Ivesia webberi |
Rosaceae subfam. rosoideae |
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Webber's ivesia, wire ivesia, wire mousetail |
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Habit | Plants ± green, ± rosetted; taproot slender to ± stout, not fleshy. | Herbs, shrubs, or subshrubs. |
Stems | decumbent to ascending, 0.5–1.5(–1.8) 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 | loosely ± cylindric, 3–7(–10) cm; sheathing base ± strigose abaxially; petiole 0.5–5(–6) cm, hairs 2–4 mm; leaflets 4–8(–10) per side, (0.5–)3–8(–10) mm, loosely long-strigose or -villous and short-hirsute, ± glandular, lobes 2–5(–12), linear to lanceolate, apex not setose. |
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Cauline leaves | 2, paired. |
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Inflorescences | 5–15(–25)-flowered, 1.5–3(–6) cm diam.; glomerules 1. |
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Pedicels | (0.5–)1–8(–13) mm. |
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Flowers | 9–12 mm diam.; epicalyx bractlets linear, 1.2–3 mm; hypanthium cupulate, 1–2(–2.5) × 2.5–5 mm; sepals 2.5–4.5(–5.5) mm, acute; petals yellow, narrowly oblanceolate, 2–3(–4) mm; stamens 5, filaments 1.8–2.5(–3) mm, anthers yellow, (0.8–)1–1.6 mm; carpels 3–8, styles 1.8–2.2 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). |
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 | light brown, often mottled darker brown, 1.9–2.5 mm. |
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x | = 7(8). |
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Ivesia webberi |
Rosaceae subfam. rosoideae |
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Phenology | Flowering late spring–early summer. | |
Habitat | Dry flats and slopes, in sagebrush communities, conifer woodlands | |
Elevation | (1300–)1500–1900 m ((4300–)4900–6200 ft) | |
Distribution |
CA; NV |
North America; Mexico; Central America; South America; West Indies; Bermuda; Eurasia; Africa; Atlantic Islands; Indian Ocean Islands; Pacific Islands; Australia |
Discussion | Of conservation concern. Ivesia webberi is known only from the eastern foothills of the northern Sierra Nevada and scattered ranges to the east in California and adjacent Nevada. It is among the more distinctive species in the genus and is only tentatively placed in sect. Ivesia. The leaflets are loosely incised into slender, sparsely villous segments, and the two cauline leaves are paired with dissected stipules. Previous reports of the stems and inflorescence branches being glandular-puberulent are due to a misinterpretation of the minute pustulose bases associated with the villous indumentum as being enlarged glands. (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.) |
Source | FNA vol. 9, p. 236. | FNA vol. 9, p. 23. |
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Sibling taxa | ||
Subordinate taxa | ||
Synonyms | Potentilla webberi | |
Name authority | A. Gray: Proc. Amer. Acad. Arts 10: 71. (1874) | Arnott: Botany, 107. (1832) |
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