Myriostigma is a genus of lichens in the family Arthoniaceae.

[1] The genus was circumscribed by German lichenologist August von Krempelhuber in 1874.

[2] Characteristics of Myriostigma include the raised maculate (spots), ascomata-like fertile areas, asci that are 8-spored, thick-walled, globular and stalked, and ascospores that are hyaline, bean-shaped, and muriform (divided into chambers by septa).

[3] As of July 2024[update], Species Fungorum (in the Catalogue of Life) accepts nine species of Myriostigma.

[4] The species once known as Myriostigma guatteriae G.Arnaud (1925) is now Myriostigmella guatteriae.