The type species of the genus Marasmius, M. rotula was first described scientifically in 1772 by mycologist Giovanni Antonio Scopoli and assigned its current name in 1838 by Elias Fries.

The fruit bodies, or mushrooms, of M. rotula are characterized by their whitish, thin, and membranous caps up to 2 cm (3⁄4 in) wide that are sunken in the center, and pleated with scalloped margins.

The mushrooms grow in groups or clusters on decaying wood such as fallen twigs and sticks, moss-covered logs, and stumps.

There are several species of Marasmius with which M. rotula might be confused due to somewhat similar overall appearances, but differences in size, gill arrangement, and substrate are usually sufficient field characteristics to distinguish them.

[6] Synonyms include names derived from generic transfers to Androsaceus by Narcisse Théophile Patouillard in 1887,[7] and to Chamaeceras by Otto Kuntze in 1898;[2] both of these genera are now obsolete and have since been sunk back into Marasmius.

[9] In 1946 Alexander H. Smith and Rolf Singer proposed to conserve the name Marasmius over Micromphale; the latter had nomenclatorial priority as it was published first.

[14] The white or slightly yellowish flesh is very thin, reaching about 0.25–1.5 mm thick in the central part of the cap, and even thinner at the margin.

[20] Note particularly the manner in which the hair-like stem is set into the tiny socket, the sparsity of the gill development, and the fine furrows and scallopings of the margin of the cap.

For example, specimens growing on logs in oak and hickory forests in the spring tend to have more yellowish-white, depressed caps than those found in the same location in autumn, which are light yellow brown and more convex in shape.

[27] There are several less-common species of Marasmius with which M. rotula might be confused due to somewhat similar overall appearances, but differences in size, gill arrangement, and substrate are usually sufficient field characteristics to distinguish between them.

[34] M. rotuloides, known only from montane forests of Trinidad, can only be reliably distinguished from M. rotula by microscopic characteristics: it has smaller, ovoid spores measuring 5 by 2.5 μm.

[35] Other Marasmius species with a pinwheel arrangement of gills are readily distinguished from M. rotula by differences in color, including the orange M. siccus, the pink M. pulcherripes, and the rust M. fulvoferrugineus.

[30] Mycena corticola is smaller than Marasmius rotula, has a pale pink-brown cap, and is usually found growing singly or in small groups on bark near the base of living trees.

[18] Marasmius rotula grows in deciduous forests and fruits in groups or clusters on dead wood (especially beech), woody debris such as twigs or sticks, and occasionally on rotting leaves.

[32] Although far less common in southerly locations, isolated collections have been reported from Africa (Congo,[37] Nigeria,[38] Sierra Leone,[39] and Tanzania)[40] and South Asia (India).

[46] Like those of many other species of Marasmius, the fruit bodies of M. rotula can desiccate and shrivel in dry periods, then revive when sufficient moisture is available again in the form of rain or high humidity.

[20] Louis Krieger, writing in National Geographic in the 1920s, noted that the mushroom was used as an addition to gravies and, when used to garnish venison, "adds the appropriate touch of the wild woodlands".

In general, enzymes that catalyze oxygen-transfer reactions are of great utility in chemical synthesis since they work selectively and under ambient conditions.

Fungal peroxidases can catalyze oxidations that are difficult for the organic chemist, including those involving aromatic substrates such as aniline, 4-aminophenol, hydroquinone, resorcinol, catechol, and paracetamol.