Myxo on moss

Didymium species perhaps

Please help with identification

This tiny slime mould grew on moss cleared from an asphalt path. When fresh it is white, maturing to the appearance of Scleroderma citrinum. There is very little hypothallus , dark in colour. The peridium is a brown covered by flaky white calcium.

Photo 1

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Photo 2

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The stem is white, fluted and where it holds the sporocyst it is sunken in, umbilicate in the one specimen I can see well. HCl shows it to be packed with calcium.

The capillitium is a fine mesh of glassy threads with occasional nodes. Small crystalline lumps and crystals are scattered about.

Photo 3

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Photo 4

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The spores are black en masse and brown in water with tiny warts, size 8.5-9.6 μm

Photo 5

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Photo 6

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I have tried to key this out in Ing and in Poulain et al. I think it is a species of Didymium on the basis of capillitium form and scattered calcium knobs and crystals but I just cannot id to species.