Diacheopsis kowalskii Meyer & Poulain (1998: 29)

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 : 178-179

Diacheopsis kowalskii Meyer & Poulain (1998: 29) . Fig. 3

Elongated sporocarps or short plasmodiocarps in groups, sessile on a broad base, 0.96–3.10 × 0.84–1.84 mm, about 1 mm high, black, shining, without or almost without colour reflections, covered with needle-like crystals ( Fig. 3A ). Hypothallus thin, delicate, shining or inconspicuous. Stalk absent. Peridium persistent, attached to capillitium, hyaline and transparent when spores are blown out, pale brownish to almost hyaline in transmitted light, surface appearing smooth or slightly roughened by brown pigment, and then pigmented area cracked into patches. Columella absent. Capillitium not very dense, white when spores are blown out, reticulate, flattened, threads 2–6 μm wide, forming a complete net with widened junctions and no free ends, ends attached to peridium, bi-coloured in transmitted light, hyaline with brown stripes from brown, rough pigment ( Figs 3B–C ). Spores black in mass, moderately dark brown in transmitted light, slightly paler at one side, globose, (13.5)14–16(16.5) μm in total range, 15.12 ±0.6 μm on average ±SD (n = 30), covered with irregularly distributed, isolated spines about 1 μm high ( Figs 3D–E ), spines slender and either pointed or divided into several finger-like outgrowths by SEM ( Figs 3F–G ).

Material examined:— USA. Crater Lake National Park, Park Headquarters, 6400 ft., on dead bark, 6 July 1967, DTK 6794, (as L. sauteri, UC 1408201!); Mt. Rainer National Park, 4 miles S of Cayuse Pass, 3500 ft., 9 June 1968, DTK 8356, (as L. sauteri, UC 1408280!).

Notes:—Examined specimens of Diacheopsis kowalskii are typical in respect to all characteristic features ( Meyer & Poulain 1998): bi-coloured reticulate capillitium composed of flattened threads, peridium surface covered with needle-like crystals, and spiny spores. Spores of examined specimens are covered with slender spines ( Figs 3F–G ) and they are very similar to the spores of Lamproderma sauteri ( Figs 19F–G ). Apparently Kowalski (1970a) identified these collections (as L. sauteri ) based mainly on spore ornamentation (see the chapter Discussion). Diacheopsis kowalskii is known from North America and Europe ( Poulain et al. 2011).

Figures

FIGURE 3. Diacheopsis kowalskii Mar. Mey. & Poulain. A. Sporocarps (note bronze colours and needle-like crystals). B. Bi-coloured capillitium in transmitted light. C. Capillitium by SEM (note flattened elements forming reticulum). 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 = 1 mm, B–C = 50 μm, D–F = 10 μm, G = 3 μm.A: coll. DTK 6794, B–G: coll. DTK 8356.

FIGURE 19. Lamproderma sauteri var. atrogriseum Meyl.A. Sporocarps. B. Open sporocarp. C. Columella and capillitium 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 = 500 μm, D–F = 10 μm, G = 3 μm. A, C: coll. DTK 7073, B, F–G: coll. DTK 7116, D–E: coll. DTK 7145.