La vegetación de los altos Andes: El flanco oriental del Cordón del Portillo (Tunuyán, Mendoza, Argentina)

the vegetation on the eastern slope of cordón del portillo is studied in order to fill gaps in the floristic and ecological information on the andean plant communities of mendoza. work is developed along an altitudinal gradient between 980 and 4300 m asl using the phytosociological method. after synthesizing of the area characteristics, are describe the major plant communities identified from the analysis of comparative survey tables. the study discriminates 18 plant communities and 26 floristic groups and the occurrence of 3 phytogeographic provinces: monte, andean and high andean, 4 geographic districts and 5 sub-districts. the monte phytogeographic province and cuyano monte district are characterized by the shrubland sub-district of larrea divaricata (980 to 1600 m asl). the andean province and cuyano andean district by the shrubland sub-districts of junellia scoparia-colliguaja integerrima and adesmia horrida (1400 to 2600 m asl) and of adesmia pinifolia (2400 to 3000 m asl). the high andean province and cuyano high andean district are represented by the sub-districts of steppes and cushions of adesmia subterranea-azorella monantha (2950 to 3800 m asl) and of the shrub steppe of nassauvia lagascae-senecio crithmoides (3700-4200 m asl). results allow extrapolation of plant communities to the n and s of the area.