Ivesia gordonii |
Ivesia gordonii var. alpicola |
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alpine ivesia, alpine mousetail, Gordon's ivesia |
alpine ivesia, Gordon's ivesia, Howell's ivesia |
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Habit | Plants green, ± tufted, sometimes rosetted; taproot stout, not fleshy. | |||||||||||||
Stems | prostrate to erect, (0.2–)0.5–4 dm. |
usually greenish, rarely reddish, usually ascending to erect, sometimes decumbent, 0.3–2 dm, not or sparsely hirsute to villous, glandular-puberulent or -pubescent. |
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Basal leaves | 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. |
2–8(–10) × 0.5–1(–1.5) cm; leaflets 2–5(–9) mm, hirsute to pilose, rarely minutely glandular at least marginally. |
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Cauline leaves | 1(–2), not paired. |
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Inflorescences | 5–50(–70)-flowered, 1–8(–11) cm diam.; glomerules 1–several. |
5–25-flowered, usually simple, 1–3(–4) cm diam., glomerules usually 1, ± capitate. |
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Pedicels | 1–3(–5) mm. |
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Flowers | 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. |
5–9 mm diam.; epicalyx bractlets (1.5–)2–3(–4) mm; hypanthium (2–)2.5–3.5(–4) × 2.5–4 mm; sepals 2–4(–5) mm, acute; anthers rarely red-margined. |
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Achenes | grayish brown to mottled brown, ± 2 mm. |
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Ivesia gordonii |
Ivesia gordonii var. alpicola |
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Phenology | Flowering summer. | |||||||||||||
Habitat | Dry grassy areas on talus, or gravelly or rocky slopes and ridges, in subalpine and alpine montane conifer woodlands, alpine tundra | |||||||||||||
Elevation | 2100–3300 m (6900–10800 ft) | |||||||||||||
Distribution |
CA; CO; ID; MT; NV; OR; UT; WA; WY
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CA; ID; MT; OR; WA |
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Discussion | 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.) |
P. A. Rydberg (1898) used var. alpicola (as Horkelia gordonii var. alpicola) for compact, high-elevation plants throughout the range of Ivesia gordonii. As circumscribed here, var. alpicola is restricted to plants occurring disjunctly in an arc around the northwestern part of the species range. Populations occur in the northern Coast Ranges and central Sierra Nevada of California, sporadically to Mount Adams and the Wenatchee Mountains in Washington, and from there to the mountains of central Idaho and the Bitterroot Range of Montana. The variety is also disjunct on the Owyhee Mountains of southwestern Idaho. Plants of var. alpicola average shorter than those of var. gordonii, which occurs farther east and south. In var. alpicola, stems with only glandular indumentum are common; such stems are rare in var. gordonii. Unlike those of var. gordonii, the leaflets of var. alpicola are frequently glandular with only marginal hairs. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 9, p. 233. | FNA vol. 9, p. 234. | ||||||||||||
Parent taxa | ||||||||||||||
Sibling taxa | ||||||||||||||
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Synonyms | Horkelia gordonii, Potentilla gordonii | I. alpicola, Horkelia gordonii var. alpicola | ||||||||||||
Name authority | (Hooker) Torrey & A. Gray: in War Department [U.S.], Pacif. Railr. Rep. 6(3): 72. (1858) | (Rydberg ex Howell) Ertter & Reveal: Novon 17: 322. (2007) | ||||||||||||
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