Beaked Earthstar

The Beaked Earthstar is the most sharply sculpted of the common Geastrum species. Its outer wall splits into a broad recurving star, but attention goes straight to the centre, where a grey spore sac is carried on a comparatively long, slender stalk and topped by a narrow, drawn-out beak scored with many fine parallel grooves like the teeth of a comb — the source of the epithet pectinatum.

Beneath the sac, at the top of the stalk, sits a small swollen apophysis, sometimes with a narrow flange, and the sac surface itself is finely granular or pruinose rather than smooth. Together these details make the species identifiable at a glance once known.

It is a fungus of conifer plantations and sandy woodland soils, usually in shade, and though nowhere abundant it is widespread. The tough fruit bodies weather slowly, and old grey beaked sacs can be found long after the season has finished.

Star and rays

Expanded specimens measure 3–7 cm across and 3–6 cm tall. The outer peridium splits into 5–9 narrow, pointed rays that recurve strongly and frequently arch enough to raise the fruit body onto their tips. Ray inner surfaces are buff to grey-brown and often crack into a mosaic as they dry.

Stalk and apophysis

The stalk is the longest of the common earthstars, typically 4–10 mm, slender, pale to grey, and clearly visible between star and sac. At its top is a distinct apophysis — a small swollen collar, sometimes with a fine projecting flange or ridge — marking the junction with the sac.

Spore sac and beak

The sac is 1–2 cm across, ovoid to globose, grey to grey-brown, with a surface that is finely granular, pruinose or minutely scurfy rather than glossy. It narrows above into a long conical to cylindrical beak, and this beak is marked with numerous fine longitudinal grooves or furrows radiating from the mouth. The beaked, sulcate peristome is the defining character.

Interior

The gleba ripens from white to a fine dark brown powder around a slender columella, and is expelled in puffs through the beak when the sac is compressed by rain.

The Beaked Earthstar grows on sandy, well-drained and often calcareous soils, especially in coniferous plantations and shelterbelts among spruce, pine and cypress litter, and also in mixed and broadleaf woodland, on shaded banks, in churchyards, gardens and dune scrub.

Fruiting is chiefly autumn, sometimes beginning in late summer, and weathered specimens persist into winter and beyond. The species is widespread but scattered across Europe, North America, Asia, Australia and South America, generally occurring as small groups on bare or moss-covered ground beneath dense cover.

This is a saprotrophic fungus, decomposing conifer needles, humus and buried fine debris in the surface soil. It often fruits where the litter is thin and shaded, its mycelium running through the fermentation layer and binding sand grains into the felted outer surface of the young fruit body.

Spores are dispersed passively. The long stalk holds the beak well above the litter, and the fine grooves converging on the mouth channel the spore puff produced when a raindrop strikes the thin, elastic sac wall. Because the structure is tough and lignified, one fruit body can go on releasing spores through repeated wettings over many weeks.

The Striated Earthstar (Geastrum striatum) is the closest relative, also with a grooved beak, but it has a conspicuous flaring collar or skirt beneath the sac, a shorter stalk, and a smoother, more evenly grey sac surface without the granular bloom of G. pectinatum.

The Crowned Earthstar (Geastrum coronatum) has a stalk and apophysis but its mouth is silky-fibrillose and completely ungrooved. The Dwarf Earthstar (Geastrum schmidelii) shares a grooved beak but is much smaller, with a very short stalk and no clear apophysis. Sessile species such as the Fringed and Rounded Earthstars are excluded immediately by having no stalk at all and a fibrous rather than furrowed mouth.