Exidia subsaccharina is a species of fungus in the family Auriculariaceae. Basidiocarps (fruit bodies) are gelatinous, reddish brown, button-shaped at first then often coalescing and becoming irregularly effused. It grows on dead branches of pine and is currently known only from France and England. Molecular research, based on cladistic analysis of DNA sequences, has shown that the species is distinct.
Exidia subsaccharina forms reddish to vinaceous brown, gelatinous fruit bodies that are button-shaped at first, typically coalescing with age and becoming irregularly effused, around 10 cm (4 in) across. The upper, spore-bearing surface is smooth to weakly papillate. The spore print is white.
The microscopic characters are typical of the genus Exidia. The basidia are ellipsoid and septate. The spores are weakly to distinctly allantoid (sausage-shaped), 12.5 to 17.5 by 4 to 5.5 μm.
Fruit bodies of Exidia saccharina also occur on conifers and are not distinguishable in the field, but have smaller basidia and spores (10 to 14 by 3 to 4.5 μm).
Exidia subsaccharina is currently only known from the type collections made on dead trees of Pinus sylvestris in France and a single collection, also on pine, from England.