polyoma: a virus the can initiate various kinds of tumors in mice
papovavirus: any of a group of animal viruses associated with or causing papillomas or polyomas
dilleniidae: a group of families of more or less advanced trees and shrubs and herbs having either polypetalous or gamopetalous corollas and often with ovules attached to the walls of the ovary; contains 69 families including Ericaceae and Cruciferae and Malvaceae; sometimes classified as a superorder