What to illustrate and how to do it?
In the field
Because the mycological terminology is still too ambiguous, illustrations remain very important to explain detailed morphology.
It is extremely important to keep in mind that drawings are of little or no value if they lack precision. Therefore, microscopic features should preferably be drawn with the help of a camera lucida or a mirror at the highest magnification possible: 400 × for sections and surface views and no less than 2000 × for spores and 1000 × for other elements.
Sections of tissues are particularly useful to illustrate the different layers at the surface of the fruit body, in particular the structure of the pileipellis, but also gill sections showing composition of lamellar trama and subhymenium can be very informative. Implantation and distribution of various cell types, such as cystidia and dermatocystidia, or the thickness of individual tissue layers are easily observed.
Cutting a extremely thin slice of the surface of cap or stipe is a first necessary step when making squash preparations. Observing the slice before proceeding with the actual dispersal of the individual cells by squashing the preparation can be very informative, particularly in Lactarius and some groups of Russula with inflated elements in the cap. In Lactarius, surface views often allow to differentiate between closely related taxa.
For more examples see the following articles:
Buyck, B. & Schoonackers, M. (1986) – Het genus Lactarius Fries in Vlaanderen, een microscopische studie (deel 1). Meded. Antwerpse Mycol. Kring 87 (1): 11-25.
Buyck, B. & Schoonackers, M. (1987) – Het genus Lactarius Fries in Vlaanderen, een microscopische studie (deel 2). Meded. Antwerpse Mycol. Kring 87 (2): 34-46.
Buyck, B. & Schoonackers, M. (1987) – Het genus Lactarius Fries in Vlaanderen, een microscopische studie (deel 3). Meded. Antwerpse Mycol. Kring 87 (4): 110-119.
Russulales are blessed with several different cell types making it possible to exploit a relatively high number of different microscopical features to distinguish between taxa. Size and shape of various cell types such as spores, dermatocystidia and hyphal extremities in cap and stipe are regularly used to describe and identify species. Although less often used for identification, the various cell types composing the hymenium (basidia, cystidia, marginal cells and pseudocystidia) are also taxonomically important to describe.
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