Cytological study has been carried out on seven species of Iridaceae, distributed under four genera, namely,
1. Babiana sulphurea 2n=14
2. Tritonia crocata 2n=60
3. T. crocata Type I 2n=22
4. Tigridia pavonia 2n=26
5. Moraea iridioides var. Mcleyii 2n=40
6. M. iridioides var. bicolor 2=40
7. M. iridioides var. johnsonii 2n=20
On the basis of the data obtained and taking into account previous reports, it has been suggested that n=7 is probably the basic number for Babiana. A distinct line of evolution has been drawn for this genus, unrelated with the three other genera studied here.
Tigridia pavonia shows abrupt size difference among the members of its complement and a different line of evolution for this genus too has been proposed.
Tritonia crocata Type I, formerly included under Montbretia, has been observed to be cytologically allied to the genus Crocosmia. Its inclusion under the latter or its status as a member of a separate genus Montbretia, is urged.
Tritonia crocata and the three varieties of Moraea iridioides show affinities in chromosome number and karyotype. A common evolutionary line had been assumed for them.
Numerical and structural alterations of chromosomes in the somatic tissue have been noticed and their significance in evolution has been emphasized.