Chorizanthe howellii is a species of flowering plant in the buckwheat family known by the common names Mendocino spineflower and Howell's spineflower. It is endemic to coastal Mendocino County, California, where it is known only from the sand dunes and coastal scrub near Fort Bragg. It is estimated that 95% of the remaining individuals of this plant are part of a single population growing at MacKerricher State Park. It is a federally listed endangered species. This is a decumbent or spreading species, growing hairy stems along the ground up to about 10 centimeters long. The inflorescence is a cluster of flowers, each surrounded by a starlike array of six spreading white bracts tipped with straight brown awns. The flower itself is a few millimeters wide and white to pale pink in color.