Oyster Mushrooms
A Guide To Identifying & Foraging Oyster Mushrooms in British Columbia
Oyster mushrooms are a staple of the spring foraging season in British Columbia. These mushrooms are relatively easy to find and identify, and make a tasty addition to most meals.
This guide will tell you what you need to know so that you can find, forage, and prepare oyster mushrooms.
Oyster Mushrooms on Vancouver Island
On Vancouver Island, the most common type of oyster mushroom is the phoenix oyster, Pleurotus pulmonarius.
They are spring and fall fruiting mushrooms which grow quickly after heavy rains, appearing in clusters on dead hardwood trees.
The other common variety of oyster mushroom found on Vancouver Island is Pleurotus populinus. However, differences between species of (true) oyster mushroom are minor and not very important if your intent is to forage them for food.
Pleurotus ostreatus is probably the most well-known pleurotoid mushroom, although it is now recognized as a European and Eastern American variety of oyster mushroom that does not occur in the Pacific Northwest.
Oyster mushrooms are voracious, known to eat even living bacteria and nematodes.
How To Identify Oyster Mushrooms
Oyster mushrooms are pale, shelf-like mushrooms with kidney-shaped caps that become wavy and curved upwards with age.
Young oyster mushrooms have more dome-like caps when growing separately, and trumpet-like when growing in clusters.
The texture of oyster mushrooms is quite delicate and rubbery. Their colour ranges from white, to pale brown, to a faint yellow ochre when dry.
Oyster mushrooms have an absent or short stubby stem, usually offset to one side as they grow horizontally from a surface. A more centred stem can be found on oysters growing straight up from the top of a log.
The spores of oyster mushrooms vary in colour, but are generally pale.
If you want to get up close and personal with some oyster mushrooms, simply find them at your local grocery store. However, store-bought varieties tend to be more trumpet shaped, unlike the more fan-like wild oysters.
Furthermore, store-bought oysters will probably be some variety of Pleurotus Columbinus, with a slate-gray cap. The texture, gill appearance, and smell should be similar though.
Some people describe the smell of oysters as similar to licorice. They should also smell delicious.
Pleurotus pulmonarius (Phoenix oyster) is the most common oyster mushroom found on Vancouver Island
Oyster mushrooms will often grow from cracked or split alder logs in the spring and fall.
Oyster Mushroom Look Alikes
Oyster mushroom lookalikes are any pale, rubbery, and shelf-like mushrooms that grow from trees, stumps, or logs. Oyster mushrooms are also relatively plain, lacking a distinctive texture, colour, or smell. This makes them particularly prone to misidentification by over-eager foragers.
Here is a list of mushrooms that could be mistaken for oyster mushrooms.
Crepidotus mollis - The "peeling oysterling" is perhaps the most oyster-like mushroom in the crepidotus genus , which includes many small, gilled, shelf-like mushrooms. They mostly have brown spores, and Crepidotus mollis has a clear skin which can be peeled from the body of the mushroom.
Crepidotus applanatus - The "flat oysterling". This appears as many small, delicate, white mushrooms on rotting wood. Much smaller when upturned than oysters.
Phyllotopsis nidulans - The "mock oyster mushroom" is orange to yellow in colour. The exterior fades with age, but a non-white interior should be a give-away that this isn't what you're looking for. They also tend to be slightly fuzzy when young, and give off a foul smell to put off any would-be foragers.
Panellus longinquus (Pleurotopsis longinquus, Pleurotopsis longinqua, Scytinotus longinquus) - Small and quite delicate. Has a pinkish cap with faint lines running towards the margin. Appears in the fall.
Tapinella atrotomentosa - The "velvet-footed pax" is sometimes suspected of being an oyster. These mushrooms can be identified by their dark, fuzzy stems (the "velvet foot") and their generally robust, agaric-like structure. They do make good dye mushrooms though.
Clitocybe sp. - Oyster mushrooms growing straight up from a log, having a centered stem, may resemble mushrooms of the Clitocybe genus. Some members of this family are poisonous and potentially deadly.
Panus conchatus - Another possible oyster lookalike. However, these mushrooms are more darkly coloured (almost purple) and more trumpet shaped.
Above - Velvet-footed pax or velvet roll-rim
The specimen pictured here is quite young. As they get older they grow out into a more fan-like shape. This shape, combined with the rubbery texture, leads some to confuse the velvet footed pax with oyster mushrooms.
The "velvet foot" is visible in the picture, a fuzzy brown section of the stipe.
The latin name is usually given as Tapinella atrotomentosa, although some books still refer to Paxillus atrotomentosus.
More pictures of oyster mushroom look alikes to follow as soon as I find them.
Above - Crepidotus applanatus the flat oysterling. Small in stature and delicate. You are unlikely to see uprolled oysters at this size (~3cm).
Edible Fungi Similar To Oyster Mushrooms
Note: Both of the mushrooms below have suspected toxicity. These reports are probably overblown, but proceed with caution anyway.
Late-Fall or Winter Oyster
Above: Panellus serotinus AKA Sarcomyxa serotina
As the name suggests, the "late", "fall" or "winter" oyster appears in the late fall or early winter, once most other mushrooms have ceased growing. Late oysters can be identified by their sticky green-grey caps and faint yellow gills. These features give them an almost fish-like appearance. Like regular oyster mushrooms, they have a kidney shape, appear in overlapping shelves, and grow on dead hardwood logs and stumps. Their flesh is slightly more dense and rubbery than regular oysters. Also, their edibility is a subject of some dispute, with some regarding them as "choice" and other sources listing them as "inedible".
Angel Wings
Above: Pleurocybella porrigens (Image source)
Angel wing mushrooms grow from dead conifers, usually in an advanced stage of rot. They form upward-sweeping, lily-like mushrooms that are often lobed at the margin. Unlike regular oysters, they and their spore print are almost completely white. Their flesh is also more delicate and less substantial than the more rubbery oyster mushroom. A relatively rare and prized edible in many parts of the world, they have fallen under suspicion due to a rash of poisonings and deaths in Japan. Read here for a more complete account of this incident, as well as some theories on the cause. Proceed with caution.
Where To Find Oyster Mushrooms
Oyster mushrooms are relatively easy to find.
On Vancouver Island, oyster mushrooms are most likely to grow from dead alder trees in moist, wet areas.
To find them, start in a low-lying wet area, like a swamp or riverbed. Look around for dead alder trees, either standing or fallen.
In optimal conditions they will break out from under the bark. Otherwise, they will grow from cracks or the broken ends of the stumps and logs. Since oyster mycelia grow just under the bark layer, you are unlikely to find them growing from logs or stumps that have lost their bark.
Oysters will often bloom profusely on a few trees. These trees are the ones to look for as they give the best chance of finding fresh blooms. They can also bloom multiple times in the same spot with successive cycles of rain and warm weather.
Read more about some other mushrooms that are easy to find and identify.
Harvesting Oyster Mushrooms
Because oyster mushrooms tend to become infested with worms, the best time to harvest them is when they are young. Young oyster mushrooms are more dome-like and paler than older ones.
If most of the caps in a cluster are flat, they are probably already past their prime. Oyster mushrooms also tend to become darker with age. Oyster mushrooms should be avoided once they begin to fray, crack, or disintegrate.
Clusters of oysters growing from a single base can be plucked off a log or stump quite easily. Clusters that are out of reach can be dislodged with a firm prod from a branch, and remain intact - just make sure to catch them on the way down.
Oysters growing in a more distributed fashion should be cut from the log to leave as much dirt, moss, and bark behind.
The large size and uprolled cap indicate a mature oyster mushroom, so it likely has some worms.
To check for worms, split the mushroom from stem to margin and inspect the flesh for small holes.
A more advanced infestation will show up in the gills as tiny black dots.
The texture and feel of oyster mushrooms is quite rubbery.
Fresh specimens are quite firm, becoming fragile with age.
If you mushrooms you've found are too old, check nearby for fresher clusters.
Preparing Oyster Mushrooms
As mentioned, oyster mushrooms are prone to becoming infested with bugs, especially fly larvae. There are some simple solutions to this:
Don't care. Many people cook oyster mushrooms, worms and all, before eating them. The worms are unlikely to be harmful or make any difference to the taste.
Soak the oysters in water with salt and/or vinegar. The worms hate this and will begin to exit the mushrooms. Not all will leave, which brings us to...
Get a small, sharp implement and start picking. If there aren't too many worms, you can probably pick them out with a small knife.
However many worms are in your oyster mushrooms, you still shouldn't eat them if they've turned bad. If your oyster mushrooms are overly frayed or smell bad, you should probably throw them in the bin and wait until you can find a fresher harvest.
Dried out oysters, ones that appear papery and wrinkled, can still be fine. In fact, drying is one of the preferred ways to preserve oysters.
If you do choose the salt and vinegar bath to remove worms, make sure you dry the mushrooms afterwards if you don't plan on using them immediately. Also, when cooking, oyster mushrooms usually require a period of dry-sautéing to work out any excess moisture.
Cooking Oyster Mushrooms
Sautéing the oyster mushrooms in a cast-iron pan
Making a quiche mixture
Adding some freshly picked nettles
Adding in the quiche mixture and cooking
Common Questions About Oyster Mushrooms
What trees do oyster mushrooms grow on?
In British Columbia and Vancouver Island you are most likely to find oyster mushrooms growing on dead alder trees. Oyster mushrooms can occasionally grow on other hardwood trees, and very rarely on conifers, but the vast majority of oyster mushrooms that you find will be on alders.
Are oyster mushrooms fuzzy?
Oyster mushrooms are not fuzzy. Oyster mushrooms have a smooth rubbery texture. If you have something that looks like an oyster mushroom, but also has a fuzzy stem, it is likely a velvet-footed pax, Tapinella atrotomentosa.
What part of oyster mushrooms do you eat?
Both the cap and the stems of oyster mushrooms are edible. The base of oyster mushroom stems or clusters can take on some wood or bark matter. The parts should be cut away when the mushroom is processed.
Are there false oyster mushrooms?
There are false oyster mushrooms because there are species of gilled, shelf-like mushrooms which inexperienced foragers may mistake for the real deal. Mock oysters (Phyllotopsis nidulans) and the peeling oysterling (Crepidotus mollis) are the most commonly named false oysters.
Are oyster mushrooms safe to eat?
Oyster mushrooms are relatively safe to eat. However, as with most mushrooms, eating oyster mushrooms could lead to illness if they are rotten or have absorbed toxins from their environment. Eat only fresh oyster mushrooms growing in areas that you are sure are free of harmful substances (like pesticides or heavy metals).
Can oyster mushrooms make you sick?
Oyster mushrooms are generally safe to eat. However, as with most mushrooms, oyster mushrooms can make you sick if you eat them when they are rotten or when they have absorbed environmental toxins. As with most foods, oysters can also make you sick if you are allergic to or intolerant of them.
How do you cook oyster mushrooms?
There are many ways to cook oyster mushrooms. Perhaps the most popular method is to saute them. Other options include adding them to soups, or baking them along with other dishes, like pizzas or casseroles.
Are oyster mushrooms good for you?
Like most mushrooms, oysters are an excellent source of trace nutrients and vitamins. While they probably don't have the fantastic curative qualities that some people claim for them, oyster mushrooms are definitely a healthy addition to any meal.
Can you eat oyster mushrooms raw?
Oyster mushrooms should not be eaten raw as they contain some potentially harmful compounds. Fortunately, these compounds are broken down by heat, so oysters should be cooked before consumption.
What do oyster mushrooms taste like?
Oyster mushrooms have a very light flavor which tends to get lost when combined with other ingredients. A bit of butter and salt is often enough to mask the subtle flavour of oysters. However, some describe them as faintly seafood or licorice-like.
Where do oyster mushrooms grow?
Oyster mushrooms grow in wet, low-lying areas, on the outside of dead and rotting hardwood trees, like alders.
How do you tell if an oyster mushrooms are bad?
An oyster mushroom is usually bad if it has one or more of these characteristics:
Bad smell
Cracked cap or gills
An abundance of flies or worms
A cap that is limp or shriveled
How do you grow oyster mushrooms?
Oyster mushrooms can be grown from a range of media, including straw and coffee grounds. You could try a relatively low-tech method, steeling an inoculated log or some mycelium to add to a growing medium at home, for example. Or go the commercial route and order a grow kit.
I recommend ordering from growmushroomscanada.ca. Read information on their oyster spawn kits and follow the link for growing instructions.
Grow Your Own Oyster Mushrooms
Fast-growing, gregarious, and adaptable - oyster mushrooms are a favourite for home growing and cultivation.
There are many methods for home growing oyster mushrooms, from outdoor straw beds to buckets and bags.
Most of these methods require a fair amount of spawn to start with (spawn is a substrate, like sawdust or straw, overgrown with mycelium). Luckily, you can buy oyster mushroom spawn from a number of places.
Oyster Mushrooms in BC
How to Identify Oyster Mushrooms
To identify an oyster mushroom, look for overlapping fan-shaped caps growing from dead alder trees. The surface of the cap should be smooth and the colour should be white to light-brown. The spore print should be pale.
Oyster mushrooms have decurrent gills and will sometimes have small offset stems. You're also unlikely to find an oyster mushroom with a completely uprolled margin.
Oyster Mushroom Look Alikes
There are a number of oyster mushroom look alikes. However, these can be ruled out by paying close attention to substrate, spore print, and texture. Avoid mushrooms that are small, delicate, growing on conifers, or with completely white or brown spores.
Types of Oyster Mushroms
There a number of oyster mushroom species prevalent in British Columbia. These include the pearl oyster (Pleurotus ostreatus) and phoenix oyster (Pleurotus pulmonarius) varieties.
Oyster Mushroom Season
The best season for oyster mushrooms in British Columbia is Spring. However, oyster mushrooms can appear whenever there is rain followed by a period of warm weather.
Above: Even when extending upward, most oyster mushroom caps will still be slightly inrolled. The presence of a completely uprolled cap is a sign that the cluster is quite mature.