1001 Mushrooms - Alden Dirks

#19 - Velvet Polypore (Ischnoderma resinosum)

10/21/2021

MycoBank Taxonomy: Fungi, Dikarya, Basidiomycota, Agaricomycotina, Agaricomycetes, Polyporales, Fomitopsidaceae, Ischnoderma

The process by which a mushroom earns the badge of "edibility" is mysterious and fascinating to me, a product of time and place and culture. Ischnoderma resinosum, or the velvet polypore, is one that is generally regarded as inedible, and not for bad reason – the mature sporocarps are tough tough. But there seems to be a growing recognition that the young polypores are indeed edible, and not half bad at that. I myself was surprised when I first learned about somebody eating these, a Russian mushroom hunter in Madison, Wisconsin. Not only did he eat the velvet polypore, but he claimed it was his very favorite mushroom of all. I first sampled Ischnoderma resinosum with my older sibling in Toronto. After explaining to them that this mushroom was safe to eat because a knowledgeable Russian said so, and enjoying the meal with no health repurcussions, they now send me pictures excited to have found the "Russian polypore" again – a good example of the randomness and obscurity of the birthing of some common names.

Pretty much everyone is shocked when I mention that the velvet polypore is edible and good. I believe the word is being spread though, and in due time the consensus will shift. Ischnoderma resinosum's transformation in the cultural consciousness from tough polypore to tasty treat has no doubt been facilitated by Alan Bergo who explored the edibility of Ischnoderma resinosum in a 2014 blog post. I can't find any sources reporting on its culinary qualities before that. To my surprise, Charles McIlvaine doesn't even mention this species in One Thousand American Fungi.

Fortunately, Ischnoderma resinosum is an easily recognized species. Fresh brackets exude colorful moisture droplets called guttation (not to be confused with guttules, the lipid bodies inside spores). The cap consists of varying shades and gradients of reddish brown with a whitish growing edge. The pore surface is whitish and quickly bruises brown, becoming pale brown in maturity. Young mushrooms are deliciously thick and soft, like a steamed bun, but soon become astonishingly tough. As a result, they often possess textural complexity that needs to be navigated during harvest. Only very soft pieces should be taken, and often times this is just the first two inches or so of the growing edge of the polypore. To top it off, the interior flesh is beautifully marbled.

Ischnoderma resinosum can be found in the fall growing on dead hardwood logs (in my experience, almost exclusively on birch). The related species Ischnoderma benzoinum grows on conifer logs and is darker, but is otherwise very similar looking such that the two species are sometimes regarded as synonyms. This is another great example of a taxonomic mystery the could be solved with the help of community scientists. By collecting and vouchering Ischnoderma species, noting their substrate, and having them DNA barcoded, we could finally settle whether these two species are distinct (check out Fungal Diverisy Survey for more information on how to get involved)!

The pictures above show the harvested mushrooms (bruised) along with the marbling of the flesh and their changing of appearance while being sauteed. The sauteed mushrooms were strangely similar to chunks of portobello, a little firm and mushroomy, with a slightly bitter aftertaste. They were a great addition to toast with garlicky sauteed cherry tomatoes. Next time, I'll have to try them according to Alan Bergo's recipe, who mentions that they really shine when stewed followed by a reduction of the cooking liquid and caramalization. Luke Smithson also does a great job exploring their culinary qualities at the Cry of the Bolete where he recommends that they be roasted and marinated in what looks like another delicious recipe.