Studying Mushrooms > Using a Microscope > The Stem Surface


Using a Microscope: The Stem Surface

by Michael Kuo

To create a section that allows you to study the surface of the stem, use the method illustrated in the graphic below and crush the section gently in a stained or unstained KOH mount. The triangle shape is not, strictly speaking, necessary--but it has the advantage of making it easier to remember which edge of your section actually represents the stem's edge.

Sectioning a Stem

What you will find under the microscope on the stem's surface varies greatly, of course, between mushrooms. For casual mycological microscopists, the most common reason for analyzing the stem's surface is to check for the presence of caulocystidia, which are more or less like cystidia on the gills or cap surface. If you are working with the genus Suillus, microscopic analysis can sometimes confirm the presence of glandular dots, which can be frustratingly hard to see with the naked eye.

In the illustration below, the left and middle photos represent the stems of a "normal" Black Morel and the morel I have called the "Black Foot Morel," respectively. The Black Foot's stem features bundles of caulocystidia-like cells that turn brown in KOH, while the "normal" morel stem features occasional strings of chained-together, blob-ish cells that do not turn brown. The right-hand photo represents a single glandular dot on the stem of Suillus neoalbidipes.

Stem surfaces

Cite this page as:

Kuo, M. (2006, February). Using a microscope: The stem surface. Retrieved from the MushroomExpert.Com Web site:

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