Ivesia argyrocoma |
Ivesia cryptocaulis |
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silver-hair ivesia, silverhair mousetail |
Charleston Peak ivesia, Charleston Peak mousetail |
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Habit | Plants green, diffusely matted. | |
Stems | prostrate to decumbent, 0.2–0.6(–1) dm. |
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Basal leaves | tightly cylindric, 1–4(–5) cm; sheathing base mostly not strigose abaxially; petiole 0.3–2 cm, hairs 0.5–1 mm; lateral leaflets 5–10(–12) per side, ± overlapping, ± flabellate, 1–2.5 mm, incised to base or nearly so into 3–5 obovate to oval lobes, apex sometimes ± setose, surfaces loosely long-strigose, sparsely glandular; terminal leaflets indistinct. |
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Cauline leaves | 1(–2); blade vestigial. |
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Inflorescences | 1–10-flowered, ± congested, 0.5–1.5 cm diam. |
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Pedicels | 3–7(–10) mm. |
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Flowers | 6–9 mm diam.; epicalyx bractlets 5, lanceolate to narrowly oblong or narrowly ovate, 0.8–1.3 mm; hypanthium shallowly cupulate, ± 1 × 2–3(–4) mm; sepals 1.5–2.3 mm, ± acute; petals yellow, oblanceolate to spatulate, 2–3.2 mm; stamens 5, filaments 0.9–1.2 mm, anthers yellow, oblong, 0.7–0.9 mm; carpels 6–10, styles 1–1.5 mm. |
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Achenes | greenish cream to light brown, 1.4–1.8(–2) mm, smooth, not carunculate. |
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Ivesia argyrocoma |
Ivesia cryptocaulis |
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Phenology | Flowering summer. | |
Habitat | Dry to moist limestone gravel, scree, or talus slopes and outcrops, subalpine conifer woodlands, alpine tundra communities | |
Elevation | 2500–3700 m (8200–12100 ft) | |
Distribution |
CA; nw Mexico
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NV |
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.) |
Of conservation concern. Ivesia cryptocaulis is known only from timberline and above in the Spring Mountains of Clark County. Plants differ from all others of the genus by having slender, elongate, diffuse caudex branches that ramify through its habitat of gravel, scree, and talus. The species is here provisionally included in sect. Setosae as a diffusely matted relative of I. shockleyi (as also suggested by D. D. Keck 1938); the ecarunculate seeds and relatively straight pedicels may indicate a greater similarity to I. pygmaea in sect. Ivesia. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 9, p. 242. | FNA vol. 9, p. 228. |
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 cryptocaulis |
Name authority | (Rydberg) Rydberg: in N. L. Britton et al., N. Amer. Fl. 22: 284. (1908) | (Clokey) D. D. Keck: Lloydia 1: 130. (1939) |
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