Stemonitis sichuanensis B. Zhang & Yu Li, 2016

Bo, Zhang & Yu, Li, 2016, A new species, Stemonitis sichuanensis, and a newly recorded species, Stemonitis marjana (Myxogastria) from China, Phytotaxa 258 (2), pp. 195-199 : 196-197

Stemonitis sichuanensis B. Zhang & Yu Li , sp. nov. figure 1

Mycobank: MB812760

Description:—Sporocarps in tufts, stalked, 10–13 mm total height, dark brown, cylindrical. Stalk black, polished, 1.5–3 mm long, about 1/8–1/6 of total height. Sporotheca cylindrical, rounded at the apex and base, dark brown. Peridium fugaceous. Columella usually ending in an ovoid to triangular expansion at the apex of the sporotheca. Internal net of the capillitium consisting of rather thick threads with many, usually large, expansions at the junctions, surface net with angular meshes, these mostly exceeding 50 μm, usually thin threads without free ends. Spores reddish brown in mass, 6–7 μm in diam., densely, evenly, minutely warted.

HOLOTYPE. CHINA, Gexigou National Natural Reserve , Sichuan province, on the bark surface of a dead log, 24 July 2013, Zhang Bo 2013051309 (Holotype, HMJAU10426 ).

Etymology:— sichuanensis (Latin) , referring to collection from Sichuan province.

Distribution:—Currently known only from the type locality, Gexigou National Natural Reserve, Sichuan Province in China.

Comments: The genus Stemonitis Gled. has been reported to contain 17 species, of which 5 species have spores with a small–meshed reticulation consisting of spinules connected by ridges. Another 12 species have spinulose or warted spores. Among these 12 species, only S. flavogenita E. Jahn and S. capillitionodosa G. Moreno, D. W. Mitch. ( Moreno et al. 2010) are similar to S. sichuanensis in having a columella with an expanded apex, but S. flavogenita has a columella usually ending in a membranous expansion just below the apex, and its spores are very densely, minutely warted, and smaller (about 7–9 μm in diam.). Stemonitis capillitionodosa is characterized by its aggregates of sporocarps, short stalk, capillitium with large meshes and prominent nodes, a columella that is widened at the apex, and densely spinose spores (about 9–11 μm in diam.). Stemonitis sichuanensis , by comparison, has larger sporocarps (about 10–13 mm in total height), a columella usually ending in an ovoid to triangular expansion at the apex of the sporotheca, and smaller spores (about 6–7 μm in diam.).

Figures

FIGURE 1. Stemonitis sichuanensis (Holotype): A. The fruiting bodies growing on decaying logs. B. Capillitium and columella by SEM. C. Columella ending in an ovoid to triangular expansion at the apex of the sporotheca by SEM. D. Part of capillitium and columella by transmitted light. E. Part of capillitium at the top of sporotheca, with a ovoid to triangular expansion at the apex by transmitted light. F. Spores marked with warts as viewed by SEM.