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Peanut Butter Cup - Galiella rufa

Galiella rufa

Good evening, friends.

Well, we got all that rain I’ve been asking for and then some. The preserve got somewhere between 8-10 inches of rain Sunday into Monday which resulted in borderline apocalyptic flooding. Nothing like coming back to work after a week of vacation and having to recover from a natural disaster. There was no, “wow your tan is awesome, how much fun did you have?”. Just “hey can you take everything out of the workshop, use the shop-vac to suck up the sludge, bleach and hose down the place… and also the septic light was flashing so there might be sewage mixed in.” Last time I ask for rain in an email for at least a few weeks.

On the bright side, there are plenty of fascinating mushrooms popping up on the preserve; we may already have enough mushrooms to keep us occupied for the rest of the year. This week’s we’re looking at a peculiar little cup, the Peanut Butter Cup Fungus (more boringly named the Hairy Cup or Galiella rufa). I was lucky to even spot this acorn-sized mushroom tucked between two rocks in Manitou on 6/30/2023. I’ll also share some other fungi pics from the past week of poking around New England and give an updated list of mushroom walks happening later this month.

Galiella rufa
I was surprised I even found this little cup. It looked just like an acorn shell tucked in between those rocks

Fun Facts

One study from Spain found that a compound in G. rufa, Galiellalactone, demonstrated anti-tumor and immunomodulatory properties. The study’s abstract teases that Galiellalactone “could serve as a lead compound for the development of novel drugs against HIV-1, cancer and inflammatory diseases” (Reference 4). Perhaps a promising medicinal mushroom and certainly worthy of further research.

Galiella rufa
When young, the cup has a membrane that covers the mouth, the hymenium - or the surface of the mushroom where spores are released. The membrane deteriorates when the mushroom is mature, notice the remains on the edge of the cup.

The genus name Galiella is named after the French mycologist Marcelle LeGal. The species epithet Rufa is Latin for red/reddish and apparently refers to the color of the mushroom (even though it’s more like different shades of brown to me).

The mushroom is allegedly edible (Reference 5) but I didn’t try it, nor really disturb it too much, because it was just a solitary little mushroom that should have the chance to spread spores. Apparently the mushroom has a gelatinous interior which doesn’t sound too appealing, but hey it’s worth trying something at least once in my opinion. Maybe next time.

Galiella rufa


G. rufa is saprobic and digests hardwood sticks and logs. It seems to be surprisingly more common to find in clusters of cups rather than just the individual specimen we have (on what I think was a cherry branch - but truthfully I don’t really remember). The cups grow in the early summer in the northeast - the vast majority of recordings on iNaturalist are from June and July. Uniquely, the fungus has only been found in North America, widely distributed east of the Rockies, and in Malaysia. Nowhere else.

Mushroom Pictures and Such

My friend, former park coworker, and former roommate, Phil, showed me around Maine two weekends ago. We found a large Northern Red Belt Polypore (Fomitopsis mounceae) while camping on Birch Island:

Fomitopsis mounceae
About the size of binoculars, on birch.

I found these Boletes with velvety brown caps in Cape Cod, perhaps the Spotted Bolete (Xanthoconium affine):

Xanthoconium affine

Painted Suillus (Suillus spraguei) also in Cape Cod:

Suillus spraguei

A preview of next week’s mushroom, The Old Man of the Woods (Strobilomyces), found today at the preserve. Almost scrapped what I had written at the time (three sentences or so) to write about it:

Old Man of the Woods

Some other fun news is that I’ll be presenting at For the Love of Fungi Mushroom and Arts Festival in New Paltz, NY the weekend of 9/29-10/1. They have a sweet video that you can watch to get stoked on the festival, or you can read more about the weekend and get tickets here. See you there :)

Here’s an updated walks list too. All walks are free and all of you are welcome to join (not all at once though, that’s too many):

10 AM on 7/22 at the Putnam Valley Town Park in Putnam Valley, NY. This is through the town’s CCE (Commission for the Conservation of the Environment - a mouthful) which I help out with. Meet at the Pavillion.

10 AM on 7/23 at Fahnestock State Park in the lot at the intersection of Dennytown Road and Sunken Mine Road. This is with the Mid-Hudson Mycological Association which is my first walk with the group.

10 AM on 7/30 at Manitou Point Preserve. Accessible by the Metro North Hudson Line if you are in NYC, too. This is the preserve I work on and the walk is with the New York Mycological Society which will be really fun.

Hopefully we’ll get to Central Park in August. I snuck through there on Sunday and wasn’t seeing too much, but that was before the rain.

If you have any questions you can email me.

Late one tonight - burning that candle,



1) Kuo, M. (2012, June). Galiella rufa. Retrieved from the MushroomExpert.Com Web site:

4) Pérez M, Soler-Torronteras R, Collado JA, Limones CG, Hellsten R, Johansson M, Sterner O, Bjartell A, Calzado MA, Muñoz E. The fungal metabolite galiellalactone interferes with the nuclear import of NF-κB and inhibits HIV-1 replication. Chem Biol Interact. 2014 May 5;214:69-76. doi: 10.1016/j.cbi.2014.02.012. Epub 2014 Mar 11. PMID: 24631022.


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