Late Oyster
It’s Mushroom Monday, and this week we have another colourful, edible, and ecologically-important species: the Late Oyster (Sarcomyxa serotina).
As its name suggests, this mushroom appears later in the season than many of our other fall-fruiting species. Late Oysters typically don’t appear until after the first good frosts of October, and they can persist well into the early winter snows of December.
At first glance, Late Oysters may look like bracket fungi (aka polypores), but a peek under the cap reveals close-spaced gills rather than pores, along with a short stem. On young specimens, cap colour is olive-green (Olive Oysterling is another name for this species) and gills may be white or the beautiful golden-yellow seen here. As the mushrooms age, their caps fade to shades of yellow and tan, and gill colour darkens to brownish-yellow.
Late Oyster is a good example of how confusing mushroom names can be. First, it isn’t an Oyster Mushroom (Pleurotus spp.); it used to be part of that genus but now isn’t even classed in the same family. Second, its scientific name has changed more times than PEI’s weather on a fall day.
I was surprised that I couldn’t find Sarcomyxa listed in any of my mushroom reference books: this is a common species, so why was it omitted? Turns out, my decade-old books list it as Panellus and other sources list it as Crepidopus, Hohenbuehelia, and Panus, among other names. These changes are a result of ongoing study into the physical and genetic features of Late Oyster, and it won’t surprise me if the name changes yet again in the future.
No matter what you call it, Late Oyster is edible, with a mild, mushroomy flavour. The tough, rubbery texture can be improved by cooking low and slow – for example browned in a frying pan and then tossed into a slow cooker soup or stew.
Late Oysters are found across the Island, mainly on dead hardwoods, especially Beech. This is one of our white rot fungi, breaking down lignin and leaving behind cellulose – a carbohydrate – that’s used by nitrogen-fixing bacteria and wood-eating invertebrates. In this way, Late Oysters contribute to healthy forest soils, available nitrogen, and forest biodiversity, and provide these services later in the year than many other species.
If you’re walking in the late fall or early winter woods, keep an eye out for this member of PEI Untamed!
