Ivesia tweedyi
in N. L. Britton et al., N. Amer. Fl. 22: 288. 1908.
Plants green, ± rosetted to tufted; taproot stout, not fleshy. Stems ascending to erect, 0.4–2(–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. Cauline leaves (0–)1–2, not paired. Inflorescences (5–)10–25(–35)-flowered, (1–)1.5–3(–4.5) cm diam.; glomerules 1–few. Pedicels 1–3(–5) 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. Achenes olive green, 1.8–2 mm.
Phenology: Flowering summer.
Habitat: Dry, gravelly to rocky flats, slopes, alpine ridges, often on serpentine, in subalpine conifer woodlands
Elevation: 1600–2300 m
Distribution
Idaho, Mont., Wash.
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.
Selected References
None.