Chrysocystidia are cystidia which have an amorphous internal body which is bright yellow in alkali solutions (such as KOH). When chrysocystidia are present, cystidia with the entire contents staining yellow in KOH are often also present.

The internal body of chrysocystidia also becomes strongly coloured in stains such as Cotton Blue.

Chrysocystidia are usually pleurocystidia (on the lamella face), but may also be cheilocystidia (on the lamella edge). They are typically fusiform in shape, with a narrow apical portion (mucro).

When a piece of lamella is laid flat on a slide in KOH solution, the chrysocystidia that are pleurocystidia are readily visible projecting towards the viewer.

In general, this character is only utilised for genera with dark (i.e. not white) spore prints.

Choose this state if: at least some chrysocystidia are present on the face and/or the edge of lamellae.