MAJOR PLANT-COMMUNITIES OF WARM NORTH-AMERICAN DESERTS

A syntaxonomic study of the major plant communities in neotropical Nor th American deserts (Sonoran, Mojave and the Baja California Deserts) is presented. The field method of the Braun-Blanquet approach was comb ined with a numerical syntaxonomical analysis (cluster analysis and pr incipal coordinate ordination). 21 associations are described for the first time: Ambrosio chenopodifoliae-Larreetum tridentatae, Acamptopap po sphaerocephali-Larreetum tridentatae, Hymenocleo monogyrae-Bacchari detum glutinosae, Bergerocacto emoryi-Agavetum shawii, Burseretum hind siano-microphyllae, Cercidio microphylli-Carnegieetum gigantaeae, Burs ero microphyllae-Cyrtocarpetum edulis, Hymenocleo salsolae-Daleetum sp inosae, Echinocereo engelmannii-Agavetum deserti, Euphorbio californic ae-Fouquierietum deguetii, Fouquierio splendentis-Larreetum tridentata e, Agavo cerulatae-Idrietum columnaris, Mascagnio macropterae-Lysilome tum candidae, Maytenetum phyllanthoidis, Opuntio basilaris-Larreetum t ridentatae, Prosopidetum torreyanae, Roso minutifoliae-Aesculetum parr yi, Opuntio taponae-Agavetum subcerulatae, Tidestromio oblongifoliae-A triplicetum hymenelytrae, Eurotio lanatae-Larreetum tridentatae and Yu cco validae-Fouquierietum deguetii. Some associations include subassoc iations. Ecological, biogeographical and floristic bioclimatic data ar e given for each association.