Oyster Mushroom

Description:

This well known mushroom is easily recognized by the way it grows on wood in shelf-like clusters; its relatively large size; its whitish gills that run down a stubby, nearly-absent stem; and its whitish to lilac spore print. It fruits in fall and winter across North America, and has a brownish cap. A number of very similar species are closely related, and the broad term "Oyster Mushroom" applies equally to Pleurotus ostreatus, Pleurotus pulmonarius (which is often paler, and appears in the summer), and Pleurotus populinus (which is found on the wood of quaking aspen). I think oyster mushrooms have a peculiar smell, but I would be hard pressed to describe it. An "oyster mushroom smell" is about all I can come up with, but the not-unpleasant odor seems fairly distinctive in the mushroom world. Because they are large and grow on trees, oyster mushrooms can be seen from the car--like, when it rains hard for days on end and you just have to get out. ( http://www.mushroomexpert.com/pleurotus_... )

Habitat:

There are some similar looking fungi that you wouldn't want to eat. One of them is pictured to the left, Lentinellus ursinus, the bear Lentinellus. They say it is "THE ONLY SPECIES THAT RACOONS WILL SPIT OUT." It is extremely bitter and hot to the taste. It has white spores and belongs in the Tricholomataceae like the oyster mushroom, but it has serrate (saw-toothed) gill edges. If you look at the basidiospores under the microscope they are small and amyloid (blue) in Melzer's reagent (the active ingredient of which is iodine). In addition, the trama (the flesh of the gills) has many amyloid hyphae in it. It is not known to be poisonous, but I certainly don't recommend eating it. Another common mushroom that can be confused with Pleurotus are Crepidotus species, shown here to the right. They have a similar lack of a stipe and are attached directly to the wood on which they grow. They can easily be distinguished if you take a spore print-- the spore print of Crepidotus species is brown, rather than the white of Pleurotus. So far as I know they are not poisonous, but I do not recommend eating them-- you certainly will not have a pleasant dining experience. Their flesh is very thin, and they do not have a pleasant taste ( http://botit.botany.wisc.edu/toms_fungi/... )

Notes:

• Habitat Forming overlapping shelves or clusters on stumps and logs of hardwoods, uncommon on conifers, from early fall to mid- winter. Pleurotus ostreatus is a member of the "Fog Flora" fruiting sporadically along the coast during the summer. • Edibility Edible and very popular, although a few people are allergic to it. • Comments Pleurotus ostreatus is believed to be a species complex. In the California, specimens can be found that vary from white and relatively thin-fleshed on oaks to thick fleshed, grey-brown shelves on cottonwood and willow. Whether these differences are environmentally induced or genetic is not clear, but most mycophagists prefer the large, thick-fleshed specimens collected from cottonwood ( http://www.mykoweb.com/CAF/species/Pleur... ) ------location: North America, Europe edibility: Choice fungus colour: White to cream, Blue, Grey to beige normal size: 5-15cm cap type: Funnel shaped stem type: Lateral, rudimentary or absent spore colour: White, cream or yellowish habitat: Grows on wood Pleurotus ostreatus (Jacq. ex Fr.) Kummer Austernseitling, Austernpilz Pleurote en forme d'huître Oyster Mushroom. Cap 6–14cm across, shell-shaped, convex at first then flattening or slightly depressed and often wavy and lobed at the margin or splitting, variable in colour; flesh-brown or deep blue-grey later more grey-brown. Stem 20–30´10–20cm, excentric to lateral, or absent, white with a woolly base. Flesh white. Taste and smell pleasant. Gills decurrent, white at first then with a yellowish tinge. Spore print lilac. Spores subcylindric, 7.5–11 x 3–4um. Habitat often in large clusters on stumps and fallen or standing trunks, usually of deciduous trees, especially beech. Season all year. Common. Edible and good. Distribution, America and Europe ( http://www.rogersmushrooms.com/gallery/D... )