Earthstar

Where it grows

The collared earthstar fruits from autumn into winter in leaf litter under broadleaf and coniferous trees on well-drained soil. It is the most widely encountered of more than a dozen Geastrum species and is common in mature beech and oak woods across the cool-temperate northern hemisphere.

How to recognise it

The species starts as an onion-shaped underground egg. As it matures, the outer skin (the exoperidium) splits and peels back into four to eight thick fleshy points like a star, often forming a “collar” beneath the central spore sac. The inner sac is grey-brown and pierced by a finely fringed mouth-pore at the apex. Raindrops striking the sac eject puffs of spores.

Edibility & cautions

Inedible — too tough and papery to eat once mature, and the soft inner egg has no flavour worth pursuing. There are no toxic look-alikes; the small genus Geastrum is harmless and the visual structure is unmistakable. Earthstars are popular subjects in nature photography for their geometric form.