The present investigation was carried out on three species of Typhonium and two species of Arisaema. Their numbers are given below-
Typhonium trilobatum Schott……… 2n=18
T. inapinatunz Prain……… 2n=26
T. cuspidatum Bl……… 2n=16
Arisaezna tortuossum Schott……… 2n=24
A. sanguineum Schott……… 2n=28
2n=16 chromosomes in T. cuspidatuin suggest that the basic number is lower than the one previously found. Meiotic study suggests that all the three species maintain homozygous state.
Karyotype analysis shows a similarity between T. trilobatum and T. inapinatum. whereas T. cuspidaturn with fairly long chromosomes and characteristic C type of chromosomes with secondary constrictions represents a primitive level as compared to others. So, it has been suggested that it will be in a more natural position if placed under a separate subgenus.
In Arisaema, the number 2n=24 in A. tortuossuni is new for the genus and the two species show clear similarity in their karyotypes. It has been suggested that aneuploidy along with structural changes of chromosomes has been effective in the evolution of this genus.
Cytological data have confirmed the close relationship of the two genera.