Species identification is one of the main tasks of lichenology. Lichen species identification is hard and effortful work carrying out of which requires good knowledge of anatomy and morphology of lichens. The only advantage here in comparison with other plants is that lichens have the same appearance all the year round, so they can be collected and identified both in summer and winter.
Identification is done through several steps. The first step is the field work during which the needed material is collected. The quality of the work is told on the further steps. One should take notice of small lichens besides noticeable ones because small forms often compose more than half of the lichen flora of any region. Collected lichens are packed and put into special packages. Each specimen must be labeled and contain information about the place, time, coordinates (if possible), characteristics of the habitat, substrate, the presumable species (genus or family) of the specimen and some data about the collector.
Microscopes, binocular microscope, water, reagent solutions, microscope slides and cover-slips, identification keys are needed for species identification. Sections of the thallus or spore-producing body are made with blades, soaked in water and examined with a microscope. Sometimes it is necessary to measure some structures like spores, asci and etc. in micrometers.
The reagents used during identification are:
K –10% potassium hydroxide (KOH). A small drop of reagent is added to the specimen to cause a colour reaction. The reaction is very fast. In the case of positive reaction specimen color turns yellow or red. The fact of positive reaction is mentioned as K+:
C – calcium hypochlorite Ca(ClO)2 water solution. Positive or negative reaction is mentioned as С+ or С- respectively. Some lichen species give a positive reaction only when the specimen is firstly soaked with K solution and then immediately with C solution (mentioned as КС+) but don’t give when used separately.
J– iodine in the form of Lugol’s solution. It gives blue or purple colour reaction in the presence of amyloid hyphae or gelatine. Postive or negative reaction is mentioned as J+ or J- respectively.
P– para-phenylenediamine C6H4(NH2)2 dissolved in sodium sulphite water solution. It is toxic and gives red, yellow or orange positive reaction when using it.
(Р+ or Р-):
Some other reagents such asHNO3, NH3, H2SO4, HCl are rarely used for specific colour reactions.
For preserving the preparation a drop of glycerin is added under the cover-slip and replaced by the concentric one some time later.
And after it the species is identified using appropriate identification keys.