Acolium (Ach.) Gray, Nat. Arr. Brit. Pl. I: 482 (1821)
Index Fungorum number: IF43;
Acolium was resurrected by Prieto & Wedin (2017), and comprises both lichenized and lichenicolous taxa. The species grow on wood or bark and are characterized by a dark excipulum, greyish-brown thallus (or are lichenicolous and do not form an independent thallus), sessile to somewhat immersed ascomata and sometimes grey pruina present on the rim of the excipulum. The species were formally affiliated in Cyphelium and presently comprise five species with the type Calicium tympanellum (lectotype, designated by) (= Acolium inquinans). Acolium sessile and A. marcianum are lichenicolous on species of Pertusaria sensu lato, while Acolium chloroconium, A. inquinans, A. karelicum and A. marcianum are recorded as lichenized taxa (Prieto & Wedin 2017).
Phylogram generated using maximum likelihood analysis based on combined LSU, ITS and β-TUB sequence data. Fifty two strains are included in the combined analyses which comprised 2124 characters (819 characters for LSU, 584 characters for ITS, 721 characters for β-TUB) after alignment. Tree topology of the maximum likelihood analysis is similar to the Bayesian analysis. The best RaxML tree with a final likelihood value of -17812.590222 is presented. Estimated base frequencies were as follows: A = 0.229337, C = 0.261337, G = 0.276938, T = 0.232388; substitution rates AC = 1.720213, AG = 3.344718, AT = 1.750478, CG = 1.168734, CT = 8.621223, GT = 1.000000; gamma distribution shape parameter a = 0.478984. Bootstrap support values for ML greater than 75% and Bayesian posterior probabilities greater than 0.95 are given near nodes respectively. The tree is rooted with Physcia aipolia (Wedin 6145 UPS and Odelvik & Hellstrm 0827 S). Ex-type strains are in bold and black. The newly generated sequences are indicated in yellow.