Spore Prints and Identification
I am on a few facebook fungi groups and one of the continuing frustration is the posting of pretty photos that lack and diagnostic characters. Generally, it is almost unidentifiable.
The characteristics we use for identifying fungi were first defined by Elias Magnus Fries (Swedish) who published a series of books between 1821 and 1874. In these books, he developed a classification system using spore colour and the arrangement of the spore-bearing tissue (gills, pores, teeth etc) as key characteristics. While molecular techniques have in recent years resulted in a lot of rearrangement of species the key characteristics are still the bases for field identification.
The arrival of smartphones means that we all now carry a digital camera so information can be quickly recorded. The majority of photos on my blog have been taken with smartphones and not stand alone cameras.
A bread and butter knife
When I am out looking at fungi I always carry my phone, a $1 coin, and an old bread and butter knife. I use the knife to dig up the mushroom I want to photograph so as to make sure that I get the base of the stem.A dollar coin
I then lay the mushrooms out so as to see the top of the cap, the underside of the cap so as to see the gills/pores/teeth, any ring or structures on the stem, and whether or not there is a bulb or other structures at the base of the stem.I include the $1 coin in the photo for scale. I also will include the leaves of any dominant plants just to remind me about the habitat. A smartphone
I may take all of these photos in the field or I might also take some when I get home (hence the carpet background in some photos.Then I make a spore print. The British mycologist George Massee described it this way in 1911:
It is wise … to prepare spore-prints … To do this, a mature agaric (mushroom) should have the stem cut off close to the gills, then place the cap gills downward, on a piece of paper, and cover the whole with a tumbler, basin, etc., to prevent undue evaporation. After an interval of eight to twelve hours, if the cap is carefully lifted up, a perfect impression of the interspaces between gills will be formed on the paper by the deposited spores.
A sheet of white paperI always make my spore prints on good quality white photocopier/printer paper. Some people say to use black paper for white-spored species but I find that white paper lets you see the difference between white, cream and pale yellow spores which is less obvious on black paper. I also will wet the tips of my fingers and flick a little water on to the top of the cap before covering it as this will help to maintain the humidity. It’s also worth noting the other reason for covering the caps is to stop air movement carrying the spores away and instead they drop straight to the surface of the paper. Although only gill mushrooms are mentioned it can be used for mushrooms with pores and teeth and for coral fungi as well. When you uncover the finished spore print you should record the spore colour as soon as possible as the spores will begin to dry out and may change colour slightly. Have a good look at these two spore prints. They superficial are dark or black prints. However, the one on the left is a very dark chocolate brown going on to brown-black. Whereas, the one on the right is a dark purple-brown. While not necessarily useful at the species level it can be useful for separating genera. In this case Leratiomyces on the left and Psilocybe on the right.
The spore print can be folded in half and stored in an envelope indefinitely.