Cytotaxonomic Studies of the Subtribe Pogostemoninae sensu Bentham (Labiatae) from South India

Abstract

Cytology of 11 taxa in three genera belonging to the subtribe Pogostemoninae in Mentheae from South India is studied. The chromosome numbers observed were Pogostemon auricularius 2n=34, P. benghalense 2n=64, P. gardneri n=16, P. heyneanus 2n=34, P. wightii 2n=32 and 64, Eusteralis stellata var. roxburghiana n=14, E. tomentosa var. gracilis 2n=32, and Colebrookea oppositifolia 2n=32. The basic chromosome numbers suggested are x=16 and 17 in Pogostemon, x=14 and 16 in Eusteralis and x=16 for Colebrookea. On the basis of cytological data it is suggested that the whole of Pogostemoninae be included under the subfamily Lamioideae as done by Wunderlich rather than split it and divide the genera among Lamioideae and Nepetoideae as done by Erdtman.