Cytogenetic studies in genus mentha.

Cytogenetic studies of 16 species consisting of 33 texa and about 100 geographical races collected in the world, India and received from botanical gardens of Europe and Japan is conducted. Chromosome numbers of 16 species and 33 varieties are determined and tabulated. These numbers range from 2n=20 to 2n=120 and fall into the two basic numbers x=5 and x=6.M. Longifolia (linn) Huds; M.rotundifolia Linn. , M.spicata Linn; are M. niliaca Linn, M.arvensis Linn and M. Pulegium Linn are considered to be the basic species in the genus. A detailed studies of the cytology of these basic species is presented which show regular meiosis. A series of texa derived from the basic species are found and these fall into three complexes i.e M. Pulegium Linn, M.piperta and M.arvensis