The pale-headed rosella was
formally described in 1790 by the English ornithologist
John Latham and given the
binomial name Psittacus adscitus. The specific epithet is from
Latin asciscere meaning "to approve". Latham did not specify a
locality but in 1912
Gregory Mathews designated the locality as
Cooktown, Queensland in northeast Australia. The pale-headed rosella is now placed in the genus
Platycercus that was introduced in 1925 by
Nicholas Aylward Vigors. There are two
subspecies, the
nominate adscitus (
Cape York Peninsula) and the better known
palliceps (eastern
Queensland), known as the blue-cheeked rosella, that was depicted in 1832 by the English artist
Edward Lear in his
Illustrations of the Family of Psittacidae, or Parrots. Its closest relative was thought to be the
eastern rosella, which replaces it in southeastern Australia. Hybrids of the two taxa have been recorded where their ranges meet in northeastern New South Wales and southeastern Queensland. However, a 2017 mitochondrial study found that the closest relative was in fact the northern rosella, and that the eastern rosella was an earlier offshoot. Other common names occasionally seen include mealy rosella, Moreton Bay rosella, blue rosella, and blue-cheeked rosella for the northern subspecies. The term white-cheeked rosella has been used for a species or superspecies combining the pale-headed and eastern forms. == Description ==