Category: Fungus Fact

Gyroporus castaneus row 0

#200: Gyroporus castaneus, The Chestnut Bolete

The most readily observable features of Gyroporus castaneus are its brown cap and small size. As any mushroom hunter knows, mushrooms with this combination of features are very hard to identify… unless your mushroom is a bolete. Only a handful of boletes are small when fully grown and most of those have a reddish cap. G. castaneus – commonly called the “Chestnut Bolete” because of its chestnut brown colors – is easy to identify thanks to its small size, light brown colors, and brittle hollow stipe. Once you’ve found a small brownish bolete, the classic test to identify it as the Chestnut Bolete is gently squeezing the stipe, which should feel hollow.

Entoloma abortivum with aborted fruitbody and honey mushrooms 0

#199: Entoloma abortivum, The Aborting Entoloma

Entoloma abortivum is a fascinating mushroom. The mushroom produces two forms of fruitbody: an agaric form that is an umbrella-like gilled mushroom and a “carpophoroid” (mycology-speak for “aborted”) form that looks like an oddly-shaped puffball. Both of these forms are usually found near honey mushrooms (Armillaria spp.) or in places honey mushrooms are known to grow. It turns out that E. abortivum is parasitic or partially parasitic on honey mushrooms; the aborted forms are actually the mycelium of E. abortivum attacking Armillaria mushrooms. Both the agaric and aborted forms are edible, although you need to be cautious when collecting Entoloma species.

Armillaria tabescens 2

#198: Armillaria tabescens

Armillaria tabescens, the “Ringless Honey Mushroom,” is out in force in my area, a sure sign that summer is drawing to a close. Field guides often note that A. tabescens is the easiest honey mushroom to identify. That is true, but it relies on you accurately identifying it as a honey mushroom. Honey mushrooms (Armillaria spp.) are typically medium-sized to large agarics that grow in dense clusters, have a partial veil that leaves a ring, produce thick black rhizomorphs, and fruit from dead or dying wood. Of those features, the only one A. tabescens displays reliably is dense clustered growth. This makes it very difficult to identify if you’re unfamiliar with honey mushrooms. Fortunately, there are not many large mushrooms that grow in dense clusters, so it’s always worth checking the Armillaria section of your field guide when you find some.

Tolypocladium ophioglossoides and Elaphomyces truffle 0

#197: Tolypocladium ophioglossoides, The Golden Thread Cordyceps

Tolypocladium ophioglossoides (also called Cordyceps ophioglossoides and Elaphocordyceps ophioglossoides) is a fun little mushroom to find, but you have to be paying attention to enjoy it. Unlike most fungi that were placed in Cordyceps, which were insect parasites, T. ophioglossoides – commonly known as the “Golden Thread Cordyceps” (even though it is no longer in that genus) – attacks other fungi. Specifically, it parasitizes truffles in the genus Elaphomyces. If you can spot this tiny brown/black mushroom, make sure to dig it up carefully and follow the golden thread that attaches the mushroom to its truffle host.

Hygrophoropsis aurantiaca 1

#196: Hygrophoropsis aurantiaca, The False Chanterelle

Hygrophoropsis aurantiaca is a bright orange mushroom that appears on rotting wood and forest debris in the summer and fall. It is not a particularly interesting mushroom on its own, but it is worth knowing to make sure you don’t confuse it with other orange mushrooms like golden chanterelles. H. aurantiaca is called the “False Chanterelle” precisely for that reason; if you’re not paying attention, it would be easy to drop one of these into your chanterelle collection.

sweet clover flowering 0

#195: Warfarin, from Cow Disease to Medicine

Warfarin is one of the most successful drugs of all time. Seventy years after it was first synthesized, warfarin is still the most widely prescribed anticoagulant. Warfarin has a unique story. What began as depression-era research into a mysterious disease of cattle ended up producing two life-saving medicines and a rat poison that are still in use today.

Pisolithus arrhizus peridioles 0

#119: Pisolithus arrhizus, the Dyeball

“Our next contestant in the Ugly Mushroom Contest performs countless of hours of community service every year and is an accomplished artist. Its goal in life is to make the world a better place and form lasting relationships with those around it. Give it up for…Pisolithus arrhizus! [applause]” There seems to be little doubt among mushroom hunters that P. arrhizus is one of the ugliest mushrooms in the world. The fruiting bodies of older specimens become distorted and can be mistaken for anything from animal feces to decomposing tree stumps. Despite its unsightly appearance, this earthball is used to dye wool, thus earning it the common name, “Dyeball.” The fungus is also prized by foresters for its ability to form robust mycorrhizas in extremely poor soil conditions.

Spathulariopsis velutipes 0

#194: Spathulariopsis velutipes

Spathulariopsis velutipes is an odd little mushroom that looks like a spatula or a canoe paddle, though perhaps in a half-melted kind of way. Its common names include “velvety fairy fan,” “velvet foot Spathularia,” and variations on those. This ascomycete is an earth tongue look-alike (ETLA)* that is easily differentiated from similar mushrooms thanks to its unique shape and the strikingly different colors and textures of its head and stipe. I always enjoy finding this mushroom because of its unique appearance.

Boletinellus merulioides 0

#143: Boletinellus merulioides, the Ash Tree Bolete

Boletinellus merulioides is an odd mushroom, both in appearance and ecology. The Ash Tree Bolete can be readily identified by its tube surface – which is only a few millimeters thick and looks more like a network of ridges – and by the fact that it fruits under only ash trees. B. merulioides appears under ash because it has a unique symbiotic relationship with a pest of ash trees: the Leafcurl Ash Aphid.

Coffee Rust 0

#049: Coffee Rust

Coffee Rust, also known as Coffee Leaf Rust and in Spanish as “roya,” is a disease of coffee plants that is caused by the fungus Hemileia vastatrix.1–3 H. vastatrix is, as its common name implies, a member of the rusts (FFF#130). Unlike most rusts, however, it has a simple infect-sporulate life cycle, which is likely one reason the disease has been so successful.1 Coffee Rust is a particular problem in Central America, produces 15% of the world’s arabica coffee and exports roughly 432 million kilograms of coffee to the United States annually. The region suffered a devastating outbreak of the disease in the early 2010’s and has yet to fully recover.4–6