Phrygilus is a genus of mainly Andean seed-eating tanagers commonly known as Sierra Finches. Phrygilos means finch in Ancient Greek.
Sometimes classified in the bunting and American sparrow family Emberizidae, more recent studies have shown them to belong in the Thraupidae. The genus appears to be polyphyletic consisting of at least three distinct lineages which in future may need to be split into separate genera.

Group 1 - The "Hooded" group. Related to yellow finches Sicalis
Black-hooded Sierra Finch, Phrygilus atriceps
Peruvian Sierra Finch, Phrygilus punensis
Grey-hooded Sierra Finch, Phrygilus gayi
Patagonian Sierra Finch, Phrygilus patagonicus

Group 2 - Upperparts mostly grey, underparts white. Sexes similar. Related to a clade containing both the "hooded" group and Sicalis olivascens
Red-backed Sierra Finch, Phrygilus dorsalis
White-throated Sierra Finch, Phrygilus erythronotus

Group 3 - male plumage grey or dull brown, females streaky. Related to Haplospiza
Plumbeous Sierra Finch, Phrygilus unicolor
Ash-breasted Sierra Finch, Phrygilus plebejus

Group 4 - Yellow bill with grey/black underparts.
Band-tailed Sierra Finch, Phrygilus alaudinus
- Related to
Yellow-billed Blue Finch, Porphyrospiza caerulescens
Carbonated Sierra Finch, Phrygilus carbonarius
Mourning Sierra Finch, Phrygilus fruticeti