Kingdom: Amoebozoa
Phylum: Mycetozoa
Class: Myxogastria
Order: Liceales
Family: Reticulariaceae
Genus: Enteridium
Species: E. lycoperdon
Binomial name: Enteridium lycoperdon (Bull.) M.L. Farr, 1976.
Synonyms: Reticularia lycoperdon (Bull.), Fuligo lycoperdon (Bull.) Schumach, Lycogala punctata Pers, Lycogala turbinata Pers, Mucor lycogalus Bolton, Reticularia umbrina Fr., Strongylium fuliginoides (Pers.) Ditmar.
Enteridium lycoperdonis a cosmopolitan slime mould whose habitat is decaying wood. It can be quite variable in size and colour. Usually, it has a cap diameter of 5-80mm. It appears frequently throughout the year but is more prevalent during Spring. The plasmodium stage is white and is more or less rounded. A mature fruiting body takes on a silvery white colour from spore deposits. The dry, spongy interior produces copious amounts of red-brown spores in the manner of a puffball which it is not.
A mature fruiting body
Photo of the underside of the fruiting body when removed from the wooden host.
Here the fruiting body is cut open to show the tightly packed spores.
Thanks to Wikipedia for text and information: https://creativecommons.org/licenses/by-sa/3.0/