 Banksia violacea is one of a small number of Banksia species that has both lignotuberous and non @-@ lignotuberous populations . In both cases , plants are adapted to release their aerial seed bank following a bushfire , ensuring seedlings are established on clear and relatively fertile ground ; however the possession of a lignotuber makes plants much less reliant on fire regime for population maintenance and regeneration , as maternal plants are not killed by bushfire , but resprout from below ground level . Lignotuberous plants generally occur among the north @-@ eastern populations , in the vicinity of Woodanilling . An investigation into the biogeography of these plants failed to find any vegetative , climatic or other environmental factors associated with the possession of a lignotuber . 
