So, is it an agaric or a bolete? At first glance, the answer seems obvious: it clearly has gills and therefore must be an agaric. However, if you spend enough time around mushrooms you might get a kind of uncanny valley feeling about this mushroom; its coloration, its stature, the way its cap looks somewhat puffy, the way the cap cracks as it dries out, and other subtleties just don’t look quite right for an agaric. When you ignore the gills, the mushroom looks for all the world like a bolete! Phylloporus rhodoxanthus, commonly called “the Gilled Bolete,” is actually closely related to the boletes and evolved gills independently of the true agaric lineages.
Fungus Fact Friday
The gilled mushrooms, informally referred to as ‘agarics,’ are the type of mushroom with which we are most familiar. The most common edible mushrooms (white/button/portabella mushrooms, oyster mushrooms, and shiitake mushrooms), Amanita muscaria – the most recognizable mushroom in the world and the inspiration for almost all mushroom art – and the ‘magic mushrooms’ are all gilled mushrooms. All these mushrooms share one feature: vertical plates of spore-producing tissue stacked under a sterile cap.
Cortinarius contains umbrella-like agaric mushrooms that are mycorrhizal, have a brown spore print, and produce a cobweb-like partial veil. It is the largest mushroom genus on Earth, with over two thousand species crammed into it. While the genus itself is fairly easy to recognize, identifying anything down to species is next to impossible. Most of the species listed in field guides are actually species groups and the field guide descriptions apply to a handful of closely related species.
Fungi appear in the news with surprising frequency. However, many of those stories do not provide any new information. Below is a summary of what we’ve learned about fungi from March through April 2017. Read below to learn about: C. auris in the U.S., aflatoxin-destroying corn, viruses defying fungal incompatibility, fungus-farming ant evolution, bat and salamander diseases, and more! Visit the associated links to get the full story.
The stropharioid mushrooms include agarics from the genera Stropharia, Hypholoma, Psilocybe,* and Pholiota. Mushrooms in this group produce a brown to dark brown spore print, have attached gills, and form a partial veil. There are actually quite a few mushrooms that can fit this description, so you might have to check some microscopic features to be sure your mushroom belongs to this group. Stropharioid mushrooms should have a cap surface composed of thread-like cells and have smooth spores with distinctive germ pores.
The family Pluteaceae contains umbrella-like agarics with pink spores and free gills. Within the group, most mushrooms are divided among the genera Pluteus and Volvariella. Pluteus mushrooms grow only on wood and never produce a volva, while Volvariella species grow on a variety of substrates and always form a volva.
The Entolomataceae are agarics with pink spore prints, attached gills, and spores with sharp corners or bumps. This family is very diverse and morphology varies widely from one species to the next. The mushrooms range in size from small to large, though most are on the small side. A majority of the Entolomataceae are just boring mushrooms, so they are not collected very often. This is probably just as well, since identifying these mushrooms down to species is a herculean task.
The waxy caps (alternately called “wax caps” or “waxcaps”) are agaric mushrooms primarily distinguished by their waxy texture, as the name suggests. Actually, the gills are the only part of the mushroom that feels waxy. To fully appreciate the unusual texture, break off a small piece of the gills and roll it between your fingers. It should have a texture reminiscent of soft candle wax.
Happy St. Patrick’s Day! To celebrate, I chose to discuss the Green Spored Lepiota, Chlorophyllum molybdites (I will return to morphological groups of agarics next week). Commonly known as the “Green Spored Lepiota,” the “Green-Gilled Lepiota,” the “False Parasol,” and various derivatives of those names, C. molybdites is the most common culprit in cases of mushroom poisoning in the United States. The large, attractive mushrooms frequently appear in lawns, making them prime candidates for consumption by people who aren’t familiar with mushrooms. Thankfully, the mushroom causes only gastrointestinal (GI) distress. People wishing to avoid this unpleasant experience can easily recognize C. molybdites thanks to its green spores.
Pleurotoid mushrooms are agarics that have a single common feature: they lack a well-developed stipe. Originally, I was not going to include pleurotoid mushrooms as a distinct agaric morphology. Their other physical characteristics vary widely and they belong to multiple unrelated taxonomic groups. To anyone classifying mushrooms, grouping them based on pleurotoid growth is decidedly unhelpful. However, it is a useful group from a field guide standpoint because it quickly reduces the number of possible matches. Eventually, I decided to discuss the pleurotoid mushrooms because they are often mentioned in field guides and because “pleurotoid” is a commonly-used mushroom descriptor.