Tom Volk's Fungus of the Month for September 2005

Mycena leaiana, the orange Mycena.

Please click for the rest of Tom Volk's pages on fungi

Beautiful specimens of Mycena leaiana

This month's fungus, Mycena leaiana, is a fun mushroom to find in the woods. It's bright orange, with bright orange marginate gills (more on that later), and thus often stands out from a long distance. Even though the mushrooms themselves are quite small at maturity, usually less than an inch (3 cm) in diameter, they can be very prolific fruiters, so there is often a large amount of it to be seen. Even in dry weather you can often find it because it uses the water found very deep in the log to produce its fruiting bodies. Remember that mushrooms are 90-95% water, so if there's no water there are no mushrooms, but Mycena leaiana seems to be a fantastic scavenger of water through its mycelium from wood.

The edibility of this fungus is unknown, but is not known to be poisonous. That being said, there seems to be nothing to recommend it for the table anyway, since it's very small and has a rather rubbery texture if you try to cut it. The orange color comes off on your hands when you touch it, and I would imagine it would do the same in your mouth.

Mycena leaiana gills. note the orange marginsSo what about these marginate gills? If you look on the underside of the mushroom, you can see that the gills are orange. This seems like a contradiction, since the spore print is white. However if you look a little closer, e.g. with a hand lens, you can see that the orange color is mostly restricted to the edge of the gills. An even closer look with a microscope reveals that the orange pigment is mostly restricted to cystidia, sterile cells at the edge of the gill. Cystidia on the edge of the gill are scientifically called "cheilocystidia" (literally, "lip cystidia"). Compare these to the "pleurocystidia" ("side cystidia") found on (you guessed it) the sides of the gills of Pluteus cervinus. Mycena leaiana microscopic cross section of the gills The cystidia are bright orangeBelow and to the left you can see what these cystidia look like microscopically. Notice that the strikingly beautiful orange cystidia comprise most of the edge of the gill, giving this species its characteristic orange margin. However if you look away from the gill edge toward the basidia (basidiospore producing structures), you can often find some wayward orange cystidia borne singly among the basidia.

In a genus not known for easy identification of its species, this is probably the easiest of all the Mycenas. On the top of the fruiting bodies you can see the characteristic orange color, with growth in caespitose clusters (meaning that many mushrooms emanate from a single point on the log). However, if it's been rainy, the orange color in the cap can actually wash out and fade to a pale tannish orange. In that case all you have to do it turn it over and see the orange marginate gills, which never lose their color. Alexander Smith described this as Mycena leaiana var. pallida, meaning the pallid (light colored) form of Mycena leaiana, but these are probably just washed out mushrooms.

A=M. luteopallens B=M. rutilaniformis C=M. galericulata D=M. strobilinoides E=M. pura F= M. subcaeruleaThere are a number of other Mycena species that are relatively easy to identify. Mycena luteopallens, A, is a paler, smaller (2-3 mm cap) orange mushroom that grows on the hulls of hickory nuts, walnuts and butternuts-- although you might have to dig down in the soil to find the substrate. About the same small size orange-red species include M. acicula and M. adonis. Another species that has marginate gills is M. rutilaniformis (B). A relatively common, although not brightly colored species is M. galericulata (C), with its dark, fading stipe. A small bright red striking species is M. strobilinoides (D). A paler pink/purple species is M. pura (E). A rather strange and relatively rare species shown in F is the bluing Mycena, M. subcaerulea. Note the blue color of the base of the stem and of the very young caps. This species is reported to actually contain the hallucinogen psilocybin, although it's not at all related to Psilocybe. A very common species, Mycena haematopus, the blood-foot mushroom, exudes a blood-colored latex when the stipe is cut. Check out that page for an explanation of the interesting origin of the genus name Mycena.

Because of their orange color and caespitose habit, you might confuse the orange Mycena with Flammulina velutipes, also known as the winter mushroom, velvet stem, velvet foot, enoki, or enokitake. However, that species has a dark black stem, at least at the base, and the gills are not marginate. Flammulina velutipes also tends to fruit when it's rather cold, such as early spring and late fall.

more gills of Mycena leaianaMycena leaiana (Berk.) Sacc. was named Agaricus leajanus (sic) by the Rev. Miles Joseph Berkeley in the London Journal of Botany, vol. 4 (1845). At that time any gilled mushroom was placed in the genus Agaricus. [In the 1880's, Saccardo moved the species to Mycena when the diverse and artificial genus Agaricus was being split into so many of the genera we know today.] So what's with the weird specific epithet, leaiana?? Berkeley himself tells us in describing several new species: "This and the greater part of the following species, are described from a rich collection of fungi consisting of above 280 species, from the neighbourhood of Cincinnati, kindly sent to Sir W. J. Hooker by T. G. Lea, Esq. and accompanied in many instances by very copious and valuable notes." (Thanks to Richard Aaron of Toronto for this information.) It seems odd to us now that Cincinnati would be considered an exotic location, but remember that North America was just being colonized by Europeans. Of course the native Americans had been here already for millennia, but there is surprisingly little evidence that they used mushrooms very often.

Unfortunately, Lea had already died by the time Berkely received Lea's 280 collections from around Cincinnati. The Rev. Berkeley also wrote "I have myself corresponded on the subject with their discoverer and can bear witness to his great kindness and zeal; and I have no doubt that mycology will be further enriched by his labours." (Thanks to Lorelei Norvell and Scott Redhead for this information, published in Mushroom the Journal of Wild Mushrooming 17(4):27-29, 1999.)

Thus Mycena leaiana was named for Thomas Gibson Lea (1785-1844), a Cincinnati naturalist who collected lots of fungi and sent them off to an expert for identification. Berkeley wanted to honor Lea for his contribution. The proper way to make an epithet honoring someone is to add -iana to the name; thus we end up with leaiana. Just remember that every other letter after the first two is an "a," and you'll be able to spell it. This is yet another example of the contribution of an amateur to the science of Mycology.

I hope you have enjoyed learning something about Mycena leaiana, the orange mushroom with the unusual name. There are many beautiful fungi in the woods, and not all of them are large and showy. Take some time to look at all the beautiful little fungi all around you.

If you have anything to add, or if you have corrections, comments, or recommendations for future FotM's (or maybe you'd like to be co-author of a FotM?), please write to me at

This page and other pages are © Copyright 2005 by Thomas J. Volk, University of Wisconsin-La Crosse.

Learn more about fungi! Go to Tom Volk's Fungi Home Page

Return to Tom Volk's Fungus of the month pages listing

Counter Image