Critical revision of Trichiales (Myxomycetes) at the Natural History Museum London (BM) Author Moreno, G. 0000-0002-9303-7181 Departamento de Ciencias de la Vida (Botánica), Facultad de Ciencias, Universidad de Alcalá, 28805 Alcalá de Henares, Madrid, Spain. & gabriel. moreno @ uah. es; https: // orcid. org / 0000 - 0002 - 9303 - 7181 gabriel.moreno@uah.es Author Castillo, A. 0000-0001-6308-5556 Departamento de Ciencias de la Vida (Botánica), Facultad de Ciencias, Universidad de Alcalá, 28805 Alcalá de Henares, Madrid, Spain. & aurelio. castillo @ uah. es; https: // orcid. org / 0000 - 0001 - 6308 - 5556 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; https: // orcid. org / 0000 - 0002 - 8697 - 4572 holger.thues@smns-bw.de text Phytotaxa 2022 2022-09-30 567 1 1 20 http://dx.doi.org/10.11646/phytotaxa.567.1.1 journal article 156928 10.11646/phytotaxa.567.1.1 6c552cda-d3de-41c2-8fbc-fb52d98d138d 1179-3163 7137881 Trichia munda (Lister) Meylan (1927: 327) ≡ Trichia botrytis var. munda Lister (1897: 216) Syntype :— UNITED KINGDOM . England : Essex , Epping Forest , Drift Way , 51.66ºN 0.05ºE , on hornbeam leaves, 29 Nov 1896 , A.G. Phear , B.M. 2942, [ BM001089762 = box, BM001089171 = slide] ( BM !), as Trichia botrytis var. munda . Trichia munda is a rare and little quoted species, which was considered as a variety of Trichia botrytis (J. F. Gmel.) Pers. by some authors such as Lister (1897) . Meylan (1927) considered it as a separate species from T. botrytis . Among other reasons he pointed out that T. munda fructifies from a white plasmodium and not purple-brown as T. botrytis . We agree with the separation of both taxa. Trichia munda shows fructifications isolated and with smaller sporocarps ( 1–1.5 mm in total height), a minute sporotheca, slender stalk (2–2.5 times the diam. of the sporotheca) and strongly ornamented spores. The spore ornamentation under SEM presents very differentiated “pila” in which the head is densely mamiliferous, very similar to the spore ornamentation of Metatrichia floripara ( Rammeloo 1981 ) .