The photosynrhetic characteristics of planes native to a Californian hot desert habitar, Death Valley, and a cool coastal locality, Bodega Head, were compared. The desert planes showed a variety of responses including species with C3 and C4 photosymhetic pathways, drought tolerance and inrolerance, a wide range of thermal optima, and biochemical and morphological thermal acclimation. Most of the desert species have high photosynrhetic light requirements for saruration and high photosynrheticcapacicies.