phy·let·ic 
(fī-lĕtĭk)
(fī-lĕtĭk)adj.
Of or relating to the evolutionary descent and development of a species or other taxonomic group of organisms, especially to gradual change rather than to the branching of taxa.
[From Greek phūletikos, of or for a tribesman, from phūletēs, tribesman, from phūlē, tribe; see bheuə- in the Appendix of Indo-European roots.]
phy·leti·cal·ly adv.