Abstract Blue-flowering genotypes of Campanula were classified into four phenotypes on the basis of the anthocyanin composition of their flowers. The flowers contained one, two, three or four of the following anthocyanins: bisdeacylplatyconin (7- O-(β- d-glueopyranosyl)-3- O-(6- O-α- l-rhamnopyranosyl-β- d-glucopyranosyl)delphinidin), violdelphin (7- O-(6- O-(4- O-(6- O-(4-hydroxybenzoyl)- β- d-glucopyranosyl)-oxybenzoyl)-β- d-glucopyranosyl)-3- O-(6- O-α- l-rhamnopyranosyl- β- d-glueopyranosyl)delphinidin), an unknown anthocyanin and campanin (7- O-(6- O-(4- O- (6- O-(4- O-(6- O- p-hydroxybenzoyl-β- d-gluCopyranosyl)oxybenzoyl)-β- d-glucopyranosyl) oxybenzoyl)-β- d-glucopyr-anosyl)-3- O-(6- O-(α- l-rhamnopyranosyl)-β- d-glucopyranosyl) delphinidin). The structure of the unknown anthocyanin has been determined as -7- O-(6- O-(4- O-(6- O-(4- O-(β- d-glucopyranosyl)oxybenZoyl)-β- d-gluc-opyranosyl)oxybenzoyl) -β- d-glucopyranosyl)- 3- O-(6- O-(α- l-rhamnopyranosyl)-β- d- glucopyranosyl)-delphinidin, i.e. monodeacyl-campanin. The genetic evidence is consistent with a biosynthetic pathway in which bisdeacylplatyconin, violdelphin and rnonodeacylcampanin are intermediates in the biosynthesis of campanin.