Ivesia rhypara |
Ivesia arizonica |
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grimy ivesia, grimy mousetail |
purpusia, rock whitefeather |
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Habit | Plants grayish, ± matted. | Plants green, ± tufted, often forming hanging clumps, sometimes rosetted. | ||||||||
Stems | ± prostrate, (0.1–)0.2–1.5(–2) dm. |
pendent or prostrate to ascending, (0.2–)0.5–1.6(–3) dm. |
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Basal leaves | tightly cylindric, 2–10 cm; sheathing base densely hairy abaxially; petiole 0.5–4(–10) cm; lateral leaflets 4–10(–15) per side, overlapping at least distally, ± flabellate, 0.5–3(–4) mm, incised to base or nearly so into (0–)2–4(–9) elliptic to obovate or orbiculate lobes, apex usually not setose, surfaces densely hirsute, cryptically glandular; terminal leaflets indistinct. |
planar, 2–15(–20) cm; sheathing base usually not strigose abaxially; petiole 3–10 cm; lateral leaflets (2–)3–4(–5) per side, separate, broadly ovate or obovate to orbiculate, (2–)5–15(–18) mm, incised 1/4–3/4 to base into (3–)7–11 ± ovate teeth, apex not setose, surfaces ± sparsely short-pilose, ± glandular; terminal leaflets ± distinct. |
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Cauline leaves | (0–)1; blade vestigial. |
1–3; blade well developed. |
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Inflorescences | 5–60(–100)-flowered, congested, 0.5–5(–7) cm diam. |
(1–)5–30(–150)-flowered, open, 0.5–14 cm diam. |
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Pedicels | 1.5–4(–8) mm. |
5–30 mm. |
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Flowers | 4–8 mm diam.; epicalyx bractlets 5, linear to elliptic or narrowly ovate, 0.8–1.6(–2.1) mm; hypanthium patelliform to shallowly cupulate, 1–1.5 × (1.5–)2–3(–3.5) mm; sepals 1.4–2.5(–2.8) mm, acute; petals white to pale yellowish, linear to narrowly oblanceolate, 1–1.5 mm; stamens 5, filaments 0.6–1.8 mm, anthers maroon or yellow with maroon margins, oblong, 0.3–0.6 mm; carpels 1–2(–4), styles 1–1.5 mm. |
6–12 mm diam.; epicalyx bractlets 0(–3), lanceolate, 0.9–1.8 mm; hypanthium turbinate or campanulate, 1.5–3(–5) × 1–3(–4) mm; sepals 2–4(–5) mm, acute; petals yellow or white, oblanceolate to elliptic or obovate, (1.6–)2–4 mm; stamens 5, filaments 0.8–1.3 mm, anthers ± yellow, oblong to narrowly ovate, 0.6–1.5 mm; carpels (2–)6–10(–13), atop a stipelike torus, styles 0.9–1.8 mm. |
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Achenes | brown, 1.2–1.6(–2) mm, smooth, prominently carunculate. |
greenish white to light tan, 1.2–2 mm, faintly rugose, ± carunculate. |
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Ivesia rhypara |
Ivesia arizonica |
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Distribution |
NV; OR
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AZ; CA; NV; UT |
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Discussion | Varieties 2 (2 in the flora). Ivesia rhypara forms densely hairy mats or mounds on isolated edaphic sites in the northern Great Basin. Only one of the widely disjunct population clusters is recognized as a distinct variety; the others have general differences in gestalt, but no significant distinctions have been determined (B. Ertter 1989). Isozyme analysis likewise does not show significant differences (T. Kaye et al., unpubl., BLM and Oregon Dept. of Agriculture, 1991). Reproductive studies by D. Wiens (pers. comm.) show low seed set (ca. 5% in var. rhypara, somewhat higher in var. shellyi), possibly indicating a deleterious genetic load. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Varieties 2 (2 in the flora). Because the epithet saxosa was retained for Potentilla saxosa upon transfer to Ivesia, a different epithet (arizonica) was needed when Purpusia was likewise transferred in the same publication (B. Ertter 1989). The correct name for this species in Potentilla is P. osterhoutii (A. Nelson) J. T. Howell, due to the existence of P. arizonica. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 9, p. 228. | FNA vol. 9, p. 224. | ||||||||
Parent taxa | Rosaceae > subfam. Rosoideae > tribe Potentilleae > Ivesia > sect. Setosae | Rosaceae > subfam. Rosoideae > tribe Potentilleae > Ivesia > sect. Setosae | ||||||||
Sibling taxa | ||||||||||
Subordinate taxa | ||||||||||
Synonyms | Purpusia arizonica | |||||||||
Name authority | Ertter & Reveal: Madroño 24: 224, fig. 1. (1977) | (Eastwood ex J. T. Howell) Ertter: Syst. Bot. 14: 233. (1989) | ||||||||
Web links |