Mycena flavescens
Description
Mycena flavescens is a species of Mycenaceae fungus. The caps are initially conical or campanulate, becoming broadly convex, sometimes with an umbo; translucently striate almost to the cap center; dark to mid-brown central disc fading to almost white at the margin. The thin cap flesh is whitish.
This little mushroom is an occasional find in most of mainland Europe from Scandinavia down to Italy and Spain. Occurring in mossy lawns, on moss-covered tree trunks, among vegetable debris under deciduous trees, and fallen needles in coniferous woods, particularly Picea. Autumn.
It is a very variable species. The stem may show a violaceous hue at the apex, although not very often. Another striking character is the wide hyphae of the pileipellis.
Mushroom Identification
Cap
5-15 mm across, conical to broadly conical or campanulate, with age becoming convex, and often with an umbo, glabrous, hygrophanous, translucent-striate, sulcate, at first often dark black-brown at the center with pale brown to beige or almost whitish margin, generally with a marked margin between the darker and the pallid parts of the pileus, then fairly dark brown at the center, paler to beige towards the margin, fading to pale grey or pale grayish-brown with pallid to whitish margin.
Lamellae
17-26 reaching the stem, ascending, narrow, narrowly adnate, white to cream or pale gray, often with a pale yellowish shine, the edge concolorous or very weakly colored pale yellow, easiest seen in young specimens and near the margin of the pileus. The yellow edge is often not perceptible in older specimens.
Stem
15-60 x 0.5-1 mm, terete, equal, hollow, straight to curved below, and even somewhat flexuous, not very fragile, experienced as fairly firm, glabrous except for the pruinose apex, grayish to brownish, often olivaceous brown at the apex and darker brown below; the base covered with coarse, white fibrils.
Odor
Usually strong, disagreeable, raphanoid, or reminiscent of raw potato.
Microscopic Features
Basidia 21-29 x 7-9 µm, clavate, 4-spored, with sterigmata 5-6 µm long. Spores 7.5-10 x 4-5 µm, Q 1.5-2.2, Qav 1.8-1.9, pip-shaped to somewhat elongated, smooth, amyloid. Cheilocystidia 19-65 x 9-27 µm, forming a sterile band, sessile to stipitate, ellipsoid to clavate, obpyriform or subglobose, densely covered with warts or evenly spaced, cylindrical excrescences 0.5-3 x 0.5-1 µm. Pleurocystidia similar. Lamellar trama dextrinoid. Hyphae of the pileipellis 3-27 µm wide, densely covered with warts or short excrescences. Hyphae of the cortical layer of the stipe 2.5-4.5 µm wide, covered with scattered, short, cylindrical excrescences. Clamp connections are present in all tissues.
Look-Alikes
Yellowish mushroom can be confused with species of the genus Hemimycena (Hemimycena delectabilis), e.g. It differs from these species, inter alia, in a distinct color, yellowish or white cap, differently shaped spores, and a different shape of caulocystides.
Within the genus Mycena, M. flavoalba is a member of the Adonideae sect, which is characterized by more or less brightly colored fruiting bodies and non-amyloid spores, smooth, spindle-shaped cheilocystidia, the presence of pleurocystidia, diverticulosis hyphae and smooth hyphae of the cortical layer of the stem. In cross-section, it differs from other species in the color of the hat - white to yellow-white.
Molecular studies conducted by Aronsen and Larsson in 2016 indicate that M. flavoalba comprises two phylogenetically different species that should be investigated further. They also found that Mycena floridula is correlated with one part of their M. flavoalba material, while the other part is a currently undefined species.
History
It was first described scientifically by the Czech mycologist Josef Velenovský in 1920, based on specimens collected in Mnichovice in 1915. The mushroom is edible.
The specific epithet flavescens comes from the prefix flavo- meaning yellow and the suffix -escens indicating a gradual change process. This is a reference to the way the gill edges of these bonnet mushrooms sometimes (but certainly not always) turn yellowish.
Photo sources:
Photo 1 - Author: christian_ap (CC BY-NC 4.0)
Photo 2 - Author: ledum (CC BY-NC 4.0)
Photo 3 - Author: faluke (CC BY-NC 4.0)
Photo 4 - Author: nschwab (CC BY-NC 4.0)
