As there was already a plant named Banksia blechnifolia, Mast and Thiele had to choose a new specific epithet; their choice, "pellaeifolia", is from Pellaea, a genus of ferns with pinnate leaves, and the Latin folium ("leaf"), in reference to the species' fern-like leaves.
For example, a hemp plant has palmate compound leaves, whereas some species of Acacia have pinnate leaves.
The fronds of R. adiantiformis contain round sori (reproductive clusters) on the underside of the pinnae (leaflets) unlike many other ferns which have separate specialized reproductive fronds.