Caps on stems; gills below caps [mushrooms or mushroom-like]


Almost all members of this group have the fleshy fruitbodies that are commonly called mushrooms. You also see them referred to as toadstools, but mushrooms will be the term used here. On the underside of the cap are the gills, extending in from the margin towards the stem. Usually gills come in a range of lengths, from very short to long and, in most species, the long gills reach the stem. If no gills reach the stem, the species is said to have free gills.

 

A universal veil is a membrane that envelopes the entire mushroom at the button stage and, as the stem expands, that veil is ruptured and may leave traces as a cup-like surround (volva) or ridges around the base of the stem or as irregular wats or flakes of tissue on the cap. A partial veil covers the gills in an immature mushroom (and is called a cortina if it has a flimsy, cobwebby appearance) and extends from the edge of the cap to the stem. As the cap expands, the partial veil breaks and may leave traces as a collar of tissue (a ring or annulus) around the stem  or as wispy, hard to see filaments on the stem in the case of a cortina. In some genera both types of veil are present, in some only one type is present and in many neither is present. Veil remnants may erode away over time.

 

In fungal field guides you see the word agaric, a collective term for fleshy fruitbodies that have a cap with gills below. A mushroom is a stemmed agaric and there are also stemless agarics.

 

In the following hints you see examples of useful identification features and a few of the more commonly seen genera in which at least some species (not necessarily all) show these features. The lepiotoid genera are: Chlorophyllum, Lepiota, Leucoagaricus, Leucocoprinus, Macrolepiota.

 

Hints

Gills white: Amanita, Armillaria, Mycena, Russula, lepiotoid genera.

Gills faintly pink: Entoloma, Pluteus, Volvopluteus.

Gills rusty brown: Cortinarius, Gymnopilus.

Gills dark chocolate brown: Agaricus, Agrocybe.

Gills purplish-brown to black: Coprinus, Hypholoma, Leratiomyces, Panaeolus, Psilocybe, Stropharia.

 

With a volva (possibly buried): Amanita, Volvopluteus.

Stem with a ring: Agaricus, Agrocybe, Gymnopilus, lepiotoid genera.

With a cortina: Cortinarius, Gymnopilus, Hebeloma, Psilocybe.

 

With free gills: Agaricus, Amanita, Pluteus, Volvopluteus, lepiotoid genera.

 

Growing in dense clusters, all stems arising from the same point: Armillaria, Flammulina, Gymnopilus, Hypholoma, Mycena.

 

Mushroom bleeds when damaged: Lactarius s.l., Mycena.

Bright yellow gills that bruise blue-green: Phylloporus.

 

Leathery texture: Lentinus, Neolentinus.

Fresh mushroom snaps a bit like chalk: Lactarius s.l., Russula.

 

Stem short & well-off centre: Melanotus, Panellus.

 

The immature mushroom has a granular coating that is easily rubbed off and may disappear with age: Cystoderma, Cystolepiota, Leucocoprinus.

Cap with dark scales, in concentric rings, over a white base & with solid colour at the centre: several lepiotoid genera.

 

On twig/leaf litter: Marasmius, Mycena.

On herbivore dung: Coprinopsis, Panaeolus, Psilocybe, Stropharia.

 

Warnings

The mutual pressure of mushrooms that grow in dense clusters may produce some distorted fruitbodies with stems off-centre to some degree, but in species of Melanotus and Panellus the off-centre stem is normal.

 

Normally stemless agarics occasionally produce fruitbodies with very rudimentary stems. If your sighting has a very rudimentary stem you may need to check that group.

 

As a mushroom dries out, gills attached to the stem may tear away and seem free. If you look very closely (best with a 10x handlens) you would see ragged evidence of tearing, which you won’t see in free gills.


Caps on stems; gills below caps [mushrooms or mushroom-like]

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Discussion

Heinol wrote:
3 Feb 2026
When the mushroom is 9 mm tall you see it still enveloped in a veil. The bulge at the top shows you where the cap is developing but it is still concealed. The second photo (the mushroom now 17 mm tall) was taken 25 hours after the first and now the cap shows clearly, though it is yet to expand. Another 24 hours later you see that the stem has extended to 3 cm and the cap has expanded. The cap flesh is very thin and can shrivel quickly. This mushroom had grown from some damp wood that I’d kept in a lidded, plastic tub. When I took it out for the final photo the cap edge was a perfect circle but here you see it with a wavy margin. The cap is already beginning to dry out and shrivel. The brown hairs are composed of tufts of multi-celled hyphae and in the inset in the third photo I show such a tuft viewed through a microscope.

Coprinopsis sp.
Heinol wrote:
22 Jan 2026
A Nordic fungal monograph includes the rarely found, yellowish species Tricholomopsis ossiliensis, that keys out in a final couplet alongside decora. That monograph allows five levels of gill spacing – very crowded, crowded, medium spaced, distant, very distant. In both species the gills are described as medium spaced and, for ossiliensis they are noted as adnate or with a short decurrent tooth. These two species are reported on decaying conifer wood and (according to GBIF, with the cf. decora of Tasmania and some environmental DNA from Thailand excluded) they have been reported only from the Northern Hemisphere. So, while I don’t think this is decora, the visual similarity prompted ‘decora group’ as a reasonable pigeonhole. I looked through NatureMapr’s unidentified agarics to see if there were any more sightings of this but didn’t find any.

Tricholomopsis 'decora group'
KenT wrote:
21 Jan 2026
With the Gates & Ratkowsky images of Tricholomopsis neither of their species show widely spaced decurrent gills that are present in the images presented here. I don't know how much weight the old physical characters have in generic and species determination in these times of modern molecular identification.

Tricholomopsis 'decora group'
Heinol wrote:
21 Jan 2026
Given the large size and the excentric stem I had assumed Pleurotus and, until yesterday, had not thought about it nor looked any further at it after collecting the specimens. The microscope showed this fungus to have colourless, warty spores – so not a species of Pleurotus. Lepista – or something closely related.

Lepista sp.
Heinol wrote:
21 Jan 2026
I've since seen that the Tasmanian fungal guide by Gates & Ratkowsky includes a photo of a Tricholomopsis that they label 'cf. decora'.

Tricholomopsis 'decora group'
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