Ivesia tweedyi |
Ivesia santolinoides |
|
---|---|---|
Tweedy's ivesia, Tweedy's mousetail |
mouse tail ivesia, Sierra mousetail, silver mousetail, stellariopsis |
|
Habit | Plants green, ± rosetted to tufted; taproot stout, not fleshy. | Plants ± grayish to silvery. |
Stems | ascending to erect, 0.4–2(–3.5) dm. |
ascending to erect, (1–)1.5–4 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. |
mousetail-like (individual leaflets scarcely distinguishable), 3–10 cm; sheathing base densely strigose abaxially; petiole 0.5–1.5 cm; leaflets 60–80 per side, 0.6–1.5 mm, lobes (0–)3–5, obovate to oval, densely villous. |
Cauline leaves | (0–)1–2, not paired. |
|
Inflorescences | (5–)10–25(–35)-flowered, (1–)1.5–3(–4.5) cm diam.; glomerules 1–few. |
(10–)30–200-flowered, 3–8(–30) cm diam. |
Pedicels | 1–3(–5) mm. |
5–30 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. |
5–8 mm diam.; epicalyx bractlets oblong to broadly ovate or orbiculate, 0.2–0.5 mm; hypanthium 0.5–1.5 × 2–3 mm; sepals 1–2 mm, apex obtuse to acute; petals white, broadly obovate to orbiculate, 2–2.5 mm; stamens 15, filaments 1.2–1.8 mm, anthers purple, broadly obcordate to pouch-shaped, 0.3–0.4 mm; carpels 1, styles 2–3 mm. |
Achenes | olive green, 1.8–2 mm. |
mottled grayish brown, 1.7–2 mm. |
2n | = 28. |
|
Ivesia tweedyi |
Ivesia santolinoides |
|
Phenology | Flowering summer. | Flowering summer. |
Habitat | Dry, gravelly to rocky flats, slopes, alpine ridges, often on serpentine, in subalpine conifer woodlands | Dry sandy granitic soil, decomposed granite accumulations, ledges and outcrops, in montane and subalpine conifer woodlands |
Elevation | 1600–2300 m (5200–7500 ft) | 1500–3600 m (4900–11800 ft) |
Distribution |
ID; MT; WA
|
CA
|
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 santolinoides is found on loose granitic substrates in the Sierra Nevada, Transverse Ranges, and San Jacinto Mountains from El Dorado to Riverside counties. The species is easily recognized by its silvery mousetail-like leaves and erect, diffuse inflorescences with small, plumlike flowers. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 9, p. 235. | FNA vol. 9, p. 246. |
Parent taxa | Rosaceae > subfam. Rosoideae > tribe Potentilleae > Ivesia > sect. Ivesia | Rosaceae > subfam. Rosoideae > tribe Potentilleae > Ivesia > sect. Stellariopsis |
Sibling taxa | ||
Synonyms | Potentilla tweedyi | Potentilla santolinoides, Stellariopsis santolinoides |
Name authority | Rydberg: in N. L. Britton et al., N. Amer. Fl. 22: 288. (1908) | A. Gray: Proc. Amer. Acad. Arts 6: 531. (1865) |
Web links |