Hi, and welcome to UK Fungi.
These are one of the Geastrum species of “Earthstars”.
There are a couple of possibilities (which can’t be differentiated without all habitat information and microscopy) but I think they are most likely to be Geastrum pectinatum – Beaked Earthstar.
These fruitbodies look quite old and dry. They would probably have been at their best at some point during last autumn – early winter.
Earthstars do take some considerable length of time, (i.e. usually many months), to fully decompose.
Regards,
Mike.