In 1950, Isabel Cookson and Suzanne Duigan showed this policy to be flawed, by demonstrating that the leaves of the two genera cannot be reliably distinguished.

Since these two genera then comprised tribe Banksieae, Cookson and Duigan erected Banksieaephyllum to contain such leaves.

[2] Others hold that Cookson and Duigan's intentions were for the genus to hold fossil leaves that are known to be Dryandra or Banksia, but cannot be attributed to either with certainty; thus they now define the genus in terms of Banksiinae rather than Banksieae.

[4] Although as yet undetermined, the latter interpretation would result in Banksieaephyllum becoming a nomenclatural synonym of Banksia.

Fossils ascribed to Banksieaephyllum have been found in sediments dating from the Paleocene to early Miocene (66 to 16 million years ago).