Scarlet Bonnet

Atheniella adonis

"Atheniella adonis", which has the recommended name of scarlet bonnet in the UK, is a species of agaric in the family Cyphellaceae. Found in Asia, Europe, and North America, it produces small orangish to reddish mushrooms with caps up to 1.2 cm in diameter and thin pinkish-white stems reaching 4 cm long. The fungus typically grows in conifer woods and peat bogs, suggesting a preference for acidic environments.
Pale pink mycena  Atheniella adonis,Fall,Geotagged,United States

Appearance

The cap initially has a sharply conic shape, but expands to a narrow bell-shape or a broad cone in maturity, typically reaching 0.5 to 1.2 cm in diameter. The cap margin, which is initially pressed against the stem, is opaque or nearly so at first. It is scarlet red when fresh and moist, becoming orange or yellowish orange before losing moisture. The mushroom is hygrophanous, and fades to an orange buff when dry. The flesh is thin, the same color as the cap, fragile, and without any distinctive taste or odor. The gills are ascending-adnate or attached by a tooth, subdistant to close, with 14–16 gills reaching the stem. Additionally, there are two or three tiers of lamellulae—short gills that do not extend fully from the cap edge to the stem. The gills are narrow, and yellowish or with a reddish tinge at first; the margins are paler and the same color as the faces. The stem is 2–4 cm long and 1–2 mm thick, and roughly equal in width throughout. It is tubular, fragile, initially pruinose, polished and smooth with age, pale yellow, becoming whitish, with the base often dirty yellow or brownish.The spores are narrowly ellipsoid, inamyloid, and measure 6–7 by 3–3.5 μm. The basidia are four-spored and measure 20–22 by 6–7 μm. The cheilocystidia and pleurocystidia are abundant and similar in shape and markings, 40–58 by 10–15 μm, tapering somewhat on either end and usually with a long needle-shaped neck. The cystidia are generally smooth, but when dried material is mounted in potassium hydroxide for observation under light microscopy, an amorphous substance apparently holds spores and debris around the neck or apex, making them appear encrusted. The flesh of the gill is very faintly vinaceous-brown when stained in iodine. The cap flesh has a thin, poorly differentiated pellicle with a region of slightly enlarged cells beneath it; the remainder is filamentous, and the filamentous portion stains vinaceous-brown in iodine.
scarlet bonnet  Atheniella adonis,Fall,Geotagged,Scarlet Bonnet,United States

Naming

The species epithet refers to the handsome youth Adonis in Greek mythology. Samuel Frederick Gray called it the "Adonis high-stool" in his 1821 "Natural Arrangement of British Plants", while Mordecai Cubitt Cooke named it the "delicate Mycena"."Mycena acicula" is typically smaller with a deep orange-red cap rather than the typical bright salmon-pink of "A. adonis". Since the colors and sizes of "M. acicula" and "A. adonis" are similar, a microscope is needed to reliably distinguish between them, with spore size and shape being different. "Mycena strobilinoides" can be distinguished by its orange cap and amyloid spores. "Atheniella aurantiidisca" can be distinguished by its lack of scarlet to pinkish tones in the cap and lack of gelatinized cortical hyphae. "Mycena oregonensis" is differentiated by its orange to yellow cap and lack of scarlet to pinkish tones. "Mycena roseipallens" has a smaller fruit body, wider spores, a less intensely colored and less conical cap, and grows on the decaying wood of elm, ash, and alder.

Distribution

The fruit bodies of "A. adonis" grow solitarily or in groups in conifer forests and heaths, and appear in the spring and autumn. The fruit bodies grow in groups or scattered on needle beds under spruce and hemlock in wet coastal conifer forests, or in the higher mountains, where it is not uncommon in the spring and autumn months. In one instance, fruit bodies were found growing on the deciduous trees Spanish Maple and willow near Amsterdam. It was hypothesized that the bark of these trees had become more acid in recent years because of increasing atmospheric pollution, providing a more suitable substrate for the fungus.

The fungus is found in Europe and in western North America, where "Mycena" specialist Alexander H. Smith found the species in Washington, Oregon, and California. In 2007, it was reported from the valley of the Ussuri River in the northeast of China.

Habitat

The fruit bodies of "A. adonis" grow solitarily or in groups in conifer forests and heaths, and appear in the spring and autumn. The fruit bodies grow in groups or scattered on needle beds under spruce and hemlock in wet coastal conifer forests, or in the higher mountains, where it is not uncommon in the spring and autumn months. In one instance, fruit bodies were found growing on the deciduous trees Spanish Maple and willow near Amsterdam. It was hypothesized that the bark of these trees had become more acid in recent years because of increasing atmospheric pollution, providing a more suitable substrate for the fungus.

The fungus is found in Europe and in western North America, where "Mycena" specialist Alexander H. Smith found the species in Washington, Oregon, and California. In 2007, it was reported from the valley of the Ussuri River in the northeast of China.

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Taxonomy
KingdomFungi
DivisionBasidiomycota
ClassAgaricomycetes
OrderAgaricales
FamilyCyphellaceae
GenusAtheniella
SpeciesA. adonis