Professional mycologists often have to resort to a microscope and the minute details of spore shape, size and colour to identify species. Amateur mycologists are usually interested in what are known as macrofungi, which are the ones big enough to see and describe with the naked eye. Even so, a hand lens is very useful for examining features, and a dentist's mirror handy for looking at the undersides of mushroom caps.
Most fungi of interest to the amateur are of the typical mushroom shape, with a stalk sticking out of the ground, and with a cap on top. But these are not the only kinds you might see on a fungus foray. There are jelly fungi, such as Tremella or Heterotextus, easily recognised because they look like jelly. There are earth stars and puff balls, which look like little golf balls with a hole in the top, and there are the stinkhorns, such as Anthurus archeri, which don't have a cap or gills, but do have a nauseating smell.
But, if your unknown fungus is of the mushroom type, here are the kinds of things we need to know before it can be identified:
- What shape is the cap (pileus)? What colour is it?
- Does it have gills? What colour are they, and how are they attached ?
- If it doesn't have gills, are there pores or spines under the cap?
- What is the colour of the stipe (stem)? Does it have a volva or ring? Does it attach centrally to the cap, or off to one side?
- What is the colour of the spore print?
- Does the stem (stipe) discolour when broken? Does it exude latex?
Cole, Fuhrer, and Holland (1978) recommend the following procedure:
Using a hand lens:
- First determine whether or not the gills are attached to the stem. You will probably need the lens to look at the point of gill attachment to the stem, or break the cap away from the stem to see.
- Determine the spore colour. A spore print is essential, but you may get a preliminary idea by looking along the gills, veil or ring with a hand lens.
- Work through the dichotomous key by comparing the choices ('ring' vs 'no ring').
- Eventually you will be led to a genus (e.g. Russula).
- Compare your specimen with the photographs, diagrams or descriptions given in your references.
- There are several errors you may make at first. These are (a) whether the gills are attached or free in some specimens; (b) whether gill attachment is short-decurrent, adnexed, etc.; (c) if cap shape is campanulate or umbonate expanding into a flat shape in older specimens.
The best way to find out the spore colour is to make a spore print. Here's how you do one:
- Place the cap (or a piece of cap) gills down on a piece of paper.
- Cover it with a container and leave for 2-3 hours
The gills will drop enough spores to give you a coloured print. Of course, if the spore print is white and you use white paper, it may be hard to see. Some people use acetate so they can change the background colour.