Annulus (mycology)

An annulus is the ring like structure sometimes found on the stipe of a mushroom. The annulus represents the remaining part of the partial veil, after it has ruptured to expose the gills or other spore-producing surface. An annulus may be thick and membranous, or it may be cobweb-like. The latter type of annulus is referred to as a cortina. An annulus may be persistent and be a noticeable feature of a mature mushroom, or it may disappear soon after the emergence of the mushroom, perhaps leaving a few remnants on the stipe as an "annular zone".

Additional recommended knowledge

Daily Visual Balance Check

Daily Sensitivity Test

Essential Laboratory Skills Guide

An annulus can be any of various shapes, which can be important in identification of the mushroom:

• pendant - drooping or skirtlike
• flaring - spreading outward from the stipe
• sheathing - opening upwards around the stipe