Pileipellis

Anatomical structure of the cap cuticle in fungi

Pileipellis

The pileipellis of Russula ochroleuca

The pileipellis is the outermost layer of the pileus, or cap, of a fungus. It is a critical structure in the identification and classification of mushrooms and other fungi. The pileipellis can vary greatly in texture, color, and structure, and these characteristics are often used to distinguish between different species.

Structure

The pileipellis is composed of hyphae, which are the thread-like structures that make up the body of a fungus. The arrangement and type of hyphae in the pileipellis can vary, leading to different types of pileipellis structures. Some common types include:

• Cutis: A pileipellis with hyphae that are arranged parallel to the surface of the cap.
• Trichoderm: A pileipellis with hyphae that are perpendicular to the surface, giving a hair-like appearance.
• Epithelium: A pileipellis with a cellular structure, often with rounded cells.
• Ixocutis: A gelatinous cutis, where the hyphae are embedded in a gelatinous matrix.

Function

The pileipellis serves several functions for the fungus:

• Protection: It protects the underlying tissues of the cap from environmental damage, such as desiccation and UV radiation.
• Water regulation: The structure of the pileipellis can help regulate the amount of water that is retained or repelled by the cap.
• Spore dispersal: In some species, the pileipellis can aid in the dispersal of spores by affecting how water interacts with the cap surface.

Identification

Close-up of the pileipellis structure

The characteristics of the pileipellis are often used in the identification of fungi. Mycologists examine the pileipellis under a microscope to determine its structure and composition. This information, combined with other features such as spore color and gill attachment, helps in identifying the species of the fungus.

Related pages

• Pileus (mycology)
• Hypha
• Spore
• Fungal morphology