Synonyms: 1,4a-(Epoxymethano)-4aH-xanthene-9,11(2H)-dione,1,3,4,9a-tetrahydro-4,8,9a-trihydroxy-3-methyl-, [1S-(1a,3b,4b,4aa,9ab)]-; 1,4ab-(Epoxymethano)-4aH-xanthene-9,11(2H)-dione, 1a,3,4,9a-tetrahydro-4a,8,9aa-trihydroxy-3a-methyl- (8CI); Xanthene-4a(2H)-carboxylic acid,1,3,4,9a-tetrahydro-1,4,8,9a-tetrahydroxy-3-methyl-9-oxo-, g-lactone (7CI); Ergochrome C