Circinaria tominii (Megasporaceae, lichenized Ascomycota) is represented by two different growth forms.

Molecular study of Circinaria specimens collected in arid habitats of the Chuya Steppe showed the existence of two different growth forms, crustose and vagrant, in C. tominii that implies a more complex lifecycle of the species compared to that postulated by Mereschkowsky for vagrant taxa. An ITS phylogeny revealed the position of Circinaria tominii relative to three vagrant species, C. alpicola, C. aschabadensis and C. jussufii. Circinaria tominii was first collected in 1926 and was rediscovered in its type locality 90 years later in the only habitat near Ortolyk settlement in the Republic of Altai (Russia). The species is found on soil in stony habitats of the Chuya Steppe. The estimated abundance of the species reaches several hundred specimens. [ABSTRACT FROM AUTHOR]