The lichen family Parmeliaceae in Poland. II. The genus Cetrelia

In a study of the genus Cetrelia in Poland, four taxa have been identified, two of which, C. chicitae and C. monachorum, are reported for the first time from the country. All taxa differ in chemistry and subtle morphological characters. Cetrelia monachorum is the commonest member of the genus in Poland (237 records), whereas C. chicitae is known only from 6 records. All taxa are endangered, and three, C. cetrarioides, C. chicitae and C. olivetorum, appear to be critically so, thus deserving the category CR; although C. monachorum is the most frequent, it is not common and should be treated as endangered (EN). The distribution of all taxa, their habitat requirements, as well as morphology and secondary chemistry, are discussed.