Dictyomeridium
Dictyomeridium is a genus of corticolous (bark-dwelling), crustose lichens in the family Trypetheliaceae. It has eight species. Taxonomy
The genus was circumscribed in 2016 by lichenologists André Aptroot, Matthew Nelson, and Robert Lücking, with Dictyomeridium proponens assigned as the type species. The seven species they included in the genus were mostly previously classified in the genus Polymeridium, while the type species was known by different names in the genus Campylothelium. Phylogenetic analysis showed that the group of species was distant from the core group of their previous genus. An eight species, from Australia, was added to the genus in 2022. Description
Dictyomeridium is distinguished from other genera in the family Trypetheliaceae  by its  (multichambered) ascospores, the lateral ostioles of its ascomata, and several subtle microscopic differences in the form of the  and the ascospores. Dictyomeridium species are distinguished from each other by their reaction to the , the dimensions of their spores, and by the presence or absence of a red pigment in their ostioles. All species lack a , and have conical to  ascomata with eccentric (i.e., not placed centrally) ostioles. Sometimes,  are present. Species
 Dictyomeridium amylosporum  – pantropical
 Dictyomeridium campylothelioides  – Asia
 Dictyomeridium immersum  – Brazil
 Dictyomeridium isohypocrellinum  – Brazil
 Dictyomeridium lueckingii  – Bolivia
 Dictyomeridium paraproponens  – Brazil
 Dictyomeridium proponens  – pantropical
 Dictyomeridium tasmanicum  – Tasmania, Australia

References

Trypetheliaceae
Dothideomycetes genera
Lichen genera
Taxa described in 2016
Taxa named by André Aptroot
Taxa named by Robert Lücking