Didymium squamulosum (Alb. & Schwein.) Fr.

Didymium squamulosum  (Alb. & Schwein.) Fr.

Saturday, 2 February 2019

One of the commonest slime moulds, and perhaps also one of the most variable,  Didymium squamulosum can occur in the form of sessile or stalked sporangia, plasmodiocarps, or a combination of them all in a single collection. The peridial lime may take the form of a powdery crust of stellate crystals, or of a smooth plicate (folded) layer.

This collection was found on leaf litter and woody débris in a hedge bank in Blakeney, Gloucestershire on 28th January 2019.

Sporangiate  D. Squamulosum  with loose, powdery lime layer.

Sessile and stalked sporangia with plicate lime layer.

Sporocarps sessile or short stalked sporangia, the stalks white, furrowed, supported on small white, circular hypothalli. Stalks, when present, up to 0.4 mm tall by 0.1 mm  ∅ . Columella white, domed, filled with lime. Sporangia apparently spherical or pulvinate but actually deeply umbilicate below; to 0.8 mm  ∅.  Peridium encrusted with stellate lime crystals, either as a loose powdery layer, or as smooth folded plates. In the absence of lime the peridium may appear transparent or faintly iridescent.

D. Squamulosum  spores, capillitium and lime. crystals.

D. Squamulosum spores and lime crystals.

Capillitium consisting of fine dark or hyaline threads, usually straight but sometimes with occasional spiral twists, with occasional swellings. Spore mass brown, spores grey-brown by transmitted light, finely warted, with a line around the spore like an equator, making them reminiscent of the planet Jupiter. 8 - 11µm  ∅.