Marasmius' best party trick is being marcescent, that is the dried fruit bodies can revive in water and come back to life, even continuing to disperse spores! The cells have a kind of gel-like sugary protective coating keeping them from being harmed when desiccated. All are saprophytic but you might find them on the ground or on wood or debris of various sizes.
Marasmius is the core of one of the three largest miscellaneous groups of white spored mushrooms, which I call the "Marasmioid clade". The other two are the Hygrophoroid clade (those related to waxy caps) and the Tricholomatoid clade (those related to Tricholoma). All of them are so similar that before DNA sequencing helped sort it all out, all three were dumped into the overly large Tricholomataceae family. Just about every mushroom from all seven stature pages was dumped there. Since they weren't obviously distinctive like Lactarius, Amanita, etc. we didn't know what else to do. Interestingly enough, most of the "tough stemmed" mushrooms, ended up being related to Marasmius (although many others are too).
|Small mushrooms with two-toned stems on cones may be Strobilurus.|
Garlic or rotten odor - closely related to Marasmius, with strong odors. The "garlic marasmius" is so strong you can smell it before you find it, and it is said to be a good garlic substitute for those who are allergic. The most common one is probably Mycetinis salalis, which grows on dead salal and Oregon grape.
Mycetinis (Marasmius) salalis/
Coloured caps - mostly in the genus Marasmius. These first few species are possibly >2.5cm across, including the fairy ring mushroom, one of many that sometimes grows in unusual fairy rings. This may not represent the magical living spaces of faeries as once thought, but might instead simply be a result of the mycelium growing out equally quickly in all directions from its germination point and sprouting mushrooms only at the limits of its growth in a circular pattern. Marasmius is also known for many of its members having big, inflated, often round cells in the cap. Not usually hygrophanous.
Marasmius oreades - found in grass in the spring. <5cm. Tough but not wiry stem. Often wavy cap, sometimes uplifted margin. Famous for sometimes growing in fairy rings.
M. cohaerens - <5cm. Colourful in a way, but never as red. Two-toned stem like Gymnopus erythropus.
Marasmiellus pluvius - ~1cm, pale orange-brown cap, red-brown stem bottom, found on conifer debris.
Heimiomyces (Xeromphalina) fulvipes - Most X. species are omphalinoid in stature, not Marasmius. It is bitter with a dark wiry stem. Found on duff and debris.
White caps - These tiny white mushrooms are recognized by only having a few gills, growing on wood or debris and having tough, darkening stems. Not hygrophanous. Some of these species, especially those currently called "Marasmiellus" on this page will likely be moved in the future to different genera. Unlike Marasmius, microscopically Marasmiellus has "normal" cap cells.
|Hemimycenas and some Mycenas are very similar, found on the ground or woody debris, but with pure white, fragile stems.|
Tetrapyrgos (Marasmiellus) candidus - <2.5cm, white with dark stem bases.
Marasmiellus papillatus - <2cm. pink and umbilicate-papillate (umbonate)
Tetrapyrgos (Marasmiellus) subdendrophora - usually veined pseudo-gills but may look normal like M. candidus, but stem is eccentric. On Rubus canes. ~1cm.
Marasmius epiphyllus - <1cm. Even fewer rudimentary gill-like veins. <1cm.
Marasmius limosus - very similar, but on grasses and sedges.
Marasmiellus filopes - ~2mm!, teensy on conifer needles, with few gills and long stem. Whitish stem like Hemimycena. Garlic odor in quantity!
If you don't find your mushroom here, you might want to try one of the other stature types as the differences are often slight and it can be very difficult to decide which group a mushroom is in. Remember to verify the spore colour too.
(return to Pictorial Key)