by ORLT Land Steward Issac Ostrom
August can be a slow time for botany. It’s too early in the summer for late season composite flowers (Asteraceae family), but too late for most “summer” forbs. So, when you do find anything, it stands out even more. The fruiting organism I really enjoy stumbling upon this time of year isn’t even a plant; it’s all the multitudes of fungi that pop out of the ground following summer downpours. Noteworthy genera you might encounter this time of year include Amanita, Boletus, and Cantharellus.
Before expanding on these genera, it’s important to understand fungi’s place in the forest ecosystem: Fungi can be parasitic, saprotrophic, mycorrhizal, or endophytic. Parasitic fungi grow on other living organisms while harming their host, saprotrophic fungi break down dead or decaying matter (usually wood, leaves, or dung), mycorrhizal fungi engage in symbiotic relationships with other organisms (often trees, which benefits both organisms) and endophytic fungi live inside of all plants, helping them in a variety of ways. Amanita, Boletus, and Cantharellus are all mycorrhizal. More specifically, they are ectomycorrhizal, meaning that they do not penetrate root tissue when forming symbiotic relationships with a host. Endomycorrhizal fungi, on the other hand, do not form above ground fruiting bodies but still engage in nutrient exchange as well as pathogen defense. All of the species discussed in this article are both ectomycorrhizal and mycorrhizal.
We’ll start with the most delicious fungus, the Cantharellus genus, which includes 4 types of chanterelle mushrooms: Cantharellus cibarius (golden chanterelle), C. cinnabarius (red chanterelle), C. lateritius (smooth chanterelle) and C. cornucopioides (black trumpet). Chanterelles are characterized by their false gills, scattered or solitary habit, and bright colors. These fungi are mycorrhizal on conifers and oak trees, and in Georgia are often associated with oak-hickory-pine, pine-hardwood, and hardwood-pine forests.
Cantharellus cibarius, photo by Issac Ostrom
Another genus of edible fungi common this time of year are the boletes – that’s pronounced ‘bowl-eat’s’. While many boletes are edible, they often have traditionally undesirable textures and flavors. A few boletes can also cause stomach problems if ingested. Instead of having gills, Boletus have long narrow tubes that form a sponge-like pore surface. The Southeast is a bolete hotspot with over 50 species identified in southern Appalachia alone! Noteworthy species include the Boletusa auripes (butterfoot bolete), Boletus bicolor (rose toned bolete) and Strobilomyces strobilaceus (old man of the woods).
Boletusa auripes (butterfoot bolete), Boletus bicolor (rose toned bolete), and Strobilomyces strobilaceus (old man of the woods)
Lastly, we arrive at the Amanita mushrooms, which some of you might recognize as the mushroom in the Super Mario video game franchise. Toadify! Many Amanita species are very toxic to humans but less so for other wildlife. Amanitas are also one of the most species-rich mushroom families, with over 600 species in the genus. Amanitas’ most common mycorrhizal hosts are conifers and the whole family is of great importance to the forest's mycelial web. The “Mario Mushroom” specifically looks just like an Amanita muscaria (fly agaric), which is more northern in distribution. We find a similar species in the Southeast – Amanita jacksonii (American slender Caesar) -- which lacks the distinctive spots on its cap. Another species you might find is Amanita bisporigera (the destroying angel), which is extremely toxic, tall and ghostly white, and dons a partial veil or ring on the stem below its cap.
Amanita jacksonii (American slender Caesar), Amanita bisporigera (the destroying angel), and Amanita muscaria (fly agaric). First two photos by Dan Crescenzo.
Finally, we turn to the Russulaceae, known colloquially as the brittlegills/milkcap family. Russula get their common name from their frail and easy to break gills. Their cell structures are circular rather than oval, and they tend to crumble like chalk when the gills or stem are broken. Russula’s are usually brightly cap colored, brittle-gilled mycorrhizal mushrooms. There are over 1300 species of them worldwide, so keying one out to a particular species can be tricky. Its sister genus (found in the same family) Lactarius only consists of 630 species, which brings the total to over 1,900 accepted species between the two genera. Lactarius mushrooms get their common name from the fact they bleed a latex compound from their gills, stem, and cap when damaged. The accepted purpose for exuding latex is to hide strong tasting compounds deemed attractive to herbivores. The taste profile of Lactarius sap can be acidic, metallic or even hot/spicy like horseradish.
Russulaceae photos by Issac Ostrom
Russualaceae initially developed as generalist saprotrophic mushrooms but have since evolved ectomycorrhizal relationships 3 separate times. Because of this generalist approach early on in their evolution, they form relationships with a wider array of host plants. Brittlecaps and milkcaps both have edible members, but their importance runs far deeper than edibility. An abundance of Russula, Lactarius, and Boletus can be indicators of strong mycological health in old growth or late succession forests. The mushrooms, aka the fruiting bodies we see above ground, are just a fraction of what is going on in the dirt. The mycelial hyphae- root like structures of some species do not start forming until 10-30 years without any major soil disturbance. Even if you don’t see mushrooms right where you stand, you can bet your bottom dollar that mycelial networks are beneath your feet helping the forest ecosystem thrive.
NOTE: Identifying mushrooms/fungi in the field can be tricky, and mushrooms that are edible can look very similar to those that are not. Identifying mushrooms for the purpose of eating them should not be attempted without expert guidance. This article does not constitute expert guidance.