Phlebia tremellosa

January 2, 2022

Good evening, friends,

This week’s fungus is the Trembling Crust (Phlebia tremellosa – also known as Merulius tremellosus on iNaturalist but seemingly nowhere else). Colloquially, I still hear it refered to as Phlebia (pronounced flee-bee-uh) as the science for moving the species to Merulius seems unsubstantiated. More importantly, next week I’m going write about a different Phlebia species and the idea of that neat continuity makes me even more inclined to stick with this traditional taxonomy. I most recently found this mushroom on 11/14/2022 but without fail find it a few times every fall. This common autumnal mushroom has a gelatinous texture and distinct growth pattern that lends itself toward an easy identification for when you yourself find it on a fall stroll.

Fun Facts
P. tremellosa and Trametes versicolor (Turkey Tail) have both displayed the ability to break down a potentially harmful industrial particle known as fullerol. The fungi take this molecule that comprises 60 carbon atoms and oxidize it (add an oxygen atom or two on these carbon atoms) down to simple carbon dioxide molecules (Reference 2). There’s potential that this mushroom is capable of other mycoremediation projects, but untl further research is conducted we’ll just settle with that study as we stick our pinky toe into the wild world of organic chemistry.

Interestingly, when I worked in Central Park I found the mushroom growing in the leaf litter on the side of a path where it seemed to be digesting a variety of dead organic waste like leaves and twigs. All while while binding them together through those gelatinous fruiting bodies. It certainly seems like this is a hardier, more opportunistic fungus in terms of what it will consume – from “carbon-based nanomaterials” like fullerol to leaf litter.

I found this mushroom most recently after a night where the mercury dropped below freezing and created a thin film of ice covering the gelatinous caps. You may have noticed the cap is hairy as well – the thinking behind this trait, displayed by other shelf mushrooms, is that the cap will retain precipitation/moisture longer which subsequently allows it to stay moist and viable longer.

The etymology of Phlebia comes from Greek where the prefix phleb- means “veins” and this refer to the wrinkled fertile surface of the mushroom. Interesting, unlike other polypores that release spores directly from pores, the whole wrinkled membrane of P. tremellosa can release spores. Tremellosa means “trembling” – straightforward enough – and refers to the aforementioned gelatinous, flexible fertile surface.

Ecology
P. tremellosa is saprobic – it decomposes dead organic material – usually on hardwoods but occasionally on conifers. It can be found in temperate forests throughout the northern hemisphere but can also pop up in Australia – perhaps as an introduced species. It grows in the fall regardless of whichever side of the equator it finds itself and adopts anywhere from a white to peachy-orange hue.

It is hopefully evident by this point that the mushroom doesn’t form the classic toadstool shape (with a cap and stipe). Instead, this mushroom adopts an effused-reflexed fruiting body. This is where the majority of the fruiting body grows resupinate (flat) on whatever substrate while forming just the slightest fold of a cap. The mushroom uses that slight cap to not only allow it to extend further, but to also orient spore release in a perpendicular manner with the pull of gravity.

Hope everyone has had a pleasant start to the New Year. Excited for what fungal oddities and adventures await in the new calendar year.
-Aubrey 

References:
1) Kuo, M. (2008, December). Phlebia tremellosa. Retrieved from the MushroomExpert.Com Web site: http://www.mushroomexpert.com/phlebia_tremellosa.html
2) Schreiner KM, Filley TR, Blanchette RA, Bowen BB, Bolskar RD, Hockaday WC, Masiello CA, Raebiger JW. White-rot basidiomycete-mediated decomposition of C60 fullerol. Environ Sci Technol. 2009 May 1;43(9):3162-8. doi: 10.1021/es801873q. PMID: 19534129; PMCID: PMC2714669.
3) https://www.messiah.edu/Oakes/fungi_on_wood/poroid%20fungi/species%20pages/Phlebia%20tremellosa.htm
4) https://www.inaturalist.org/taxa/179113-Merulius-tremellosus
5) https://www.jungledragon.com/specie/6828/trembling_crust.html