The origin of mushrooms is ancient — in fact, a 2020 scientific paper reported the discovery of fossilized fungi found in the Democratic Republic of Congo dating from 715 to 810 million years ago! Yet there is much scientists still do not understand about these fruiting bodies of the Earth’s mycelium layer (a network of interconnected microscopic fungal strands). For instance, take “guttation,” the emergence of liquid droplets on mushrooms, such as the ones you see in this photo which was taken last week near Cunningham Falls in Maryland.
The process isn’t the same as plants (reminder that fungi are evolutionarily closer to animals than to plants), but does seem to happen often at night and when the mushroom is experiencing growth. There are a myriad of functions for the weeping of mushrooms — protection from ultraviolet light, communication, to protect from possible toxic molecules, and as a sort of water reservoir for nearby airborne hyphae (a branching part of the mycelium). Scientists have begun testing the content of these water droplets — many of them might contain molecules with potential medicinal use.
Regardless, guttation looks really cool.
Sources: “Fungal guttation, a source of bioactive compounds, and it’s ecological role — a review,” Adam Krain and Piotr Siupka, _Biomolecules_ 2021 Sep 11 (9): 1270. _GFZ German Research Centre for Geosciences_, “Mushrooms are older than we thought,” 1/24/2020, quoting study by S. Bonneville, F Delpomdor etc al, 2020, “Molecular identification of fungi microfossils in a Neoproterozoic shale rock,” _Science Advances_.