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Ivesia gordonii

alpine ivesia, alpine mousetail, Gordon's ivesia

Jaeger's ivesia, Jaeger's mousetail

Habit Plants green, ± tufted, sometimes rosetted; taproot stout, not fleshy. Plants green, ± tufted to ± matted, often forming hanging clumps, sometimes rosetted.
Stems

prostrate to erect, (0.2–)0.5–4 dm.

pendent or prostrate to ascending, 0.3–1.5 dm.

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.

± loosely cylindric to weakly planar, 2–8(–10) cm; sheathing base not or sparsely strigose abaxially;

petiole 0.5–4 cm;

lateral leaflets (1–)4–6(–8) per side, ± overlapping at least distally, ± flabellate, 2–6(–7) mm, incised nearly to base into 3–6 oblanceolate to narrowly obovate lobes, apex not or scarcely setose, surfaces ± sparsely short-pilose, ± glandular;

terminal leaflets indistinct.

Cauline leaves

1(–2), not paired.

(1–)2;

blade well developed.

Inflorescences

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

glomerules 1–several.

(1–)3–15-flowered, open, (0.5–)1.5–4(–7) cm diam.

Pedicels

1–3(–5) mm.

5–30 mm.

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.

5–11 mm diam.;

epicalyx bractlets 5, lanceolate, 1–2 mm;

hypanthium patelliform, 1 × 2–4 mm;

sepals 2–3 mm, ± acute;

petals yellow, narrowly oblanceolate, 1.5–2 mm;

stamens 20, filaments 1–1.5(–1.8) mm, anthers yellow, subrotund, 0.2–0.3 mm;

carpels 3–8, styles 1.5–2 mm.

Achenes

grayish brown to mottled brown, ± 2 mm.

tan to light brown, 1–2 mm, ± rugose, ± carunculate.

Ivesia gordonii

Ivesia jaegeri

Phenology Flowering summer.
Habitat Dry, rocky outcrops of limestone origin, usually crevices of more or less vertical protected cliffs or boulders, mainly in conifer woodlands
Elevation 1600–3600 m (5200–11800 ft)
Distribution
from FNA
CA; CO; ID; MT; NV; OR; UT; WA; WY
[WildflowerSearch map]
[BONAP county map]
from FNA
CA; NV
[BONAP county map]
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.)

Of conservation concern.

Ivesia jaegeri is known only from the Spring Mountains, Clark County, Nevada, and the Clark Mountains, San Bernardino County, California.

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

Key
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. 223.
Parent taxa Rosaceae > subfam. Rosoideae > tribe Potentilleae > Ivesia > sect. Ivesia Rosaceae > subfam. Rosoideae > tribe Potentilleae > Ivesia > sect. Setosae
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. aperta, I. argyrocoma, I. arizonica, I. baileyi, I. callida, I. campestris, I. cryptocaulis, I. gordonii, 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
Subordinate taxa
I. gordonii var. alpicola, I. gordonii var. gordonii, I. gordonii var. ursinorum, I. gordonii var. wasatchensis
Synonyms Horkelia gordonii, Potentilla gordonii Potentilla jaegeri
Name authority (Hooker) Torrey & A. Gray: in War Department [U.S.], Pacif. Railr. Rep. 6(3): 72. (1858) Munz & I. M. Johnston: Bull. Torrey Bot. Club 56: 165. (1929)
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