Scattered to gregarious among grass and
moss or on conifer needle beds, on fallen twigs, in deciduous
as well as coniferous woods. Summer to autumn. Widely distributed all over the area. See the records in The Norwegian Mycological Database.
Pileus 5-15(-30) mm across, narrowly to broadly conical, becoming parabolical, convex to almost plane, sometimes with a small umbo, sulcate, translucent-striate, ivory-white to yellowish white, sometimes more yellowish at the centre. Lamellae 20-24 reaching the stipe, ascending, narrowly adnate, with or without a short decurrent tooth, dorsally intervenose with age, white. Stipe 20-80 x 1-2 mm, hollow, terete, equal, straight, pruinose at the apex, glabrous farther down, white, the base densely covered with long, coarse, flexuous white fibrils. Odour indistinctive.
Basidia 24-30 x 5.5-6.5 μm, slender-clavate, 4-spored, clamped. Spores 6.5-9 x 3-4.5 μm, Q=1.6-2.2, Qav=1.9, pip-shaped, smooth, non-amyloid. Cheilocystidia 30-60 x 5.5-12.5 μm, occuring mixed with the basidia, fusiform, long- to short-stalked, clamped, apically sometimes subcapitate or covered by a gelatinous drop. Pleurocystidia similar. Lamellar trama non-amyloid and non-dextrinoid. Hyphae of the pileipellis 2-6.5 μm wide, clamped, covered with simple to much branched, cylindrical to strongly inflated excrescences 2-20 x 2-6.5 μm, which tend to form very dense masses and becoming gelatinized. Hyphae of the cortical layer of the stipe 2.5-4.5 μm wide, clamped, smooth; caulocystidia up to 65 x 20 μm, fusiform, lageniform, subcylindrical or clavate to globose.
Microphotos of cheilocystidia and hyphae of the pileipellis
Maas Geesteranus (1990:173) discussed a possible placement of Mycena flavoalba in the genus Hemimycena Singer. He chose to keep it in Mycena sect. Adonidae together with the five species M. adonis, M. aurantiidisca, M. floridula, and M. ochrogaleata. The latter species is by many authors recognized as a Hemimycena, e. g. by Antonín & Noordeloos (2004), and is excluded from this site. M. flavoalba may be confused with species of Hemimycena, for example Hemimycena lactea (Pers.) Singer and H. delectabilis (Peck) Singer. It differs from these species, among other features, by the distinctly pigmented, yellowish or ivory white pileus, differently shaped spores and different shape of the caulocystidia.
Within the genus Mycena, M. flavoalba is a member of sect. Adonideae (Fr.) Quél., which is characterized by more or less brightly coloured species with non-amyloid spores, smooth, fusiform cheilocystidia, presence of pleurocystidia, diverticulate hyphae of the pileipellis, and smooth hyphae of the cortical layer of the stipe. Within the section it differs from the other species by the white to yellow-white pileus. The section should probably be separated from Mycena, as suggested by Redhead et al. (2012), who proposed the new genus Atheniella to accommodate A. adonis, A. amabillissima, A. aurantiidisca, and A. flavoalba.
Molecular studies performed by Aronsen & Larsson (2016) are indicating that M. flavoalba comprises two phylogenetic species, which should be explored further. They also found that the pink taxon, currently known as M. floridula, is conspecific with one part of the M. flavoalba material that they investigated, while the other part constitutes a sibling species currently not circumscribed.
Further images on the Internet: