Myriostigma is a genus of lichens in the family Arthoniaceae. The genus was circumscribed by German lichenologist August von Krempelhuber in 1874.
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).
, Species Fungorum (in the Catalogue of Life) accepts nine species of Myriostigma.
The species once known as Myriostigma guatteriae is now Myriostigmella guatteriae.