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.
For example, Marasmius capillaris has a pale tan cap with a white center, and grows on oak leaves without forming clusters.
Furthermore, its cap is evenly rounded, unlike the pleated and furrowed cap of M. rotula, and its stem is somewhat thinner (usually less than 0.3 mm) and slightly darker in color.

M. rotula is distinguished from M. bulliardii by its larger size, and greater number of gills.
M. limosus is found in marshes, where it fruits on the dead stems of reeds and rushes.
Tetrapyrgos nigripes (formerly treated in Marasmius) has white caps that are 5 to 10 mm (0.2 to 0.4 in) in diameter, attached gills that are sometimes slightly decurrent, a dark stem covered with tiny white hairs that give it a powdered appearance, and triangular to star-shaped spores.
M. neorotula, described from Brazil, was considered by its discoverer Rolf Singer to be closely related to M. rotula.
In addition to its tropical distribution, it can distinguished from M. rotula by its smaller size and more widely spaced gills.
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.

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.
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.
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. For example, Marasmius capillaris has a pale tan cap with a white center, and grows on oak leaves without forming clusters. Furthermore, its cap is evenly rounded, unlike the pleated and furrowed cap of M. rotula, and its stem is somewhat thinner (usually less than 0.3 mm) and slightly darker in color.
M. rotula is distinguished from M. bulliardii by its larger size, and greater number of gills. M. limosus is found in marshes, where it fruits on the dead stems of reeds and rushes. Tetrapyrgos nigripes (formerly treated in Marasmius) has white caps that are 5 to 10 mm (0.2 to 0.4 in) in diameter, attached gills that are sometimes slightly decurrent, a dark stem covered with tiny white hairs that give it a powdered appearance, and triangular to star-shaped spores. M. neorotula, described from Brazil, was considered by its discoverer Rolf Singer to be closely related to M. rotula. In addition to its tropical distribution, it can distinguished from M. rotula by its smaller size and more widely spaced gills. 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.
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. 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.
Marasmius rotula