Pileipellis

The pileipellis is the uppermost layer of hyphae in the pileus of a fungal fruiting body. It is more or less synonymous with the cuticle, however, the cuticle generally describes this layer as a macroscopic feature, while pileipellis refers to this structure as a microscopic layer. Pileipellis type is an important character in the identification of fungi. Pileipellis types include the cutis, trichoderm, epithellium, and hymenoderm types.

Cutis
A cutis is a type of pileipellis characterized by hyphae that are repent, that is, that run parallel to the pileus surface.

Trichoderm
In a trichoderm, the outermost hyphae emerge roughly parallel like hairs, perpendicular to the cap surface. The prefix "tricho-" comes from a Greek word for "hair".

Epithelium
An epithelium is a pileipellis consisting of rounded cells in multiple layers, often connected in chains, and sometimes breaking off.

Hymenoderm
When viewed from above, a hymenoderm or "cellular cuticle" appears to be paved with roughly circular polygonal elements (similar to the fertile cells of the actual hymenium on the gills). The elements may be globular cells or may be the tips of hyphae extending deeper into the surface.

External link

 * IMA Mycological Glossary: Pileipellis