Meadow Puffball
Vascellum pratense
Also called flat-topped puffball, field puffball
A small flat-topped white puffball of short turf, distinguished by a membranous internal diaphragm that separates the spore mass from the sterile base. Mature bodies open by a wide ragged mouth.
Overview
Meadow Puffball (Vascellum pratense, long known as Lycoperdon pratense) is the characteristic small puffball of mown and grazed grassland. It is top-shaped or turbinate, broad and slightly flattened above and abruptly narrowed into a short pinched base, which gives it a squat, spinning-top profile.
Its diagnostic feature is internal. A thin but tough membranous diaphragm runs horizontally across the fruit body, cleanly separating the spore-bearing upper chamber from the spongy sterile base below. No Lycoperdon has this structure, and a vertical section through a mature specimen shows it at once.
After the spores have gone, the upper wall breaks away and the remaining base persists in the turf as a small shallow bowl with the diaphragm forming its floor.
How to identify it
Fruiting body
2–4 cm wide and 2–3.5 cm tall, top-shaped with a broad flattened or slightly domed top and an abruptly narrowed, wrinkled, short sterile base. Frequently in scattered groups across turf.
Surface
White to cream, ageing greyish then ochre-brown, covered with fine granular warts and short soft spines that soon rub away to leave a nearly smooth, slightly shining surface.
Interior and diaphragm
White and firm when young throughout. The spore mass matures to olive then olive-brown and is separated from the sterile base by a distinct flat membranous diaphragm — the key character. At maturity the top of the head disintegrates, leaving a wide, irregular, ragged-edged opening rather than a small neat pore, and eventually a persistent cup-like base.
Spore print
Not applicable in the usual sense; the mature spore mass is olive-brown.
Where and when it grows
Meadow Puffball is a grassland species, fruiting in short mown or grazed turf: lawns, playing fields, churchyards, pastures, roadside verges, coastal dunes and upland grassland. It avoids woodland and rank vegetation, favouring open, well-cropped swards.
The season runs from summer through autumn, with old bases lingering in the grass for months. It is widespread across Europe, North America and much of the temperate world.
Ecological role
The fungus is a saprophyte of grassland soil and thatch, decomposing dead grass roots, litter and humus in the upper soil layer. It is a common member of the wider grassland fungal community that includes waxcaps, earthstars and other small puffballs, and it tolerates regular mowing well.
Spore dispersal occurs through the broad ragged opening of the collapsed head, with wind and rain scattering the olive-brown powder across the turf.
Similar species
Lycoperdon perlatum is pear-shaped with a much longer stalk-like base, has conical gem-like spines, opens by a small neat apical pore and has no internal diaphragm; it also grows in woodland litter rather than short turf. Bovista plumbea is nearly spherical with almost no sterile base, breaks free of the ground when mature and exposes a papery lead-grey inner wall. Bovista nigrescens is larger and blackens. Calvatia excipuliformis is far taller with a long thick pestle-like stalk.
A vertical section is decisive: only the Meadow Puffball shows a clean membranous partition between spore mass and base.