Mast's analyses placed B. subulata not with the other Dryandra species sampled, but rather within a small clade of Banksia species with independently reduced inflorescence axes. For this reason, B. subulata was placed incertae sedis in B. subg.
Mast's studies positioned B. subulata apart from other Dryandra species sampled, but rather within a small group of Banksia species that have independently diminished inflorescence axes. Consequently, B. subulata was placed in an uncertain position within the B. subg.