Gametophytic chromosome numbers in Indian species of <i>Mammillaria</i> Haw.

Male meiotic studies were carried out in 13 accessions of species belonging to the genus Mammillaria. Accessions of Mammilaria beneckei Ehrenb. and M. petterssonii Hildm. were observed to bear the gametophytic chromosome number of n=11. This is the first report on the chromosome number of these species. Gametophytic chromosome number of n=11 was observed in accessions of M. carnea Zucc. ex Pfeiff, M. compressa DC., M. elongata subsp. echinaria (DC.) D. R. Hunt, and M. magnimamma Haw. These taxa have been cytologically worked out for the first time in India. Chromosome numbers for four taxa, M. carmenae Castañeda (n=11), M. plumosa F.A.C. Weber (n=11), M. prolifera (Mill.) Haw. (n=22), and M. prolifera subsp. texana (Engelm.) D.R. Hunt (n=22) were validated with previous reports.