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Ivesia gordonii

alpine ivesia, alpine mousetail, Gordon's ivesia

club-moss ivesia, clubmoss mousetail

Habit Plants green, ± tufted, sometimes rosetted; taproot stout, not fleshy. Plants green, usually rosetted, sometimes ± tufted; taproot fusiform, fleshy.
Stems

prostrate to erect, (0.2–)0.5–4 dm.

decumbent to erect, 0.3–3 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, 1–15 cm; sheathing base glabrous abaxially;

petiole 0.5–4 cm, hairs 0.2–1 mm;

leaflets 10–35 per side, 1–8 mm, glabrous or short-hirsute, minutely glandular, lobes (2–)4–8(–10), linear to obovate or ± orbiculate, apex sometimes setose.

Cauline leaves

1(–2), not paired.

0–2(–3), not paired.

Inflorescences

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

glomerules 1–several.

3–20(–25)-flowered, (0.5–)1–2.5(–3.5) cm diam.;

glomerules usually 1.

Pedicels

1–3(–5) mm.

(0.5–)1–7(–11) 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.

6–12 mm diam.;

epicalyx bractlets oblong to oval, 0.8–2.5(–3) mm;

hypanthium shallowly cupulate, 1–2 × 2.5–5 mm;

sepals (1.8–)2–4(–4.5) mm, obtuse to acute;

petals golden yellow, obovate, 2–5 mm;

stamens 5, filaments 0.8–2 mm, anthers yellow, 0.6–0.8 mm;

carpels (5–)8–15(–18), styles 1–3 mm.

Achenes

grayish brown to mottled brown, ± 2 mm.

greenish tan to light brown, 1.2–1.5 mm.

Ivesia gordonii

Ivesia lycopodioides

Distribution
from FNA
CA; CO; ID; MT; NV; OR; UT; WA; WY
[WildflowerSearch map]
[BONAP county map]
from FNA
CA; NV
[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 3 (3 in the flora).

The three varieties of Ivesia lycopodioides are for the most part readily distinguished, though intergradation is known. The high-elevation var. lycopodioides extends farthest north; var. scandularis is the only variety in the White Mountains. Variety megalopetala is found mostly at somewhat lower (subalpine) elevations and generally has a more southern range.

(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. Leaflets short-hirsute, apical setae (0–)0.5–1(–2) mm; White Mountains and c Sierra Nevada.
var. scandularis
1. Leaflets glabrous or sparsely short-hirsute, apical setae 0–0.5 mm; Sierra Nevada and Sweetwater Mountains
→ 2
2. Leaflet lobes ± orbiculate, ± 1 mm; petals 2–3 × 1 mm.
var. lycopodioides
2. Leaflet lobes linear to oblanceolate, 2–8 mm; petals 3–5 × 2–4 mm.
var. megalopetala
Source FNA vol. 9, p. 233. FNA vol. 9, p. 232.
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. 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. 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
I. lycopodioides var. lycopodioides, I. lycopodioides var. megalopetala, I. lycopodioides var. scandularis
Synonyms Horkelia gordonii, Potentilla gordonii Potentilla lycopodioides
Name authority (Hooker) Torrey & A. Gray: in War Department [U.S.], Pacif. Railr. Rep. 6(3): 72. (1858) A. Gray: Proc. Amer. Acad. Arts 6: 530. (1865)
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