'', stained with
Congo red 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 or other
alkaline 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) and can sometimes selectively be coloured by sulphovanillin or other reagents.
Metuloids are thick-walled cystidia with an apex having any of several distinct shapes. ==References==