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silver-hair ivesia, silverhair mousetail

Charleston Peak ivesia, Charleston Peak mousetail

Habit Plants green, diffusely matted.
Stems

prostrate to decumbent, 0.2–0.6(–1) dm.

Basal leaves

tightly cylindric, 1–4(–5) cm; sheathing base mostly not strigose abaxially;

petiole 0.3–2 cm, hairs 0.5–1 mm;

lateral leaflets 5–10(–12) per side, ± overlapping, ± flabellate, 1–2.5 mm, incised to base or nearly so into 3–5 obovate to oval lobes, apex sometimes ± setose, surfaces loosely long-strigose, sparsely glandular;

terminal leaflets indistinct.

Cauline leaves

1(–2);

blade vestigial.

Inflorescences

1–10-flowered, ± congested, 0.5–1.5 cm diam.

Pedicels

3–7(–10) mm.

Flowers

6–9 mm diam.;

epicalyx bractlets 5, lanceolate to narrowly oblong or narrowly ovate, 0.8–1.3 mm;

hypanthium shallowly cupulate, ± 1 × 2–3(–4) mm;

sepals 1.5–2.3 mm, ± acute;

petals yellow, oblanceolate to spatulate, 2–3.2 mm;

stamens 5, filaments 0.9–1.2 mm, anthers yellow, oblong, 0.7–0.9 mm;

carpels 6–10, styles 1–1.5 mm.

Achenes

greenish cream to light brown, 1.4–1.8(–2) mm, smooth, not carunculate.

Ivesia argyrocoma

Ivesia cryptocaulis

Phenology Flowering summer.
Habitat Dry to moist limestone gravel, scree, or talus slopes and outcrops, subalpine conifer woodlands, alpine tundra communities
Elevation 2500–3700 m (8200–12100 ft)
Distribution
from FNA
CA; nw Mexico
[WildflowerSearch map]
[BONAP county map]
from FNA
NV
[BONAP county map]
Discussion

Varieties 2 (1 in the flora).

Plants from the central Sierra San Pedro Mártir in northern Baja California belong to var. moranii Ertter & Reveal, which may be distinguished by its compact stature (to 0.5 dm), densely villous basal stipules 2–4 mm, decumbent stems 2–7 cm that are stipitate-glandular under the villous indumentum, and solitary, loosely congested cyme. The petals are oblanceolate to narrowly obovate and 2.5–3.5 mm. The grayish, faintly mottled achenes are 1.3–2 mm.

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

Of conservation concern.

Ivesia cryptocaulis is known only from timberline and above in the Spring Mountains of Clark County. Plants differ from all others of the genus by having slender, elongate, diffuse caudex branches that ramify through its habitat of gravel, scree, and talus. The species is here provisionally included in sect. Setosae as a diffusely matted relative of I. shockleyi (as also suggested by D. D. Keck 1938); the ecarunculate seeds and relatively straight pedicels may indicate a greater similarity to I. pygmaea in sect. Ivesia.

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

Source FNA vol. 9, p. 242. FNA vol. 9, p. 228.
Parent taxa Rosaceae > subfam. Rosoideae > tribe Potentilleae > Ivesia > sect. Unguiculatae Rosaceae > subfam. Rosoideae > tribe Potentilleae > Ivesia > sect. Setosae
Sibling taxa
I. aperta, 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. shockleyi, I. tweedyi, I. unguiculata, I. utahensis, I. webberi
I. aperta, I. argyrocoma, I. arizonica, I. baileyi, I. callida, I. campestris, 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
Subordinate taxa
I. argyrocoma var. argyrocoma
Synonyms Horkelia argyrocoma, Potentilla argyrocoma Potentilla cryptocaulis
Name authority (Rydberg) Rydberg: in N. L. Britton et al., N. Amer. Fl. 22: 284. (1908) (Clokey) D. D. Keck: Lloydia 1: 130. (1939)
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