Lamproderma retirugisporum G. Moreno, H. Singer, C. Illana et A. Sánchez

Ronikier, Anna, 2022, Revision of the Donald T. Kowalski’s collections of Lamproderma (Myxomycetes, Amoebozoa) reveals twice higher species diversity, Phytotaxa 531 (3), pp. 175-210 : 197-199

Lamproderma retirugisporum G. Moreno, H. Singer, C. Illana et A. Sánchez , in Singer et al. (2003b: 14). Fig. 18

Sporocarps in groups, stipitate, total height 1.54–2.00 mm ( Fig. 18A ). Sporotheca globose or wider than high, 0.90– 1.00 mm high, 0.90–1.24 mm diam, ash grey, silvery grey, shining, but with few colour reflections, brownish at base ( Fig. 18A ). Hypothallus well developed, orange brown, continuous and connecting many sporocarps. Stalk about one-half of the total sporocarp height, 0.64–1.00 mm long, black, tapering upwards, sometimes with membranous hypothallus remnants in lower part ( Figs 18A–B ). Peridium persistent, dehiscing irregularly in large patches from apex, remaining at lower half of sporotheca, almost hyaline when spores are blown out, hyaline and smooth in upper part of sporotheca in transmitted light, pale orange and not evenly coloured at the base of the sporotheca. Columella reaching about one-half of the sporotheca height, cylindrical, often with membranous expansions at apex ( Fig. 18C ). Capillitium originating from the apical part of columella, not dense, not rigid, delicate, pale, orange when spores are blown out, tips white, orange with hyaline extremities in transmitted light, dichotomously branched, with few anastomoses in central part and more connections in peripheral part, with pointed ends ( Fig. 18C ). Spores dark ash grey in mass, grey brown in transmitted light, uniformly coloured and not very dark but appearing dark because of dense ornamentation, globose or broadly ovoid, (13)13.5–15.5(16) μm in total range, 14.57 ±0.6 μm on average ±SD (n = 60), covered with dense, complete reticulum, ( Figs 18D–E ), reticulum up to 2 μm high, regular, mostly without a perforated muri by SEM ( Figs 18F–G ).

Material examined:— USA. Olympic National Park, Hurricane Ridge, 5200 ft., on dead twig, 14 July 1967, DTK 7072 (as L. cribrarioides, UC 1408206!); on twigs, 25 June 1968, DTK 9446 (as L. cribrarioides, UC 1408202!).

Notes:—The name Lamproderma retirugisporum was proposed for L. cribrarioides after discovery that its type collection is a taxon with evanescent peridium, currently classified within the genus Meriderma ( M. cribrarioides ) ( Singer et al. 2003b), not a taxon with persistent peridium as interpreted by most authors ( Martin & Alexopoulos 1969, Neubert et al. 2000). Kowalski (1970a) interpreted L. cribrarioides as a species with evanescent peridium, in its original sense, but since he considered peridium differences not meaningful and based species identification mostly on spore characteristics he apparently was not able to distinguish the two taxons that have almost identical spores ( Figs 18D–G , 22D–G ). Examined Kowalski’s collections of L. cribrarioides are either L. retirugisporum or Meriderma cribrarioides (see below). Lamproderma retirugisporum is a cosmopolitan species ( Poulain et al. 2011).

Figures

FIGURE 18. Lamproderma retirugisporum G. Moreno, H. Singer, C.Illana etA. SánchezA. Sporocarps. B. Open sporocarp. C. Columella and capillitium in transmitted light (note few anastomoses). D. Spores in transmitted light (edge view). E. Spores in transmitted light (top view). F. Spore by SEM. G. Details of spore ornamentation by SEM. Bars: A–B = 1 mm, C = 500 μm, D–F = 10 μm, G = 3 μm. A–G: coll. DTK 7072.

FIGURE 22. Meriderma cribrarioides (Fr.) Mar. Mey. et Poulain A. Sporocarps. B. Open sporocarp. C. Funnel-shaped capillitium tip in transmitted light. D. Spores in transmitted light (edge view). E. Spores in transmitted light (top view). F.Spore by SEM.G. Details of spore ornamentation by SEM. Bars:A–B = 1 mm, C–F = 10 μm, G = 3 μm. A, C–G: coll. DTK 8285, B: coll. DTK 9077.