They look like some type of mushroom to me, I'm probably wrong though!!!

I have come across this before, its like a type of fungus, one of the gardens i work in has it at the base of a ceder tree, the ground is extremely dry with alot of white powdery spores going all through the soil, have tried various ways of ridding it but find it very difficult, have even dug most of it out on occaisions and replaced with new soil but it always returns, however it is only confined to this very dry dense shade area and these fungi appear round about this time of the year, possibly be aware not to transfer spores elsewear in your garden. julien.

it is a fungus, belonging to the huge group that the puffballs belong to.

Probably a lycoperdon of some sort, or a bovista, but very difficult to be sure as they are old specimens. The hole is where the spores have escaped from - they burst open and shoot the spores out.

They are harmless - no need to worry about getting rid of them. They probably grew on some buried woody material. What you see is just the fruiting body - the main "plant" is an underground network of white threads, mycelium, so removing the fungus that you can see makes no difference to the life of the plant.