The genus was described by naturalist Nicholas Aylward Vigors in 1825; the name Platycercus derived from the Greek platykerkos meaning "broad-" or "flat-tailed", from platys "broad, wide, level, flat" and kerkos "tail of a beast".

[8] However, a mitochondrial study published in 2017 found that P. eximius was the earlier offshoot of the lineage that split into P. adscitus and P. venustus, and that nonsister taxa were hence able to hybridise.

[10] In 2015, Ashlee Shipham and colleagues published a molecular study based on nuclear DNA finding that P. venustus and P. adscitus were sister species, and that P. elegans nigrescens diverged earlier than P.

[12] Sexual dimorphism is absent or slight – males and females generally have similar plumage, apart from the western rosella.

[6] Rosellas are native to Australia and nearby islands, where they inhabit forests, woodlands, farmlands, and suburban parks and gardens.

[15] Mutual preening is not exhibited by the genus, and the courtship display is simple; the male waves his tail sideways, and engages in some head bobbing, and the female reciprocates.

[6] Like most parrots, they are cavity nesters, generally nesting high in older large trees in forested areas.

Their diet in aviculture includes seeds, fruit such as apple, pear, and grapes, and vegetable matter such as lettuce, grass, and silver beet.