Environment

May Mushroom of the Month: The Spring Oyster, Pleurotus populinus

|Kevyn Fowler|

After a long winter daydreaming of mushrooms to hunt for, photograph and eat, this early gilled mushroom is a welcome sight to a mushroom enthusiast like me!

Pleurotus populinus, or as it’s common name implies, the Spring Oyster, is one of the first “choice” edible gilled mushrooms to fruit in Maine. The various oyster mushrooms fruit throughout the season, appearing in spring, mid-summer and fall, depending on the species. Oysters are also very popular for the commercial growing businesses, as they are happy to grow in great clusters, are very tasty and versatile for many recipes, and also are great for home cultivation kits.

Knowing how to find the many species of mushrooms starts with a good knowledge of tree species, as many fungi either form a symbiotic relationship (mycorrhizal species) with certain tree species, or feed on the dead wood and organic matter (saprobic species) of the forest.

Learning to recognize trees is very important to help find mushrooms you might be looking for.

Fresh Spring Oyster mushrooms on a poplar tree
     Spring Oysters grow specifically on dead or dying poplar trees. Most often those trees that are still standing but also on fallen poplar as well.
Photo: Kevyn Fowler

Poplar trees are very common in Maine. They often grow in large stands like weeds, usually at the edge of fields, and as they grow quickly, they don’t live very long. Another name for poplar is Quaking Aspen, which refers to how the leaves quiver in the slightest breeze.

A big flush of Spring Oysters on an old, gnarly poplar tree. Photo: Kevyn Fowler

Identifying Spring Oysters is fairly easy, and there’s not any close lookalikes if you are careful to match up the several identifying markers unique to the oysters.

First, they grow directly on the wood, with little to no visible stem, often in clusters, in beautiful fan shapes. The cap of Spring Oysters is light cream-colored at first fruiting, changing to a tan color as they mature.

Note the gills visible under the cap. Photo: Kevyn Fowler

Underneath the cap the Spring Oysters have gills that run all the way back to the base, and partly down the stem if there is one. This gill structure is called “decurrent” and is an important marker for identifying many species of mushrooms, both edible and toxic.

 Note the smell of fresh oysters; put the mushroom up to your nose and get a good sniff, they’ll smell a bit like anise, or licorice. Some people say fishy but I think they smell heavenly.

Once you’ve identified the tree, the cap color, the gills, and the smell, the next and probably most important identification step is to get a spore print. Put simply, mushrooms are the fruit of the fungus, and that fruiting body releases spores, like seeds, by the millions.


 An example of a spore print. Seen here, the chocolatey spores of Agaricus campestris. Spring Oysters spore print will be white to pale lilac. Photo: Kevyn Fowler
 

To obtain a spore print is very simple, take the mushroom and lay it gills-down on a piece of paper or tin foil in a room with little air movement. Leave the mushroom there for a few hours, and then carefully lift the mushroom. You’ll see the dusting of spores left there.

To get that last solid check on oysters the spore print should be white to pale lilac. If that’s the color of your print, the chances are very good you’ve got a Spring Oyster, and a delicious snack in the offing. If you’re still not sure, send me some photos through Facebook messenger and I’ll try to help you out.In the end, if you “have any doubt, throw them out” is the common phrase you need to remember.

Once you’re 150 percent sure you’ve got the real thing, cooking can be as easy as you want, sautéed in butter, or part of a recipe like cream of mushroom soup.

A beautiful flush of Spring Oysters. Make sure you check behind the trees you find, these were not visible from the path I was on! Photo: Kevyn Fowler

I prefer my mushrooms sliced not too thinly, not crowded in the pan, cooked simply in a bit of butter and canola oil, lightly toasted and finished with a dash of salt and pepper. To get the best flavor from Spring Oysters they should be cooked soon after harvesting, though they’ll be fine even days later. I keep my extra mushrooms in the fridge in a plain brown paper bag, with a paper towel between layers. In the paper bag they stay good for up to a week.

The important thing about 99 percent of mushrooms is they should be cooked and cooked well. Undercooked mushrooms can cause gastric issues, as the proteins in them can be hard to digest if not broken down by heat.

A couple last tips for eating oysters. Firstly remember that these are good food for other little creatures. Sometimes you’ll find tunnels or even larvae inside the mushroom near the base of the cap. If it’s dry and crumbly and looks well eaten it might not be worth the trouble, but often that buggy part can be cut off to reveal clean, white meat that’s perfectly fine to enjoy.

Also there’s usually no need to wash most mushrooms, especially oysters, as that will make them soggy and hard to cook properly. Instead simply brush clean or wipe the cap with a damp paper towel if there’s any dirt or dust on them.

So get out there, making sure to protect yourself from ticks and those hungry black flies, and search the poplar groves for this early-season choice edible.

Happy Hunting!

——————Disclaimer: you should never, ever eat any mushrooms unless you are 150 percent certain you know you have the right species. The old adage, “when in doubt throw it out” has likely saved many a novice forager’s life. Also the author (and NGXchange) assume no responsibility or risk arising from the information in this article.