Ivesia gordonii |
Ivesia saxosa |
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alpine ivesia, alpine mousetail, Gordon's ivesia |
rock ivesia, rock mousetail |
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Habit | Plants green, ± tufted, sometimes rosetted; taproot stout, not fleshy. | Plants green, ± tufted, often forming hanging clumps, sometimes rosetted. | ||||||||||||
Stems | prostrate to erect, (0.2–)0.5–4 dm. |
pendent or prostrate to ascending, 0.4–2.6(–3) dm. |
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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. |
planar, 2–15 cm; sheathing base not strigose abaxially; petiole 3–9 cm; lateral leaflets (1–)2–4(–7) per side, separate to slightly overlapping, obovate to orbiculate or flabellate, (3–)5–15(–22) mm, incised 1/4–3/4 to base into 5–15 broadly ovate teeth or oblanceolate lobes, sometimes also medially split to base (Kern Plateau), apex not setose, surfaces ± sparsely short-pilose, prominently glandular; terminal leaflets ± distinct. |
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Cauline leaves | 1(–2), not paired. |
1–2(–4); blade well developed. |
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Inflorescences | 5–50(–70)-flowered, 1–8(–11) cm diam.; glomerules 1–several. |
(1–)3–30(–60)-flowered, open, (0.5–)2–8 cm diam. |
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Pedicels | 1–3(–5) mm. |
(5–)10–30 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. |
6–12 mm diam.; epicalyx bractlets 5, broadly lanceolate to oblong, 1–2.5 mm; hypanthium patelliform, 0.5–1.5 × 2–4(–4.5) mm; sepals 2–4.5 mm, acute; petals yellow, oblanceolate to obovate, (1.5–)2–4 mm; stamens 15–35(–40), filaments 0.3–1 mm, anthers yellow, subrotund, 0.2–0.3(–0.5) mm; carpels (3–)10–20(–40), styles 1–2 mm. |
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Achenes | grayish brown to mottled brown, ± 2 mm. |
greenish white to light tan, 1–1.8 mm, faintly rugose, ± carunculate. |
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Ivesia gordonii |
Ivesia saxosa |
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Phenology | Flowering late spring–summer. | |||||||||||||
Habitat | Dry, rocky outcrops of granitic or volcanic origin, usually crevices of more or less vertical protected cliffs or boulders, mainly in oak and conifer woodlands | |||||||||||||
Elevation | 900–3300 m (3000–10800 ft) | |||||||||||||
Distribution |
CA; CO; ID; MT; NV; OR; UT; WA; WY
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CA; Mexico (Baja California)
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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.) |
Ivesia saxosa is encountered in the foothills and mountains of southeastern California from the White Mountains and adjacent eastern slopes of the Sierra Nevada of Mono County to the Transverse Ranges (including the Little San Bernardino Mountains) of Kern and San Bernardino counties. Populations on the Kern Plateau tend to have more dissected leaflets and may deserve recognition as a distinct variety. On the Peninsular Ranges, I. saxosa occurs in Riverside and San Diego counties and into northern Baja California, Mexico, as far south as the western slopes of the Sierra Juárez and Sierra San Pedro Mártir. (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. 223. | ||||||||||||
Parent taxa | Rosaceae > subfam. Rosoideae > tribe Potentilleae > Ivesia > sect. Ivesia | Rosaceae > subfam. Rosoideae > tribe Potentilleae > Ivesia > sect. Setosae | ||||||||||||
Sibling taxa | ||||||||||||||
Subordinate taxa | ||||||||||||||
Synonyms | Horkelia gordonii, Potentilla gordonii | Potentilla saxosa, P. acuminata, P. saxosa subsp. sierrae | ||||||||||||
Name authority | (Hooker) Torrey & A. Gray: in War Department [U.S.], Pacif. Railr. Rep. 6(3): 72. (1858) | (Lemmon ex Greene) Ertter: Syst. Bot. 14: 232. (1989) | ||||||||||||
Web links |