Flora of North America species comparison

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Ivesia muirii

Ivesia gordonii

granite mousetail, Muir's ivesia
Ivesia gordonii

alpine ivesia, alpine mousetail, Gordon's ivesia
Habit Plants silvery, usually ± rosetted; taproot stout, sometimes fleshy. Plants green, ± tufted, sometimes rosetted; taproot stout, not fleshy.
Stems

usually ± erect, sometimes nearly prostrate, 0.5–1.5(–2) dm.

prostrate to erect, (0.2–)0.5–4 dm.
Basal leaves

very tightly cylindric (mousetail-like, with individual leaflets scarcely distinguishable), 2–5(–10) cm; sheathing base densely strigose abaxially;

petiole 0.2–0.8(–1) cm, hairs 0.5–1.5 mm;

leaflets 25–40 per side, 0.4–1 mm, densely sericeous, glands obscured, lobes 2–5, obovate or oval to orbiculate, apex not setose.

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.
Cauline leaves

(0–)1–2, paired if 2.

1(–2), not paired.
Inflorescences

10–30-flowered, 1–2(–3.5) cm diam.;

glomerules usually 1.

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

glomerules 1–several.
Pedicels

0.3–2(–3.5) mm.

1–3(–5) mm.
Flowers

5–6 mm diam.;

epicalyx bractlets oblong to obovate, 0.5–1 mm;

hypanthium shallowly cupulate, 0.5–1(–1.5) × 1.5–2.5 mm;

sepals (1–)1.5–2.5 mm, acute;

petals yellow, linear to oblanceolate or narrowly oblong, 1–2 mm;

stamens 5, filaments 0.3–0.6 mm, anthers yellow, 0.4–0.6 mm;

carpels 1–4, styles 0.7–1.2 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.
Achenes

grayish brown, mottled with red, 1.6–2 mm.

grayish brown to mottled brown, ± 2 mm.

Ivesia muirii

Ivesia gordonii
Phenology Flowering summer.
Habitat Dry rocky slopes, fellfields, mostly in alpine conifer woodlands and tundra
Elevation 2900–4000 m (9500–13100 ft)
Distribution
from FNA
CA
[WildflowerSearch map]
[BONAP county map]
from FNA
CA; CO; ID; MT; NV; OR; UT; WA; WY
[WildflowerSearch map]
[BONAP county map]
Discussion

Ivesia muirii is known from alpine areas in the Sierra Nevada. It is one of the more distinctive species of the genus, in its silvery mousetail-like leaves and usually tightly capitate inflorescences. Putative hybrids are known with I. lycopodioides (D. D. Keck 1938) and I. pygmaea (Center Basin area of Tulare County).

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

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.)
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. 236. FNA vol. 9, p. 233.
Parent taxa Rosaceae > subfam. Rosoideae > tribe Potentilleae > Ivesia > sect. Ivesia Rosaceae > subfam. Rosoideae > tribe Potentilleae > Ivesia > sect. Ivesia
Sibling taxa
I. aperta, I. argyrocoma, I. arizonica, I. baileyi, I. callida, I. campestris, I. cryptocaulis, I. gordonii, I. jaegeri, I. kingii, I. longibracteata, I. lycopodioides, 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. 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 Potentilla muirii Horkelia gordonii, Potentilla gordonii
Name authority A. Gray: Proc. Amer. Acad. Arts 8: 627. (1873) (Hooker) Torrey & A. Gray: in War Department [U.S.], Pacif. Railr. Rep. 6(3): 72. (1858)
Web links 
Unless otherwise noted, all data comes from the online version of the Flora of North America, who have made most of their content available via a Creative Commons license (CC BY 4.0).



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