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

The chemical variation in Lecanora epibryon and L. subimmersa, two spe cies of the L. subfusca group, has been examined. In both species the chemical differences are correlated with geographical distribution, bu t not with morphological differences. As a consequence the chemotypes are recognized at subspecific level. In L. epibryon three chemical rac es are segregated according to the various chemosyndromes present. Sub species epibryon, containing atranorin and triterpenoids, occurs in th e northern hemisphere and South America, while the other two subspecie s occur only in the southern hemisphere. The subsp. broccha (NYL.) LUM BSCH, comb. nova, contains atranorin, the stictic acid and the 2,5,7-t richloro-3-O-methylnorlichexanthone chemosyndromes, while subsp. xanth ophora LUMBSCH, subsp. nova, is similar but lacks the stictic acid che mosyndrome. Two chemical races occur in the pantropical species L. sub immersa. While subsp. subimmersa contains atranorin and zeorin, subsp. ramboldii LUMBSCH & ELIX, subsp. nova, contains an additional ten chl orinated xanthones. L. impressa is reduced to synonymy to L. subimmers a.