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Chicken Fat Mushroom - Suillus americanus

Suillus americanus

Good evening, friends and Happy Columbus and Indigenous’ Peoples Day - whichever you celebrate. Unfortunately, it appears my employer celebrates neither because I’m writing this from work - what the heck is that?

This week’s mushroom is the Chicken Fat mushroom (Suillus americanus). I found a huge flush of these mushrooms this past Wednesday underneath a white pine (Pinus strobus) at Manitou. There truly aren’t enough days of the week to document all the fall mushrooms that are popping right now, but as a bonus I’ll include a few pictures to highlight some of my favorite finds so far. This week’s publication is also the three year anniversary which is neat, but before we get into that let’s learn about this slimy little mushroom that appears by the dozen.

Suillus americanus
Suillus mushrooms are boletes, and like other boletes they release their spores through tubes underneath the cap.

Fun Facts

The mushroom gets the quirky common name because it is yellow, soft, and slimy like chicken fat. The mushroom is edible but not considered “choice”. Ciara chopped and fried up a couple of these slippery little suckers but neither of us found them too appealing. The taste was neutral but it was really the texture which was less than desirable. I’m more of a crunchy guy when it comes to texture and this was slimy and gooey. The late, great mycologist Tom Volk compares them to snails and that checks out. A tough swallow.

Suillus americanus
Not even a quarter of the mushrooms in flush. There were easily over 100.

Fascinatingly, people have reported allergic reactions from just handling these mushrooms. There is a study (Reference 2) on an individual that suffered contact dermatitis while handling five different species of Suillus, including S. americanus. The reaction comes on a day or two after contact but fortunately it’s not terribly severe. The symptoms dissipate after a week without any special treatment.

This directly contradicts the “you can safely handle any mushroom” mantra that I confidently spew on walks. Always good to know that just when we’re comfortable and think there’s an absolute rule in mycology, we go home with swollen, red, and itchy fingers. To quote my friend Eric who quotes Socrates, “The only thing that I know is that I know nothing”.

Suillus americanus
Large mycelial clump at the base of a mushroom.


The mushroom also goes by the moniker “white pine mushroom” because they grow mycorrhizally (symbiotically) with white pines. The fungus actually grows with pines that produce their needles in clusters of five - this includes western white pine, Swiss pine, and a couple others. That specific symbiosis is an important identifying characteristic, along with the reddish spots on the cap and a hollow stipe (stem). The cap, when fresh, has a distinct mucilage - viscous secretion - that is found throughout Suillus species and could potentially be cause of the allergic reaction.

Pine needles
Eastern white pines (Pinus strobus) grow needles in clusters of five, like you see here, while pitch pines (Pinus rigida) grow needles in clusters of three. This was very difficult to photograph.

The fungus grows throughout eastern and western North America - always near partner pines - but also in parts of Europe and Asia where other five-needled pines occur. The mushrooms pop up late summer through early fall in the northern hemisphere with observations on iNaturalist peaking in September. As alluded to in the introduction, when these mushrooms pop they fruit gregariously around the base of the partner pines and their numbers can reach into the hundreds.

Suillus americanus
A naturally occurring spore print on the cap of one of the mushrooms. The brown spores, released from the two mushrooms I’m pushing away, stuck to the yellow, viscous cap.

Other Autumnal mushrooms

Lion's mane
I found a Lions Mane (Hericium erinaceus) the size of my head fruiting on beech in Fahnestock State Park while on a run.

Resinous polypore
Resinous polypore (Ischnoderma resinosum) overlooking a pond

Some nice sized Maitake/Hen of the Woods/Ram’s Head (Grifola frondosa) growing at the base of an oak in Manitou.

An Earthstar (Geastrum saccatum) found near the large flush of Chicken Fat mushrooms.

Wedding cake
A whole lotta different mushrooms on cake. Congrats to John and Gabriela on their mycelial nuptials this past weekend.

This upcoming weekend we’ve got back to back mushroom activities. On Saturday at 10AM I’m leading a mushroom walk in Stamford, CT for the Stamford Land Conservation Trust. We’ll meet at the end of Mill Stream Road.

The next day, Sunday, I’m presenting on lichen at the New York Mycological Society’s Fungus Festival on Randall’s Island. My presentation is at 1pm but I’ll be mc’ing at the presenter’s tent throughout the day so come say hi :). More info here.

3 Year Anniversary

This week’s newsletter marks the three year anniversary of Mushroom Monday. Three years and we haven’t missed a week. Sure, there was a Toadstool Tuesday stretch for a bit there, but we’re at more than 150 straight weeks of learning different mushrooms. That probably won’t continue, but it’s definitely been a good run from the inception three years ago this Wednesday.

I went from emailing coworkers in the break room as a way to kind of avoid work until now where I stay up later than I’d like on the worst work day of the week in the hopes that someone (myself included) might learn something. All for the love of the game. I’ll probably start mixing in weeks off, but that’ll only be to help the long-term longevity of the publication. Love you all and thank you so much (okay, mush) for reading,



  1. Kuo, M. (2022, August). Suillus americanus. Retrieved from the MushroomExpert.Com Web site:

  2. Bruhn JN, Soderberg MD. Allergic contact dermatitis caused by mushrooms. A case report and literature review. Mycopathologia. 1991 Sep;115(3):191-5. doi: 10.1007/BF00462225. PMID: 1749402.





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