A cystidium (: cystidia) is a relatively large cell found on the sporocarp of a basidiomycete (for example, on the surface of a

mushroom A mushroom or toadstool is the fleshy, spore-bearing Sporocarp (fungi), fruiting body of a fungus, typically produced above ground on soil or another food source. ''Toadstool'' generally refers to a poisonous mushroom. The standard for the n ...

gill), often between clusters of basidia. Since cystidia have highly varied and distinct shapes that are often unique to a particular species or genus, they are a useful micromorphological characteristic in the identification of basidiomycetes. In general, the adaptive significance of cystidia is not well understood.

Classification

By position

Cystidia may occur on the edge of a lamella (or analogous hymenophoral structure) (cheilocystidia), on the face of a lamella (pleurocystidia), on the surface of the cap (dermatocystidia or pileocystidia), on the margin of the cap (circumcystidia) or on the stipe (caulocystidia). Especially the pleurocystidia and cheilocystidia are important for identification within many genera. Sometimes the cheilocystidia give the gill edge a distinct colour which is visible to the naked eye or with a hand lens.

By morphology

Chrysocystidia are cystidia whose contents contain a distinct refractive yellow body, that becomes more deeply yellow when exposed to

ammonia Ammonia is an inorganic chemical compound of nitrogen and hydrogen with the chemical formula, formula . A Binary compounds of hydrogen, stable binary hydride and the simplest pnictogen hydride, ammonia is a colourless gas with a distinctive pu ...

or other

alkaline In chemistry, an alkali (; from the Arabic word , ) is a basic salt of an alkali metal or an alkaline earth metal. An alkali can also be defined as a base that dissolves in water. A solution of a soluble base has a pH greater than 7.0. The ...

compounds. Chrysocystidia are characteristic of many (though not all) members of the agaric family Strophariaceae. Gloeocystidia have an oily or granular appearance under the microscope. Like gloeohyphae, they may be yellowish or clear (

hyaline A hyaline substance is one with a glassy appearance. The word is derived from , and . Histopathology Hyaline cartilage is named after its glassy appearance on fresh gross pathology. On light microscopy of H&E stained slides, the extracellula ...

) and can sometimes selectively be coloured by sulphovanillin or other reagents.Moser M (translated by S Plant). 1983. ''Keys to Agarics and Boleti''. Roger Phillips. . Metuloids are thick-walled cystidia with an apex having any of several distinct shapes.Largent D, et al. 1977. ''How to Identify Mushrooms to Genus III: Microscopic Features''. Arcata, CA: Mad River Press. .

References

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External links

BCERN Glossary: Cystidia

* ttp://www.ne.jp/asahi/mushroom/tokyo/Inocybe/kobuasetake/kobuasetake.htm Wild Mushrooms from Tokyo: Inocybe nodulosospora– Includes very good photograph of cystidia. Fungal morphology and anatomy