# Cystidium

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Fungus cell type

"Cystidia" redirects here. For the moth genus, see [*Cystidia* (moth)](/source/Cystidia_(moth)).

Two chrysocystidia on gill face of *Hypholoma lateritium*, mounted in KOH.

A **cystidium** (pl.: **cystidia**) is a relatively large cell found on the [sporocarp](/source/Sporocarp_(fungi)) of a [basidiomycete](/source/Basidiomycete) (for example, on the surface of a [mushroom](/source/Mushroom) gill), often between clusters of [basidia](/source/Basidium). 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

Metuloid-type cystidium of *[Inocybe](/source/Inocybe)*, stained with [Congo red](/source/Congo_red)

### By position

Cystidia may occur on the edge of a [lamella](/source/Lamella_(mycology)) (or analogous [hymenophoral](/source/Hymenophore) 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](/source/Stipe_(mycology)) (**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](/source/Ammonia) or other [alkaline](/source/Alkaline) compounds. Chrysocystidia are characteristic of many (though not all) members of the [agaric](/source/Agaric) family [Strophariaceae](/source/Strophariaceae).

**Gloeocystidia** have an oily or granular appearance under the microscope. Like [gloeohyphae](/source/Gloeohypha), they may be yellowish or clear ([hyaline](/source/Hyaline)) and can sometimes selectively be coloured by sulphovanillin or other reagents.[1] **Metuloids** are thick-walled cystidia with an apex having any of several distinct shapes.[2]

## References

1. **[^](#cite_ref-1)** Moser M (translated by S Plant). 1983. *Keys to Agarics and Boleti*. Roger Phillips. [ISBN](/source/ISBN_(identifier)) [0-9508486-0-3](https://en.wikipedia.org/wiki/Special:BookSources/0-9508486-0-3).

1. **[^](#cite_ref-largent_2-0)** Largent D, et al. 1977. *How to Identify Mushrooms to Genus III: Microscopic Features*. Arcata, CA: Mad River Press. [ISBN](/source/ISBN_(identifier)) [0-916422-09-7](https://en.wikipedia.org/wiki/Special:BookSources/0-916422-09-7).

## External links

- [BCERN Glossary: Cystidia](https://web.archive.org/web/20060526103839/http://www.pfc.forestry.ca/biodiversity/ecto/glossary/cystidia_e.html)

- ["Using a Microscope: Basidia and Cystidia" by Michael Kuo. *MushroomExpert.com*](http://www.mushroomexpert.com/microscope_cystidia.html)

- [Wild Mushrooms from Tokyo: Inocybe nodulosospora](http://www.ne.jp/asahi/mushroom/tokyo/Inocybe/kobuasetake/kobuasetake.htm) – Includes very good photograph of cystidia.

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