Ceanothus perplexans (Ceanothus greggiivar perplexans) syn. with the common name cup leaf ceanothus, is a species of shrub in the buckthorn family, Rhamnaceae.
It is native to the Southwestern United States, California, New Mexico, Texas, and northern Mexico. It grows in desert scrub, sagebrush, chaparral, and other dry habitats such as inland mountain slopes, at elevations of 1,000 m (3,300 ft) to 2,300 m (7,500 ft) .
C. perplexans is a many-branched shrub that grows erect to nearly 2 m (6.6 ft) in maximum height. Its woody parts are gray in color and somewhat woolly. Branches are opposite and rigid.
The evergreen leaves are oppositely arranged, 2 to 9mm long, and variable in shape, with a prominent midvein. They may be toothed or smooth along the edges, and are indeed usually somewhat cupped.
The inflorescence is a small (less than 2 cm long) cluster of many white flower, on short lateral branchess. It blooms in spring. Blooms are considered highly fragrant.
The fruit is a horned capsule a few millimeters wide which bursts explosively to expel the three seeds which require thermal scarification from wildfire before they can germinate.
This shrub is eagerly browsed by livestock and wild ungulates such as mule deer and desert bighorn sheep.