DNA hybridization and evolutionary relationships in three osmunda species.

Molecular hybridization techniques have been used to estimate the degree of DNA base sequence homology between some members of the fern genus Osmunda. Under conditions permitting extensive reassociation, measurements of the extent of inter-specific reaction and the thermal stability of the hybrid molecules indicated that O. claytoniana L. (interrupted fern) shares more DNA homology with O. cinnamomea L. (cinnamon fern) than it does with O. regalis L. (royal fern). These findings are in conflict with predictions from a recent analysis of living and fossil specimens by numerical techniques. However, they are consistent with the earlier, more traditional, taxonomic assignments.