Leafl. W. Bot. 3: 207. 1943.
Stems decumbent, 5–10 (–15) cm, glandular-puberulent and pilose. Leaves glandular-puberulent and pilose; proximal 10–30 mm, margins entire or 3-lobed, lobes 1–2 mm wide; distal 10–20 × 1 mm, margins entire. Inflorescences spikes, 2-flowered or 3-flowered, or flowers solitary; bracts 2 or 3, 10–15 mm, margins 3-lobed, lobes purple distally, linear to filiform. Pedicels: bracteoles 10–15 mm, margins entire. Flowers: calyx 10–16 mm, tube 0 mm, apex entire; corolla white with purple veins, 10–15 mm, throat 5–7 (–9) mm diam., abaxial lip 3–5 mm, ca. equal to and appressed to adaxial; stamens 4, filaments hairy, fertile pollen-sacs 2 per filament, equal. Capsules oblong-ovoid, 5–7 mm. Seeds 7–10, dark-brown, ovoid to reniform, 1.5–2 mm, irregularly striate. 2n = 28.
Phenology: Flowering Jul–Aug.
Habitat: Dry, open serpentine in chaparral.
Elevation: 600–800 m.
Cordylanthus nidularius is the only member of the genus with decumbent stems. The species is similar to C. tenuis; it differs in its white (versus pale yellow) corollas and decumbent (versus erect to ascending) stems. It grows on the eastern slopes of Mt. Diablo.