fungus characterized by spore-bearing gills on the underside of an umbrella- or cone-shaped cap. The term mushroom is properly restricted to the plant's above-ground portion, which is the reproductive organ. Once a delicacy for the elite, edible mushrooms are now grown commercially, especially strains of the meadow mushroom (Agaricus campestris). Although mushrooms contain some protein and minerals, they are largely water and hence of limited nutritive value. Inedible, or poisonous, species are often popularly referred to as toadstools; one of the best-known poisonous mushrooms is the death angel (genus Amanita).
member of a kingdom (Fungi) of non-photosynthesizing organisms that live as PARASITES */articles/09834.html*, symbionts, or SAPROPHYTES */articles/11467.html*. Fungi are multicellular (with the exception of YEASTS */articles/14076.html*); the body of most consists of slender cottony filaments, or hyphae.
All fungi are capable of asexual REPRODUCTION */articles/10898.html* by cell division, budding, fragmentation, or SPORES */articles/12235.html*. Those that reproduce sexually alternate a sexual generation (GAMETOPHYTE */articles/04896.html*) with a spore-producing one.
The three divisions of fungi are the zygomycetes (e.g., black bread MOLD */articles/08618.html*), the ascomycetes (e.
g., yeasts, powdery mildews, TRUFFLES */articles/13079.html*, and blue-green molds such as Penicillium) and deuteromycetes (the imperfect fungi, e.g., species that cause RINGWORM */articles/10999.
html*), and the basidiomycetes (e.g., MUSHROOMS */articles/08890.html*, smuts, and puffballs).
Fungi help decompose organic matter (important in soil renewal) and are valuable as a source of ANTIBIOTICS */articles/00579.html*, vitamins, and various industrial chemicals and for their role in FERMENTATION */articles/04432.html*.
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