Flora of North America species comparison

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Ivesia tweedyi

Ivesia setosa

Tweedy's ivesia, Tweedy's mousetail

bristly ivesia
Habit Plants green, ± rosetted to tufted; taproot stout, not fleshy. Plants green, tufted to ± densely matted.
Stems

ascending to erect, 0.4–2(–3.5) dm.

± ascending to nearly erect, 0.7–2.5(–2.8) 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.

weakly planar to loosely cylindric, 5–9(–12) cm; sheathing base ± strigose abaxially;

petiole 1–8 cm;

lateral leaflets 5–10 per side, separate to overlapping distally, ± flabellate, 2–8 mm, incised ± 3/4 to base, sometimes nearly to base, into (3–)7–11 ovate teeth to narrowly obovate lobes, apex usually ± setose, surfaces ± sparsely hirsute, conspicuously glandular;

terminal leaflets ± indistinct.
Cauline leaves

(0–)1–2, not paired.

(0–)1;

blade vestigial.
Inflorescences

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

glomerules 1–few.

(1–)5–15(–30)-flowered, ± open, 1–6(–12) cm diam.
Pedicels

1–3(–5) mm.

5–15(–20) 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.

7–10 mm diam.;

epicalyx bractlets 5, lanceolate, 1.3–2.5(–3) mm;

hypanthium patelliform, (1–)1.5–2 × 2–3.5(–4) mm;

sepals (1.5–)2–3.5 mm, ± acute;

petals yellow, oblanceolate to narrowly spatulate, 1.5–2.5 mm;

stamens 5, filaments 0.8–1.5 mm, anthers yellow, oblong, 0.4–0.7 mm;

carpels 2–8, styles 1.2–2 mm.
Achenes

olive green, 1.8–2 mm.

greenish white to light tan, 1.7–2 mm, smooth, ± carunculate.

Ivesia tweedyi

Ivesia setosa
Phenology Flowering summer. Flowering summer.
Habitat Dry, gravelly to rocky flats, slopes, alpine ridges, often on serpentine, in subalpine conifer woodlands Dry, rocky talus slopes, boulders and outcrops, most often but not always of calcareous origin, occasionally away from immediate outcrops, sagebrush communities, conifer woodlands
Elevation 1600–2300 m (5200–7500 ft) 1800–2600(–3100) m (5900–8500(–10200) ft)
Distribution
from FNA
ID; MT; WA
[WildflowerSearch map]
[BONAP county map]
from FNA
NV; UT
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.)

Ivesia setosa occurs mostly to the east and south of I. baileyi, from southeastern Humboldt and Churchill counties to Elko, White Pine, and northern Nye counties, Nevada, and in the Deep Creek Range of western Utah. It represents a transition between the planar-leaved, chasmophytic members of sect. Setosae and the cylindric-leaved, matted species of flatter sites. Stems of I. setosa are more generally erect than in other species in the section, and the usually calcareous substrate is noteworthy. The deeply incised (usually not quite to base) leaflets are somewhat intermediate between the toothed leaflets of I. baileyi and the leaflets of I. shockleyi that are incised to the base into separate lobes. The individual leaflets of both I. baileyi and I. setosa are more or less flat and distichously paired; in I. shockleyi, groups of leaflet lobes are folded over onto each other, giving a verticillate appearance to the leaflet arrangement.

(Discussion copyrighted by Flora of North America; reprinted with permission.)
Source FNA vol. 9, p. 235. FNA vol. 9, p. 227.
Parent taxa Rosaceae > subfam. Rosoideae > tribe Potentilleae > Ivesia > sect. Ivesia 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. 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. shockleyi, I. tweedyi, I. unguiculata, I. utahensis, I. webberi
Synonyms Potentilla tweedyi I. baileyi var. setosa, Potentilla baileyi var. setosa
Name authority Rydberg: in N. L. Britton et al., N. Amer. Fl. 22: 288. (1908) (S. Watson) Rydberg: in N. L. Britton et al., N. Amer. Fl. 22: 290. (1908)
Web links 
Unless otherwise noted, all data comes from the online version of the Flora of North America, who have made most of their content available via a Creative Commons license (CC BY 4.0).



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