Meadow Puffball Identification Guide

First Impression and Setting

Meadow puffball is a fungus of short turf. You come across it on mown lawns, grazed pasture, playing fields, path verges, dune grassland and old churchyards, usually in scattered groups of a few to a few dozen. From above, young specimens look like small white or off-white buttons sitting in the grass, two to four centimetres across and roughly as tall.

The silhouette in profile is the first useful character. This is not a sphere on a stalk and not a pear on a stem. It is top-shaped or turbinate: broad and rounded above, narrowing downward into a short, wrinkled, tapering foot that is often no more than a stub. There is no true stipe. As the fruit body ages the whole thing dulls to grey-brown or ochre, the top opens, and by winter you are left with a shallow, torn-edged cup sitting in the sward like a small saucer.

The Outer Surface

On a fresh young specimen, look closely at the outer wall with a lens. It is white to cream and covered with a dense layer of very short, fine spines, granules and mealy warts. These are not the long pyramidal spines of some relatives; they are minute and soft, and they are shed easily. Rubbing a finger across the surface removes them, and rain does the same, so weathered specimens are smooth and often faintly cracked or areolate where the outer layer has flaked away.

Beneath that shedding layer is a thin, papery to slightly leathery inner wall, pale buff to grey-brown, which is what you see on older material. Toward the base the surface becomes distinctly wrinkled and folded, another aid to recognising the top-shaped build.

How It Opens

Maturation is worth watching, because the mode of opening is diagnostic at the genus level. Many small puffballs open by a neat, well-defined circular pore at the apex, through which spores puff out when the wall is struck by a raindrop.

This species does something different. The top of the fruit body breaks down and tears away irregularly, and the opening widens progressively until the entire upper wall is gone. The end state is a broad, open bowl with a ragged, torn margin, exposing the remains of the spore mass and the sterile base beneath. If you find a group of specimens in the field, you can usually see the whole sequence: sealed white buttons, a small irregular apical tear, a wide gaping mouth, and finally the empty cup.

The Section Test: The Decisive Character

Everything above is supporting evidence. The identification is made by cutting a fruit body vertically from top to bottom with a sharp knife and reading the internal structure.

You are looking for three zones. The upper part is the gleba, the fertile spore-producing tissue, which is pure white and firm in young specimens, then passes through olive-yellow to olive-brown and finally to a dry, powdery brown mass. The lower third or so is the subgleba, a sterile base which is spongy and visibly chambered, like a fine white foam, and which stays paler than the gleba above it.

Between the two, and this is the character that names the genus, there is a distinct, thin, papery membrane: a diaphragm stretched across the fruit body separating fertile from sterile tissue. In a clean vertical cut it shows as a sharp horizontal line, and in older material you can sometimes tease it out with a needle as an intact sheet. Small puffballs of the genus Lycoperdon lack this membrane; their fertile and sterile tissues grade into one another without a defined partition.

The practical routine is therefore: find the top-shaped outline in short grass, check for the fine shedding granules, then cut one specimen in half lengthwise and look for the papery line. Carry a knife and expect to sacrifice one fruit body per collection.

Spores and the Spore Print Question

Puffballs are gasteroid: the spores mature inside a closed chamber and there is no exposed hymenium, so a conventional spore print cannot be taken. There is nothing to lay face-down on card.

The equivalent procedure is to sample the gleba directly. Take a mature specimen in which the interior has become brown and powdery, tap it gently over a sheet of white paper, and you will collect a fine dust of spores. That dust is the material to examine, and it also gives you the mature spore colour, which here is olive-brown to warm brown.

Under the microscope, spores are globose, roughly 3 to 5 micrometres in diameter, minutely warted or spiny, and typically carry a very short pedicel or none at all. The capillitium, the sterile threads running through the spore mass, is sparse, thin-walled and lacks the conspicuous pores found in some related genera. Loose short sterile fragments mixed with the spores are usual for this species.

Substrate, Season and Ecology

This is a soil saprotroph of grassland, growing on the ground among short grasses and mosses, decomposing organic matter in the turf. It has no association with wood, and it does not fruit from stumps, logs or buried timber. Nutrient-poor to moderately fertile short swards suit it, including mown amenity grassland, so unlike some grassland fungi it tolerates managed lawns.

The season is long: fruit bodies appear from summer through late autumn, with the peak in early to mid autumn after rain. Because the empty cups persist, remnants can be found through winter and into the following spring, which makes old material a useful clue to where fresh specimens will appear.

Separating the Closest Look-alikes

Lycoperdon perlatum. Distinctly pear-shaped with a well-developed stalk-like base, larger overall, and clothed in prominent conical spines surrounded by rings of granules that leave a pitted net pattern when they fall. It opens by a single defined apical pore, and cut in half it shows no diaphragm.

Lycoperdon pyriforme. Grows in dense clusters on wood, stumps and buried timber, connected by conspicuous white rhizomorphs at the base. Substrate alone usually settles it, and again there is no internal diaphragm.

Lycoperdon lividum and Lycoperdon molle. Both occur in grassland and dunes at a similar size. They are more nearly pear-shaped, have a longer sterile base, open by a defined pore, and lack the papery partition. Always cut, because these are the collections most often confused.

Bovista plumbea. Grows in the same short turf, but the mature fruit body breaks free of the soil and blows about. The outer white layer flakes off entirely to reveal a smooth, tough, lead-grey inner wall, and there is essentially no sterile base and no diaphragm. Roll a mature specimen between your fingers and the papery grey ball is unmistakable.

Calvatia excipuliformis. Much larger and taller, with an elongated, distinctly stalked sterile base, and the upper wall breaking away in a similar untidy manner. Size and proportion separate the two immediately.

Scleroderma species. Firm, tough, thick-walled, with a warty or scaly rind rather than a delicate spiny wall. Cut young and the interior is already firm and marbled dark purplish black rather than white, and there is no chambered sterile base.

Amanita egg stages. Any smooth white ball in grass should be cut vertically as a matter of routine. An immature Amanita shows the outline of a folded miniature mushroom inside, with cap, gills and stipe visible in section, rather than uniform white tissue.

Field Checklist

• Short grassland: lawns, pasture, playing fields, dunes, verges
• Top-shaped outline, 2 to 4 cm, with a short wrinkled tapering foot and no true stalk
• Outer surface white with fine short shedding granules and spinules
• Top tearing away irregularly and widening into a ragged open bowl
• Vertical cut shows a distinct papery diaphragm between gleba and chambered sterile base
• Gleba white, then olive, then powdery brown; spores globose and minutely warted