This page will cover some of the basics for Pleurotus - the Oyster mushrooms. As with all of these pages, they are NOT intended to be used as a key or diagnostic tool, but a guide of basic identifying characteristics so that you can make informed decisions and easy-access to other, more detailed resources.
What They Have In Common | Helpful Trick | P. ostreatus Pleurotus ostreatus are considered the "true oyster" and are stimulated to fruit by drops in the temperature, so expect to see these in fall-winter. P. ostreatus tend to fruit in clusters, almost shelves as seen in the image above. Caps are often buff/tan and usually covered in the white spores of those fruitbodies directly above them. |
Pleurotus have several possible cap shapes that are heavily influenced by the environment but typically like to grow as above, with an off-center stipe and cap protruding away from the substrate. The off-center cap is slightly more typical of P. ostreatus than P. dryinus/levis, which can have more central stipes. |
Frankly, these two species are difficult to separate both morphologically and microscopically, so we won't bother. Both may have a finely hairy-to-velvety cap surface and a stipe ornamented with fuzz. They are less likely to grow in shelves and fruit when warm-to-cool temperatures following good precipitation. Gills may be more distant than P. ostreatus, but are still close. I find that these species have a more defined boundary between their gills and the stipe, likely due to the ornamentation. Photo by Cyndee Helms |
The "summer oyster" is a rather delicate species and prefers the warmer months to fruit. |
Crepidotus/Panellus These "Pleurotoid" mushrooms drop a brown spore-print and lack of stem. They can come in a variety of white-to-brown colors and are often delicate. | Pluteus This genus grows on wood and will have a central stipe without decurrent gills. The gills will start white and turn a salmon color as the pink spores drop | Phyllotopsis nidulans This is one of the most convincing look-a-likes, sometimes even called the "mock-oyster". Phyllotopsis nidulans has a densely hairy texture to the cap and is usually some orange color and the fruitbody often smells foul. Photo by Richard Davis |
Please remember to seek other sources for confirmation before consuming any wild mushroom