Cheilocystidia

Cheilocystidia are specialized sterile cells found on the gill edges of many species of fungi, particularly agarics. They are typically clavate, fusiform, or lageniform in shape and vary in size and appearance depending on the fungal species. Their primary function is believed to be protective, shielding the basidia (spore-producing cells) and other delicate structures on the gill surface from desiccation or mechanical damage. They can also contribute to the overall texture and appearance of the mushroom's margin. In some cases, cheilocystidia can be a key diagnostic feature for identifying fungal species, as their morphology is often consistent within a species. Their presence and characteristics are important considerations for mycologists in taxonomic studies. They are distinct from pleurocystidia, which are found on the gill faces. The term "cheilo" refers to the lip or edge, highlighting their location. Their observation often requires microscopic examination of fresh specimens.