Apparently the Collared Earthstar (Geastrum triplex) is widespread and fairly common in warmer regions in the northern temperate zones from Asia to the US, and despite being the largest member of its genus. But I have never seen before until I spotted a clump of them in Plumpton just before Christmas. They grow in woodlands and hedgerows with deep humus rich soils and derive nutrients from decomposing organic matter. Luckily for them they are not regarded as good eating so will be visible to the observant for longer than many fungi.
JW
JW