Critical revision of Physarales and Reticulariales (Myxomycetes) at the Natural History Museum London (BM) Author Moreno, G. 0000-0002-9303-7181 Departamento de Ciencias de la Vida (Botánica), Universidad de Alcalá, 28805 Alcalá de Henares, Madrid. Spain gabriel.moreno@uah.es Author Castillo, A. 0000-0001-6308-5556 Departamento de Ciencias de la Vida (Botánica), Universidad de Alcalá, 28805 Alcalá de Henares, Madrid. Spain aurelio.castillo@uah.es Author Thüs, H. 0000-0002-8697-4572 Current Address: State Museum of Natural History Stuttgart, Germany & The Natural History Museum, London, United Kingdom holger.thues@smns-bw.de text Phytotaxa 2024 2024-04-11 644 2 79 101 http://dx.doi.org/10.11646/phytotaxa.644.2.1 journal article 10.11646/phytotaxa.644.2.1 1179-3163 13214565 Reticularia jurana Meyl. (1908: 297) Material studied:— NETHERLANDS . Doorwerth , beech branch fallen, 13 Feb 1960 , N.E. Nannenga-Bremekamp , box B.M. 4079 [ BM001247526 ], + one slide, s.n. [ BM001247536 ]. IRELAND . W. Galmay, Co. Galway , 5 Sept 1905 , C. Torrend , B.M. 2822 [ BM001247526 ] . The specimen B.M. 4079 was collected and determined by Nannenga-Bremekamp as Reticularia jurana as noted on the herbarium label. However, specimen B.M. 2822, originally determined as R. lycoperdon was corrected by Nannnenga-Bremekamp in 1965 to R. jurana , as noted on the revision label. Reticularia jurana is characterised by an extensive pseudocapillitium varying from a network of thin filaments with irregular membranous expansions at the junctions to wider filaments with perforated plates. Although the original diagnosis describes the spores as 5–6, rarely 7 µm in diam., the specimens studied by us are somewhat larger (7.5 µm in diam.), in agreement with the observations of Kowalski (1975) . Additional data on its outer morphology and microscopic traits were added by Nannenga-Bremekamp (1958) .