A phytosociological and phytogeographical survey of the coastal vegetation of western North America. Part I: Plant communities of Baja California, Mexico

Through tabular and average linkage cluster analyses, 737 phytosociological relev�s were classified. Based on these relev�s, we described and typified the associations, alliances, orders, and classes grouping the coastal plant communities of the Baja California peninsula. Diagnostic tables, classification by average linkage clustering, and climatic, edaphic, and biogeographical data were used to establish floristic affinities among these syntaxa and to interpret their distributions. Syntaxa were characterized by their floristic composition, physiognomy, and biogeographical distribution, along with their positions in halophilous and psammophilous gradients. Thirty-three associations were identified, of which 22 are here described for the first time. Our syntaxonomical proposal includes descriptions of nine new alliances, seven new orders and four new classes: Allenrolfeetea occidentalis, Atriplici julaceae-Frankenietea palmeri, Euphorbio leucophyllae-Sporoboletea virginici and Achyronichio cooperi-Abronietea villosae. � 2007 Springer Science+Business Media B.V