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Field Characteristics

Important field characteristics:

It is important to familiarise yourself with the significant macroscopic features that will help you to identify your mushroom or toadstool. The following information will help to focus you. 
The three most important features that you will need to take account of are:
  • The spore colour
  • The type of gill attachment
  • The shape of the stem / stipe (particularly the base)

Fig. 1:
The surface and surrounding vegetation are covered in thick cocoa-like spore deposits from this Ganoderma.

Fig. 2:

Folds e.g. Cantharellus

Pores e.g. Suillus



Fig. 3:
Sinuate or emarginate gills

Decurrent gills






Fig. 4:

Bulbous stem base

Rooting stem


Fig. 5:

Cobwebby partial veil or cortina still partially intact on the younger fruit body



















Fig. 6:
Amanita fulva showing 
distinct volva


Membranous volva of Amanita phalloides


Fig. 7:


Some caps are covered with small scales like this one. Nothing to do with any veil remains.

Some caps are apparently covered in fine hairs.


Fig. 8:
Pink milk of Lactarius acris

Spore colour:

You may be able to find evidence of the spore colour on leaves or other caps below your toadstool (Fig. 1). It is however strongly recommended that you take a spore print, as most keys will start by asking you the colour of the spores. Spores vary considerably in colour between the genera.


Spore producing surfaces of mushrooms and toadstools:

Before deciding on the gill attachment you need to be able to distinguish the different spore producing surfaces (i.e. hymenium) in toadstools (Fig. 2):

  • Gills e.g. Agaricus, Collybia, Conocybe, Hygrocybe, Lepiota, Mycena etc 
  • Folds - like blunt edged gills e.g. Cantharellus, Craterellus. 
  • Pores e.g. Boletus, Leccinum, Stobilomyces, Suillus, Tylopilus. 
  • Teeth e.g. Auriscalpium, Bankera, Hydnellum, Hydnum, Phellodon, Sarcodon.

Gill attachments: 

Examine specimens to familiarise yourself with the basic types of gill attachments (Fig. 3). 
  • Adnate – gill attached to stipe by its full depth e.g. species of Agrocybe, most species of Conocybe, Galerina, Russula and many others. 
  • Adnexed – gill much narrower where attached to the stipe. Many species have this gill attachment.
  • Decurrent – gills extend downwards on the stipe e.g. species of Clitocybe, Omphalina, Rickenella. 
  • Free – gills not attached to the stipe e.g. species of Amanita, Lepiota, Pluteus. 
  • Sinuate – gill has a concave indentation near the stipe e.g. species of Cortinarius, Entoloma, Tricholoma. 

Stipe (stem) shapes (Fig. 4):

  • Bulbous base e.g. some Inocybe (I. rimosa, I. maculata). 
  • Marginately bulbous base e.g. some Cortinarius,Inocybe (I. cookie, I. grammata, I. godeyi, I. napipes). Rooting base e.g. Hebeloma radicosum, Hypholoma radicosum, Xerula radicata. 
  • Tapering - most marked in Collybia fusipes.
  • Rooting stem








Ring types (Fig. 5):

Some of the cobwebby rings can disappear very quickly – don’t forget to check the stipe and edge of the cap for fibres that might be all that is left of a cortina (the name of a cobwebby veil). Having young material of your toadstool will help with this enormously.
  • Cobwebby ring or cortina this is a key feature for the huge genus Cortinarius but not unique to this genus.Cortinas also occur in someHebeloma, Inocybe andLepiota species.
  • Double ring e.g.Macrolepiota species
  • Hoop like ring e.g. Coprinus comatus, Amanita pantherina.
  • Pleated skirt like ring e.g.Amanita excelsa.
  • Skirt like hanging ring e.g.Amanita muscaria, A. phalloides.
  • Stocking like / sheath like e.g. Cortinarius torvus, Phaeolepiota aurea.

Volva types (Fig. 6):

In Britain, only Amanita species (white spores), Cortinarius caperatus (a brown spored species with a very weak volva, appearing as Rozites caperatus in any but the most recent books) and Volvariella species (pink spored), have volvas. The nature of the volva is very important in identifying Amanita species. Note that if the toadstool is not collected properly, it is easy to loose this feature. 


Volvas will vary from large membranous sac like structures that the stem is sitting in, to concentric rings of veil material, both types left behind at the bottom of the stem when the fruit body expanded and broke the veil.




Cap shape, colour and consistency:

A small, labelled sketch of your collection can give you as much information as a page full of notes. Look at the outline of the cap - is it conical, flat or with a central depression or nipple. Is the surface smooth, radially fibrillose, scaly (Fig. 7). Is it dry, sticky or covered in gluten (remember this will vary according to the weather). If possible comment on how these features might have changed as the fruit body expands to maturity. Write down what you see - it is unlikely to look exactly like the pictures in field guides.







‘Milking’ - or not (Fig 8)

The exudation of a milky fluid or latex when flesh or gills are damaged is a characteristic feature of the genus Lactarius and a primary difference between this genus and Russula. The colour of the fluid, whether the colour changes and whether it is hot or mild (see also ‘Taste’) are all useful aids to species identification. Here are some characteristic milk colours and tastes.

N.B. only taste a small amount and do not swallow it.














Gills e.g. Russula


Teeth e.g. Hydnum




 
Adnate gills
Adnexed gills





Marginate stem base

















The skirt-like ring ofAmanita muscaria.






















Friable volva as concentric rings at the base of the stem of Amanita muscaria.


















Some caps are radially fibrillose and have a sharp bump or umbo in the centre.















Yellow milk of Lactarius chrysorrheus

Cap cuticle – does it peel?

This character is particularly important in identification of Russula species. Try examining a range of species to see how much they peel. The best technique to use for this character is to pinch the edge of the cap with the fingernails and gently peel back the cuticle until it breaks.
  • Peels completely e.g.Russula betularum, R. emetica, R. fragilis, R. lutea. 
  • Peels ¼ to ¾ of cap radius e.g. R. atropurpurea, R. claroflava, R. cyanoxantha, R. ochroleuca.
  • Peels hardly at all (up to 1/5) e.g. R. chloroides, R. decolorans, R. delica, R. lepida, R. sardonia.

Smell: Check out with your nose!

Some people find this character very difficult. Practice does help, particularly with naming the smell! Note that very old, very dry or very wet material is unlikely to hold the smell typical of a particular species. Smell is best detected by sniffing the gills of the toadstool and if necessary by bruising them. Occasionally the smell is confined mostly to the base of the stem (Russula turci – iodoform,Cortinarius stillatitius - honey). Always check the smell at the time of collection and make a note – sometimes the smell is fleeting.Here are some common smells.

Taste:

Only taste a collection if a key or book specifically indicates that it is of significance. For Russula andLactarius species, taste is particularly important. For Russulatake a very small portion of the gills on the tongue and do not swallow. For Lactarius see ‘Milk’ above.
  • Usually acrid, hot or peppery e.g. Chalciporus piperatus, Russula betularum,R. sardonia, Tricholoma album.
  • Usually mild e.g. Russula adusta, R. cyanoxantha, R. heterophylla.
  • Usually bitter e.g. Boletus calopus, Tricholoma sejunctum, Tylopilus felleus.
  • Meally e.g. Entoloma sericuem, Tricholoma portentosum.
  • Nutty e.g. Boletus edulis.
  • Bad cabbage e.g.Hemimycena mairi(when chewed – hmm, yummy!)

Other features to note:

Flesh brittle of cheesy consistency – this means a dry crumbly cheese like Cheshire or Wensleydale! It is specifically characteristic of Russula and Lactarius and is particularly noticeable in the gills. This is because of the cell structure in the flesh particular to these two genera.

Stipe tough and fibrous or cartilaginous - this is a feature particularly of Collybia andMarasmius. Marasmius collections can be revived by wetting after drying out – you might like to try this out.

Useful references for macro features:

  1. Marriott J.V.R. 1994 Guides for the amateur mycologist 2. Guide to identification with a microscope. British Mycological Society
  2. Stuntz D.E. & Largent D.L. How to Identify Mushrooms to Genus: Macroscopic Features v. 1. Mad River Press
  3. Watling R. 1973 Identification of the larger fungi. Hulton Educational Publications Ltd. (out of print)