In
mycology, a
universal veil is a temporary membranous tissue that fully envelops immature fruiting bodies of certain
gilled mushrooms. The developing
Caesar's mushroom (
Amanita caesarea), for example, which may resemble a small white sphere at this point, is protected by this structure. The veil will eventually rupture and disintegrate by the force of the expanding and maturing mushroom, but will usually leave evidence of its former shape with remnants. These remnants include the
volva, or cup-like structure at the base of the
stipe, and patches or "warts" on top of the
cap. This
macrofeature is useful in wild mushroom identification because it is an easily observed, taxonomically significant feature. It is a character present among species of
basidiomycete fungi belonging to the genera
Amanita and
Volvariella. This has particular importance due to the disproportionately high number of potentially lethal species contained within the former genus.