Cordylanthus nidularius is a rare species of flowering plant in the family Orobanchaceae known by the common name Mt.

[3] It grows in chaparral habitats and only on serpentine soils, at elevations of 600–800 metres (2,000–2,600 ft).

It foliage is red-tinted gray-green in color, and coated with glandular hairs and woolly fibers.

[2] The flowers are each surrounded by 2 or 3 bracts divided into three narrow lobes up to 1.5 centimeters long.

[3] This is a state and California Native Plant Society listed Critically endangered species.