Ivesia argyrocoma |
Ivesia saxosa |
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silver-hair ivesia, silverhair mousetail |
rock ivesia, rock mousetail |
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Habit | Plants green, ± tufted, often forming hanging clumps, sometimes rosetted. | |
Stems | pendent or prostrate to ascending, 0.4–2.6(–3) dm. |
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Basal leaves | planar, 2–15 cm; sheathing base not strigose abaxially; petiole 3–9 cm; lateral leaflets (1–)2–4(–7) per side, separate to slightly overlapping, obovate to orbiculate or flabellate, (3–)5–15(–22) mm, incised 1/4–3/4 to base into 5–15 broadly ovate teeth or oblanceolate lobes, sometimes also medially split to base (Kern Plateau), apex not setose, surfaces ± sparsely short-pilose, prominently glandular; terminal leaflets ± distinct. |
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Cauline leaves | 1–2(–4); blade well developed. |
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Inflorescences | (1–)3–30(–60)-flowered, open, (0.5–)2–8 cm diam. |
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Pedicels | (5–)10–30 mm. |
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Flowers | 6–12 mm diam.; epicalyx bractlets 5, broadly lanceolate to oblong, 1–2.5 mm; hypanthium patelliform, 0.5–1.5 × 2–4(–4.5) mm; sepals 2–4.5 mm, acute; petals yellow, oblanceolate to obovate, (1.5–)2–4 mm; stamens 15–35(–40), filaments 0.3–1 mm, anthers yellow, subrotund, 0.2–0.3(–0.5) mm; carpels (3–)10–20(–40), styles 1–2 mm. |
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Achenes | greenish white to light tan, 1–1.8 mm, faintly rugose, ± carunculate. |
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Ivesia argyrocoma |
Ivesia saxosa |
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Phenology | Flowering late spring–summer. | |
Habitat | Dry, rocky outcrops of granitic or volcanic origin, usually crevices of more or less vertical protected cliffs or boulders, mainly in oak and conifer woodlands | |
Elevation | 900–3300 m (3000–10800 ft) | |
Distribution |
CA; nw Mexico
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CA; Mexico (Baja California)
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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 saxosa is encountered in the foothills and mountains of southeastern California from the White Mountains and adjacent eastern slopes of the Sierra Nevada of Mono County to the Transverse Ranges (including the Little San Bernardino Mountains) of Kern and San Bernardino counties. Populations on the Kern Plateau tend to have more dissected leaflets and may deserve recognition as a distinct variety. On the Peninsular Ranges, I. saxosa occurs in Riverside and San Diego counties and into northern Baja California, Mexico, as far south as the western slopes of the Sierra Juárez and Sierra San Pedro Mártir. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 9, p. 242. | FNA vol. 9, p. 223. |
Parent taxa | Rosaceae > subfam. Rosoideae > tribe Potentilleae > Ivesia > sect. Unguiculatae | Rosaceae > subfam. Rosoideae > tribe Potentilleae > Ivesia > sect. Setosae |
Sibling taxa | ||
Subordinate taxa | ||
Synonyms | Horkelia argyrocoma, Potentilla argyrocoma | Potentilla saxosa, P. acuminata, P. saxosa subsp. sierrae |
Name authority | (Rydberg) Rydberg: in N. L. Britton et al., N. Amer. Fl. 22: 284. (1908) | (Lemmon ex Greene) Ertter: Syst. Bot. 14: 232. (1989) |
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