Hairy-stalked Gymnopus (Gymnopus spongiosus)
- Aubrey
- Sep 28
- 3 min read
Good evening, friends,
This week’s mushroom is a fresh one. We found it just yesterday on a walk with the 300 Committee after some overnight rain. From above, the mushroom looks like any other LBM (little brown mushroom), but then you flip it over and the hairy, red stipe lets you know you’ve found the Hairy-stalked Gymnopus (Gymnopus spongiosus).
Fun Facts
Aside from the small, dense hairs present on the stipe, there are also robust rhizomorphs (root-like mycelial strands) present at the base of the mushroom. Interestingly, a study out of Mexico found that certain birds (flycatchers) will use the rhizomorphs of Gymnopus as nesting material (Reference 2). I’m not sure if birds here are using these rhizomorphs for nesting material, but I did have a red squirrel gnaw off my shoe lace while camping this weekend to presumably use it for winter nesting material.
A different species of Gymnopus, G. fusipes, was found to possess compounds known as Gymnopeptides A and B, which could potentially be present in other species of Gymnopus as well. These Gymnopeptides displayed “striking antiproliferative activity on several human cancer cell lines” (Reference 3).
Etymology
The genus Gymnopus comes from the Greek gymnos which means “naked,” and pous which means “foot”. The “naked foot” moniker is a reference to the (typically) bare stem of mushrooms in the genus, as they lack any sort of annulus (ring). Of course, in this instance the stipe is anything but bare — it is tomentose, coated in dense hairs.
The species epithet spongiosus is derived from spongia, Latin for “sponge”, and the suffix -osus which means “full of.” Michael Kuo of mushroomexpert.com, notes that the bottom of the mushroom has a spongy texture.
Ecology
The fungus is saprobic, digesting organic materials on the forest floor. We found these popping out of old oak leaves and pine needles in mixed woods. They pop up summer through fall east of the Rockies in North America, and rarely in South America. There is another species, Gymnopus semihirtipes, which grows in the spring and turns an olive green in KOH.
The fungus used to be Collybia spongiosa, and nearly all mushrooms that used to be in the genus Collybia have now been moved to Gymnopus or a similar genus. There are a variety of these “Collybioid” mushrooms, that span several different genera, and share the same characteristics: small, brown, white-spored, and decompose the leaf litter on the forest floor.
Errors & Ommissions
A couple from the last two articles:
In In Memoriam and Mushrooms, I mentioned that Richard Hall’s ambulance was struck in Moosch, when it was actually struck in the neighboring Willer-sur-Thur. He was buried in Moosch.
In last week’s NEMF recap, I incorrectly called Cayuga Lake, “Lake Cayuga”. This one kills me. I thought I’d double checked, and I try to be particular about getting the names of locations and geographic features correct, so I doubled over when this error was pointed out. I’ll be better.
October Events
Good to be back to our regularly scheduled single species article. The backbone of this publication. Next Monday is a full moon, and the Monday after that marks the five-year anniversary of the newsletter, so we’ve got some big Mondays on the docket. The publication started in NYC, and I hope to see some of you down there this weekend,
Aubrey
References:
Kuo, M. (2013, January). Gymnopus spongiosus. Retrieved from the MushroomExpert.Com Web site: http://www.mushroomexpert.com/gymnopus_spongiosus.html
César E, Bandala VM, Montoya L, Ramos A. A new Gymnopus species with rhizomorphs and its record as nesting material by birds (Tyrannideae) in the subtropical cloud forest from eastern Mexico. MycoKeys. 2018 Nov 21;(42):21-34. doi: 10.3897/mycokeys.42.28894. PMID: 30510469; PMCID: PMC6262046.
Ványolós A, Dékány M, Kovács B, Krámos B, Bérdi P, Zupkó I, Hohmann J, Béni Z. Gymnopeptides A and B, Cyclic Octadecapeptides from the Mushroom Gymnopus fusipes. Org Lett. 2016 Jun 3;18(11):2688-91. doi: 10.1021/acs.orglett.6b01158. Epub 2016 May 19. PMID: 27194202.
https://www.facebook.com/groups/mycologicalwordoftheday/posts/1486239188317921/
https://www.mobot.org/mobot/latindict/keyDetail.aspx?keyWord=spongiosus