DWM 3143, 3175.

Fruiting body a sessile sporangium, scattered, discoid, 0.5–0.7 mm in diameter, or sometimes forming expanding and lobed, flattened plasmodiocarps 1–3 mm in diameter. Stalk, when present, very short, dark brown. Hypothallus inconspicuous. Peridium consisting of a single layer, membranous, with deposits of round or angular lime granules united to form a rather rough and irregular crust or sparsely distributed, sometimes limeless or nearly so, often with scattered deposits of amorphous material, white or purplish grey when limeless, dehiscence irregular. Columella flesh-coloured, sometimes nearly lacking. Capillitium consisting of coarse threads, these purplish or colourless, often with membranous expansions at the joints. Spores dark grey in mass, pale purplish grey by transmitted light, minutely and closely spiny, 12–13 µm in diameter. Plasmodium white, then violet.

Reported from widely scattered localities in Europe and North America (Martin & Alexopoulos 1969). Reported from New Zealand by Mitchell (1992), based on a specimen appearing on bark samples of Metrosideros excelsa placed in moist chamber culture. The bark samples were collected in Auckland.

Bark of living trees, especially bark with bryophytes present.

Martin & Alexopoulos (1969), Ing (1999).

This species is more likely to be encountered in a moist chamber culture than as a field collection. It is not common, and most fruitings consist of limited material. Diderma chondrioderma resembles the more common D. effusum but the latter has smaller spores and fruiting bodies that are noticeably flattened.