Populations from the three regions of Cupressus goveniana ---north coast, Santa Cruz Mountains, and Monterey Peninsula---differ in foliage and seed characters and have been treated as varieties or species; additional interpopulational variation occurs within these regions. Trees from Santa Cruz Mountain populations may have originated through hybidization with C . sargentii (E. Zavarin et al. 1971). The pygmy forests of this species and Pinus contorta Douglas ex Loudon on the shallow hardpan soils of coastal terraces of the Mendocino white plains are a remarkable example of phenotypic plasticity.