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pine nut mountain mousetail, pine nut mountains ivesia

Tweedy's ivesia, Tweedy's mousetail

Habit Plants grayish green to silvery, sometimes reddish tinged; glands sparse. Plants green, ± rosetted to tufted; taproot stout, not fleshy.
Stems

prostrate-decumbent to ascending, 0.5–2(–3) dm.

ascending to erect, 0.4–2(–3.5) dm.

Basal leaves

6–12(–15) cm; sheathing base weakly strigose abaxially;

stipules absent;

petiole (1–)1.5–2.5(–3) cm, hairs abundant, ascending to spreading, 1–4 mm;

leaflets 15–25 per side, loosely overlapping, (1.5–)2–7 mm, lobes 0–4(–6), lanceolate or oblanceolate to elliptic, hairs abundant, spreading to ascending, 1–3 mm.

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

2–5.

(0–)1–2, not paired.

Inflorescences

(7–)15–50-flowered, 2–8 cm diam., flowers arranged individually and/or in several to many loose few-flowered glomerules.

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

glomerules 1–few.

Pedicels

(3–)6–15(–22) mm.

1–3(–5) mm.

Flowers

8–13 mm diam.;

epicalyx bractlets lanceolate to elliptic, 2–3 mm;

hypanthium patelliform to shallowly cupulate, 1.5–2.5 × 3–4.5 mm, ± 1/2 as deep as wide;

sepals often purple-suffused, 2.3–4(–5) mm, acute;

petals white, broadly spatulate or obovate to orbiculate, (2.8–)3–5(–6) mm;

stamens 20, filaments filiform, (1–)1.5–3 mm, anthers light pink, 0.3–0.5 mm;

carpels 8–20, styles 2.2–3 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

light brown, 1.2–1.3 mm.

olive green, 1.8–2 mm.

Ivesia pityocharis

Ivesia tweedyi

Phenology Flowering summer. Flowering summer.
Habitat Vernally saturated meadows, in sagebrush communities Dry, gravelly to rocky flats, slopes, alpine ridges, often on serpentine, in subalpine conifer woodlands
Elevation 2100–2700 m (6900–8900 ft) 1600–2300 m (5200–7500 ft)
Distribution
from FNA
NV
[BONAP county map]
from FNA
ID; MT; WA
[WildflowerSearch map]
[BONAP county map]
Discussion

Of conservation concern.

Ivesia pityocharis is known only from the Pine Nut Mountains, Douglas County. Plants are somewhat intermediate between those of I. kingii and I. sericoleuca in having relatively shallow hypanthia and loosely sericeous vestiture. Hairs on petioles and stem bases of I. pityocharis are to 4 mm; those of I. kingii are 1 mm and generally appressed-ascending.

(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. 241. FNA vol. 9, p. 235.
Parent taxa Rosaceae > subfam. Rosoideae > tribe Potentilleae > Ivesia > sect. Unguiculatae 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. jaegeri, I. kingii, I. longibracteata, I. lycopodioides, I. muirii, I. multifoliolata, I. paniculata, I. patellifera, I. pickeringii, 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 tweedyi
Name authority Ertter: Syst. Bot. 14: 241, fig. 6. (1989) Rydberg: in N. L. Britton et al., N. Amer. Fl. 22: 288. (1908)
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