in W. H. Brewer et al., Bot. California 1: 556. 1876.
Annuals 7–40 cm. Stems erect, branched, sometimes simple, glandular-pilose. Leaves: petiole 0–15 mm; proximal cauline leaves simple or tripartite, margins entire or crenate to dentate or serrate, medial cauline leaves deeply tripartite, segments lanceolate-elliptic, margins entire, sometimes crenate to serrate; surfaces sparsely pilose adaxially, abaxially along midvein, and along margins, sometimes glabrous. Racemes: flowers 2–10 per node; bracts deeply tripartite, sometimes simple, segments linear to narrowly lanceolate or elliptic, margins entire or serrate. Pedicels 10–25 mm, sparsely to densely glandular-pubescent. Flowers: calyx subrotate, lobes narrowly triangular to lanceolate, 0.5–2 × 0.4–1 mm; lateral lobes of abaxial lip appearing closely associated with medial lobe; corolla 5–7 × 6–12 mm; style 5–7 mm. Capsules 2–3 × 2–3 mm. Seeds 4, 1.2–3 × 0.7–1 mm.
Phenology: Flowering Apr–Jul.
Habitat: Open rocky canyons and slopes, open pine forests.
Elevation: 30–1600 m.
Idaho, Oreg., Wash.
Populations of Tonella floribunda are concentrated mainly in the Snake River Canyon and close tributaries in west-central Idaho, northeastern Oregon, and southeastern Washington, with scattered, disjunct populations in northern (Shoshone County) and southwestern (Owyhee County) Idaho, and along the Columbia River below its confluence with the Snake River.