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Ivesia gordonii

alpine ivesia, alpine mousetail, Gordon's ivesia

Tahquitz ivesia, Tahquitz 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.

usually pendent or prostrate to ascending, sometimes nearly erect, 0.2–1.5 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, 1–7 cm; sheathing base sparsely strigose abaxially;

petiole 0.3–3 cm;

lateral leaflets (1–)5–8 per side, slightly overlapping, elliptic to flabellate, 2–6(–7) mm, incised nearly to base into (0–)2–4 oblanceolate to elliptic lobes, apex sometimes ± setose, surfaces loosely long-strigose, sparsely glandular;

terminal leaflets indistinct.

Cauline leaves

1(–2), not paired.

(1–)2;

blade reduced.

Inflorescences

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

glomerules 1–several.

1–10(–15)-flowered, open, (0.5–)2–5 cm diam.

Pedicels

1–3(–5) mm.

5–15 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.

7–10 mm diam.;

epicalyx bractlets 5, narrowly lanceolate, 1.5–3 mm;

hypanthium patelliform, 0.5–1 × 2–3 mm;

sepals 2–3.5 mm, acute;

petals white, obovate, 2–3.5 mm;

stamens 20, filaments 1.5–3 mm, anthers maroon, subrotund, 0.2–0.3 mm;

carpels 4–8, styles 1.5–1.8 mm.

Achenes

grayish brown to mottled brown, ± 2 mm.

greenish white to light tan, 1.5 mm, smooth to lightly rugose, ± carunculate.

Ivesia gordonii

Ivesia callida

Phenology Flowering summer.
Habitat Crevices of dry, rocky outcrops of granite, sometimes more or less vertical protected cliffs, in montane conifer woodlands
Elevation 2400–2500 m (7900–8200 ft)
Distribution
from FNA
CA; CO; ID; MT; NV; OR; UT; WA; WY
[WildflowerSearch map]
[BONAP county map]
from FNA
CA
[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 callida occurs in the Tahquitz Peak area of the San Jacinto Wilderness Area, San Jacinto Mountains, Riverside County, where two populations are known (K. Berg 1983). Plants form tight mats in horizontal crevices and loose pendent clumps on vertical rock faces.

(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. 224.
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. campestris, I. cryptocaulis, I. gordonii, 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
Subordinate taxa
I. gordonii var. alpicola, I. gordonii var. gordonii, I. gordonii var. ursinorum, I. gordonii var. wasatchensis
Synonyms Horkelia gordonii, Potentilla gordonii Potentilla callida
Name authority (Hooker) Torrey & A. Gray: in War Department [U.S.], Pacif. Railr. Rep. 6(3): 72. (1858) (H. M. Hall) Rydberg: in N. L. Britton et al., N. Amer. Fl. 22: 286. (1908)
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