GEOGRAPHICAL DISTRIBUTION OF OPUNTIA IN MEXICO - J. A. Reyes-Agüero &  J. R. A. Rivera

Instituto de Investigación de Zonas Desérticas, Universidad Autónoma de San Luis Potosí, Altair 200, Fracc. del Llano, San Luis Potosí, S. L. P. México 78377

The objective of this paper is to show the patterns of distribution of Opuntia in Mexico. There are species of wide distribution, i.e. O. robusta (5 natural regions), O. phaeacantha (6 regions), O. tomentosa (6 regions), O. decumbens (7 regions) and O. pubescens (12 regions). Seventeen patterns of distribution were identified from species with restricted distribution. The first five patterns are from northern Mexico and they include 38 species that are endemic to one region. In this sense, the pattern of the Meridional Highland Plateau is important with 16 endemic species. The other four patterns (Septentrional Highland Plateau, California, North Occidental and Northeastern Coastal Plains) include 17 species Two patterns are from southern Mexico, i.e. Oaxaca Sierra Madre and Chiapas, with 5 endemic species. The rest of the 10 patterns include species that are distributed in two to four regions. Four patterns relate to Highland Plateaus (Meridional -Septentrional Highland Plateau, Meridional Septentrional Highland Plateau - Northeastern Coastal Plains, Septentrional Highland Plateau – North Occidental Coastal Plains, Meridional Highland Plateau - Neovolcanic Mountain - Occidental Sierra Madre - Oaxaca Sierra Madre), one to the northwest (California - North Occidental Coastal Plain), another to the central south of the country (Balsas Depression - Neovolcanic Mountain - South Sierra Madre - Oaxaca Sierra Madre). One pattern includes the whole slope of the Gulf (Northeastern Coastal Plains - Southeast - Yucateca Platform) and the other most of the slope of the Pacific (North Occidental Coastal Plain - South Sierra Madre - Balsas Depression). The rest of the patterns are in southern Mexico, one related with the Sierras Madre (South Occidental Coastal Plain - Oaxaca Sierra Madre - South Sierra Madre) and another with Yucatan (South Occidental Coastal Plain - Oaxaca Sierra Madre - South Sierra Madre)