A NATURAL HYBRID POPULATION BETWEEN NEOBUXBAUMIA TETETZO AND CEPHALOCEREUS-COLUMNA-TRAJANI (CACTACEAE)

A supposed hybrid population between Neobuxbaumia tetetzo and Cephaloc ereus columna-trajani (Cactaceae) in a semi-arid ecosystem at Zapotitl an de las Salinas, in the Mexican State of Puebla, was investigated by analysing number of ribs, number of areoles per cm and number of bran ches. Tests for equality of means using the Games and Howell method an d Stepwise Discriminant Analysis, indicated that the number of ribs an d number of areoles per cm supported our hypothesis for the existence of these naturally occurring hybrids, which are intermediate and disti nct from the parental species. Other qualitative characteristics which distinguished hybrids and parental species are highlighted, and the p ossible meaning of the phenomenon is discussed. (C)1996 Academic Press Limited