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Ivesia gordonii

alpine ivesia, alpine mousetail, Gordon's ivesia

Photo is of parent taxon

Wasatch ivesia

Habit Plants green, ± tufted, sometimes rosetted; taproot stout, not fleshy.

prostrate to erect, (0.2–)0.5–4 dm.

usually greenish, ± erect, (1–)1.5–4 dm, sometimes sparsely villous, minutely glandular, often glandular-pubescent.

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.

9–20(–25) × 1–2(–3) cm;

leaflets 7–13(–18) mm, glabrous or sparsely hirsute or villous marginally.

Cauline leaves

1(–2), not paired.


5–50(–70)-flowered, 1–8(–11) cm diam.;

glomerules 1–several.

10–50(–70)-flowered, usually branched, 2–8(–11) cm diam., glomerules (1–)2–6(–10), ± capitate.


1–3(–5) 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.

9–12 mm diam.;

epicalyx bractlets 2–4 mm;

hypanthium 2.5–4(–4.5) × 2.5–4(–5) mm;

sepals 3–5(–6) mm, acute to obtuse;

anthers sometimes red-margined.


grayish brown to mottled brown, ± 2 mm.

Ivesia gordonii

Ivesia gordonii var. wasatchensis

Phenology Flowering summer.
Habitat Talus slopes and outcrops, in montane and subalpine conifer woodlands
Elevation 2000–3200 m (6600–10500 ft)
from FNA
[WildflowerSearch map]
[BONAP county map]
from FNA

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.)

Variety wasatchensis is more broadly defined here than the “wasatchensis” of N. H. Holmgren (1997b). The variety is most distinct in the greater Wasatch Range and in the western Uinta Mountains, where plants are generally larger than other varieties with larger leaves, more elongated leaflets, and multi-headed inflorescences. Less distinctive populations extend along the Idaho-Wyoming border to southwestern Montana. Variety wasatchensis merges with var. gordonii at low elevations in Montana and Wyoming, and with the high-elevation phase assigned here to var. gordonii in Utah.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

1. Leaflets 7–13(–18) mm, glabrous or sparsely hirsute or villous marginally; stems (1–)1.5–4 dm; inflorescences usually branched, 2–8(–11) cm diam., glomerules (1–)2–6(–10), ± capitate.
var. wasatchensis
1. Leaflets (1–)2–7(–9) mm, hairy or ± glabrous except marginally ciliate; stems (0.2–)0.5–2.5 dm; inflorescences simple or branched, 1–3(–5) cm diam., glomerules 1(–3), ± capitate to loosely congested
→ 2
2. Stems usually prostrate to ascending, rarely nearly erect, usually dark reddish, minutely glandular or glandular-puberulent to -pubescent; leaves to 0.8 cm diam.; anthers usually red-margined.
var. ursinorum
2. Stems usually ascending to erect, sometimes decumbent, usually greenish, rarely reddish, hirsute to villous, glandular-puberulent to -pubescent; leaves to 1.5 cm diam.; anthers rarely red-margined
→ 3
3. Stems usually hirsute to villous, sometimes densely so, glandular-pubescent or eglandular; basal leaves (3–)5–10(–15) cm; flowers 7–12 mm diam.; e Idaho and w Montana to Utah, Wyoming, and w Colorado.
var. gordonii
3. Stems not or sparsely hirsute to villous, glandular-puberulent or -pubescent; basal leaves 2–8(–10) cm; flowers 5–9 mm diam.; s Washington to California and e to w Montana.
var. alpicola
Source FNA vol. 9, p. 233. FNA vol. 9, p. 235.
Parent taxa Rosaceae > subfam. Rosoideae > tribe Potentilleae > Ivesia > sect. Ivesia Rosaceae > subfam. Rosoideae > tribe Potentilleae > Ivesia > sect. Ivesia > Ivesia gordonii
Sibling taxa
I. aperta, I. argyrocoma, I. arizonica, I. baileyi, I. callida, I. campestris, I. cryptocaulis, I. jaegeri, I. kingii, I. longibracteata, I. lycopodioides, I. muirii, I. multifoliolata, I. paniculata, I. patellifera, I. pickeringii, I. pityocharis, I. pygmaea, I. rhypara, I. sabulosa, I. santolinoides, I. saxosa, I. sericoleuca, I. setosa, I. shockleyi, I. tweedyi, I. unguiculata, I. utahensis, I. webberi
I. gordonii var. alpicola, I. gordonii var. gordonii, I. gordonii var. ursinorum
Subordinate taxa
I. gordonii var. alpicola, I. gordonii var. gordonii, I. gordonii var. ursinorum, I. gordonii var. wasatchensis
Synonyms Horkelia gordonii, Potentilla gordonii
Name authority (Hooker) Torrey & A. Gray: in War Department [U.S.], Pacif. Railr. Rep. 6(3): 72. (1858) N. H. Holmgren ex Ertter & Reveal: Novon 17: 323. (2007)
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