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 Hemitrichia intorta (Lister) Lister (Fig. 3) Syntype box B.M. 1483 [ BM001088829 ]: the sample consists of seven pieces of bark in which isolated sporocarps are found and most are broken. Sporocarps sessile or with a short stalk, 1–1.5 mm high, sporotheca spherical to clavate, 0.3–0.7 mm diam., yellow-ochreous in colour. Stalk shorter than diameter of the sporotheca. Peridium thin and membranous, with small papillae on the inside, dehiscence irregular. Capillitium formed by slightly branched yellowish filaments of 4–5 µm diam., free ends absent. Filaments with 2–3 tight spiral bands covered in small and abundant spines (very evident in phase contrast). The spirals are connected by longitudinal striae. Under the SEM the spiral bands show abundant obtuse apex spines or scattered teeth in the spirals; the abundant longitudinal striae are confirmed. Hypothallus dark discoid. Spores are globose to subglobose, 7.8‒9.9(‒10) × (8‒)8.2‒10 µm, av. 9.1 × 8.8 µm, Qav = 1.04 (n = 25), pale to pale yellowish in LM, warty, with marked and tight warts. Under the SEM , the ornamentation is of verrucate type, the verrucae are abundant and of irregular distribution .