Analysis of lichen secondary chemistry doubled the number of Cetrelia W. L. Culb. & C. F. Culb. species (Parmeliaceae, lichenised Ascomycota) in Hungary Author Farkas, Edit Author Biró, Bernadett Author Varga, Nóra Institute of Ecology and Botany, Centre for Ecological Research, H- 2163 Vácrátót, Alkotmány u. 2 - 4 (Hungary) farkas. edit @ ecolres. hu (corresponding author) edit@ecolres.hu Author Sinigla, Mónika Bakony Museum of the Hungarian Natural History Museum, H- 8420 Zirc, Rákóczi tér 3 - 5 (Hungary) Author Lőkös, László Department of Botany, Hungarian Natural History Museum, H- 1431 Budapest, Pf. 137 (Hungary) text Cryptogamie, Mycologie 2021 2021-02-02 20 1 1 16 http://dx.doi.org/10.5252/cryptogamie-mycologie2021v42a1 journal article 249256 10.5252/cryptogamie-mycologie2021v42a1 022e0c1a-dfb8-44be-91df-d179184fc267 1776-100X 7815130 Cetrelia monachorum (Zahlbr.) W.L. Culb. & C.F. Culb. ( Figs 2 ; 5C ; 9 ; 12 ) It was not known before this revision as it was repeatedly misidentified before as either C. cetrarioides or C. olivetorum . It now turns out to be the most frequent Cetrelia species in Hungary ( Fig. 9 ). The presence of atranorin, imbricaric acid (major) ± perlatolic acid (minor), anziaic acid and 4-O-demethylimbricaric acid is characteristic. Cetrelia sayanensis Otnyukova, Stepanov & Elix ( Otnyukova et al. 2009 ) , a closely related species, has a slightly different chemical composition containing atranorin (minor), imbricaric acid (major), perlatolic acid (minor), divaricatic acid (minor)], anziaic acid (minor), 4-O-demethylimbricaric acid (minor), glomelliferic acid (trace) and loxodellic acid (trace). However, it has pustulate-capitate soralia with farinose soredia, while C. monachorum has only seldom laminal, capitate soralia and is further characterised by coarse soredia, 52.7± 5.6 µm in Hungarian samples [vs (35)40-55 µm diam. in Obermayer & Mayrhofer (2007) ], small (50-150 µm), raised pseudocyphellae on upper cortex, but very rare or lacking on lower cortex. Cetrelia monachorum is most frequently collected from rocks (70%), but also grows on Quercus (14%), Fagus (6%), Carpinus (2%), Acer pseudoplatanus L. (1%) and on unidentified bark (7%) between 100-1000 m a.s.l. reaching the highest possible elevation in Hungary (Mátra Mts). The species is proposed for the category near threatened (NT) in Hungary .