Banksia plagiocarpa, commonly known as Dallachy's blue banksia, blue banksia or Hichinbrook banksia, is a species of shrub or tree in the plant genus Banksia. It occurs only on Hinchinbrook Island, Queensland and the immediately adjacent mainland. First collected in 1867, Banksia plagiocarpa was not described until 1981, when Alex George named it in his monograph of the genus Banksia. Genetic studies show it to be related to Banksia aquilonia, Banksia oblongifolia and Banksia robur.

Banksia aquilonia, commonly known as the northern banksia and jingana, is a tree in the family Proteaceae and is endemic to north Queensland on Australia's northeastern coastline. With an average height of 8 m (26 ft), it has narrow glossy green leaves up to 20 cm (7.9 in) long and 6 to 10 cm high pale yellow flower spikes, known as inflorescences, appearing in autumn. As the spikes age, their flowers fall off and they develop up to 50 follicles, each of which contains two seeds.