CHEMICAL VARIATION IN 2 SPECIES OF THE LECANORA-SUBFUSCA GROUP (LECANORACEAE, LICHENIZED ASCOMYCOTINA)

The chemical variation in Lecanora epibryon and L. subimmersa, two species of the L. subfusca group, has been examined. In both species the chemical differences are correlated with geographical distribution, but not with morphological differences. As a consequence the chemotypes are recognized at subspecific level. In L. epibryon three chemical races are segregated according to the various chemosyndromes present. Subspecies epibryon, containing atranorin and triterpenoids, occurs in the northern hemisphere and South America, while the other two subspecies occur only in the southern hemisphere. The subsp. broccha (NYL.) LUMBSCH, comb. nova, contains atranorin, the stictic acid and the 2,5,7-trichloro-3-O-methylnorlichexanthone chemosyndromes, while subsp. xanthophora LUMBSCH, subsp. nova, is similar but lacks the stictic acid chemosyndrome. Two chemical races occur in the pantropical species L. subimmersa. While subsp. subimmersa contains atranorin and zeorin, subsp. ramboldii LUMBSCH & ELIX, subsp. nova, contains an additional ten chlorinated xanthones. L. impressa is reduced to synonymy to L. subimmersa.