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 Siemaszkoa I.I.Tav. & T.Majewski MB#5028 Mycotaxon 3: 202 ( Tavares & Majewski 1976 ). – Type species: S. flexa (T.Majewski) I.I.Tav. & T.Majewski Brief description Monoecious. Receptacle uniseriate, unbranched, consisting of three or more superposed cells supporting cell VI and the perithecium. Antheridia are sessile, short phialides, on appendages. Remarks The genus consists of seven species, of which six in Europe, four in Denmark . The most recently described species are S. ramificans and S. valida ( Majewski 1991 ) . All the species have diminutive thalli and occur on Ptiliidae beetles. In the species descriptions, when we describe the receptacle, it refers to cells from foot to the cell subtending cell VI; this is because the primary septum cannot be identified with certainty. Key to the Danish species (partially following Majewski 1994b ) 1. The perithecium is a continuation of the receptacle axis.................................................................. 2 – The perithecium is lateral to the axis which is formed by the receptacle and the appendage. Perithecium narrowly elongate. Round black spot on the foot ............................... S. ptenidii (Scheloske) I.I.Tav. 2. Appendage unbranched, strongly bent backward in mature thalli; bearing broad sessile antheridia near its base.......................................................................................... S. flexa (T.Majewski) I.I.Tav. – Appendage branched or, if unbranched, antheridia are the cells of appendage axis themselves which bear lateral short efferent necks ........................................................................................................ 3 3. Appendage directed upwards, unbranched or sparsely branched. Perithecium ovate......................... ............................................................................................................................... S. fennica Huldén – Appendage branched and directed backwards in mature thalli. Antheridia flask-shaped, borne on the appendage branches. Lower cells of appendage variably inflated and with strongly constricted septa ........................................................................................................... S. ramificans T.Majewski