Chromosomes of Takhtajania, other Winteraceae, and Canellaceae: Phylogenetic implications

The somatic chromosome number of Takhtajania perrieri, the only relict repr esentative of Winteraceae on Madagascar, is documented as 2n = 36. The poss ibly paleotetraploid karyotype appears "diploidized." Chromosome size and b ehavior, as well as structure of interphase nuclei, correspond to the proch romosome type, widespread among the Magnoliid assemblage. Chromosome number s available for all other Winteraceae and the related Canellaceae (Winteral es) are critically compiled, compared, and interpreted. In light of the pos tulated molecular phylogeny of the two families, it appears that several su ccessive phases of polyploidization and parallel descending dysploid series coupled with much extinction can explain the karyological features and dis tribution of the few surviving taxa.