Mycena adonis

In forests and grassland, among grass and moss, on fallen twigs or decayed wood, under deciduous as well as coniferous trees. Also found under Salix in alpine sites. Autumn. Not common.

Pileus 3-20 mm across, narrowly to broadly conical, without or with a small papilla, flattening with age, more or less umbonate, pruinose, glabrescent, shallowly sulcate to smooth, little translucent-striate, bright pink-salmon, scarlet or orange red, fading with age, rarely white. Lamellae 11-24 reaching the stipe, ascending, somewhat ventricose, narrowly to broadly adnate, decurrent with a short tooth, pink to white, edge white. Stipe 15-40 x 0.5-2 mm, hollow, fragile, straight, equal, terete, pruinose, glabrescent, white or pink, often pink at the apex, attached with a patch of whitish, interwoven mycelial fibrils. Odour none.

Basidia 25-35 x 6.5-7 μm, slender-clavate, 2-spored. Spores 7.2-9.5 x 5-5.5 μm, Q 1.4-1.9, broadly pip-shaped, smooth, non-amyloid. Cheilocystidia 35-45 x 12-14 μm, occuring mixed with basidia, (the lamellar edge heterogenous), smooth, fusiform, lageniform. Pleurocystidia similar. Lamellar trama not vinescent in Melzer's reagent. Hyphae of the pileipellis up to 5 μm wide, covered with simple to branched cylindrical excrescences. Hyphae of the cortical layer of the stipe up to 3 μm wide, smooth, the terminal cells (caulocystidia) clavate to fusiform. Clamp connections absent.

Microphotos of cheilocystidia and hyphae of the pileipellis

More microphotos of cheilocystidia and hyphae of the pileipellis

According to Maas Geesteranus (1990: 167-169) Atheniella adonis can also be 4-spored and clamped but I have not seen this.

There has been some uncertainty about how to distinguish A. adonis from 'M. floridula'. This matter was discussed by Maas Geesteranus (1990). M. floridula was described as a 4-spored species and A. adonis generally is 2-spored. Maas Geesteranus stated, however, that A. adonis also has a 4-spored form. It will, however, never show any trace of yellow, nor turning yellowish when fading, as is a typical feature of M. floridula. In addition, according to Maas Geesteranus (1990), the lamellae of A. adonis are delicately pink, turning white and with white edge, whereas they are bright pink-red to coral red at the base, pallescent with age, in M. floridula. I can not confirm the latter information. It should also be mentioned that Aronsen & Larsson (2016) published molecular data indicating that 'M. floridula' is merely a pink form of A. flavoalba.

In the 2-spored form of A. adonis the spores are significantly broader than the spores of 'M. floridula' but according to Maas Geesteranus (1990) the spores of 4-spored A. adonis are of the same size as those of 'M . floridula'.

Redhead et al. (2012), proposed the new genus Atheniella to accommodate A. adonis, A. amabillissima, A. aurantiidisca, and A. flavoalba.

A. adonis was formerly recognized as a member of Mycena sect. adonideae (Fr.) Quél.