CEANOTHUS, in botany, a genus of North American shrubs or trees of the buckthorn family (Rhamnaceae), comprising more than 5o species found chiefly in the Pacific coast region, 3o of which are native to California. The small but showy white or blue flowers are usually borne in dense panicles or umbels. Sev eral species and various hybrids are grown as garden plants. Only two species occur east of the Rocky Mountains, the New Jersey tea or great red-root (C. americanus) and the lesser red-root (C. ovatus), both widely distributed. The genus attains its maximum development in the foothills and mountains of California, often constituting a considerable part of the shrubs of the chaparral belt. Noteworthy representatives are the California lilac and the Oregon tea-tree (qq.v.).