Laboulbeniomycetes (Fungi, Ascomycota) of Denmark Author Santamaria, Sergi Unitat de Botànica, Departament de Biologia Animal, de Biologia Vegetal i d’Ecologia, Facultat de Biociències, Universitat Autònoma de Barcelona, 08193 Cerdanyola del Vallès (Barcelona), Spain. sergi.santamaria@uab.cat Author Pedersen, Jan Natural History Museum of Denmark (Zoological Museum), University of Copenhagen, Universitetsparken 15, 2100 København Ø, Denmark. japedersen@snm.ku.dk text European Journal of Taxonomy 2021 2021-11-26 781 1 425 http://dx.doi.org/10.5852/ejt.2021.781.1583 journal article 10.5852/ejt.2021.781.1583 2118-9773 5828924 Genus Coreomyces Thaxt. MB#1243 Proceedings of the American Academy of Arts and Sciences 38: 56 ( Thaxter 1902 ) . – Type species: C. corixae Thaxt. Paracoreomyces R.A.Poisson, Compte rendu hebdomadaire des Sciences de l’Académie des sciences , Paris 188: 826 ( Poisson 1929 ) [MB#3697] Brief description Monoecious. Receptacle consisting of a series of superposed cells, with a three-celled lower receptacle (cells I, II and III), some flattened cells above (known as the appendiculate cells; Fig. 4G , ac) giving rise to lateral slender branchlets including intercalary antheridia. Perithecium solitary, found on the top of the receptacle. Primary appendage vanishing with perithecium development. Remarks The genus consists of 20 described species, of which five in Europe, three in Denmark . The most recently described species is C. javanicus ( Lee & Na 2009 ) . This genus has recently been the subject of a Ph.D. dissertation (Sundberg 2018) and two papers generated from it ( Sundberg et al. 2018a , 2018b ) where, with the help of molecular techniques, the reliability of some European species, like those included here, has been demonstrated. Sundberg (2018) mentioned and named two more species which have not yet been formally or validly described at the moment this work was written. Key to the Danish species (partially following Majewski 1994b and Santamaria 2003 ) 1. Cells III and VI flattened to isodiametric. Thalli growing on abdominal sternites.............................. ................................................................................................................................ C. corixae Thaxt. – Cells III and VI longer than broad.................................................................................................... 2 2. Thalli growing on inferior margin of hemielytra. Perithecium symmetric......... C. macropus Thaxt. – Thalli growing on abdominal sternites, in middle part of 5 th segment. Perithecium asymmetric ....... .............................................................................................................................. C. arcuatus Thaxt.