Ivesia muirii |
Ivesia utahensis |
|
---|---|---|
granite mousetail, Muir's ivesia |
Utah ivesia, Utah mousetail |
|
Habit | Plants silvery, usually ± rosetted; taproot stout, sometimes fleshy. | Plants green, rosetted to tufted; taproot proximally enlarged, not fleshy. |
Stems | usually ± erect, sometimes nearly prostrate, 0.5–1.5(–2) dm. |
prostrate to ascending, 0.5–1.5(–2) dm. |
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. |
± tightly cylindric, 2–7(–9) cm; sheathing base glabrous abaxially; petiole 0.5–2 cm, hairs 0.5–1 mm; leaflets 15–20 per side, 2–4 mm, glabrate or sparsely short-hirsute, sparsely to densely glandular, lobes (2–)3–8, narrowly oblanceolate to obovate, apex not setose. |
Cauline leaves | (0–)1–2, paired if 2. |
(0–)1, not paired. |
Inflorescences | 10–30-flowered, 1–2(–3.5) cm diam.; glomerules usually 1. |
(5–)10–30-flowered, 1–2.5(–5) cm diam.; glomerules 1–few. |
Pedicels | 0.3–2(–3.5) mm. |
1–7 mm. |
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. |
7–9 mm diam.; epicalyx bractlets narrowly oblong to oval, 0.8–2 mm; hypanthium shallowly cupulate, (1–)1.5–2 × 2.5–3.5 mm; sepals (1.8–)2–3 mm, acute; petals white, sometimes pink-tinged, oblanceolate to spatulate, 1.8–3 mm; stamens 5, filaments 1.3–1.8 mm, anthers orangish to reddish brown, 0.4–0.6 mm; carpels (1–)2–4, styles 1.5–2 mm. |
Achenes | grayish brown, mottled with red, 1.6–2 mm. |
yellowish green to light tan or gray-brown, 1.7–1.9 mm. |
Ivesia muirii |
Ivesia utahensis |
|
Phenology | Flowering summer. | Flowering summer. |
Habitat | Dry rocky slopes, fellfields, mostly in alpine conifer woodlands and tundra | Talus slopes, bare ridges, in high-elevation sagebrush communities, subalpine to alpine conifer woodlands |
Elevation | 2900–4000 m (9500–13100 ft) | 3200–3700 m (10500–12100 ft) |
Distribution |
CA
|
UT |
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.) |
Of conservation concern. Ivesia utahensis is known from the Wasatch and adjacent Uinta Mountains in northern Utah. The species stands as the white-petaled counterpart to the yellow-petaled Sierran I. lycopodioides, possibly indicating a common ancestral stock that was once more continuous across the Great Basin. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 9, p. 236. | FNA vol. 9, p. 233. |
Parent taxa | Rosaceae > subfam. Rosoideae > tribe Potentilleae > Ivesia > sect. Ivesia | Rosaceae > subfam. Rosoideae > tribe Potentilleae > Ivesia > sect. Ivesia |
Sibling taxa | ||
Synonyms | Potentilla muirii | Potentilla utahensis |
Name authority | A. Gray: Proc. Amer. Acad. Arts 8: 627. (1873) | S. Watson: Proc. Amer. Acad. Arts 17: 371. (1882) |
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