Cytology of the Genus Selaginella

Cytological investigations on 8 species of Selaginella (including an unidentified species) indigenous to South India were conducted. The chromosome numbers in the species studied are as follows: S. gracilis (n=10 and 2n=20), S. wallichii (n=10 and 2n=20), S. braunii (n=10), S. plana (n=10 and 2n=20), S. crassipes (n=9), S. involvens (n=9), S. willdenovii (n=9 and 2n=18), Selaginella sp. (unidentified) (n=18 and 2n=36).2. All the species studied except the unidentified species are diploids on basic number 9 or 10. The unidentified species is a tetraploid based on the number 9.3. Aneuploid change of chromosome number (from 10 to 9 as observed in this study), hybridization followed by chromosome doubling, and probably accumulation of intrachromosomal changes have been suggested to be operative in speciation of the genus Selaginella.