The Carlisle Mosquito Online

Friday, November 16, 2007


Late Fall Oyster Mushroom

photo by Kay Fairweather
In a year of normal rainfall there are very few fresh fungal fruitings timed to enhance the Thanksgiving dinner. This year my expectations were lower than usual and so my heart leapt up when I beheld a cluster of late fall oysters on a log along the Acorn trail in Great Brook Farm State Park last Friday. One day later, on November 10, I found another cluster on a standing tree along Maple Street near the bridge. This is a mushroom that doesn't usually appear until there has been a frost. Other years I have found partly frozen ones during cold spells in November. It is quite a common species and I am hopeful that I will find more before Thanksgiving.

Name. The late fall oyster mushroom is Panellus serotinus. It is a different species from its well-known cousin, the "true" oyster mushroom (Pleurotus ostreatus). Late fall oyster mushroom is also known as the green oyster mushroom or the greenback. Like employees in large corporations, mushrooms are subject to frequent reorganizations — for reasons that will benefit some and keep the others guessing. The late fall oyster has been reorg'ed from the genus, Pleurotus, that it used to share with the normal oyster mushroom, into the genus Panellus. In older editions of mushroom books, you will still find it under the old name, Pleurotus.

Identification. This mushroom has a fan-shaped cap on a short stubby lateral stalk. Under the cap, it has off-white to pale yellow gills packed fairly closely. The cap usually has a green tinge. The ones from Great Brook were distinctly green. The ones from Maple Street had barely a suggestion of green. There is a gelatinous layer just under the skin on the cap making it feel a bit slimy or viscid when moist (how oystery is that?). The caps can reach up to four inches in diameter (one book says six inches). Mine were no larger than three inches. The books all say they can occur singly as well as in clusters but I have only found them in clusters.

You would never confuse the late fall oyster with the orange mock oyster which also occurs this time of year. There are some of those in the Greenough Land and along the Old Morse Road trail. They grow in clusters on wood and are a similar size and shape to the late fall oyster but are orange-yellow and smell very nasty.

Edibility. The late fall oyster is an edible species that I enjoy more than the regular oyster mushroom. It could be that I am a heavy-handed cook who is incompetent to deal with the comparatively delicate flavor of the oyster mushroom and whose culinary methods are more suited to the tougher, sturdier, stronger flavored late fall oyster. Last week's finds ended up being sauteed in olive oil and added to a stir-fry with barley and chicken thighs.

The Phillips book says the late fall oyster is "not edible." I think this is an editorial opinion — similar to Arora's which states it is edible but mediocre and becomes bitter with age. The Fischer, Bessette, Brown book has an opinion closer to mine and suggests that it is one of the underrated edible species. It suits my palate just fine and has another benefit. Because it fruits so late in the year, it is seldom infested with bugs and beetle larvae like the widely admired "true" oyster. I am hoping to find more that will be chopped, sauteed and added to the turkey stuffing.

References. Mushrooms of North America, Roger Phillips; Mushrooms Demystified, David Arora; National Audubon Society Field Guide to Mushrooms, Gary Lincoff; Edible Wild Mushrooms of North America, David W. Fischer, Alan E. Bessette, R. McKenna Brown.

Submissions for the Biodiversity Corner are encouraged from everyone. What are you finding? Write the whole column or just send a note or a photo to Kay Fairweather at 392 School Street, Carlisle, MA 01741 or to

2007 The Carlisle Mosquito