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mouse tail ivesia, Sierra mousetail, silver mousetail, stellariopsis

Ivesia gordonii

alpine ivesia, alpine mousetail, Gordon's ivesia

Habit Plants ± grayish to silvery. Plants green, ± tufted, sometimes rosetted; taproot stout, not fleshy.
Stems

ascending to erect, (1–)1.5–4 dm.

prostrate to erect, (0.2–)0.5–4 dm.

Basal leaves

mousetail-like (individual leaflets scarcely distinguishable), 3–10 cm; sheathing base densely strigose abaxially;

petiole 0.5–1.5 cm;

leaflets 60–80 per side, 0.6–1.5 mm, lobes (0–)3–5, obovate to oval, densely villous.

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

1(–2), not paired.

Inflorescences

(10–)30–200-flowered, 3–8(–30) cm diam.

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

glomerules 1–several.

Pedicels

5–30 mm.

1–3(–5) mm.

Flowers

5–8 mm diam.;

epicalyx bractlets oblong to broadly ovate or orbiculate, 0.2–0.5 mm;

hypanthium 0.5–1.5 × 2–3 mm;

sepals 1–2 mm, apex obtuse to acute;

petals white, broadly obovate to orbiculate, 2–2.5 mm;

stamens 15, filaments 1.2–1.8 mm, anthers purple, broadly obcordate to pouch-shaped, 0.3–0.4 mm;

carpels 1, styles 2–3 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

mottled grayish brown, 1.7–2 mm.

grayish brown to mottled brown, ± 2 mm.

2n

= 28.

Ivesia santolinoides

Ivesia gordonii

Phenology Flowering summer.
Habitat Dry sandy granitic soil, decomposed granite accumulations, ledges and outcrops, in montane and subalpine conifer woodlands
Elevation 1500–3600 m (4900–11800 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 santolinoides is found on loose granitic substrates in the Sierra Nevada, Transverse Ranges, and San Jacinto Mountains from El Dorado to Riverside counties. The species is easily recognized by its silvery mousetail-like leaves and erect, diffuse inflorescences with small, plumlike flowers.

(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. 246. FNA vol. 9, p. 233.
Parent taxa Rosaceae > subfam. Rosoideae > tribe Potentilleae > Ivesia > sect. Stellariopsis 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. muirii, I. multifoliolata, I. paniculata, I. patellifera, I. pickeringii, I. pityocharis, I. pygmaea, I. rhypara, I. sabulosa, 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 santolinoides, Stellariopsis santolinoides Horkelia gordonii, Potentilla gordonii
Name authority A. Gray: Proc. Amer. Acad. Arts 6: 531. (1865) (Hooker) Torrey & A. Gray: in War Department [U.S.], Pacif. Railr. Rep. 6(3): 72. (1858)
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