Ivesia webberi |
Ivesia gordonii |
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Webber's ivesia, wire ivesia, wire mousetail |
alpine ivesia, alpine mousetail, Gordon's ivesia |
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Habit | Plants ± green, ± rosetted; taproot slender to ± stout, not fleshy. | Plants green, ± tufted, sometimes rosetted; taproot stout, not fleshy. | ||||||||||||
Stems | decumbent to ascending, 0.5–1.5(–1.8) dm. |
prostrate to erect, (0.2–)0.5–4 dm. |
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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. |
tightly to loosely cylindric, (1–)3–20(–25) cm; sheathing base ± glandular abaxially, otherwise glabrous; petiole 0.5–8 cm, hairs 0.2–0.5 mm; leaflets (6–)10–25 per side, (1–)2–13(–18) mm, glabrous or ± hirsute or villous, glandular-puberulent or -pubescent, lobes (2–)4–8(–15), linear or narrowly oblanceolate to obovate, apex rarely setose. |
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Cauline leaves | 2, paired. |
1(–2), not paired. |
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Inflorescences | 5–15(–25)-flowered, 1.5–3(–6) cm diam.; glomerules 1. |
5–50(–70)-flowered, 1–8(–11) cm diam.; glomerules 1–several. |
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Pedicels | (0.5–)1–8(–13) mm. |
1–3(–5) 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. |
5–12 mm diam.; epicalyx bractlets linear to narrowly elliptic, (0.5–)1–3.5(–4) mm; hypanthium turbinate to campanulate, (1.5–)2–4(–4.5) × 2–4(–5) mm; sepals (2–)2.5–5(–6) mm, obtuse to ± acute; petals yellow, narrowly oblanceolate to narrowly spatulate, (1–)1.5–3 mm; stamens 5, filaments 1.3–2.5 mm, anthers yellow, sometimes red-margined, 0.5–1 mm; carpels (1–)2–4(–6), styles 2.5–4.5(–6) mm. |
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Achenes | light brown, often mottled darker brown, 1.9–2.5 mm. |
grayish brown to mottled brown, ± 2 mm. |
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Ivesia webberi |
Ivesia gordonii |
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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 |
CA; CO; ID; MT; NV; OR; UT; WA; WY
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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.) |
Varieties 4 (4 in the flora). Ivesia gordonii is the most widespread species of the genus, occurring from Washington to Montana, south to central California and Colorado. The species can be distinguished from other members of sect. Ivesia by the relatively deep hypanthium, which is about as deep as wide. Four varieties are provisionally recognized here (B. Ertter and J. L. Reveal 2007), with the likelihood that future work may indicate additional and/or alternate circumscriptions. Populations that are difficult to assign to a variety can be found where the recognizable taxonomic units come together, for example, in northeastern Utah and western Wyoming, involving var. gordonii and var. wasatchensis, and in California and central Idaho where var. alpicola and var. ursinorum tend to merge. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 9, p. 236. | FNA vol. 9, p. 233. | ||||||||||||
Parent taxa | ||||||||||||||
Sibling taxa | ||||||||||||||
Subordinate taxa | ||||||||||||||
Synonyms | Potentilla webberi | Horkelia gordonii, Potentilla gordonii | ||||||||||||
Name authority | A. Gray: Proc. Amer. Acad. Arts 10: 71. (1874) | (Hooker) Torrey & A. Gray: in War Department [U.S.], Pacif. Railr. Rep. 6(3): 72. (1858) | ||||||||||||
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