polyphyletic pol·y·phy·let·ic (pŏl'ē-fī-lět'ĭk)
Descended or derived from more than one ancestral stock or source.
Of or being the theory that blood cells are derived from several different stem cells, depending on the particular blood cell type.
Relating to a taxonomic group that does not include the common ancestor of the members of the group and whose members have two or more separate origins. A group that consists of flying vertebrates would be polyphyletic, as bats and birds independently evolved flight and do not share a common ancestor. Compare monophyletic, paraphyletic.