Diderma crustaceum

Sporangia:- sessile gregarious, crowded, globose to 1mm diameter, often forming a pulvinate colony.

Outer layer of Peridium calcerous, fragile, rough, breaking away readily and distorted by pressure. Inner layer blue irredescent and remote from outer.

Columella:- small white, often lacking not always obvious.

Capillitium:- sparsely branched with few anastomoses, dark, fading toward the tips.

Spores:- Dark on mass and finely spiny, lighter by transmitted light.