The value of primary chemical compounds correlated with known secondary chemistry and morphological variation within the Ramalina siliquosa group has been investigated. A hundred specimens were collected on two different occasions from 13 different populations on the Swedish west coast during April 1984. Protein extracts were prepared from 27 on secondary constituents identified and morphologically analysed populations. The protein bandings were performed by means of isoelectric focusing. Twenty-two different banding patterns were analysed since two were destroyed during preparation and three others yielded weak patterns. The results indicated that three different banding pattern types could be discerned: type A originated from material containing norstictic acid, stictic acid, norstictic acid in combination with stictic acid and on acid-deficient material; type B originated from material containing salazinic acid or salazinic acid in combination with protocetraric acid; and type C originated from material containing salazinic acid, protocetraric acid, salazinic acid in combination with protocetraric acid or on acid-deficient material. Material of banding type A belonged morphologically to R. cuspidata (Ach.) Nyl. and material of banding types B and C to R. siliquosa (Hudson) A. L. Smith. Seasonal and developmental factors can, however, affect the production of both primary and secondary constituents. Since there are no obvious morphological differences between the different chemical races within R. siliquosa s. str. and as material of salazinic acid in combination with protocetraric acid yielded both type B and type C banding patterns, the results do not support a taxonomy in the R. siliquosa group recognizing more than two species.