Two new species of the genus Isoetes L. (Isoetaceae­Lycopsida) from India

Abstract Two new, primitive quillwort species, I . udupiensis and I . divyadarshanii , are described from peninsular India. Cytologically both species are diploid and unique for India in having 22 chromosomes without fragments. Megaspores of both species are monomorphic, whereas in the previously described species, they are di­to polymorphic. Isoetes udupiensis is unique in having deltoid­shaped megaspores and dominant microspory. The similarity in morphology of both species to sub­genus Euphyllum and to the remaining Indian species of subgenus Isoetes , suggests that they may be connecting links between primitive and derived forms within the genus in India.