Marasmius rotula is a saprobic species and as such obtains nutrients by decomposing dead organic matter.
It 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.
The fruit bodies, which are easily overlooked because of their diminutive size, are often present in abundance after rains.
The species is relatively intolerant of low water potentials, and will grow poorly or not at all under water stress conditions.
It is unable to degrade leaf litter until it becomes more fragmented and more compacted so that the water-holding capacity increases in the deeper layers of the soil.
The magnolia warbler has been noted to line its nests with the fruit bodies' stems.

In 1975 American mycologist Martina S. Gilliam investigated the periodicity of spore release in M. rotula and concluded that spore discharge did not follow a regular circadian rhythm, as is typical of agaric and bolete mushrooms, but rather was dependent on rain.
A threshold of rainfall is required to elicit a spore discharge response and the duration of peak spore discharge correlates with the amount of rainfall, rather than its duration.
Furthermore, Gilliam noted that spore prints were more readily obtained if the stem ends were placed in water, suggesting that water must enter through the fruit body for discharge to occur.

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.
Gilliam's study demonstrated that revived fruit bodies were capable of discharging spores over a period of at least three weeks, whereas previous studies using similar methods with other Agaricomycetes showed spore discharge occurred over a shorter period of up to six days after revival.
The potential for sustained spore production and discharge may be due to the growth of new basidioles (immature basidia) during periods of growth, which then complete maturation when the mushroom revives.
This may also explain why the gills become thicker as the mushroom matures.

The fungus is widespread and common in its preferred habitats in North America, Europe, and northern Asia.
Although far less common in southerly locations, isolated collections have been reported from Africa (Congo, Nigeria, Sierra Leone, and Tanzania) and South Asia (India).
In North America M. rotula is most common in the eastern part of the continent.
Marasmius rotula is a saprobic species and as such obtains nutrients by decomposing dead organic matter. It 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. The fruit bodies, which are easily overlooked because of their diminutive size, are often present in abundance after rains. The species is relatively intolerant of low water potentials, and will grow poorly or not at all under water stress conditions. It is unable to degrade leaf litter until it becomes more fragmented and more compacted so that the water-holding capacity increases in the deeper layers of the soil. The magnolia warbler has been noted to line its nests with the fruit bodies' stems.
In 1975 American mycologist Martina S. Gilliam investigated the periodicity of spore release in M. rotula and concluded that spore discharge did not follow a regular circadian rhythm, as is typical of agaric and bolete mushrooms, but rather was dependent on rain. A threshold of rainfall is required to elicit a spore discharge response and the duration of peak spore discharge correlates with the amount of rainfall, rather than its duration. Furthermore, Gilliam noted that spore prints were more readily obtained if the stem ends were placed in water, suggesting that water must enter through the fruit body for discharge to occur.
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. Gilliam's study demonstrated that revived fruit bodies were capable of discharging spores over a period of at least three weeks, whereas previous studies using similar methods with other Agaricomycetes showed spore discharge occurred over a shorter period of up to six days after revival. The potential for sustained spore production and discharge may be due to the growth of new basidioles (immature basidia) during periods of growth, which then complete maturation when the mushroom revives. This may also explain why the gills become thicker as the mushroom matures.
The fungus is widespread and common in its preferred habitats in North America, Europe, and northern Asia. Although far less common in southerly locations, isolated collections have been reported from Africa (Congo, Nigeria, Sierra Leone, and Tanzania) and South Asia (India). In North America M. rotula is most common in the eastern part of the continent.
Marasmius rotula