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Mock Oyster/Stinking Orange Oyster - Phyllotopsis nidulans

Good afternoon, friends,

This week's mushroom is Phyllotopsis nidulans, commonly known as the mock oyster or the stinking orange oyster. Some of you may be familiar with the oyster mushroom, and P. nidulans shares some characteristics, but notice they're not in the same genus (phyllotopsis vs pleurotus) so the relation is based more on physical traits rather than genetics. These mushrooms were found in the ramble on 11/2/2021 and they're still there today.


P. nidulans is saprobic on dead wood, both hardwoods and conifers. It is found in temperate forests throughout the northern hemisphere (North America, Europe, and Asia) and grows in the spring and fall. In fact, detailed in the first reference, a mating study was conducted on P. nidulans mushrooms collected from Alaska down through Costa Rica and the results deemed they were all compatible for reproduction - constituting the same species of mushroom - which is rare for mushrooms that are separated across great distances/physical barriers. It is a gilled mushroom that typically grows in overlapping clusters, as seen in the photos. It is quite hairy - or tomentose - on the top of the caps. The species name "nidulans" means "partly encased" which I believe refers to how the margin of the cap rolls down to encase the gills, but I couldn't find clarification on that.

As noted by the common name, P. nidulans usually has quite an odor. Unfortunately, as is sometimes the case, these mushrooms were not that pungent. I've been carrying one around in my pocket for a few hours and the most I can glean from it is a mild "generic mushroom" smell - as if you were to smell a button mushroom in the supermarket. Apparently, the odorous mushrooms smell sulphureous, like rotten eggs. The orange color is from alpha and beta carotenes which are also responsible for producing the orange pigment in carrots, pumpkins, sweet potatoes, and your other favorite orange-colored fruits and vegetables. However, while the mushroom isn't poisonous, it's not considered edible.

Mushroom Walk 12/4 10AM

This Saturday, 12/4, at 10am I'm going to do a mushroom walk in the ramble. We'll probably mix some winter tree ID in there too. Bring binoculars if you're so inclined and we can look at some late migratory birds or winter residents as well (hopefully cedar waxwings which are my favorite). We're going to meet by the toolboxes on the west side (I've attached the location). If I really have my puppies in order I'll make banana bread too. You can respond to this email or call me at 203-252-9421 if you have any questions. Hope to see you then 🙂.

Happy Hannukah to everyone who celebrates,



1) Kuo, M. (2017, May). Phyllotopsis nidulans. Retrieved from the MushroomExpert.Com Web site:


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