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Pickering's ivesia, silky mousetail

Jaeger's ivesia, Jaeger's mousetail

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

ascending to erect, 3–5 dm.

pendent or prostrate to ascending, 0.3–1.5 dm.

Basal leaves

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.

± 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.

Cauline leaves

5–10.

(1–)2;

blade well developed.

Inflorescences

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

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

Pedicels

(1–)2–10 mm.

5–30 mm.

Flowers

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.

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.

Achenes

dark brown, 2.5–3 mm.

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

Ivesia pickeringii

Ivesia jaegeri

Phenology Flowering summer. Flowering summer.
Habitat Moist, rocky, grassy meadows, mainly on ultramafic-derived clayey soil, in montane conifer woodlands Dry, rocky outcrops of limestone origin, usually crevices of more or less vertical protected cliffs or boulders, mainly in conifer woodlands
Elevation 800–1500 m (2600–4900 ft) 1600–3600 m (5200–11800 ft)
Distribution
from FNA
CA
[BONAP county map]
from FNA
CA; NV
[BONAP county map]
Discussion

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.)

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.)

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