Lamproderma aff. ovoideum

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 : 195

Lamproderma aff. ovoideum Fig. 16

Sporocarps in loose groups, stipitate, total height 2.34–3.20 mm ( Figs 16A–B ). Sporotheca ovoid, higher than wide, base obtuse, broadly conical or slightly decurrent on the stalk, 1.30–1.84 mm high, 1.04–1.5 mm diam, with numerous, blue, violet and green colour reflections, brownish at base ( Figs 16A–B ). Hypothallus well-developed, red-brown, continuous and connecting many sporocarps. Stalk 1/3 to 4/9 of the total sporocarp height, 0.80–1.40 mm long, black ( Figs 16A–B ). Peridium persistent, thin, thicker only at the base, dehiscing irregularly in large patches, with persistent colour reflections when spores are blown out ( Fig. 16B ), hyaline and smooth in upper part of sporotheca in transmitted light, pale brown at the base of sporotheca. Columella reaching about one-half of the sporotheca height, cylindrical or tapering upwards ( Fig. 16C ), often with membranous expansions at apex. Capillitium originating from the greater part of the columella, dense, rigid, brown with white extremities when spores are blown out, rusty brown, dark brown with hyaline extremities in transmitted light, with many anastomoses and many pointed ends ( Figs 16B–C ). Spores in mass dark brown, blackish brown, moderately brown in transmitted light, slightly paler on one side, globose 11.5–13 μm in total range, 12.11 ±0.4 μm on average ±SD (n = 60), covered with low warts ( Figs 16D–E ), baculate by SEM, baculae less than 1 μm high, cylindrical ( Figs 16F–G ).

Material examined:— USA. Tehama Co.: 3 miles W of Child’s Meadows, 5200 ft., on dead twigs and duff, 20 May 1967, DTK 6237 (as L. carestiae, UC 1408244!); Well’s Cabin Campground, 6300 ft., on dead twigs, 24 June 1967, DTK 6361 (as L. carestiae, UC 1408246!).

Notes:—The two examined specimens seem to be intermediate between L. ovoideum and L. ovoideoechinulatum var. microsporum Mar. Mey. & Poulain. They differ from the first by smaller spores and by blue, violet and green reflections dominating in the peridium, that are persisting in detached parts of the peridium. From the latter they differ by less delicate capillitium and spore ornamentation that is in the form of warts, not spines. This morphotype has also larger dimensions of sporocarps (total heigth) and longer stalk than the two other species. More material is needed to unequivocally identify these two collections.

Figures

FIGURE 16. Lamproderma aff. ovoideum Meyl. A. Sporocarps (note ovoid shape of sporotheca and numerous colour reflections). B. Open sporocarp (note brown capillitium). 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–B, F–G: coll. DTK 6361, C–E: coll. DTK 6237.