Annuals 8–40 cm. Stems erect to ascending. Leaf blades ± linear, length usually 6+ times width, margins entire, rarely crenate. Inflorescences scaly and spreading-glandular; nodes 1–3(–5)-flowered; flowers not crowded; distalmost bracts linear, 2–5 mm. Pedicels ascending, longer than calyx, visible. Flowers: caly× lobes lanceolate to ovate, equal to capsule, ape× subacute to slightly rounded; corolla purplish lavender, rarely white, 4–8 mm, glabrous or keel sometimes sparsely glandular; banner length 0.8–1 times wings, lobe base with folds bulging less than 0.5 mm away from throat opening, reflexed portion length 1 times throat; throat barely angled to tube, pouch ± hidden by calyx; stamens: abaxial filaments glabrous, adaxials hairy at base, basal spur 0(or 1). Seeds (3 or)4–6, oblong to ovate, 1.5–2 mm, margins thickened, inrolled. 2n = 14.
Phenology: Flowering May–Jul(–Aug).
Habitat: Open coniferous forests.
Elevation: 60–1500 m.
Calif., Oreg., Wash.
Collinsia rattanii is best distinguished from C. linearis by corolla shape (floor of throat nearly parallel to abaxial side of caly× and reflexed portion of adaxial lip about equal to throat) and smaller size.