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purpusia, rock whitefeather

mouse tail ivesia, Sierra mousetail, silver mousetail, stellariopsis

Habit Plants green, ± tufted, often forming hanging clumps, sometimes rosetted. Plants ± grayish to silvery.
Stems

pendent or prostrate to ascending, (0.2–)0.5–1.6(–3) dm.

ascending to erect, (1–)1.5–4 dm.

Basal leaves

planar, 2–15(–20) cm; sheathing base usually not strigose abaxially;

petiole 3–10 cm;

lateral leaflets (2–)3–4(–5) per side, separate, broadly ovate or obovate to orbiculate, (2–)5–15(–18) mm, incised 1/4–3/4 to base into (3–)7–11 ± ovate teeth, apex not setose, surfaces ± sparsely short-pilose, ± glandular;

terminal leaflets ± distinct.

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.

Cauline leaves

1–3;

blade well developed.

Inflorescences

(1–)5–30(–150)-flowered, open, 0.5–14 cm diam.

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

Pedicels

5–30 mm.

5–30 mm.

Flowers

6–12 mm diam.;

epicalyx bractlets 0(–3), lanceolate, 0.9–1.8 mm;

hypanthium turbinate or campanulate, 1.5–3(–5) × 1–3(–4) mm;

sepals 2–4(–5) mm, acute;

petals yellow or white, oblanceolate to elliptic or obovate, (1.6–)2–4 mm;

stamens 5, filaments 0.8–1.3 mm, anthers ± yellow, oblong to narrowly ovate, 0.6–1.5 mm;

carpels (2–)6–10(–13), atop a stipelike torus, styles 0.9–1.8 mm.

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.

Achenes

greenish white to light tan, 1.2–2 mm, faintly rugose, ± carunculate.

mottled grayish brown, 1.7–2 mm.

2n

= 28.

Ivesia arizonica

Ivesia santolinoides

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
AZ; CA; NV; UT
[BONAP county map]
from FNA
CA
[WildflowerSearch map]
[BONAP county map]
Discussion

Varieties 2 (2 in the flora).

Because the epithet saxosa was retained for Potentilla saxosa upon transfer to Ivesia, a different epithet (arizonica) was needed when Purpusia was likewise transferred in the same publication (B. Ertter 1989). The correct name for this species in Potentilla is P. osterhoutii (A. Nelson) J. T. Howell, due to the existence of P. arizonica.

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

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.)

Key
1. Petals yellow; hypanthia campanulate.
var. arizonica
1. Petals white; hypanthia turbinate.
var. saxosa
Source FNA vol. 9, p. 224. FNA vol. 9, p. 246.
Parent taxa Rosaceae > subfam. Rosoideae > tribe Potentilleae > Ivesia > sect. Setosae Rosaceae > subfam. Rosoideae > tribe Potentilleae > Ivesia > sect. Stellariopsis
Sibling taxa
I. aperta, I. argyrocoma, 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. 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. saxosa, I. sericoleuca, I. setosa, I. shockleyi, I. tweedyi, I. unguiculata, I. utahensis, I. webberi
Subordinate taxa
I. arizonica var. arizonica, I. arizonica var. saxosa
Synonyms Purpusia arizonica Potentilla santolinoides, Stellariopsis santolinoides
Name authority (Eastwood ex J. T. Howell) Ertter: Syst. Bot. 14: 233. (1989) A. Gray: Proc. Amer. Acad. Arts 6: 531. (1865)
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