Good evening, friends,
This week we’re shrinking down and looking at a tiny little polypore without a common name, Porodisculus pendulus. I found this mushroom on black birch (Betula lenta) after rain up in Manitou on March 6th. Just like the size of the mushroom, there is very little known about them, but let’s see what information we can glean from these hairy little fungal drops.
Fun Facts
The mushrooms aren’t just small, they’re the smallest out of all polypore species (that we know of). The size of the mushrooms are measured in millimeters and can be smaller than 1mm in diameter. Not only is the mushroom small, but there is only one other species in the Porodisculus genus, Porodisculus orientalis.
One study (Reference 2) from back in 1965 found that the fungus produces a high amount of malic acid, the same naturally occurring chemical that makes fruit sour. The study aimed to find producers of high quantities of malic acid for potential commercial use, and while P. pendulus was a high producer, Schizophyllum commune and Merulius tremellosus were the largest producers in the study.
While there is no common name - maybe “Birch Bells” or "Beehive Fungus” if we’re just spitballing - the latin name Porodisculus can be broken down into a few components. Poro-, like a skin pore, is a tiny hole, while -discus signifies a round shape like a dish or a disk. Combined you get “porodiscus”, and the suffix -ulus emphasizes the diminutive size. The species epithet pendulus means “hanging” in latin and describes how the mushrooms grow from the wood.
Ecology
The fungus is saprobic and creates a white rot on recently dead branches of deciduous trees. One source says the mushrooms pop up summer through fall, but looking at the iNaturalist observations it seems like they’re more common winter through spring. The fungus can be found in eastern North America and the sister species, P. orientalis, is found in Asia.
The pore surface consists of individual tubes (seen in the image below), like those of the Beefsteak polypore (Fistulina hepatica), instead of a congealed fertile surface. A similar species you’ll see this time of the year is the Veiled Panus (Tectella patellaris) I wrote about just a few weeks ago. In fact, I think I used a picture of these mushrooms in that blog (the second picture). Shows what I know.
Next Monday, barring any issues, I’ll be in Ecuador on my way to look for mushrooms in the Amazon. I hope to publish Chaz’s mushroom story that I talked about last week, but I have no idea if I’ll get a publication out the following Monday, 4/1. Nonetheless, I’ll have tons to share if/when I do return on 4/3 (big “if” I mean folks have you read about those Boeings? Looks like the company killed that whistleblower too, allegedly of course).
Tomorrow is the spring equinox which is encouraging. Remember to get outside and enjoy,
Aubrey
References:
Takao S. Organic acid production by Basidiomycetes. I. Screening of acid-producing strains. Appl Microbiol. 1965 Sep;13(5):732-7. doi: 10.1128/am.13.5.732-737.1965. PMID: 5867653; PMCID: PMC1058333.
https://www.inaturalist.org/taxa/126946-Porodisculus-pendulus