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Yosemite ivesia, Yosemite mousetail

Pickering's ivesia, silky mousetail

Habit Plants ± grayish, often purple-tinged; glands sparse to abundant. Plants grayish green; glands abundant.
Stems

decumbent to ascending, 1–3.5 dm.

ascending to erect, 3–5 dm.

Basal leaves

(4–)7–15 cm; sheathing base ± glabrous abaxially;

stipules linear, 3–6 mm;

petiole (0.3–)0.5–4(–5) cm, hairs sparse to abundant, ascending to spreading, 1–2 mm;

leaflets 15–20(–25) per side, loosely overlapping, 3–6 mm, lobes 3–8, linear to oblanceolate, hairs sparse to abundant, spreading, 1–2 mm.

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

3–6.

5–10.

Inflorescences

(15–)30–100(–200)-flowered, (1–)1.5–4(–8) cm diam., flowers mostly arranged in 1–several loose to tight glomerules of 5–10 flowers.

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

Pedicels

1–3 mm.

(1–)2–10 mm.

Flowers

6–9 mm diam.;

epicalyx bractlets linear or narrowly lanceolate to elliptic or narrowly oblong, 1.2–2(–3) mm;

hypanthium shallowly turbinate, 1.5–2.5 × 2–3(–3.5) mm, often nearly as deep as wide;

sepals heavily purple-mottled, (1.5–)2–3(–3.5) mm, acute;

petals white, often tinged with pink, oblanceolate to spatulate or obovate, 3–4 mm;

stamens 10–15, filaments filiform, 0.6–1.1 mm, anthers maroon, 0.3–0.5 mm;

carpels (1–)3–9, styles 1.4–2 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

light brown, 1.2–1.5 mm.

dark brown, 2.5–3 mm.

Ivesia unguiculata

Ivesia pickeringii

Phenology Flowering summer. Flowering summer.
Habitat Moist meadows and slopes, in montane conifer woodlands Moist, rocky, grassy meadows, mainly on ultramafic-derived clayey soil, in montane conifer woodlands
Elevation 1500–2500 m (4900–8200 ft) 800–1500 m (2600–4900 ft)
Distribution
from FNA
CA
[BONAP county map]
from FNA
CA
[BONAP county map]
Discussion

Of conservation concern.

Ivesia unguiculata is found in mid-elevation meadows of the central Sierra Nevada, mostly north of the Kings River. The distinctive deep red to purplish coloration of the inflorescence, and the plant in general, can make patches of this species conspicuous as a smoky purplish haze in meadows. The shape and color of the inflorescences are similar to those of the sympatric Horkelia fusca var. parviflora, suggesting shared pollinators.

The description and illustration by J. D. Hooker (1881), supposedly of Potentilla (Ivesia) unguiculata, were based actually on material grown from seed of I. sericoleuca due to initial confusion of the two species (W. H. Brewer et al. 1876–1880, vol. 1).

The type (Kellogg s.n., CAS) of Potentilla ciliata Greene (not Rafinesque) is unquestionably this species; however, the purported locality (Owens Valley, Inyo County) is dubious and most likely an error in the labeling of the specimen by the collector.

(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. 241. FNA vol. 9, p. 239.
Parent taxa Rosaceae > subfam. Rosoideae > tribe Potentilleae > Ivesia > sect. Unguiculatae 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. 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. 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 unguiculata Potentilla pickeringii
Name authority A. Gray: Proc. Amer. Acad. Arts 7: 339. (1868) Torrey ex A. Gray: Proc. Amer. Acad. Arts 6: 531. (1865)
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