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Jaeger's ivesia, Jaeger's mousetail

Tweedy's ivesia, Tweedy's mousetail

Habit Plants green, ± tufted to ± matted, often forming hanging clumps, sometimes rosetted. Plants green, ± rosetted to tufted; taproot stout, not fleshy.
Stems

pendent or prostrate to ascending, 0.3–1.5 dm.

ascending to erect, 0.4–2(–3.5) dm.

Basal leaves

± loosely cylindric to weakly planar, 2–8(–10) cm; sheathing base not or sparsely strigose abaxially;

petiole 0.5–4 cm;

lateral leaflets (1–)4–6(–8) per side, ± overlapping at least distally, ± flabellate, 2–6(–7) mm, incised nearly to base into 3–6 oblanceolate to narrowly obovate lobes, apex not or scarcely setose, surfaces ± sparsely short-pilose, ± glandular;

terminal leaflets indistinct.

loosely cylindric, (3–)4–12(–17) cm; sheathing base glabrous abaxially;

petiole 0.5–7 cm, hairs 1–1.5 mm;

leaflets 10–16 per side, 4–7(–10) mm, glabrous or sparsely hirsute, glandular-puberulent or -pubescent, lobes (2–)5–15, linear to narrowly oblanceolate, apex not setose.

Cauline leaves

(1–)2;

blade well developed.

(0–)1–2, not paired.

Inflorescences

(1–)3–15-flowered, open, (0.5–)1.5–4(–7) cm diam.

(5–)10–25(–35)-flowered, (1–)1.5–3(–4.5) cm diam.;

glomerules 1–few.

Pedicels

5–30 mm.

1–3(–5) mm.

Flowers

5–11 mm diam.;

epicalyx bractlets 5, lanceolate, 1–2 mm;

hypanthium patelliform, 1 × 2–4 mm;

sepals 2–3 mm, ± acute;

petals yellow, narrowly oblanceolate, 1.5–2 mm;

stamens 20, filaments 1–1.5(–1.8) mm, anthers yellow, subrotund, 0.2–0.3 mm;

carpels 3–8, styles 1.5–2 mm.

9–12 mm diam.;

epicalyx bractlets linear, 1–2 mm;

hypanthium shallowly campanulate, 1–1.5 × 2–4(–5.5) mm;

sepals 2–3.5 mm, acute;

petals golden yellow, broadly elliptic to spatulate, 2.5–3.3 mm;

stamens 5, filaments 1–1.7 mm, anthers yellow, 0.5–0.8 mm;

carpels (2–)4–6(–9), styles 2–3 mm.

Achenes

tan to light brown, 1–2 mm, ± rugose, ± carunculate.

olive green, 1.8–2 mm.

Ivesia jaegeri

Ivesia tweedyi

Phenology Flowering summer. Flowering summer.
Habitat Dry, rocky outcrops of limestone origin, usually crevices of more or less vertical protected cliffs or boulders, mainly in conifer woodlands Dry, gravelly to rocky flats, slopes, alpine ridges, often on serpentine, in subalpine conifer woodlands
Elevation 1600–3600 m (5200–11800 ft) 1600–2300 m (5200–7500 ft)
Distribution
from FNA
CA; NV
[BONAP county map]
from FNA
ID; MT; WA
[WildflowerSearch map]
[BONAP county map]
Discussion

Of conservation concern.

Ivesia jaegeri is known only from the Spring Mountains, Clark County, Nevada, and the Clark Mountains, San Bernardino County, California.

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

Of conservation concern.

Ivesia tweedyi is found from the Cascade Range in Washington to Boundary and Shoshone counties in Idaho, barely entering Montana in Mineral County.

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

Source FNA vol. 9, p. 223. FNA vol. 9, p. 235.
Parent taxa Rosaceae > subfam. Rosoideae > tribe Potentilleae > Ivesia > sect. Setosae 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. gordonii, 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. shockleyi, I. unguiculata, I. utahensis, I. webberi
Synonyms Potentilla jaegeri Potentilla tweedyi
Name authority Munz & I. M. Johnston: Bull. Torrey Bot. Club 56: 165. (1929) Rydberg: in N. L. Britton et al., N. Amer. Fl. 22: 288. (1908)
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