The mushroom usually grown in gardens or hot-beds, in cellars, sheds, &c., is a distinct variety known as Agaricus hortensis.
Many other species of Agaricus more or less resemble A.
The common mushroom (Agaricus campestris) is propagated by spores, the fine black dust seen to be thrown off when a mature specimen is laid on white paper or a white dish; these give rise to what is known as the "spawn" or mycelium, which consists of whitish threads permeating dried dung or similar substances, and which, when planted in a proper medium, runs through the mass, and eventually develops the fructification known as the mushroom.
An Agaricus named A.
Outflows of resinResinosisalro come under this general heading; but although some resin-fluxes are traced to the destructive action of Agaricus melleus in Conifers, others, as well as certain forms of Gummosis, are still in need of explanation.