Grey Puffball

The Grey Puffball is a common fungus of closely grazed and mown grassland, where it appears as scattered white marbles 2-3 cm across sitting on the turf. It is defined by a two-layered skin: a thin, chalky white outer layer that soon cracks and flakes off in patches, and beneath it a smooth, papery, lead-grey to bluish-grey inner ball.

Bovista differs from the pear-shaped Lycoperdon puffballs in having little or no sterile base, so almost the whole fruiting body is given over to spore production. Species of the genus are typically globose, attached only weakly to the ground, and free to break loose once mature.

That detachment is central to how the Grey Puffball works. Rather than sitting anchored and being drummed by raindrops, mature fruiting bodies snap free and are blown across open ground, puffing spores through a ragged opening as they tumble.

Fruiting body

Globose to slightly flattened or egg-shaped, 2-3 cm across, occasionally to 4 cm. When young it is entirely white and smooth to very finely felted.

Skin layers

The defining feature. The white outer layer (exoperidium) is thin and brittle and soon cracks and sheds in irregular flakes, revealing a smooth, shining, papery inner layer (endoperidium) coloured lead-grey, bluish-grey or slate. The exposed grey ball is the classic look of the species.

Attachment and stipe

There is no stalk and effectively no sterile base. The ball is held to the soil only by a tuft of fine white mycelial threads at a small basal point; these break easily and mature specimens are commonly found loose on the turf.

Flesh and spore mass

The interior is white and firm when young, becoming olive and finally a dark purplish-brown or umber powder that fills the grey shell. At maturity an irregular torn mouth opens at the top. Spores in mass are purplish-brown; microscopically each spore carries a long tail-like pedicel, a classic Bovista character.

A fungus of short, open, well-grazed or mown turf: pastures, downland, lawns, playing fields, roadside verges, coastal grassland, links and fixed sand dunes. It avoids woodland and rank vegetation and does well on nutrient-poor, closely cropped swards.

Widely distributed across Europe, North America, Asia and beyond in temperate regions. Fruiting is mainly from summer into late autumn, and the tough empty grey shells often persist through winter, rolling into hollows and hedge bottoms.

The Grey Puffball is saprotrophic, its mycelium living in the turf layer and breaking down grass roots, thatch and soil organic matter. It is one of a suite of small grassland fungi that fruit in unimproved and lightly managed swards.

Its dispersal strategy is unusual and effective: the fruiting body abscises from its slender mycelial anchorage and becomes a tumbleweed. Each bounce and roll across the ground compresses the papery shell and squirts spores through the apical tear, spreading them far from the parent mycelium in the open, windy habitats the species prefers.

Bovista nigrescens is larger, usually 3-6 cm, and its inner skin is a shining purplish-black to blackish-brown rather than lead-grey. Bovista pila, mainly a North American species, is bigger still, has a bronze to purplish-bronze inner skin, and hangs from a single tough basal cord before breaking free.

Lycoperdon puffballs of similar size, such as L. pratense in grassland, are pear-shaped with a distinct spongy sterile base that keeps them anchored, and they open by a neat circular pore rather than an irregular tear. Small Scleroderma earthballs are firm with a tough warty rind and a marbled dark interior even when young, and never show the white-flaking-to-grey layering of Bovista.