Reticularia (Enteredium) lycoperdon --- the False Puffball is a Slime mould (Myxomycete).
Colin put a younger looking specimen on Blog (18.3.2014) and there was a comment asking ---- if it might be dangerous. Not dangerous but I was very suspicious of this deposit on a conifer stump as it looked much like a 'dog-deposit' so touched with care! When cut into the powdery spore mass was obvious and microscopy confirms this species. The French common name for puffball is 'vesse de loup' or 'woolf's fart' and for this Myxo is exactly the same as the English = 'fausse vesse de loup'. there are other 'common names' such as 'Caca de luna' = Moon's excrement so it is not surprising that I was suspicious.