–4 mm, decumbent stems 2–7 cm that are stipitate-glandular under the villous indumentum, and solitary, loosely congested cyme. The petals are oblanceolate to narrowly obovate and 2.5–3.5 mm. The grayish, faintly mottled achenes are 1.3–2 mm. (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.) |
Source | FNA vol. 9, p. 242. | FNA vol. 9, p. 236. |
Parent taxa | Rosaceae > subfam. Rosoideae > tribe Potentilleae > Ivesia > sect. Unguiculatae | Rosaceae > subfam. Rosoideae > tribe Potentilleae > Ivesia > sect. Ivesia |
Sibling taxa | ||
Subordinate taxa | ||
Synonyms | Horkelia argyrocoma, Potentilla argyrocoma | Potentilla muirii |
Name authority | (Rydberg) Rydberg: in N. L. Britton et al., N. Amer. Fl. 22: 284. (1908) | A. Gray: Proc. Amer. Acad. Arts 8: 627. (1873) |
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