Ivesia arizonica |
Rosaceae subfam. rosoideae |
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purpusia, rock whitefeather |
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Habit | Plants green, ± tufted, often forming hanging clumps, sometimes rosetted. | Herbs, shrubs, or subshrubs. | ||||
Stems | pendent or prostrate to ascending, (0.2–)0.5–1.6(–3) dm. |
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Leaves | alternate, rarely opposite, pinnately compound, sometimes simple or palmately compound; stipules present, rarely absent. |
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Basal leaves | 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 | 1–3; blade well developed. |
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Inflorescences | (1–)5–30(–150)-flowered, open, 0.5–14 cm diam. |
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Pedicels | 5–30 mm. |
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Flowers | 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. |
torus usually enlarged, sometimes small or absent; carpels 1–260(–450), distinct, free, styles distinct, rarely connate (Roseae); ovules 1(or 2), collateral (Rubeae) or superposed (Fallugia, Filipendula). |
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Fruits | achenes or aggregated achenes sometimes with fleshy, urn-shaped hypanthium or enlarged torus, sometimes aggregated drupelets; styles persistent or deciduous, not elongate (elongate but not plumose in Geum). |
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Achenes | greenish white to light tan, 1.2–2 mm, faintly rugose, ± carunculate. |
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x | = 7(8). |
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Ivesia arizonica |
Rosaceae subfam. rosoideae |
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Distribution |
AZ; CA; NV; UT |
North America; Mexico; Central America; South America; West Indies; Bermuda; Eurasia; Africa; Atlantic Islands; Indian Ocean Islands; Pacific Islands; Australia |
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Discussion | 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.) |
Variation in the number of genera in subfam. Rosoideae is due to differences in generic delimitation between D. Potter et al. (2007) and the authors of some Potentilleae genera. Cyanogenic glycosides and sorbitol are absent in the subfamily. Tribes 6, genera 28–35, species ca. 1600 (6 tribes, 26 genera, 302 species, including 1 hybrid, in the flora) (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 9, p. 224. | FNA vol. 9, p. 23. | ||||
Parent taxa | ||||||
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Synonyms | Purpusia arizonica | |||||
Name authority | (Eastwood ex J. T. Howell) Ertter: Syst. Bot. 14: 233. (1989) | Arnott: Botany, 107. (1832) | ||||
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