Category Archives: Fungi

“Under the spreading chestnut tree…” (via telescreen)

Hill Craddock and Tom Saielli visited Sewanee today with four hybrid chestnut trees to plant in our forest. Hill is in the Biology Department at UT Chattanooga and has worked for many years on American chestnut breeding and restoration; Tom is the Southern Regional Science Coordinator for the American Chestnut Foundation.

Photo credit for this photo and all others in this post: Buck Butler. Thank you, Buck!

Some backstory: the American chestnut (Castanea dentata) was formerly one of the dominant trees in our region, comprising half of all the trees in many forests. In some places the species grew in pure stands, a fact that is commemorated in many place names (Chestnut Ridge, Chestnut Hollow, etc). Chestnuts produced annual crops of tasty nuts and many animals depended on this massive burst of autumnal nutrition to make it through the year. In the late 1800s a fungus (Cryphonectria parasitica, an ascomycete) came into the U.S. on trees (of another chestnut species) imported from Japan. The fungus spread from the New York City area across the entire Eastern U.S., wiping out chestnuts as it went. From about 1900 to 1940, almost every tree was killed. The ecology of our forests was forever changed; other trees increased in abundance and many animal populations undoubtedly declined significantly due to the loss of the chestnut crop. These changes took place at the same time as the forest was being hit hard by unsustainable logging and grazing, so these were not happy decades for woodlands.

These days, the chestnut survives in the wild mostly as scattered small trees that grow for a few years, then get knocked back to their roots by the fungus. The fungus also infects scarlet oak, an unfortunate state of affairs because scarlet oak now acts as a continual reservoir of spore-producing fungus ready to attack chestnut saplings. A few large trees survive, either through luck or through the presence of a fungus-weakening virus that keeps the infection in check. But in the big ecological picture, the tree is functionally extinct.

All may not be lost. For many years now, scientists have been crossing the American chestnut (obtaining pollen and nuts from a few survivors) with the Chinese chestnut, a different species that is more resistant to the fungus. The resulting hybrids are indeed resistant to the fungus, but they have many characteristics of the Chinese parent that make them unsuitable for becoming true ecological “substitutes” for our lost Americans (e.g., their growth form is more bushy, they are more vulnerable to late freezes, etc). So, these hybrids (F1s, in biological lingo) are back-crossed to the American chestnuts for several generations (summarized here). These crosses produce plants that are nearly all American, with a few Chinese genes thrown in. The important step is then to pick out the offspring of these back-crosses that are truly disease resistant. This is where the trip to Sewanee comes in. Only by placing thousands of back-crossed seedlings in the forests, then testing them for disease resistance, can we ascertain which trees have inherited the right combination of genes.

So today we planted four seedlings in an area that had previously been cleared of planted pine. We hope in the future to establish a larger test area with hundreds of seedlings. The seedlings today were B3s — meaning that they are the result of three generations of back-crosses.

I’ll close with thanks to my colleagues Nate Wilson and Ken Smith who arranged for this visit and planting, and to Hill (in the green shirt above) and Tom for sharing their plants, their expertise, and their good cheer.

Inky cap

I made a quick visit to Shakerag Hollow this morning and found the biggest Inky Cap mushroom that I’ve ever seen (genus Coprinus, probably — but see here for identification complications). It stood about a foot tall, growing right next to the trail.

Inky Caps are named for the dripping black goo that edges their caps. Like other mushrooms, spores are produced under the cap. Unlike other mushrooms, the cap liquifies after the spores have been released. Spores mature first on the outer edge of the cap, so the cap shrinks as the spores are released. This keeps the edge of the cap adjacent to the mature spores, letting them catch the best air currents. Liquefaction through self-digestion is somewhat horrifying but also strangely beautiful process (Salvador Dali, anyone?).

Some early stirrings in Shakerag Hollow

After work yesterday I headed down into Shakerag Hollow to see what was stirring at the end of the warm afternoon. It was a pleasure to walk with just a shirt on my back — discarding the wintry weight and confining clutter of jackets and gloves and fleeces and hats. Ah!

Scarlet cup fungi (Sarcoscypha sp.were fruiting in one or two places on the side of the trail. They feed on decaying plant matter and grow their striking red “cups” throughout the year, but especially in cooler months. Spores are produced from the inner surface of the cup. These blow away (or are carried on mouse feet) to colonize more dead vegetation, of which there is no shortage on the forest floor. The scarlet cup is a favorite of mine –saturated with color at a time of year when the rest of the forest is mostly muted.

Bloodroot plants were poking up their flowers. Most were still tightly closed, but one or two had cracked open a little. The deeply incised leaves are held clasped against the stem, only relaxing into an open posture when the flower is mature or dead.

I was not the only mammal out and about in the balmy woods. Junebug the Hound found this skunk, but fortunately she paid attention to my bark: leave it! The skunk had its tail arched, ready to express its opinion.

Turkey Tails

"Turkey tail" fungus, Trametes versicolor

The surface of the downed log is covered -- a spectacular display of hundreds of colorful fungal fans.

And, for good measure, some real turkey tail feathers. These were "donated" by birds from Lost Cove, just south of Sewanee.

Puffball fungi

A row of puffballs curves down the grassy hillside at Lake Cheston. These fungi are related to mushrooms (in the Basidiomycota) but grow all their spores internally, then either puff them from an orifice at the top of their swollen bodies, or let them passively disperse when the puffball disintegrates.

Puffballs, possibly genus Scleroderma, with Canis junebugi for scale

Several puffballs had been gnawed. The size of the bite marks suggests that deer were responsible. This one has three large bites taken out.

The skin is like bread that has been baked in a wood oven.

Xolotrema denotatum and others at the Powdermill Nature Center

A dozen snail enthusiasts joined the American Malacological Society’s field trip to Powdermill, ably led by Tim Pearce, Head of the Carnegie Museum’s Section of Mollusks.

Xolotrema denotatum was one of the twenty five species that we found. I have been wanting to see this species for some time. We have its cousins, Xolotrema obstrictum and Xolotrema caroliniense, around Sewanee; both of these species have beautiful shells.

Xolotrema denotatum at Powdermill – note the very hairy covering to the shell. This is formed by the protein coating of the mineral shell.

Xolotrema denotatum seen from the side.

Xolotrema caroliniense shell from Sewanee

Xolotrema obstrictum shell from Sewanee.

A swarm of malacologists

I found these snail eggs hiding under a piece of fallen rotting wood on the forest floor:

The whole cluster is about half an inch across. I’m guessing they are Mesodon or Mesomphix eggs.

Some spectacular fungi were growing under rotting bark.


“Indian pipe” plants were poking up from the leaf litter.

Monotropa uniflora, a parasite on fungi that live in symbiosis with tree roots. So, this plant parasitizes trees through an intermediary.

Although Monotropa is only four inches tall, it is a relative of blueberries and azaleas (in the plant Family Ericaceae). It has lost is chlorophyll, giving it another common name, the "Ghost plant."

You can see more photos from the trip at Aydin Örstan’s blog, The Snail’s Tales.

Low down

Growing close to the ground:

Small red 'shrooms, about 3-4 cm tall. I think they are Catharellus cinnabarinus, the Cinnabar Chanterelle

Reclining St Andrew's Cross, Hypericum straulum. Grows about 10-15 cm high along the trail, a bit higher farther back in the woods.

The species gets its name from the elongated X of the petals.

Bolete eruption

The Two-colored Bolete (Boletus bicolor) is poking up all over the forest. Each mushroom is an impressive six to ten inches across.

Unlike other mushrooms, the underside of bolete caps are covered with tiny pores rather than gills. These holes lead into tubes from which spores are shed.

Boletus bicolor is a mycorrhizal species — its below-ground parts are fused with the roots of oaks and other hardwoods. The trees supply the fungi with sugars; the fungi mine minerals from the soil and send them to the trees.


Mystery fungi

Assorted unidentified gilled fungi from my rambles of the last day or so. Please post identifications in comments section!


This one is nearly two feet across.

Mycena? Tiny mushrooms sprouting from a stump.