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Ivesia gordonii

alpine ivesia, alpine mousetail, Gordon's ivesia

Shockley's ivesia, sky mousetail

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

prostrate to erect, (0.2–)0.5–4 dm.

prostrate to ascending, 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.

tightly to loosely cylindric, (1–)2–12(–14) cm; sheathing base strigose to hirsute abaxially;

petiole 0.5–4 cm;

lateral leaflets (3–)5–15(–18) per side, separate to overlapping at least distally, ± flabellate, 1–4(–6) mm, incised to base or nearly so into 2–10(–12) oblanceolate to obovate or elliptic lobes, apex sometimes setose, surfaces ± sparsely hirsute, ± glandular;

terminal leaflets indistinct.

Cauline leaves

1(–2), not paired.

(0–)1;

blade vestigial or reduced.

Inflorescences

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

glomerules 1–several.

2–20-flowered, ± open, 0.5–4(–6) cm diam.

Pedicels

1–3(–5) mm.

3–10(–12) 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.

5–10 mm diam.;

epicalyx bractlets 5, elliptic or narrowly oblong to ovate, 0.7–2(–3) mm;

hypanthium patelliform, 1–2 × 2.5–4.5(–5) mm;

sepals 1.5–3.5(–4) mm, acute to obtuse;

petals ± yellow, oblanceolate to spatulate or narrowly obovate, 1–3 mm;

stamens 5, filaments 0.8–1.8 mm, anthers yellow, oblong, 0.4–0.9 mm;

carpels 2–5(–6), styles 1.8–2.5 mm.

Achenes

grayish brown to mottled brown, ± 2 mm.

greenish cream to light brown, 1.5–2.2(–2.5) mm, smooth, prominently carunculate.

Ivesia gordonii

Ivesia shockleyi

Distribution
from FNA
CA; CO; ID; MT; NV; OR; UT; WA; WY
[WildflowerSearch map]
[BONAP county map]
from FNA
CA; NV; OR; UT
[WildflowerSearch map]
[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.)

Varieties 2 (2 in the flora).

(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
1. Lateral leaflets: lobes 2–5(–7); inflorescences 2–10-flowered, 0.5–3 cm diam.; e California, c, se Oregon, c, n Nevada.
var. shockleyi
1. Lateral leaflets: lobes (4–)6–10(–12); inflorescences 5–20-flowered, (1–)3–4(–6) cm diam.; wc Utah.
var. ostleri
Source FNA vol. 9, p. 233. FNA vol. 9, p. 227.
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. 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. 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
I. shockleyi var. ostleri, I. shockleyi var. shockleyi
Synonyms Horkelia gordonii, Potentilla gordonii Potentilla shockleyi
Name authority (Hooker) Torrey & A. Gray: in War Department [U.S.], Pacif. Railr. Rep. 6(3): 72. (1858) S. Watson: Proc. Amer. Acad. Arts 23: 263. (1888)
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