Since 1998 , an American botanist , Austin Mast , have been publishing results of ongoing cladistic analyses of DNA sequence data for the subtribe Banksiinae . His analyses suggest a phylogeny that is very greatly different from George 's arrangement , and somewhat different from Thiele and Ladiges ' . With respect to B. violacea , Mast 's results agree with its placement near B. laricina and B. incana , placing it in a clade with these two species and B. sphaerocarpa var. dolichostyla ( treated at species rank as B. dolichostyla ) . However , Thiele 's B. subseries Longistyles appear to be polyphyletic , as do both definitions of B. ser . Abietinae — that is , none form a natural grouping .