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Jaeger's ivesia, Jaeger's mousetail

Pickering's ivesia, silky mousetail

Habit Plants green, ± tufted to ± matted, often forming hanging clumps, sometimes rosetted. Plants grayish green; glands abundant.
Stems

pendent or prostrate to ascending, 0.3–1.5 dm.

ascending to erect, 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.

8–20 cm; sheathing base ± strigose abaxially;

stipules linear to narrowly lanceolate, 3–5 mm;

petiole 1–3.5 cm, hairs abundant, ascending to spreading, 1–2 mm;

leaflets 35–50 per side, loosely overlapping, 2–6 mm, lobes 3–5, oblanceolate to obovate or oval, hairs abundant, ± ascending, 1–2(–3) mm.

Cauline leaves

(1–)2;

blade well developed.

5–10.

Inflorescences

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

10–100-flowered, (1.5–)5–15 cm diam., flowers usually arranged individually, sometimes more congested.

Pedicels

5–30 mm.

(1–)2–10 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.

8–13 mm diam.;

epicalyx bractlets linear-lanceolate to lanceolate, (1.8–)2–2.5 mm;

hypanthium cupulate to turbinate, 1.5–3 × 2.5–4 mm, often nearly as deep as wide;

sepals often purple-suffused or -mottled, (2.5–)3–5 mm, acuminate;

petals white, becoming pink-tinged with age, oblanceolate to narrowly spatulate, (2.8–)3–5(–6) mm;

stamens 20, filaments filiform, 1.5–2.3 mm, anthers white to cream, 0.3–0.6 mm;

carpels 2–4, styles 2.5–3.5 mm.

Achenes

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

dark brown, 2.5–3 mm.

Ivesia jaegeri

Ivesia pickeringii

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 Moist, rocky, grassy meadows, mainly on ultramafic-derived clayey soil, in montane conifer woodlands
Elevation 1600–3600 m (5200–11800 ft) 800–1500 m (2600–4900 ft)
Distribution
from FNA
CA; NV
[BONAP county map]
from FNA
CA
[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 pickeringii is known from Siskiyou and Trinity counties. Some early treatments (for example, P. A. Rydberg 1898, 1908–1918; W. L. Jepson [1923–1925], 1909–1943, vol. 2) conflated this species with I. aperta, hence reports of I. pickeringii in the Sierra Nevada. Historic collections from Edgewood, at the headwaters of the Shasta River in Siskiyou County, have inflorescences more glomerulate than elsewhere in the species range.

The chromosome count of 2n = 28 (P. A. Munz 1959) needs confirmation. If based on Kruckeberg 3665, which was distributed as a voucher for that count, the determination of this collection has been changed to Ivesia sericoleuca.

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

Source FNA vol. 9, p. 223. FNA vol. 9, p. 239.
Parent taxa Rosaceae > subfam. Rosoideae > tribe Potentilleae > Ivesia > sect. Setosae 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. 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. 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
Synonyms Potentilla jaegeri Potentilla pickeringii
Name authority Munz & I. M. Johnston: Bull. Torrey Bot. Club 56: 165. (1929) Torrey ex A. Gray: Proc. Amer. Acad. Arts 6: 531. (1865)
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