A mushroom is the above ground fruiting body of a fungus that contains spores. A visual overview is available in Figure 1.
Pileus/cap- is the prominent horizontal component of a mushroom bearing lamellae/gills or tubes on the underside. It can have a variety of shapes (including margin appearances overall and in edge cross-section), sizes and colours.
Hymenium- is the spore-bearing layer containing asci or basidia in a fruiting body of a fungus. This could be in the form of lamellae or tubes. The attachment of the hymenium to the pileus and stipe can vary depending on the species, with several lamellae/gill and tube attachment shapes possible, seen in cross section. Lamellae/gill spacing can also vary.
Lamellae/gills- are platelike structures on the underside of the pileus. They are arranged radially from the stipe towards the margin of the pileus. Spore-bearing basidia is found on the lamellae.
Tubes- instead of gills some mushrooms (genus Boletus) have a thick, sponge-like tube layer with pores of these tubes open to the under surface of the pileus.
Stipe/stalk- is present in most mushrooms and can be attached to the centre, off-centre or to the side of a pileus. The shape, size and the colour of the stipe can vary between different fungi species. Occasionally the stalk could be absent or very small.
Some mushrooms have membranes referred to as veils that cover and protect the immature mushroom or the immature lamellae. There are two types of veils.
The membrane protecting the immature lamellae is called the partial veil and the membrane covering the immature mushroom is called the universal veil. As the mushroom matures these membranes break, sometimes leaving remnants on the stipe or the pileus.
Annulus- is a ring like structure found on the stipe of a mushroom. This is a remnant of the partial veil.
Volva- is part of the universal veil found at the base of some mushroom stipes, either as a cup like structure or as scaly remnants.
Cortina- is the silky, cobweb-like partial veil found only in some mushrooms (genus Cortinarius).
Hyphae- is one of the threadlike strands that form the mycelium of the fungus. It consists of a single or double nuclei cells. The wall like structure dividing each cell is known as the septum. A loop like structure called a clamp connection is found at the septum in some fungal hyphae.
Mycelium is the mass of hyphae that forms the vegetative part of a fungus.
Ascus- Fungi of class Ascomycetes produce spores in a tube-shaped container known as an ascus. Usually an ascus contains 8 spores, which are dispersed through an opening at the tip of the ascus.
Basidia- Fungi of the class Basidiomycetes produce spores on short appendages called sterigmata that project out of a club shaped basidia. Usually basidia contain 4 spores but sometimes can contain only 2 spores.
Spore - is the reproductive structure of the fungus, which is walled, single or multicelled and is capable of giving rise to a new individual. In fungi spores can have a variety of morphological forms.