Arcyria imperialis (G. Lister) Q. Wang & Yu Li, 2006

Moreno, G., Castillo, A. & Thüs, H., 2022, Critical revision of Trichiales (Myxomycetes) at the Natural History Museum London (BM), Phytotaxa 567 (1), pp. 1-20 : 2

Arcyria imperialis (G. Lister) Q. Wang & Yu Li (Fig. 1)

Lectotype box B.M. 4067 [ BM001085195 ]: sporocarps clustered and shortly stalked (rarely sessile). Sporotheca cylindrical, sloping, up to 0.1 mm height, pale coppery in colour, changing to yellowish brown when ripe. Stalk black, 0.1–0.2 mm long. Capillitium separated from the peridium, yellowish reddish, threads branched and anastomosing, 4–6 µm diam., ornamented with 2–3 spirals bands and spines on edges of the spirals. Under the SEM the capillitium shows spines that bend easily on the edges of the spirals bands, with variable length and density, reaching up to 1 µm in length. Spores globose, 6.3‒7.5 × 6.3‒7.5 µm, av. 6.9 × 6.9 µm, Qav = 1 (n = 25), pale to yellowish in mass, hyaline to slightly yellowish and smooth to slightly warty by LM. Under the SEM, spore ornamentation is formed by short and regulary distributed baculae 0.1–0.15 µm in length, of the baculate type in the sense of Rammeloo (1974). Among a majority of smaller warts larger warts are scattered that are also visible by LM. Examination by SEM reveals that they are made up of 2–5 baculae joined to form a larger wart (0.2–0.3 µm).

Syntypus, box B.M. 4068 [ BM001085196 ]: This sample has been obtained from a culture from spores of the type, and it is better preserved than the lectotype. It consists of numerous sporocarps and the morphological and microscopic characters of this species are more uniformly developed compared to the lectotype specimen .