Little brown mushrooms on thin stems: why they can't be identified from a photo

Little brown mushrooms can't be identified from a photo: dozens of species look almost identical, and the harmless ones grow side by side with deadly ones such as the funeral bell. The features that separate them are microscopic, and some species can only be told apart by DNA.

You've almost certainly seen them: a cluster of plain brown caps in the lawn, on an old stump, in bark mulch or in moss. Below we look at what these mushrooms are, which of them are dangerous, what's growing in your lawn, and how to show a find so you get an honest answer.

What "LBM" means

LBM stands for "little brown mushroom", an informal label from English-language field guides. It isn't a species or even a genus. It's a catch-all for small gilled mushrooms with no striking features: a cap from a coin's width down to a fingernail, brown, tan or buff, a thin stem and brownish gills. David Arora made the term famous in Mushrooms Demystified, where he noted that it fits nearly half of the mushrooms you'll find, and that for a beginner trying to name them is "downright foolish".

The group mixes genera that aren't closely related at all: Galerina, Conocybe, fibrecaps (Inocybe), webcaps (Cortinarius), brittlestems (Psathyrella), bonnets (Mycena), twiglets (Tubaria), mottlegills (Panaeolus) and Psilocybe. They look alike because they live similar lives, not because they're relatives.

This is one of ours, from a roadside verge: a tight clump of beige bell-shaped caps on gravel next to nettles. Most likely brittlestems. We can't say more from the photo, and with LBMs that's the honest answer.

Why you can't identify them from a photo

The cap changes colour as it dries. Many LBMs have hygrophanous caps: dark and almost translucent when wet, much paler when dry, often in bands or from the centre outwards. The funeral bell, the sheathed woodtuft, the brown mottlegill and many brittlestems all do this. A photo taken in the morning and one taken at noon can look like two different species.

Young features disappear. A thin ring, or a cobweb-like veil between the cap edge and the stem, is often there only while the mushroom is young. It tears and falls away with age, so "no ring" in a photo proves nothing.

The deciding features are microscopic. Mycologists separate these genera by the cells of the cap skin, special cells on the gill edges, and the size and shape of the spores. Sometimes even that isn't enough: when researchers sequenced Galerina specimens that looked the same, they turned out to be dozens of separate species.

We photographed this brown mushroom with a long fibrous stem in grass under oaks. The gills didn't make it into the shot, so even the genus stayed uncertain: possibly a webcap, possibly not. For a step-by-step way to read a mushroom photo, see how to identify a mushroom from a photo.

Are little brown mushrooms poisonous?

Most aren't dangerous, just not worth eating. The problem is that the group contains three different kinds of toxin, and two of them can kill.

Amatoxins: liver damage. This is the toxin of the death cap. Symptoms start only 6 to 24 hours after the meal, the person often feels better for a day or so, and meanwhile the liver is being destroyed. Cooking doesn't break it down.

• The funeral bell (Galerina marginata) grows on rotting wood, stumps, moss and wood chips. It's dangerous mainly because it looks like the edible sheathed woodtuft: both have a brown cap, a ring and the same rusty-brown spore print.
• Pholiotina rugosa, a tiny relative of Conocybe with a fragile ring, found on flowerbeds, compost and mulch. It contains amatoxins. We found no documented poisonings, but that doesn't make it safe: its toxin is the death cap's.
• Small dapperlings: the deadly dapperling, Lepiota helveola and Lepiota subincarnata. Strictly speaking they aren't brown-spored LBMs, as their gills and spores are white. But they're small brownish mushrooms with scaly caps, they grow in parks, gardens and grassy places, and that's exactly where people pick them by mistake. Fatal poisonings have been recorded in Europe and Asia.

Orellanine: kidney damage. Fool's webcap and the deadly webcap (Cortinarius rubellus) contain it. To be fair, they're larger than a typical LBM, with orange-brown caps 3 to 8 cm across. But they have rusty spores like hundreds of other similar webcaps, which is why they belong here. Symptoms can take several days, sometimes up to three weeks, by which time the kidneys are already damaged. More in webcaps: how to recognize the genus and why to leave them be.

Muscarine: fast-acting poisoning. It has been found in most of the fibrecaps ever tested, including the white fibrecap, the split fibrecap and the deadly fibrecap, as well as the fool's funnel and even the lilac bonnet. Within 15 minutes to 2 hours come heavy sweating, drooling, watery eyes, stomach pain and a slow pulse. Most people recover with hospital care, though a few deaths have been recorded. There are around 470 fibrecap species in Germany and neighbouring countries alone, and most have never been tested, so none should be assumed safe.

Psilocybin mushrooms. The liberty cap and a few other small brown mushrooms contain psilocybin. In Ukraine, where MycoNote is based, any part of a mushroom containing psilocybin or psilocin is on the government's list of especially dangerous psychotropic substances, and handling it is prohibited (Cabinet of Ministers Resolution No. 770). The bigger safety issue: people looking for these mushrooms have repeatedly picked funeral bells or webcaps instead and ended up in hospital with liver or kidney damage.

The harmless majority. The LBMs you'll meet most often are harmless or simply inedible: brittlestems, twiglets, toughshanks, most bonnets, the brown mottlegill. The trouble is that nobody can tell them from the dangerous ones by eye.

Little brown mushrooms in your lawn

The most common one on a mown lawn, the brown mottlegill (Panaeolina foenisecii, also called the lawnmower's mushroom), usually does people no serious harm. But the same lawn or flowerbed can also grow mushrooms with amatoxins, and you can't tell them apart by looking.

The brown mottlegill is inedible. Its brown cap is 1 to 3 cm across and dries paler in bands; the stem is thin and fragile. Poison centres in Germany and Switzerland followed 19 cases in which toddlers ate one to five caps confirmed by a mycologist, and none had serious symptoms or hallucinations. Whether it contains traces of psilocybin is still debated.

A lawn rarely belongs to one species, though. Conocybe, Pholiotina rugosa, fibrecaps, funnels and small dapperlings turn up in the same places.

This is the fairy ring champignon, an edible mushroom that also grows in rings in grass. Its white-spored neighbours, the fool's funnel and small dapperlings, can grow in the same turf. People picking fairy ring champignons have eaten Lepiota subincarnata instead: in Genoa in 2023 one ended up in intensive care, and near Vancouver a man died.

If a child has eaten a mushroom from the lawn, call emergency services (112 across Europe) or your poison centre straight away, without waiting for symptoms, and keep the rest of the mushrooms. Parents have no way of knowing whether it was a harmless mottlegill. Ukraine's health ministry advises not giving wild mushrooms to children under 12 at all.

If your dog has eaten one, go to the vet immediately and bring the mushroom or a photo. Dogs have died from muscarine mushrooms growing in grass and from funeral bells.

What a spore print can and can't tell you

A spore print narrows down the genus, but it can't tell edible from deadly.

Cut the cap off a mature mushroom and lay it gills down on paper that's half white and half black. Cover it with a glass to keep out drafts and leave it for a few hours or overnight. The colour of the dust points to a group:

• white: fairy ring champignon, funnels, bonnets, toughshanks, dapperlings;
• rusty brown: funeral bell, sheathed woodtuft, Conocybe, webcaps, twiglets;
• dull brown: fibrecaps, poisonpies (Hebeloma), fieldcaps (Agrocybe);
• purple-brown to almost black: brittlestems, Psilocybe;
• black: mottlegills, inkcaps.

Here's the catch. The deadly funeral bell and the edible sheathed woodtuft leave the same rusty-brown print. So do the amatoxin-bearing Pholiotina rugosa and harmless Conocybe. And the edible fairy ring champignon shares its white print with the poisonous funnels and dapperlings growing next to it. A spore print helps with the genus, not with whether you can eat it.

How to get a little brown mushroom checked

Photograph it from every side: the cap from above, the gills from below so you can see how they meet the stem, and the whole stem. Dig the mushroom up with its base rather than cutting it. Show what it was growing on (soil, grass, rotten wood, moss or wood chips), which trees were nearby, and put a coin next to it for scale. A photo of the spore print helps a lot. For the full shot list, see how to photograph a mushroom for ID.

Post your find to our mushroom identifier and other foragers will try to help. For LBMs, "genus only" or "can't be identified from a photo" is a normal answer, and it's what a mycologist would say too. Don't rely on ID apps here: tested on mushrooms from real poisoning cases, even the best one was wrong about half the time. More on that in mushroom ID apps: can you trust them?

One rule covers the whole group: don't eat little brown mushrooms. Even when one looks familiar.

If someone has already eaten one

Call emergency services (112) or your poison centre at once, without waiting for symptoms. Poisoning by funeral bells and webcaps shows up late, and every hour of waiting counts against the patient. Don't treat it yourself and don't drink alcohol. Keep the leftover mushrooms, the dish or at least a photo, so doctors and a mycologist can work out which toxin they're dealing with. No amount of cooking destroys these toxins. More in mushroom poisoning: symptoms and first aid.