Calomyxa metallica (Bek.) Nieuw.

Calomyxa metallica  (Bek.) Nieuw.

Tuesday, 19 March 2019

A sample of spruce bark was collected from Oldcroft Plantation on 23rd January 2019, and incubated in moist chamber. In March, small sporangia began to appear, attracting attention by their bronze or coppery iridescence. 

Calomyxa metallica immature sporangia.

Calomyxa metallica mature sporangia.

Sporocarps small scattered sporangia up to 1.0 mm Ø, subspherical or slightly elongated, to 1.5 mm long, sessile or very short stalked. Peridium thin, iridescent with a coppery or brassy metallic sheen. 

Calomyxa capillitium x 100

Calomyxa  capillitial swellings.

Columella absent. Capillitium abundant, of long, thin, dull yellowish threads up to 1µm Ø, flexuous and coiled, minutely spinulose, unbranched and unattached, but with occasional swellings reaching 0.2 µm Ø. 

Spores in mass dull olivaceous, very pale in transmitted light, minutely warted, 9-10 µm Ø.

Plasmodium not observed, hypothallus inconspicuous.

Calomyxa metallica is widespread and not uncommon, though this is the first example that I have found. It occurs in litter and on the bark, mainly of broadleaved trees. 

Calomyxa spores x 1000