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granite mousetail, Muir's ivesia

Ash Meadows ivesia, King's ivesia, King's mousetail

Habit Plants silvery, usually ± rosetted; taproot stout, sometimes fleshy. Plants usually grayish green to silvery, often glaucous; glands sparse.
Stems

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

usually prostrate-decumbent to ascending, sometimes ± erect, 1–4(–5.5) 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.

5–20 cm; sheathing base glabrous or densely strigose abaxially;

stipules absent or linear to lanceolate, 1–4 mm;

petiole 0.2–1.2 cm, hairs absent or sparse to dense, appressed or ascending, 0.5–2 mm;

leaflets 15–60 per side, loosely to tightly overlapping, (1.8–)2–6(–8) mm, lobes (0–)2–4, narrowly oblanceolate to obovate, hairs absent or sparse to dense, ± appressed, 0.2–0.5(–1) mm.

Cauline leaves

(0–)1–2, paired if 2.

4–15.

Inflorescences

10–30-flowered, 1–2(–3.5) cm diam.;

glomerules usually 1.

5–100-flowered, 1–12 cm diam., flowers arranged individually and/or in few to several loose glomerules of 2–10 flowers.

Pedicels

0.3–2(–3.5) mm.

(1–)2–20(–25) 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.

8–12 mm diam.;

epicalyx bractlets lanceolate to elliptic or ovate, (0.8–)1–2(–2.5) mm;

hypanthium shallowly cupulate, 0.5–2 × 1.5–4 mm, ± 1/2 as deep as wide;

sepals sometimes purple-suffused, 2–4(–5) mm, narrowly acute to acuminate;

petals white, spatulate or obovate to orbiculate, (2.8–)3–5(–6) mm;

stamens 20, filaments filiform, 1.5–2.5 mm, anthers white to cream, 0.3–0.6 mm;

carpels 2–9, styles 2–2.5(–3) mm.

Achenes

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

light brown, 1.8–2.5 mm.

Ivesia muirii

Ivesia kingii

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; NV; UT
[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 2 (2 in the flora).

Significant variation in habit, indument, leaflet lobing, and compactness of inflorescence can be found among and within populations of Ivesia kingii; no taxonomic structure has yet been discerned beyond the varieties recognized here. The variation within widespread var. kingii suggests that var. eremica resulted from a southward, late Pleistocene migration of a hairy phase of I. kingii with compact leaflets out of the Great Basin onto the northern edge of the Mojave Desert (J. L. Reveal 1980). Although densely hairy plants are encountered widely in the Great Basin, only in the Ash Meadows area of southernmost Nye County, the home of var. eremica, is there a consistently hairy phase. The leaflets of var. eremica are so tightly compacted that individual leaflets cannot be distinguished; in var. kingii, leaflets are individually distinct, though plants from Mineral County sometimes approach var. eremica in this regard. In the field, shoots of var. kingii arise directly from a taproot with the spreading branches flowing outwardly from a single point of attachment. In var. eremica, older, mature plants form compact mats with short, spreading caudex branches.

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

Key
1. Leaflets individually ± distinguishable, loosely to tightly overlapping; caudices simple or few branched; Great Basin, ec California, Nevada, w Utah.
var. kingii
1. Leaflets mostly not individually distinguishable, tightly overlapping; caudices often much branched; n Mojave Desert, Nevada.
var. eremica
Source FNA vol. 9, p. 236. FNA vol. 9, p. 238.
Parent taxa Rosaceae > subfam. Rosoideae > tribe Potentilleae > Ivesia > sect. Ivesia Rosaceae > subfam. Rosoideae > tribe Potentilleae > Ivesia > sect. Unguiculatae
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. gordonii, I. jaegeri, 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. kingii var. eremica, I. kingii var. kingii
Synonyms Potentilla muirii Potentilla kingii
Name authority A. Gray: Proc. Amer. Acad. Arts 8: 627. (1873) S. Watson: Botany (Fortieth Parallel), 91, 448. (1871)
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