Cystidia are regarded as thick-walled if the wall is obviously greater than 1 micrometre in thickness. Thick-walled cystidia are often associated with a capping of crystalline material, when they are known as metuloids (or lamprocystidia) (see Capped cystidia).

Choose this state if: at least some hymenial cystidia (cheilocystidia and/or pleurocystidia) are distinctly thick-walled.