Stemonitis planusis B. Zhang & Yu Li, 2017

Bo, Zhang & Yu, Li, 2017, A new Stemonitis species and a new record of Elaeomyxa from China, Phytotaxa 323 (1), pp. 83-87 : 84-86

Stemonitis planusis B. Zhang & Yu Li , sp. nov. Figs 1 , 2

Mycobank: MB 819533

Sporocarps in dense tufts, slender, cylindrical, stalked, 10–13 mm in total height. Sporocysts 8–10 mm long and 0.5–0.7 mm in diam., usually plane at the apex of the sporotheca, brown to dark brown. Hypothallus membranous, transparent. Stalk black, polished, 2–4 mm long. Peridium early fugacious. Columella a continuation of the stalk in the sporocarps, attenuate upwards, dissipating into the capillitium near the apex. Capillitium forming a very lax, tubular net around the columella and below the periphery, surface net irregular, 60–300 μm in diam., many expansions in the axils of the surface net capillitium. Spores mass dark brown, 9–10 μm in diam., densely and minutely warted, brown in transmitted light.

HOLOTYPE. CHINA, Shennongjia National Nature Reserve, Shiyan City , Hubei Province, on the bark surface of a dead log, 16 September 2013, Zhang Bo 2016120103 (Holotype, HMJAU11323 ).

Etymology: — planusis (Latin) , referring to the plane at the end of sporocarps.

Distribution: — Currently known only from the type locality, Shennongjia National Nature Reserve, Hebei Province, China.

Comments: Stemonitis Gled. has been reported to contain 18 species, of which S. flavogenita E. Jahn ( Jahn 1904), S. capillitionodosa G. Moreno, D. W. Mitch. (Moreno et al. 2010), and S. sichuanensis B. Zhang & Yu Li ( Zhang & Li 2016) are similar to S. planusis based on the inflated capillitial axils and bigger sporocarps. However, S. flavogenita has a membranous expansion at the top of the columella, its surface net is much smaller (usually less than 25 μm in diam.), and its spore is slightly smaller (7–9 μm in diam.). Stemonitis capillitionodosa is characterised by its sporocarps aggregates, short stalk, capillitium with large meshes and prominent nodes, a columella that is widened at the apex, and densely spinose spores (approximately 9–11 μm in diam.). Stemonitis sichuanensis has larger sporocarps (approximately 10–13 mm in total height), a columella usually ending in an ovoid to triangular expansion at the sporotheca apex, and smaller spores (approximately 6–7 μm in diam.). Stemonitis planusis , by comparison, has bigger sporocarps (approximately 10–13 mm total height) that usually ends in a plane at the apex of the sporotheca, expands in the axils of the capillitium, and has bigger spores (usually 9–10 μm in diam.).

Figures

FIGURE 1. Stemonitis planusis (Holotype). A. Sporocarps. B. Apex of the sporotheca, usually plane. C, Part of the sporotheca under transmitted light. D. Part of the capillitium and some spores. Bar=1 mm

FIGURE 2. Stemonitis planusis (Holotype). A. Part of the sporotheca. B. Part of the capillitia and columella. C. Expanded axils of the capillitia. D. Spore marked with some warts.