October 8, 2008:
Collared Earth-star is a locally scarce fungus of quite striking appearance with its bulbous spore sac on a raised roughly star-shaped base. This is due to the rays splitting transversely and opening outwards. It is an autumn-flowering fungus and usually occurs amongst leaf litter in deciduous woodland, as here.
Having an aperture at the apex of the spore sac, any slight disturbance or even falling rain will cause the mature spores to be expelled. There are several species of Geastrum in Britain, many of them rare. Although uncommon, this is one which is more frequently met.