What is sky blue and named for poo?
A beautiful new mushroom with a less beautiful name
Fungi of the family Psathyrellaceae generally have fragile fruiting bodies and dark colored spores. About half of them digest themselves when their spores are mature, creating an inky ooze as they dissolve. The family Coprinaceae used to include all such ink-cap mushrooms, but DNA analyses indicate that this was an artificial grouping and its former genera have been divided in contemporary classifications, some being more nearly related to Agaric mushrooms.
The saprophytic fungus genus Coprinopsis includes about 200 species found growing on wood, soil, decaying vegetable matter, dung, and burnt ground. It is one of the genera that used to be included in the genus Coprinus. One species, Coprinopsis cinerea is a model organism whose genome has been completely sequenced. Coprinopsis are described as agaricoid, meaning that they have a cap that is differentiated from a stalk. Their fruiting bodies are noted for being short-lived, sometimes deliquescent, simply melting away and becoming liquid, like the Wicked Witch of the West.
Coprinopsis pulchricaerulea. Photo by Steve Axford at Tara Ridge, Booyong, New South Wales. CC BY-SA 3.0.
Another species, Coprinopsis atramentaria, the common ink cap or “tippler’s bane,” is widely distributed in Europe and North America. Although edible, it becomes poisonous when combined with alcohol, making the drinker acutely sensitive to ethanal, much like the medication disulfiram used as a treatment for alcoholism, causing the patient to immediately have severe hangover-like symptoms upon alcohol consumption. Those combining alcohol and the mushroom suffer nausea, vomiting, a tingling sensation of the limbs, facial redness and other symptoms within five to ten minutes of drinking. It may also cause arrhythmia as well as tachycardia. Clumps of its species are often found after precipitation in open, grassy areas including both disturbed and urban habitats. Its bell-shaped caps flatten over time, then disintegrate.
In 2012, nature photographer Stephen Axford came upon beautiful blue mushrooms in northern New South Wales. Later determined to belong to Coprinopsis, they represented a species new to science and were remarkable in several ways. First they are absolutely beautiful. Second, spores are pale in contrast to blackish spore deposits common in the genus. And third, the species has sequestrate fruiting bodies enclosing spores in truffle-like fashion.
These are small mushrooms, standing 6-22 mm tall, with caps 8-28 mm in diameter, growing in small groups or singly on wood or in leaf litter in wet forest conditions. Their spherical form becomes ovate or convex as the fruiting body matures. In life, they are pale to bright blue in color, becoming grey or greenish as they age or when dried. The surface of the cap sometimes glistens with white, powdery bumps. Gills begin white or creamy color, becoming light tan.
So far, the species has been observed only in limited areas of subtropical rainforest in New South Wales, New Caledonia and Lord Howe Island. The specific epithet, pulchricaerulea, combines word roots meaning beautiful and blue, which stands in contrast to the genus name which combines -opsis, meaning to appear or resemble, with coprinus, a Greek word root meaning dung.
DNA analysis indicates that the species is closely related to Coprinopsis aesontiensis which is similar in size to slightly larger, grey in color, with small white tufts or powdery scales on the surface. It was described from northeastern Italy in 2016, near the border with Austria and Slovenia. It is named for the Aesontius river, known today as the Isonzo river in Slovenia.
Further reading
Lebel, T., Davoodian, N., et al. 2022. A mixed bag of sequestrate fungi from five different families: Boletaceae, Russulaceae, Psthyrellaceae, Strophariaceae, and Hysterangiaceae. Swainsona 36: 33-65.