Ivesia setosa |
Ivesia argyrocoma |
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bristly ivesia |
silver-hair ivesia, silverhair mousetail |
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Habit | Plants green, tufted to ± densely matted. | |
Stems | ± ascending to nearly erect, 0.7–2.5(–2.8) dm. |
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Basal leaves | weakly planar to loosely cylindric, 5–9(–12) cm; sheathing base ± strigose abaxially; petiole 1–8 cm; lateral leaflets 5–10 per side, separate to overlapping distally, ± flabellate, 2–8 mm, incised ± 3/4 to base, sometimes nearly to base, into (3–)7–11 ovate teeth to narrowly obovate lobes, apex usually ± setose, surfaces ± sparsely hirsute, conspicuously glandular; terminal leaflets ± indistinct. |
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Cauline leaves | (0–)1; blade vestigial. |
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Inflorescences | (1–)5–15(–30)-flowered, ± open, 1–6(–12) cm diam. |
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Pedicels | 5–15(–20) mm. |
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Flowers | 7–10 mm diam.; epicalyx bractlets 5, lanceolate, 1.3–2.5(–3) mm; hypanthium patelliform, (1–)1.5–2 × 2–3.5(–4) mm; sepals (1.5–)2–3.5 mm, ± acute; petals yellow, oblanceolate to narrowly spatulate, 1.5–2.5 mm; stamens 5, filaments 0.8–1.5 mm, anthers yellow, oblong, 0.4–0.7 mm; carpels 2–8, styles 1.2–2 mm. |
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Achenes | greenish white to light tan, 1.7–2 mm, smooth, ± carunculate. |
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Ivesia setosa |
Ivesia argyrocoma |
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Phenology | Flowering summer. | |
Habitat | Dry, rocky talus slopes, boulders and outcrops, most often but not always of calcareous origin, occasionally away from immediate outcrops, sagebrush communities, conifer woodlands | |
Elevation | 1800–2600(–3100) m (5900–8500(–10200) ft) | |
Distribution |
NV; UT |
CA; nw Mexico
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Discussion | Ivesia setosa occurs mostly to the east and south of I. baileyi, from southeastern Humboldt and Churchill counties to Elko, White Pine, and northern Nye counties, Nevada, and in the Deep Creek Range of western Utah. It represents a transition between the planar-leaved, chasmophytic members of sect. Setosae and the cylindric-leaved, matted species of flatter sites. Stems of I. setosa are more generally erect than in other species in the section, and the usually calcareous substrate is noteworthy. The deeply incised (usually not quite to base) leaflets are somewhat intermediate between the toothed leaflets of I. baileyi and the leaflets of I. shockleyi that are incised to the base into separate lobes. The individual leaflets of both I. baileyi and I. setosa are more or less flat and distichously paired; in I. shockleyi, groups of leaflet lobes are folded over onto each other, giving a verticillate appearance to the leaflet arrangement. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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.) |
Source | FNA vol. 9, p. 227. | FNA vol. 9, p. 242. |
Parent taxa | ||
Sibling taxa | ||
Subordinate taxa | ||
Synonyms | I. baileyi var. setosa, Potentilla baileyi var. setosa | Horkelia argyrocoma, Potentilla argyrocoma |
Name authority | (S. Watson) Rydberg: in N. L. Britton et al., N. Amer. Fl. 22: 290. (1908) | (Rydberg) Rydberg: in N. L. Britton et al., N. Amer. Fl. 22: 284. (1908) |
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