Wild Food Guide — 'T'

This is the description page for Oyster Mushroom (Pleurotus ostreatus) and includes a description as well as an image, if available and a selection of recipes from this site that relates to the wild foodstuff: Oyster Mushroom.

Oyster Mushroom, Pleurotus ostreatus is a very distinctive species of basidomycete fungus (filamentous fungi composed of hyphae that reproduce sexually) and is a member of the Tricholomataceae family of the Agaricales (Agaricus) order that have pale lilac spore prints (though the spores appear white under the microscope). It is a very common species distributed world-wide that is saprophytic (ie lives by digesting dead and dying wood). The oyster mushroom is also one of the few known carnivorous mushrooms, for its mycelia can kill and digest nematodes and this may be a way for it to gain additional nitrogen. Typically it friuts maximally in Decmber, with a smaller fruiting in October, but can be found in the wild each month apart from July (though they are most common in late Autumn and Winter). The mushroom typically grows gregariously in tiers on the trunks of deciduous trees, especially beech, and is rare on coniferous wood but is most commonly found on stumps, fence posts and all kinds of decaying wood. The mushroom is braoadly flat and fan-shaped and can be very variable in colour, with young specimens typically being slate blue though older specimens can range from grey through buff to almost white. They are fan shaped, growing between 5 and 20cm in length and some 3cm thick and with in-rolled edges when young. They are smooth and moist to the touch. The gills are on the hymenium, start out white and age to straw are pronounced, distant, unbranched and decurrent. The stem is also variable, and thugh typically eccentric (at an angle to the main fruiting body) can also be lateral or even eccentric. When the fruiting bodis are densely clustered the stems may become fused and will bear caps of different ages. The flesh is firm and white and smlls distinctly of mushrooms, though there can be an anisedy overtone due to the production of benzaldehyde. The flesh can be tough near te stem and it's best to discard this part in older specimens.

The oyster mushroom is an excellent eating species and is much used in Asian cuisines. It is also one of the few mushroom species to be successfully cultivated and can commonly be found in supermarkets. You can also buy kits to grow this mushroom at home. Typically it is used in soups, is stuffed or stir-fried with soy sauce. The 'oyster' description in both the common and Latin names derives from the mushroom's grey oyster-like appearance when young and to the mushroom's oyster-like texture and taste. The oyster mushroom can be preserved by pickling, but does not freeze or dry well dries well.

The colour, shape, season of fruiting and growth on dead wood means that there are no poisonous species with which it can be confused in most of the world (the exception is Australia and Japan, where there is a toxic look-alike, Omphalotus nidiformis). In britain there are some species with which it can be confused, in that they have similar habitats and growth forms, and which are best avoided. The first of these is Hohenbuehelia petaloides that tends to grow on old stumps and which has a beige cap, white gills and gelatinous flesh and smells faintly mealy. This fungus creates antibiotics that may cause allergic reactions in some people. The next mushroom is Panellus serotinus (the Olive Oysterling) which has an olive-coloured, slimy, cap and gills that turn brown with age. Authorities differ on the edibility of this mushroom, with some saying it is edibe but others saying it is not (or, at least, is not worthwhile). The third common lookalike is Crepidotus mollus (the Peeling Oysterling) which has smaller of-white caps, as compared with the oyster mushroom with crowded gills that are white when young and turn brown as the spores ripen and has fibrous flesh. This is not edible and should be avoided. It should also be noted that spores of oyster mushrooms can cause respiratory allergies in those sensitive to them and it is possible that the trace levels of arabitol found in oyster mushrooms could cause gastric upsets in a small percentage of susceptible people. As always, if you are uncertain of the identification of a mushroom, do not pick it and, if you have not eaten a mushroom before, cook it well and only eat a small amount the first time, in case you are susceptible.

Mushroom and Epazote Soup
Mushroom and Spinach Rustic Pie
Pasta for All Seasons
Beef and Mushroom Tshoem
Baked Sausages with Apples, Oyster Mushrooms and Cider
Oyster Mushroom Tom Yum
Mushroom Pickle