CYTOEVOLUTIONARY PATTERNS IN RUTACEAE

Chromosome numbers for 9 tribes and 73 genera of Rutaceae are examined for the probable chromosome base numbers in these taxa. There is abun dant dysploidy and infrageneric polyploidy in the large Rutoideae/Todd alioideae complex. We found that x = ls was typical for the tribes Zan thoxyleae and Toddalieae; probably ancestral in the Boronieae and perh aps in the Ruteae, Diosmieae, and Cusparieae; and characteristic of su bfamily Flindersioideae. Considering the basic position of elements of Zanthoxyleae and Toddalieae in the family it appears that diploid x = 18 is ancestral in the Rutaceae. The morphologically advanced Citroid eae are invariant for x = 9 and may be a product of dysploid reduction .