Physarum nivale (Meyl.) Mar. Mey. & Poulain, 2011

Baba, Hayri & Sevindik, Mustafa, 2022, Myxomycetes diversity in Adana Province (Turkey) with two new records, Phytotaxa 547 (1), pp. 31-42 : 39

Physarum nivale (Meyl.) Mar. Mey. & Poulain ( Fig. 4 ) (new record)

Description:— Fructification sporocarps and highly clustered short plasmodiocarps sessile, irregularly round, 0.7–1.5 mm, sometimes curved kidney-shaped, or rarely short plasmodiocarps, 1.5–3 mm long, worm-shaped, base usually clearly indented. Sporotheca subglobous, more or less deformed by pressure of the group. Hypothallus indistinct. Peridium quite variable, with distinct limestone and whitish, or sometimes irregular scale-like, easily detachable lime flakes, sometimes completely free of lime, then shiny metallic blue or grey and looking like a sedentary species of Lamproderma , simple, like a calcified layer and rough, something greyish white, translucent, shiny membrane, more or less densely covered with calcareous scales. Columela absent. Capillitium well developed, a clear physaroid network of larger, round or elongated calcareous nodes and colourless, calcareous threads, densely networked, sometimes completely without calcareous nodes if there is a lack of calcareous tissue, formed by nodules of white lime, large, angular, grouped, sometimes forming a pseudocolumella, nodes profuse, consisting of very small, tight granules. Spores in mass dark brown. Spores sometimes almost blackish in transmitted light brown to dark brown, on one side ± significantly lighter and with a thinner wall in the area of the germ pore, always round, sometimes with indistinct groups of darker ones, 9–11 µm, warty or spinous.

Specimen examined:— Adana, Karataş on debris, moist chamber, 36° 33’ N- 35° 23’ E, 16 m, 4 Nov. 2019, Baba 80 .

Distribution:— Germany.

Comments:— This species is similar to P. vernum but this usually has lighter spores that are evenly light brown in colour in transmitted light, plasmodiocarps and a rather reddish-brown mass of spores under magnification ( Kuhnt 2014). Poulain et al. (2011) separated this taxon from P. vernum by greyish colour of the peridium covered by scattered lime flakes, the darker spore mass, a well developed badhamioid capillitium with large, angular nodes densely stuffed with granules (0.5–2 μm in diam.) which are not very distinct in outline and the appearance of the spores which are darker but have a paler side and show a more regular ornamentation of warts ( Novozhilov et al. 2013). The main features are the occurrence in the nivicolous environment, more rounded sporocarps in outline, absence of extensive plasmodiocarps, very dark spore mass under the microscope and spores which are lighter on one side.

Figures

FIGURE 4. Physarum nivale a, b. Sporocarp. c. Physaroid capillitium and spores. d. Spores.