Mushroom anatomy in photos: cap, gills, ring and volva

The mushroom we pick in the forest is only the fruiting body, while the organism itself is the mycelium (the fungal network) in the soil or wood. The fruiting body has a cap, beneath it the hymenophore (gills, tubes or folds), a stem, and in many species also a ring, volva, bulb or cobweb veil. Each of these details is more than textbook anatomy: it is a feature that tells an edible mushroom from a deadly one.

Below we'll go over a mushroom from top to bottom. All the photos are our own, taken in the forest from spring to October 2026 (and one from April 2025).

Mycelium and fruiting body

The real fungus lives underground. It is a tangle of fine threads, the hyphae, that grows for years in leaf litter, soil or rotting wood and feeds from there. When the mycelium has enough moisture and warmth, it “throws up” a fruiting body — the very mushroom with a cap. Its only job is to scatter spores.

For a forager, this leads to two practical conclusions. First: a carefully picked mushroom does not destroy the mycelium; what harms it is disturbed and trampled leaf litter. Second: this is exactly why mushrooms come up in the same spots year after year. More on this in the article how mycelium grows.

Cap

The cap is the “roof” that shelters the spore-bearing layer. Foragers look at its shape, colour, surface (dry, velvety, slimy, scaly) and margin (smooth, inrolled, grooved).

In a young parasol mushroom the cap is still egg-shaped, densely covered with brown scales, and only later opens into a wide “umbrella”. The photo below shows just such a young parasol in a pine and oak forest, with another one lying beside it, pulled up together with its base.

Important: you can almost never identify a mushroom by its cap alone. The colour fades in the sun, rain washes the scales off, slime dries out. The cap is only the first stroke of the portrait.

Hymenophore: what's under the cap

Turning a mushroom over is the very first habit of an experienced forager. Under the cap sits the hymenophore, the layer on which the spores ripen. The three most common types are gills, tubes with pores, and folds (as in the chanterelle). Less often there are spines, as in the wood hedgehog, or an almost smooth spore-bearing layer. We made a detailed comparison with examples in the article pored vs. gilled mushrooms, and here we'll show what it looks like in real life.

Gills are thin plates that radiate from the stem to the edge of the cap like spokes. Here is a red brittlegill on a palm: crowded cream gills and a firm white stem with no ring.

Gill colour is one of the most important features. In plums and custard they are sunny yellow and contrast sharply with the purplish scaly cap. In the death cap, on the other hand, the gills stay white all their life and never turn pink or brown, as they do in Agaricus mushrooms. White gills together with a ring and a volva are a signal to stop.

Tubes and pores. In boletes, the underside of the cap is a sponge of tightly packed tubes, and from below we see their openings, the pores. In the larch bolete the pores are small, angular and bright yellow.

In the weeping bolete, white droplets of juice bead on the pores of young mushrooms. As they dry, they leave the very “granules” on the stem that gave the mushroom its Latin name, granulatus.

Pore size is a clue too. In the suede bolete the angular yellow pores are noticeably wider than in porcini and turn blue when pressed. Why that is nothing to fear, we explain in the article why Xerocomus boletes turn blue when cut.

Compound pores. In the bovine bolete, large angular pores are divided by thin walls into even smaller ones, like a honeycomb. This is its “signature”: if you see such a honeycomb under a brown cap in a pinewood, it is most likely a bovine bolete.

Milky latex

Some gilled mushrooms “weep” juice when damaged. This is what milk caps do, a group that includes the various milk caps, saffron milk caps and woolly milk caps (mycologists now split them into two genera, Lactarius and Lactifluus). This feature sets them apart from their closest relatives: a brittlegill, similar in appearance, gives no juice. Just remember that an old milk cap, or one dried out in the heat, may have very little latex, so break a fresh gill. The colour of the latex and how it changes in the air help tell milk caps apart from each other.

Here you see the ugly milk cap that we laid on its side next to a knife: where the blade nicked the gills, white drops of milky latex appeared.

Cobweb veil (cortina)

In many young mushrooms, the gills are at first covered by a thin film, the partial veil. When the cap opens, the film tears. In webcaps it is not solid but looks like a cobweb, which is why it is called a cortina. It leaves fine fibres on the stem, which the ripe spores stain rusty brown.

Here is a webcap from the side among the leaves: violet gills under a brown cap and a lilac stem base. You can't name its species from the photo: several webcaps have violet gills, and in the violet webcap the cap is violet too.

Why it matters: among webcaps there are deadly poisonous species, such as the fool's webcap. Its toxin, orellanine, damages the kidneys, and the first symptoms usually appear a week or two later, when the mushrooms have long been forgotten. So a cobweb veil and rusty-brown spores are a reason for a beginner not to take the mushroom.

Ring

The ring is what remains of that same partial veil, left on the stem as a “skirt”. In a mature fly agaric a white membranous ring hangs from the stem under the cap, and it is easy to see even from a distance. In the spring fieldcap, however, the ring is thin and fragile and often disappears in mature mushrooms, so the absence of a ring does not prove there never was one.

A ring guarantees nothing on its own: it is found both in tasty Agaricus mushrooms and in the deadly death cap. But together with white gills, a ring should make you check the base of the stem. And in the parasol mushroom the ring is thick and movable: you can slide it up and down the stem. We've gathered what else a ring can tell you in the article mushrooms with a ring on the stem.

Volva

Volva is a sac or shell at the base of the stem, a remnant of the universal veil that wrapped the whole young mushroom like an egg. A sac-like volva is most often found in amanitas, including the deadly death cap, but not only in them: it is also present in Volvariella species, whose gills turn pink with age, and in the “egg” of the stinkhorn. So a volva is a signal to stop, not a precise identification. And the reverse: its absence does not mean “not an amanita”, because the fly agaric and the panther cap have only bands and flakes on the bulb instead of a sac. Besides, a volva can be fragile and is often completely hidden in the leaf litter.

Here you see the tawny grisette, an amanita without a ring. All three of its telltale features are visible here: the grooved cap margin, the ringless stem and the white sac-like volva sticking out of the ground.

Hence a rule that saves lives: an unfamiliar gilled mushroom is not cut with a knife at ground level, but carefully twisted out or dug up so you can see the base (more on this in cut or twist?). A cut-off stem base with its volva stays in the leaf litter, and a death cap in your basket starts to look like a brittlegill. Read more about it in the article death cap, the most dangerous mushroom in Europe.

Bulb

Not every swelling at the bottom of the stem is a volva. In a young parasol mushroom the base is noticeably swollen, like a bulb, but there is no sac around it: it is simply a widened stem. On the palm is that same young parasol, its base still covered in soil.

Amanitas have a bulb too, but there it either sits in a sac-like volva, has a distinct rim, or is girdled with ring-like bands and flakes. So when you see a bulb, take a closer look: is it just a swelling, or the remains of a veil?

Stem: net, scales, pattern

The surface of the stem is another important feature, especially in pored mushrooms.

Net. In porcini, the stem is covered with a raised pale net. In the photo: a summer bolete: a pale net on the stem, and under the cap a white tube layer that turns yellow and then green with age. A dark brown net on the stem should put you on guard: this is how the bitter bolete looks. But on its own the net proves nothing, because in some porcini, for example the bronze bolete, the net is brownish too. The main difference of the bitter bolete is its tubes, which turn pink with age, and its very bitter flesh.

Scales. In the brown birch bolete the pale stem is densely covered with dark scales, a feature of the whole genus of birch and aspen boletes. From a low angle you can see the mushroom's whole structure: a domed cap, and beneath it a scaly stem.

Pattern. In the parasol mushroom, the stem is covered with brown crosswise bands, like snakeskin — you can already see it in the first photo above.

What's inside: the cross-section

Cutting a mushroom lengthwise is the easiest way to see what you can't see from the outside: the colour of the flesh, how it changes in the air, insect tunnels and hollows.

The best example is spring mushrooms. In the black morel the cap and stem are fused, and inside there is a single continuous hollow with no cottony filling and no partitions. We cut it in half right on our palm in April 2025.

In the dangerous false morel a cut does not show one clean hollow: the cap and stem are divided into several irregular chambers and pockets, and in places the flesh is solid. And in the early false morel the cap is attached to the stem only at its very top and hangs like a hood, while the stem of a young mushroom is stuffed with cottony fibres. One cut, and the question is settled. More on this in the article false morel: why this spring mushroom is dangerous.

How to examine a find: a quick routine

• Look at the cap: shape, colour, surface, margin.
• Turn the mushroom over: gills, tubes or folds, and what colour they are.
• Break off a bit of gill: does juice appear, and what colour is it?
• Examine the stem: ring, cobweb fibres, net, scales.
• Carefully free the base from the leaf litter: is there a volva, or a bulb with flakes?
• Cut the mushroom lengthwise: flesh colour, change in the air, hollows.

No single feature proves anything on its own — a mushroom is identified only by the combination. And if even one detail doesn't fit, the mushroom stays in the forest.