Jelly fungi are peculiar organisms to say the least. My first encounter with a jelly fungus was a perplexing, alarming experience that is engraved in the back of my mind. Hiking in a mixed deciduous forest by a stream, I stepped over a decomposing log. As I looked down to get stable footing, I saw three different decomposers- the vividly purple Ascocoryne sarcoides, the vibrant sunshine yellow Tremella mesenterica and an unidentified white/translucent species that was probably a slime mold. My first thought was that this was toxic waste; a remnant of industrialization that had made its way into this ecosystem. This sight resembled the toxic waste you see in movies, you know, the radioactive bright colored slime that seems to spread and grow over a surface. This initial shock resided upon closer investigation, as the organisms seemed to be enzymatically breaking down the log. I took pictures and finished my hike, but the sight of these odd forms of life are all I really thought about for the remainder of the day.
Since my first encounter, I have learned much more about these jelly fungi. They’re mainly decomposers with only a small subset of species being plant parasites, stealing carbohydrates from living trees. In times of drought, many species of these fungi shrivel up and enter a dormant state. A fresh rain plumps them right back up, and they begin to feed on their woody substrate again. I have revisited logs that different jelly species grow from to see this process in action and I am never disappointed. They really are always an exciting find!
Possibly my favorite jelly fungus to find is the species featured today; Pseudohydnum gelatinosum, commonly known as the jelly tooth fungus. The first time I found this species was yet again another perplexing encounter. This time, I knew I wouldn’t gain superpowers if I had touched it, but I was still confused at what I was looking at. It felt like it was a jelly fungus, but it had tiny teeth on its underside. Hydnellumspecies have tiny teeth like this but are much hardier than these small gelatinous globules. This is yet another example of convergent evolution we see in the fungal realm.
Morphologically alike spore bearing surfaces on mushrooms occur on species with distant evolutionary histories. This just goes to show, then evolution will “figure out” an efficient trait it can pass on, that other species already have. However, even though genetically dissimilar species may have similar looking and functioning traits, the way these similar morphologies form can be drastically different.
In higher fungi the fruiting bodies, no matter how complex, are made up from the same building block-hyphae. These extremely fine threads of fungal cells carry out numerous biological functions besides the formation of the fruit body. These functions include the excretion of enzymes to digest their substrate, the scavenging and mining of scant soil nutrients, and even the predation seen in nematophagous fungi. Fungi that have gelatinous fruiting bodies actually form these gel-like surfaces more
By staining hyphae in developing fruiting bodies, Elizabeth Moore studied how these structures form in different species. She found that in the 10 species of mucilage forming fungi she tested, the gelatinous structures formed in different ways. In Pseudohydnum gelatinosum, its hyphae develop into the scaffold of the mature mushroom. More and more hyphae fill in the gaps of the developing fungus, and then, simultaneously, the fungal threads dissolve into the gel. In other non-related species tested in this study, the hyphae secrete mucilaginous compounds that give mature mushrooms their jelly consistency.
In Pseudohydnum gelatinosum, the teeth-like spore bearing surface mimics the underside of Hydnellumspecies, which ultimately increases the surface area the organism has to synthesize potential offspring. Its gel like interior also has an ecological function as these mucilaginous, compounds act as water reservoirs, allowing the fungus to drop spores even during times of desiccation. It also allows the organism to shrivel up in arid conditions, enter a dormant stage and reanimate when water becomes available. This species always is a welcoming find, and always reminds me of convergent evolution from a spore bearing and textural standpoint.