Cladonia deformis, also known as the lesser sulphur cup or the lesser sulphur cup lichen,[1] is a light-coloured, fruticose, cup lichen belonging to the family Cladoniaceae.

[2] This lichen was first described as Lichen deformis by Carl Linnaeus in 1753,[3][4] and transferred to the genus Cladonia in 1796 by Georg Franz Hoffmann.

[3][5] As of July 2021, its conservation status has not been estimated by the IUCN.

In Iceland, its conservation status is denoted as data deficient (DD).

[6]