Coyote ceanothus is an evergreen shrub belonging to the buckthorn family. It is known from only three locations, all of which are within a few miles of each other within Santa Clara County, California. Coyote ceanothus was listed as endangered on February 3, 1995. At the time of listing, fewer than 6,000 coyote ceanothus plants were known to exist, with the largest population estimated at approximately 5,000 plants. In 2011, that same population was estimated to be over 100,000 plants. 

Ceanothus species are an important cultural resource for Native American tribes who have used these plants for producing baskets, cradles, teas, and medicines.

Threats to the coyote ceanothus include residential and recreational development, unauthorized dumping, landfill activities, cattle grazing, construction activities at the Anderson Dam spillway, altered fire regimes, Phytophthora pathogen and invasive plants. 

Coyote ceanothus grows on arid slopes in serpentine chaparral, valley, and bunchgrass foothill grasslands below about 300 meters (about 1,000 feet). All three known populations of coyote ceanothus occur in an area that receives frequent exposure to a summer marine layer of fog and low cloud stratus. 

Coyote ceanothus can reach 1 to 2 meters (3 to 6 feet) in height at maturity, and is characterized by long, stiff divergent branches that can become woody with age. The leaves are opposite and round with a dark green, hairless upper surface and a lighter green undersurface with minute hairs. Leaf margins have short teeth or sometimes lack teeth; the leaf base is abruptly tapering or rounded. Small white flowers are borne in clusters 1.3 to 2.5 centimeters (0.5 to 1.0 inch) in length. Seed capsules are seven to nine millimeters (0.3 to 0.35 inch) in width and have conspicuous apical horns.