In early October my partner mentioned they had seen a solitary mushroom emerging from a wound in an elm tree on our local trail. This especially interested me because of the Muskoka Mushroom Mystery. I took my camera up there to get some pictures on site before collecting the specimen to clone for possible cultivation.

With help from the FaceBook Mushroom ID Forum and a look at the Mushroom Expert website it seemed we had found an Elm Oyster (Hypsizygus ulmarius). Mystery solved. Perhaps, but this raised another question for me, because I thought I knew the Elm Oyster.

I had bought some Elm Oyster (H ulmarius) liquid culture from Gallboys on Amazon in 2015 and I have been growing it quite successfully ever since. I find them particularly suited to indoor fruiting. Where the Blue and Pearl Oysters tend to produce “coral-like” fruits in my FC, the Elms produce big fleshy, but delicate, fruitbodies. Too tender,and quick to dry out, they would not do well in shipping or shelf life; but nice eating. The trouble is, they look like the mushrooms in the picture on the right. I wonder if these are Pleurotus ulmarius, a name which is sometimes mentioned as synonymous or outdated.

It’s not just that Gallboys have mixed up their cultures (they do also sell what they call White Elm Oysters – P ulmarius which I have not seen). A search of the internet for “Hypsizygus ulmarius” turns up about a 50/50 split between pictures of the two distinct species. The divide is pretty clearly between growers and field mycologists.

No less than Paul Stamets has touted the H ulmarius on his site and trademarked the name Hypsizygus ulmarius Garden Patch (HUG) on a PDF which depicts a Pleurotus-like oyster. Studies have shown this mushroom to be a great companion for vegetables. The study is mentioned in Mycelium Running and specs for growing it are featured in his Growing Gourmet & Medicinal Mushrooms.  But how can these studies have gotten so far with the species misnamed?

I’m leaving the comments open on this post because I’d really like to hear from some of you who are in the know. I’ll  be posting a links on a couple of FB pages like MycTor and Mushroom ID in hope of getting some feed back.

Thanks in advance, fellow Mycophiles!