It starts off as a white globular mass about the size of half a golf ball, and then develops a silver-grey papery skin beneath which the brown spores develop. When the seeds have been dispersed all they leave behind is a faint brown 'spore print' patch on the tree bark.

Good field photos

On tree bark.

Spring.

Widespread and fairly frequent in Britain.

Fairly frequent in Leicestershire and Rutland.

The position of Reticularia or Enteridium lycoperdon in the taxonomic hierarchy is unclear. On the NBN, it is not assigned to a family.  As Enteridium lycoperdon it is listed under Reticulariaceae on Wikipedia and under Lycogalaceae in Ing, B. (1999).