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Tweedy's ivesia, Tweedy's mousetail

Yosemite ivesia, Yosemite mousetail

Habit Plants green, ± rosetted to tufted; taproot stout, not fleshy. Plants ± grayish, often purple-tinged; glands sparse to abundant.
Stems

ascending to erect, 0.4–2(–3.5) dm.

decumbent to ascending, 1–3.5 dm.

Basal leaves

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.

(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.

Cauline leaves

(0–)1–2, not paired.

3–6.

Inflorescences

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

glomerules 1–few.

(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.

Pedicels

1–3(–5) mm.

1–3 mm.

Flowers

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.

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.

Achenes

olive green, 1.8–2 mm.

light brown, 1.2–1.5 mm.

Ivesia tweedyi

Ivesia unguiculata

Phenology Flowering summer. Flowering summer.
Habitat Dry, gravelly to rocky flats, slopes, alpine ridges, often on serpentine, in subalpine conifer woodlands Moist meadows and slopes, in montane conifer woodlands
Elevation 1600–2300 m (5200–7500 ft) 1500–2500 m (4900–8200 ft)
Distribution
from FNA
ID; MT; WA
[WildflowerSearch map]
[BONAP county map]
from FNA
CA
[BONAP county map]
Discussion

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.)

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.)

Source FNA vol. 9, p. 235. FNA vol. 9, p. 241.
Parent taxa Rosaceae > subfam. Rosoideae > tribe Potentilleae > Ivesia > sect. Ivesia 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. 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. tweedyi, I. utahensis, I. webberi
Synonyms Potentilla tweedyi Potentilla unguiculata
Name authority Rydberg: in N. L. Britton et al., N. Amer. Fl. 22: 288. (1908) A. Gray: Proc. Amer. Acad. Arts 7: 339. (1868)
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