Mushroom of the Week - Forest shellfish
Oysters that grow on trees.
Oyster Mushroom, Pleurotus ostreatus
While equating this species with oysters may be a bit of a stretch, some people do maintain that when they are breaded and fried they do have a mild flavor slightly reminiscent of seafood.
While Oyster Mushrooms can, of course, just be sautéed in margarine or butter, I prefer to first plop them into some raw scrambled eggs, and then dip them in seasoned bread crumbs before placing in the frying pan. While rated highly by many, it is still a mild flavored mushroom, that compared to seafood, is at best, probably more like a very mild white fish--like some anonymous tasting tilapia filet.
Oyster mushroom, which are most often found growing on wood on the side of snag, are fan shaped and laterally attached, off-center, with the caps supported from the side. The name Pleurotus is from the Greek root “pleur”-- meaning on the side.
While the cap color frequently varies from white, grey to brown, all have white gills that run down the very short stipe (stem), that is sometimes completely lacking altogether. The spore color is white to lilac grey. While they can be confused with some similar looking (harmless) species, if you have any doubts, the main thing to be sure that the spores are not some other color, particularly brown—which is definitely not an oyster mushroom or one you should eat. Also, the very base of the stem, or point of attachment on the tree, is very tough or hard when squeezed between your fingers. While this part of the Oyster Mushroom is too tough to eat, I find it aids in making a proper identification.
When you consult other references, it is important to note that the scientific name of this species has been changed. While Oyster Mushrooms are still shown in most books as Pleurotus ostreatus, this is now considered to be the related European species. What we have long called Pleurotus ostreatus in the Pacific Northwest is most likely now considered to be Pleurotus pulmonarius—and grows on either conifers or hardwoods. If your oysters are on a cottonwood or an aspen, you are probably actually eating what is now called Pleurotus populinus. But, other than for the substrate, macroscopically, both of these species are basically identical, and equally edible.
Oyster mushrooms (otherwise saprophytic but sometimes parasitic: producing white flakey heart and sapwood rot in conifers) also sometimes produce droplets of a potent “nematotoxin” that doesn’t hurt you, but can paralyze microscopic worms called nematodes. Once paralyzed the mushroom’s hyphae filaments penetrate these tiny animals, that are then absorbed as food. Thus this mushroom’s mode of nutrition, if not “predatory”, can at least be described as omnivorous.
(The discussion here summarizes, but does not provide a fully detailed description of all the characteristics of this mushroom. Thus, please consult a mushroom book for a more thorough description if you are collecting mushrooms for the table.)