# Common Earthball (*scleroderma citrinum*)

The Common Earthball is a round, spongy fungus that can be found on the forest floor! Its unique shape makes it look like a little ball just waiting to be discovered during your outdoor adventures.

- **Category:** [Fungi](https://www.snappit.app/explore/categories/fungi)
- **Rarity:** Common
- **Danger:** 2/5 · Low
- **Snaps:** 2
- **Habitat:** Forests, grasslands, and sometimes gardens.
- **Also known as:** Common Earthball Fungus, Earthball Mushroom, Scleroderma

![Common Earthball](https://commons.wikimedia.org/w/index.php?title=Special:Redirect/file/Scleroderma_citrinum.jpg&width=800)

Photo: Eric Steinert, CC BY-SA 3.0 · [Wikimedia Commons](https://commons.wikimedia.org/wiki/File:Scleroderma_citrinum.jpg)

## Appearance

The Common Earthball is a firm, round fungus, typically 3-10 cm wide. It has a yellowish-brown, warty or scaly outer skin, making it look like a tough, bumpy potato. Inside, it's firm and white when young, turning dark purple-brown and powdery as it matures.

## Taxonomy

- **Kingdom:** Fungi
- **Phylum:** Basidiomycota
- **Class:** Agaricomycetes
- **Order:** Boletales
- **Family:** Sclerodermataceae
- **Genus:** Scleroderma

## Earthball, up close

Earthballs (genus Scleroderma) are round, stemless fungi with a tough, scaly skin and a dark mass of spores inside. The common earthball, Scleroderma citrinum, grows on acid, sandy soils in woods across Europe and North America, where its threads team up with tree roots. It is poisonous, and although it looks like a puffball, it is more closely related to boletes.

Also called: Common earthball, Pigskin poison puffball, Citrine earthball, Earth ball.

A tough, scaly fungus ball that partners with trees, turns purple-black inside and splits open to let its spores go. It is poisonous, so look but never eat.

### Special abilities

- **Spore Puff** (8–13 µm per spore, far too small to see): When an earthball is ripe, its tough skin tears open. Wind and rain then carry clouds of dark spores out into the wood. [3][1][6][13]
  - There is no ready-made hole: the ripe skin splits into a large, irregular opening.
  - In dry spells the wind blows the spores out; in wet weather the rain washes them out.
  - Each spore is a spiny ball 8–13 µm across, two to three times as wide as a common puffball’s (3.5–4.5 µm).
  - Don’t sniff or play with spore clouds. In 1994, eight teenagers in Wisconsin, USA, needed a doctor after breathing in lots of puffball spores.
  - Width of one spore: Common earthball 8–13 µm; Common puffball 3.5–4.5 µm
- **Dark Heart** (3 stages pale, purple-black, spore dust): Look inside with x-ray vision. The spore mass starts pale and firm, turns purple-black with white marbling, then crumbles into dust. [3][2][1]
  - Young: whitish flesh, sometimes with a pink-purple tinge.
  - Maturing: purple-grey to purple-black, marbled with white veins, still firm.
  - Ripe: a blackish to dark brown, powdery mass of spores.
  - Young puffballs are pure white inside. An earthball never is, which is one of the best clues for experts.
- **Autumn Swell** (4–12 cm across when full-grown): Earthballs push up from July and swell through late summer and autumn, darkening inside and splitting open as the year cools. [1][3][2][6]
  - Fruiting season in Britain and Ireland runs from July to early December.
  - Full-grown common earthballs are usually 4–12 cm across and 3–6 cm tall.
  - North American guides describe smaller ones, about 2–5 cm across.
  - They grow alone, scattered or in groups, often on moss, sandy paths and the banks of forest ditches.
  - Width across: Common earthball 4–12 cm; Common puffball 3–6 cm
- **Root Web** (Up to 80% of a plant’s N and P can come via mycorrhizal fungi): Underground, the earthball’s threads grow out from its base and wrap the tips of tree roots. This partnership between a fungus and a root is called a mycorrhiza. [14][2][15][16]
  - Almost all land plants team up with mycorrhizal fungi. Across all kinds, these fungi can supply up to 80% of a plant’s nitrogen and phosphorus.
  - The common earthball partners oaks and other trees. Earthball strains from chestnut woods formed mycorrhizal roots on chestnut seedlings in the lab.
  - Earthball relatives that partner many kinds of trees are spread more widely, which suggests being a generalist helps a fungus travel.
  - Earthball genomes have only a small set of genes for digesting plant walls, a sign of living as a partner rather than a rotter.
- **Sugar Swap** (1–21% of a plant’s yearly growth goes to its root fungi): Fungi can’t make food from sunlight. The tree sends sugars down to the earthball’s threads, and the fungus pays back with nutrients from the soil. [12][14][11][17]
  - In culture studies, plants handed 1–21% of their total yearly production to their mycorrhizal fungi.
  - Slow-growing plants on poor soils gave the biggest share.
  - In return the fungi deliver nitrogen and phosphorus. Around oak and earthball roots, bacteria also help free minerals from rock.
  - Whether these fungi bring trees much water is less clear: studies disagree.
  - A plant’s yearly growth (100% of its net production): Up to 21% to its root fungi
- **Hard Skin** (1–3 mm thick rind): Scleroderma means “hard skin”. The thick, leathery rind keeps the spores sealed inside until they are ripe. [1][2][7][3]
  - The rind of a fresh common earthball is 1–3 mm thick. Experts warn that measurements taken from dried museum specimens can mislead.
  - Cut or bruised, the skin often blushes yellowish, pinkish or red.
  - Coarse, warty scales cover the surface, darker than the skin between them.
- **Bolete Rider** (1 host the parasitic bolete grows on nothing else; still debated): Sometimes a small bolete mushroom sprouts straight out of a common earthball. Pseudoboletus parasiticus grows on this species and nowhere else. [10][3][18][1]
  - Its cap is 2.5–7 cm across, yellowish brown with a hint of olive, on a stem 4–8 cm long.
  - It grows alone or in small clusters in summer and autumn, in Europe and eastern North America.
  - Both fungi belong to the Boletales, so the bolete is growing on a distant relative.
  - How it feeds, and how much it harms the earthball, is still not well understood. Some experts question whether it is a true parasite.
- **Not a Puffball** (123 times closed spore balls evolved separately): Earthballs look like puffballs, but they are not close relatives. The closed spore-ball shape has evolved again and again in different fungus families. [7][6][19][20][3][21]
  - Earthballs belong to the Boletales, with boletes. Common puffballs belong to the Agaricales, with gilled mushrooms.
  - In a family tree of 8,400 mushroom-forming fungi, scientists counted 123 separate origins of these closed, ball-like shapes.
  - Clues: earthballs have a thick, scaly skin, no hole on top and are never pure white inside. Puffballs are pear-shaped and open by a small hole.
  - Earthballs are poisonous. Never eat a wild fungus you find, wash your hands after touching one and tell an adult if someone may have eaten some.

### Body parts

- **Skin** (1–3 mm thick rind) [1][2]
  - The name Scleroderma comes from Greek words meaning “hard skin”.
  - In a fresh common earthball the rind is 1–3 mm thick and whitish inside. Cut it and it often blushes yellowish or reddish.
  - The skin keeps the spore mass sealed in until the earthball is ripe.
- **Scales** (citrinum means lemon-yellow) [3][2][1][4][5]
  - The skin is dirty yellow to ochre-brown and covered in coarse, warty scales of irregular shapes and sizes.
  - The scales are darker than the skin between them, a bit like crocodile skin.
  - Its species name, citrinum, refers to the lemon-yellow tinge of most common earthballs. Field guides compare the whole ball to a warty potato.
  - Its skin holds unusual pigments, including one named sclerocitrin. Chemists found the same rare family of pigments in a bolete, the peppery bolete.
- **Spore mass (gleba)** (Never pure white inside) [3][2][1]
  - The inside, called the gleba, is where the spores form.
  - In a young earthball it is firm and whitish, sometimes with a pink-purple tinge.
  - It soon turns purple-grey to purple-black, marbled with white veins, and ends as a dark, dusty spore powder.
- **Spores** (8–13 µm across, one spore) [1][2][6]
  - Each spore is a tiny sphere covered in spines, 8–13 µm (thousandths of a millimetre) across.
  - Ridges join many of the spines into a net, although the net is sometimes only partial or missing.
  - A common puffball’s spores are much smaller: 3.5–4.5 µm.
- **Crack** (Wind + rain carry the spores away) [3][1][6]
  - An earthball has no ready-made opening. When it is ripe, the skin tears into a large, irregular hole.
  - In dry spells the wind blows the spores out; in wet weather the rain washes them out.
  - Puffballs are different: a small round hole opens at the top.
- **Rooting base** [2][1][7]
  - Earthballs have no real stem. The common earthball is pinched where it meets the ground.
  - Its base is tied into the soil by whitish to yellowish cords of fungal threads, called rhizomorphs.
  - Some other earthballs that live in sand grow a thick, stem-like base to lift themselves above the shifting sand.
- **Mycelium** (10 mg/L cadmium one strain grew through) [8][9]
  - The ball is only the fruiting body. The fungus itself is a web of fine threads in the soil, the mycelium.
  - On beech roots, a close relative, the scaly earthball, forms silvery-white sheaths with lots of rope-like cords reaching into the soil.
  - In a lab test, a common earthball strain from mine waste kept growing normally at the highest cadmium level tested, 10 mg per litre.
- **Tree partner** (1–21% of a plant’s yearly growth paid to its root fungi) [2][10][11][12]
  - The common earthball is mycorrhizal: its threads wrap the tips of tree roots and trade with the tree.
  - It was first described growing with European oaks and also partners other broadleaved trees and conifers.
  - Bacteria living around oak and earthball roots in poor, acid forest soil are especially good at breaking down minerals.
- **Parasitic bolete** (2.5–7 cm cap of the parasitic bolete) [10][3][2]
  - Pseudoboletus parasiticus is a small bolete that grows right out of common earthballs, alone or in small clusters.
  - It grows on the common earthball and nowhere else.
  - How exactly it lives off its host is still not well understood.
- **Smell** [3][1]
  - The common earthball has an unpleasant, rubbery smell, a bit like gas.
  - Some popular fact lists say it smells of raw potato, but the expert guides we checked describe gas. The potato comparison is about its looks.

### Stats

| Stat | Value | Notes |
|---|---|---|
| Size | 4–12 cm | across and 3–6 cm tall in Britain; North American ones are often 2–5 cm [3][2] |
| Rind | 1–3 mm | thick, whitish inside, blushes when cut [2] |
| Spore width | 8–13 µm | spiny, net-patterned spheres [1][6] |
| Season | Jul–Dec | July to early December in Britain and Ireland [1] |
| GBIF records | 85,784 | records worldwide, 77,486 of them in Europe; 53% of all records for the genus [18][24] |
| Earthball species | ≈25 | described in the genus Scleroderma, with new ones still being found [7][25] |
| Family age | 66+ million yrs | the earthball group (Sclerodermatineae) began in the late Cretaceous [16] |
| Hospital cases | 4.7% | of mushroom-poisoning cases at one German university hospital were common earthballs [26] |
| Sugar share | 1–21% | of a plant’s yearly growth goes to its mycorrhizal fungi (culture studies) [12] |
| Ball shapes evolved | 123 times | separate origins of closed spore balls like earthballs and puffballs [20] |

### Photos

- [A common earthball in a German wood](https://commons.wikimedia.org/wiki/File:Scleroderma_citrinum_-_earth_ball_-_Kartoffelbovist_-_Boletales_-_Sclerodermatineae_-_08.jpg) (photo: Norbert Nagel, CC BY-SA 3.0)
- [Coarse scales on the tough skin](https://commons.wikimedia.org/wiki/File:Gemeiner_Kartoffelbovist_Scleroderma_citrinum.jpg) (photo: Holger Krisp, CC BY 3.0)
- [Ripe and splitting open: about to release its spores](https://commons.wikimedia.org/wiki/File:Scleroderma_citrinum_-_earth_ball_-_Kartoffelbovist_-_Boletales_-_Sclerodermatineae_-_05.jpg) (photo: Norbert Nagel, CC BY-SA 3.0)
- [Spores spreading through cracks in the skin](https://commons.wikimedia.org/wiki/File:Kartoffelbovist_Staubloch.jpg) (photo: Dat doris, CC BY-SA 4.0)
- [Cut open: the black spore mass of mature earthballs](https://commons.wikimedia.org/wiki/File:Dickschaliger_Kartoffelbovist_(Scleroderma_citrinum).jpg) (photo: Hans-Martin Scheibner, CC BY-SA 3.0)
- [Fully ripe: the inside has turned to spore powder](https://commons.wikimedia.org/wiki/File:Dickschaliger_Kartoffelbovist_(Scleroderma_citrinum)-Reife_Sporenmasse_im_Querschnitt.jpg) (photo: Hans-Martin Scheibner, CC BY-SA 3.0)
- [A good year: hundreds of earthballs in a Dutch forest](https://commons.wikimedia.org/wiki/File:Hundreds_of_Scleroderma_citrinum_(Common_earthballs_-_Gele_aardappelbovist)_in_the_forest%5E_This_year_they_are_very_common_-_panoramio.jpg) (photo: Henk Monster, CC BY 3.0)
- [Parasitic boletes growing on their only host](https://commons.wikimedia.org/wiki/File:Boletus_parasiticus_on_Scleroderma_citrinum.jpg) (photo: Hans Hillewaert, CC BY-SA 4.0)
- [Pseudoboletus parasiticus on a common earthball](https://commons.wikimedia.org/wiki/File:Lukas_Large_-_Pseudoboletus_parasiticus_on_its_host_Scleroderma_citrinum_(54043775301).jpg) (photo: Lukas Large, CC BY-SA 2.0)
- [For comparison: common puffballs, which are not earthballs](https://commons.wikimedia.org/wiki/File:Common_Puffball_(Lycoperdon_perlatum)_-_La_P%C3%AAche%2C_Qu%C3%A9bec_2016-09-20_(01).jpg) (photo: Ryan Hodnett, CC BY-SA 4.0)

### Questions

- **Is an earthball poisonous?** Yes. The common earthball is poisonous and causes mushroom poisonings in the UK and elsewhere every year. It is not usually described as deadly, but it should never be eaten. [3][26]
- **How can you tell an earthball from a puffball?** Earthballs have a thick, warty, yellow-brown skin, no hole on top, and are never pure white inside: they turn purple-black early. Common puffballs are pear-shaped and open by a small hole at the top. Even so, never eat a wild fungus you find. [3][6]
- **What is inside an earthball?** The gleba, a mass of developing spores. It is whitish when young, turns purple-black with white marbling, and ends as a dark, dusty spore powder. [3][2]
- **Is it safe to touch an earthball?** It’s best not to pick wild fungi, and if you do touch one, wash your hands afterwards. Keep your face away from the dusty spores of ripe ones. If you’re worried someone has swallowed, touched or breathed in something harmful, in the UK call NHS 111, or 999 if they are seriously unwell. [13][21]
- **What is the mushroom growing on an earthball?** It is probably the parasitic bolete, Pseudoboletus parasiticus. It grows only on the common earthball, alone or in small clusters, in summer and autumn. [3][10]
- **Are earthballs related to truffles?** Not closely. Earthballs belong to the Boletales, with boletes, while truffles are ascomycetes that form their fruiting bodies underground. Earthballs were reportedly once passed off as truffles. [2][27][3]
- **Where and when do earthballs grow?** On acid, sandy soils in woods, often on moss, forest paths and the banks of ditches, near the trees they partner. In Britain and Ireland they appear from July to early December. [3][1]
- **How does an earthball get its food?** Fungi can’t use sunlight. The earthball’s threads partner tree roots: the tree sends down sugars, and the fungus delivers nitrogen and phosphorus from the soil. In culture studies, plants gave 1–21% of their yearly production to such fungi. [12][14]

### Earthball myths and facts

Lookalikes, old stories and popular claims, checked against the evidence.

- "An earthball is just a kind of puffball." **Myth!** Earthballs belong to the Boletales, the same order as boletes. Common puffballs belong to the Agaricales, with gilled mushrooms. Their ball shapes evolved separately. [7][6][19][20]
- "Earthballs are fine to eat, like puffballs." **Myth!** The common earthball is poisonous and is behind many mushroom poisonings in the UK each year. At one German hospital it caused 4.7% of mushroom-poisoning cases. [3][26]
- "An earthball’s inside gives it away." **Fact!** An earthball is never pure white inside: it is whitish with a pink-purple tinge at first and soon turns purple-black. Young puffballs are pure white. Even so, never eat wild fungi. [3][2]
- "Earthballs have a hole on top to puff out their spores." **Myth!** That is a puffball. An earthball has no ready-made opening: its ripe skin tears into a large, irregular hole. [3][1][6]
- "Earthballs smell like raw potato." **Not proven!** The expert guides we checked describe an unpleasant, rubbery smell like gas. The potato comparison is about its warty, potato-like look. [3][1]
- "Earthballs help trees." **Fact!** Earthballs are mycorrhizal fungi: their threads partner tree roots, swapping nutrients from the soil for the tree’s sugars. [2][14][12]
- "Another mushroom can grow on an earthball." **Fact!** The parasitic bolete, Pseudoboletus parasiticus, sprouts out of common earthballs and grows nowhere else. [3][10]
- "Earthballs were once passed off as truffles." **Fact!** Reportedly, yes: the Woodland Trust notes that earthballs were sometimes sold as truffles in the past. Real truffles are a different group of fungi that grow underground. [3][27]

### Earthball records

Superlatives with numbers behind them.

- Only home: Common earthball, 1 host (The parasitic bolete Pseudoboletus parasiticus grows on the common earthball and nowhere else.) [3][10]
- Most-recorded earthball: Common earthball, 85,784 records (More than half of the 160,942 records for the whole genus Scleroderma on GBIF.) [18][24]
- Most reinvented fungus shape: Closed spore balls, 123 origins (In a family tree of 8,400 mushroom-forming fungi, closed spore balls such as earthballs and puffballs evolved separately 123 times.) [20]
- Named at the starting line: Christiaan Persoon’s 1801 book, 1801 (Persoon described the common earthball in Synopsis Methodica Fungorum, the official starting point for naming this kind of fungus.) [2][1]
- Old family line: Earthball group (Sclerodermatineae), Late Cretaceous (Scientists estimate the group began in the late Cretaceous, more than 66 million years ago, when dinosaurs still lived.) [16]
- Metal-tough threads: A common earthball strain, 10 mg/L cadmium (Grown from mine waste, it kept growing normally at the highest cadmium level tested, while two strains of another fungus slowed to half growth at 4.8 and 6.9 mg/L.) [9]

### An earthball’s year

What happens above and below the ground, from summer into early winter (Britain and Ireland).

- **Spring and early summer**: Trading underground. Below ground, the mycelium is linked to tree root tips, trading nutrients from the soil for the tree’s sugars. [2][12]
- **July**: First earthballs. Firm, yellow-brown balls push up on moss, sandy paths and the banks of forest ditches. [1][3]
- **Late summer**: Darkening inside. The pale inside turns purple-black with white marbling as the spores form. [3][2]
- **Summer to autumn**: Bolete visitors. On some earthballs, small parasitic boletes sprout from the skin. [10]
- **Autumn**: Skin splits. Ripe earthballs tear open, and wind and rain carry the dark spores away. [3][1]
- **Early December**: Season ends. The last earthballs of the year finish as winter begins. [1]

### Staying safe around earthballs

Earthballs are poisonous, but a few simple habits keep everyone safe. Admire them, photograph them and leave them where they grow.

- **Don’t eat** any wild fungus. Earthballs are poisonous and are often mistaken for edible puffballs. Never eat a mushroom you find. [3][26]
- **Don’t sniff** spore clouds. Breathing in lots of puffball spores has made people ill, so keep your face away from dusty, ripe fungi. [13]
- **Wash** your hands. If you touch a fungus, wash your hands before eating, and keep your fingers away from your mouth and eyes.
- **Tell** an adult. If someone may have eaten part of a mushroom, tell an adult straight away. A photo or a piece of the mushroom helps experts work out what it was. [4]
- **111 / 999** in the UK. Call NHS 111 if you’re not sure whether something swallowed, touched or breathed in is harmful. Call 999 if someone is seriously unwell. [21]

This page is for learning, not medical advice. Outside the UK, call your local poison centre or emergency number.

### Earthball vs puffball vs truffle

Three kinds of fungus balls that people mix up.

| | Common earthball | Common puffball | Périgord black truffle |
|---|---|---|---|
| Fungus group [18][6][27] | Boletales, with boletes | Agaricales, with gilled mushrooms | Ascomycetes (sac fungi) |
| Where it grows [3][23][27] | On the ground in woods, often on moss or sandy soil | On the ground in woods, by roadsides and in towns | Underground, in chalky soils of southern Europe |
| How it lives [2][23][27] | Partner of tree roots (mycorrhizal) | Recycles dead plant matter | Partner of tree roots (mycorrhizal) |
| How spores get out [3][1][6][27] | Skin tears open; wind and rain | Small hole on top; raindrops squeeze out puffs | Forms underground (not covered here) |
| Spore width [1][6] | 8–13 µm, spiny | 3.5–4.5 µm | Not covered here |
| Food? [3][6][27] | No: poisonous | Young ones are eaten by experts; lookalikes are risky | A prized delicacy, sold by experts |

Never eat any wild fungus you find. Lookalikes fool people every year.

### Is the earthball endangered?

The common earthball is the most-recorded earthball in the GBIF database, but like many fungi it has never been formally assessed.

- **IUCN Red List:** Not Evaluated (NE) (Trend unknown). The IUCN Red List has not assessed Scleroderma citrinum. It is very common: GBIF holds 85,784 records, 77,486 of them from Europe. [18][28]
- Not evaluated (IUCN status checked via GBIF, 2026)
- **Threat: Changing forests**: Mycorrhizal fungi depend on their host trees. Across European forests, the environment and the host trees explain most of the variation in which of these fungi are found. [29]
- **Threat: Hungrier trees**: Many European forests show worsening tree nutrition. Scientists suspect changes in mycorrhizal fungi may be part of the reason, but this is still being tested. [30]
- **Threat: Unknown trend**: Without a Red List assessment, nobody knows whether earthball numbers are rising or falling. [18]
- **Helping: Record sightings** (85,784): Photos and records shared by naturalists build maps like GBIF’s. Snap it, don’t pick it. [18]
- **Helping: Earthballs at work**: A tropical earthball, Scleroderma bermudense, partners seagrape trees that are planted to stabilise and restore damaged coastal sand dunes. [31]
- **Helping: Stronger seedlings** (1.13–2.48×): Hazel seedlings partnered with another earthball, Scleroderma bovista, grew roots 1.13 to 2.48 times bigger in length, area and volume than seedlings without it. [32]
- **Parasitic bolete (Pseudoboletus parasiticus)** (LC): Least Concern on the IUCN Red List. It depends entirely on the common earthball. [22][3]
- **Common puffball (Lycoperdon perlatum)** (LC): Least Concern on the IUCN Red List. [33]

### Reading an earthball

- Firm ball, pale inside: Young: the spores are still forming. [3]
- Purple-black, marbled inside: Maturing: the spores are darkening. [2]
- Skin torn open, dark dust: Ripe: spores are leaving on the wind and in the rain. Keep your face away. [3][1][13]
- Pink or red blush where it is cut or bruised: A normal reaction of the rind. [2]
- A small bolete growing on top: The parasitic bolete has moved in. [10]
- Smell like gas: Typical of the common earthball. [1]

### Looks

- **Young earthball**: Firm, round and stemless, with a dirty-yellow, scaly skin. Inside it is whitish, sometimes with a pink-purple tinge. (Already poisonous at this stage) [3][1]
- **Ripe earthball**: The skin has torn into a large, irregular hole, and the inside has turned into purple-black to dark brown spore powder. (Wind and rain carry the spores away) [3][2][1]
- **With parasitic bolete**: Small yellowish-brown boletes, caps 2.5–7 cm, growing straight out of the earthball. (IUCN Red List: Least Concern) [10][22]
- **Common puffball (to compare)**: Pear-shaped, 3–6 cm across and 4–9 cm tall, with a pale, spiny skin and a small hole that opens at the top. (Lives on dead plant matter instead of partnering trees) [6][23]

### Earthball quiz

1. What does the name Scleroderma mean? **Hard skin.** It comes from Greek words for “hard” and “skin”. [1]
2. What colour does a common earthball turn inside as it matures? **Purple-black with white marbling.** The pale inside turns purple-black with white veins, then becomes dark spore powder. [3][2]
3. How does a ripe earthball release its spores? **Its skin tears open and wind and rain carry them away.** There is no ready-made hole: the skin splits into a large, irregular opening. [3][1]
4. Which group of fungi do earthballs belong to? **Boletales, with boletes.** Despite looking like puffballs, earthballs are related to boletes. [7][18]
5. What is the partnership between the earthball’s threads and tree roots called? **A mycorrhiza.** A mycorrhiza is a partnership between a fungus and plant roots. [2][14]
6. What does the tree give the earthball in their swap? **Sugars.** Plants hand 1–21% of their yearly production to their mycorrhizal fungi as sugars. [12]
7. Which mushroom grows only on the common earthball? **Parasitic bolete.** Pseudoboletus parasiticus grows on the common earthball and nowhere else. [3][10]
8. How wide is one common earthball spore? **8–13 µm.** That is a few thousandths of a millimetre: far too small to see on its own. [1]
9. When do common earthballs appear in Britain and Ireland? **July to early December.** Their season runs from July to early December. [1]
10. What should you do if someone may have eaten part of a wild mushroom? **Tell an adult straight away and get medical advice.** Tell an adult. In the UK, call NHS 111, or 999 if someone is seriously unwell. [21]
11. How many times did closed spore balls evolve separately in one big study? **123 times.** Earthballs, puffballs and other closed spore balls evolved separately 123 times. [20]
12. What is the common earthball’s IUCN Red List status? **Not evaluated.** The IUCN has not assessed it, although it is very common. [18]

### Sources (checked 2026-10-16)

1. [O'Reilly P. Scleroderma citrinum, Common Earthball. First Nature.](https://www.first-nature.com/fungi/scleroderma-citrinum.php)
2. [Kuo M. Scleroderma citrinum. MushroomExpert.com.](https://www.mushroomexpert.com/scleroderma_citrinum.html)
3. [Woodland Trust. Common earthball (Scleroderma citrinum). Species page.](https://www.woodlandtrust.org.uk/trees-woods-and-wildlife/fungi-and-lichens/common-earthball/)
4. [Sato Y, Tomonari H, Kaneko Y, Yo K (2020). Mushroom poisoning with Scleroderma albidum: a case report with review of the literature. Acute Medicine & Surgery 7:e460.](https://doi.org/10.1002/ams2.460)
5. [Winner M, Giménez A, Schmidt H, Sontag B, Steffan B, Steglich W (2004). Unusual pulvinic acid dimers from the common fungi Scleroderma citrinum (common earthball) and Chalciporus piperatus (peppery bolete). Angewandte Chemie International Edition 43:1883–1886.](https://doi.org/10.1002/anie.200352529)
6. [O'Reilly P. Lycoperdon perlatum, Common Puffball. First Nature.](https://www.first-nature.com/fungi/lycoperdon-perlatum.php)
7. [Kuo M (2025). The genus Scleroderma. MushroomExpert.com.](https://www.mushroomexpert.com/scleroderma.html)
8. [Mrak T, Kühdorf K, Grebenc T, Štraus I, Münzenberger B, Kraigher H (2017). Scleroderma areolatum ectomycorrhiza on Fagus sylvatica L. Mycorrhiza 27:283–293.](https://doi.org/10.1007/s00572-016-0748-6)
9. [Carrillo-González R, González-Chávez MdCA (2012). Tolerance to and accumulation of cadmium by the mycelium of the fungi Scleroderma citrinum and Pisolithus tinctorius. Biological Trace Element Research 146:388–395.](https://doi.org/10.1007/s12011-011-9267-7)
10. [Kuo M. Pseudoboletus parasiticus. MushroomExpert.com.](https://www.mushroomexpert.com/pseudoboletus_parasiticus.html)
11. [Uroz S, Oger P (2017). Caballeronia mineralivorans sp. nov., isolated from oak–Scleroderma citrinum mycorrhizosphere. Systematic and Applied Microbiology 40:345–351.](https://doi.org/10.1016/j.syapm.2017.05.005)
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14. [van der Heijden MGA, Martin FM, Selosse MA, Sanders IR (2015). Mycorrhizal ecology and evolution: the past, the present, and the future. New Phytologist 205:1406–1423.](https://doi.org/10.1111/nph.13288)
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## Measurements & details

- **Edible:** poisonous
- **Size:** 3-10 cm
- **Growth Substrate:** soil
- **Season:** Summer to Fall
- **Spore Color:** Olive-brown to purplish-brown

## Ecological connections

- **Symbiotic with:** [Oak](https://www.snappit.app/explore/oak) (*Quercus robur*) — Helps oak trees get water and nutrients from the soil.
- **Symbiotic with:** [Scots Pine](https://www.snappit.app/explore/scots-pine) (*Pinus sylvestris*) — Forms beneficial root connections, aiding pine tree growth.
- **Eaten by:** [Black Slug](https://www.snappit.app/explore/black-slug) (*Arion ater*) — Slugs occasionally nibble on its developing fruiting body.
- **Eaten by:** [Ground Beetle](https://www.snappit.app/explore/ground-beetle) (*Pterostichus melanarius*) — Some beetles might feed on its decomposing tissues.

## Traits

- [Spotted](https://www.snappit.app/explore/traits/spotted): Marked with spots or patches of a different color.
- [Solitary](https://www.snappit.app/explore/traits/solitary): Solitary animals live alone for most of their lives, only interacting with others for mating or parental care.
- [Decomposer](https://www.snappit.app/explore/traits/decomposer): Describes organisms that break down dead organic material, recycling nutrients back into the ecosystem.
- [Forest](https://www.snappit.app/explore/traits/forest): Forest habitats are terrestrial environments dominated by dense tree cover, supporting a high diversity of plant and animal life.

## Collections

- [Fungi](https://www.snappit.app/explore/collections/fungi)

## Safety

**Danger:** 2/5 · Low

Do not touch or eat wild mushrooms without adult supervision.

## Frequently Asked Questions

### How to identify Common Earthball?

Compare the cap shape, the underside, the stem and base, and whether the fungus grows on wood or soil. Some fungi have gills, others pores or teeth. A cap seen only from above often hides the most useful features. Mushroom Identifier: upload a photo and compare the visible details.

### Is Common Earthball edible?

poisonous

### How big is Common Earthball?

3-10 cm

### Where is Common Earthball usually found?

Forests, grasslands, and sometimes gardens.

### What does Common Earthball grow on?

soil

### When is Common Earthball in season?

Summer to Fall

### What color are Common Earthball spores?

Olive-brown to purplish-brown

## Where to spot

- [Bear Meadows Natural Area](https://www.snappit.app/guides/places/bear-meadows-natural-area) — Pennsylvania, US · Nature Reserve
- [Old Harbor Historic District](https://www.snappit.app/guides/places/old-harbor-historic-district) — Rhode Island, US · Historic District
- [W.J. Freeman Park](https://www.snappit.app/guides/places/w-j-freeman-park) — Tennessee, US · Park

[View all places to see Common Earthball](https://www.snappit.app/guides/where-to-see/common-earthball)

## More Fungi

- [Field Mushroom](https://www.snappit.app/explore/field-mushroom) (*Agaricus*)
- [Button Mushroom](https://www.snappit.app/explore/button-mushroom) (*Agaricus*)
- [Portobello Mushroom](https://www.snappit.app/explore/portobello-mushroom) (*Agaricus*)
- [Shiitake](https://www.snappit.app/explore/shiitake) (*Lentinula*)

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Source: [Common Earthball: Facts & Places to See — Snappit](https://www.snappit.app/explore/common-earthball)