Arctomiaceae
Arthrorhaphidaceae
Baeomycetaceae
Cameroniaceae
Hymeneliaceae
Protothelenellaceae
Trapeliaceae
Xylographaceae
The Baeomycetales are an order of mostly lichen-forming fungi in the subclass Ostropomycetidae, in the class Lecanoromycetes. It contains 8 families, 33 genera and about 170 species.[1] As a result of molecular phylogenetics research published in the late 2010s, several orders were folded into the Baeomycetales, resulting in a substantial increase in the number of taxa.
The family Baeomycetaceae was originally proposed by Barthélemy Charles Joseph Dumortier in 1829 (under the spelling Baeomyceae); he included two genera, Baeomyces and Calicium.[2] Baeomycetaceae was initially classified in the Lecanorales,[3][4] and Baeomycetaceae and Cladoniaceae were thought to be closely related, sharing a phylogenetic origin in Lecideaceae.[5] It was transferred to the order Helotiales based on the structure of its ascus, which is similar to those in genus Leotia.[6] However, the Helotiales consists of mostly non-lichenised fungi. The first DNA studies conducted with Baeomyces species did not suggest any phylogenetic relatedness with Leotia.[7][8] Later studies demonstrated a sister group relationship between Baeomyces and the order Ostropales, and Baeomycetales was informally suggested as a suitable name for this lineage.[9]
After additional molecular studies confirmed the placement of the Baeomycetaceae in the subclass Ostropomycetidae,[10][11] the order Baeomycetales was formally circumscribed in 2007 by H. Thorsten Lumbsch, Sabine Huhndorf, and Francois Lutzoni. They suggested that Ainoa, Baeomyces, and Phyllobaeis were exemplar genera in the order.[12] The composition of the Baeomycetales has been amended several times since its original circumscription, as molecular phylogenetic analyses have helped to resolve the phylogenetic relationships amongst its members. In 2011, the order was considered to contain two families, Baeomycetaceae and Anamylopsoraceae.[13] The latter family, proposed by Lumbsch and Thomas Lunke in 1995,[14] was later shown with molecular phylogenetics to nest within the Baeomycetaceae,[15] and is now placed in synonymy with that family.[16]
In 2018, the class Lecanoromycetes was revised using a temporal approach that uses time-calibrated chronograms to define temporal bands for comparable ranks for orders and families. In this work, the orders Arctomiales, Hymeneliales, and Trapeliales were synonymized with Baeomycetales.[17] In a later review of the use of this method for biological classification of lichens, Robert Lücking considered this merge justified.[18] This synonymy was also accepted in a 2020 review of fungal classification.[1]
According to a 2020 review on fungal classification, the Baeomycetales contain 8 families and 33 genera. The following list give the families, their taxon authority and year of publication, a brief synopsis of some major characteristics of the family, the genera in each family, and estimated number of species in each genus.[1]