Charnia is an extinct genus of frond-like lifeforms belonging to the Ediacaran biota with segmented, leaf-like ridges branching alternately to the right and left from a zig-zag medial suture (thus exhibiting glide reflection, or opposite isometry).

Despite Charnia's fern-like appearance, it is not a photosynthetic plant or alga because the nature of the fossil beds where specimens have been found implies that it originally lived in deep water, well below the photic zone where photosynthesis can occur.

Some specimens of C. masoni were described as members of genus Rangea or a separate genus Glaessnerina: Two other described Charnia species have been transferred to two separate genera A number of Ediacaran form taxa are thought to represent Charnia, Charniodiscus and other Petalonamids at varying levels of decay; these include the Ivesheadiomorphs Ivesheadia, Blackbrookia, Pseudovendia, and Shepshedia.

[10] Charnia masoni was first described from the Maplewell Group in Charnwood Forest in England and was subsequently found in Ediacara Hills in Australia,[3][11] Siberia and the White Sea area in Russia,[12][13] and Precambrian deposits in Newfoundland, Canada.

[15] The holotype (the actual physical example from which the species was first described) now resides, along with a cast of the related taxon Charniodiscus, in Leicester Museum & Art Gallery.

Originally interpreted as an alga, Charnia was reinterpreted as a sea pen (a group related to the modern soft corals) from 1966 onwards.

[22] An alternative theory has developed, since the mid-1980s, from the work of Adolf Seilacher who suggested that Charnia belongs to an extinct group of unknown grade which was confined to the Ediacaran Period.