Those of you who were at the North American Mycological Association foray in North Carolina in 1994 may remember this specimen. About 9 inches tall, it smelled so bad it was not placed inside on the display tables with the other fungi, but relegated to the outside, far away from the door. I think it may have been the most photographed mushroom that day. The common name stinkhorn for this month's fungus is very appropriate. The fruiting body begins as an "egg" stage, from which the phallic-looking fruiting body emerges over the course of just a few hours. As it becomes erect the black slimy mass of spores on the cap begins to mature-- and begins to smell like rotting meat. This attracts flies, which think they're getting a great meal of roadkill or some other dead animal. The flies are visible on the black spore mass in the picture. Instead they get a meager portion of spore mass. More importantly for the fungus, some of the spores stick to the legs and mouth parts of the flies. Eventually the flies land on some real rotting material and the spores are transferred to a substrate they can grow on. The fly may visit more than one stinkhorn, and this helps to ensure cross-fertilization among the members of the species. You may see some very striking similarities with the pollination activities of insects on flowers here. The stinkhorns seem to be absolutely dependent on the flies for the dissemination and mating of their spores; unlike most basidiomycetes, there is no wind dispersal of spores. Dictyophora duplicata is a member of the class Gasteromycetes (the stomach fungi). Maybe we'll take a step back for a minute. There are usually considered to be four classes in the phylum Basidiomycota: Hymenomycetes-- the hymenium (fertile layer) is exposed before the spores mature. This class includes most mushrooms, shelf fungi, jelly fungi, crust fungi and so on. Gasteromycetes-- the hymenium is exposed after the spores mature. This class includes the stinkhorns, the puffballs (such as Calvatia gigantea), and bird's nest fungi. Urediniomycetes-- no fruiting body, complex life cycle, obligate parasites. This class is commonly called the rusts. Ustilaginomycetes-- no fruiting body, simple life cycle, facultative parasites. This class is commonly called the smuts, and includes the corn smut Ustilago maydis. Click here for Smuts on the Internet The stinkhorns are all members of the order Phallales. All member of this order produce a stinking mass of spores at some point. The genera and species are differentiated on the basis of what kind of fruiting bodies they produce and where they bear their spores on the fruiting body. Dictyophora and Phallus species have a pileus differentiated at the top of the stalk. Dictyophora species all have a veil-like structure hanging down, while Phallus species lack the veil. Phallus impudicus is probably the most famous of the stinkhorns-- it certainly has the most descriptive name! The two fruiting bodies here are members of the genus Mutinus, often called the "dog stinkhorns." (If you don't know the reason for this I don't think you're ready for me to explain it to you...). To the left is the red/orange Mutinus elegans and to the right is the white and more slender Mutinus caninus. On each of them you can see the saclike structure at the base from which the rest of the fruiting body emerged. Mutinus species lack a cap at the top of the stalk. The slimy spore mass is borne directly on the pointed apex. I get at least seven or eight emails per year from people who have one of these Mutinus species growing in their yard, especially in bark mulch. I have also found them in very rich soils in wet areas. They're actually kind of fun to fund. Usually when you find one stinkhorn fruiting you can find more. If you look around you can sometimes find the egg stage, before the stalk emerges. I collect these and put them in a high humidity chamber (like a glass jar) and use them for my mycology class. Under the right circumstances, we can watch the fruiting body emerge from the egg within a few hours. It's certainly an interesting class activity, one that students will remember for a very long time. Surprisingly there are some human uses for members of the Phallales. You're probably not going to believe this, but some of these members of the Phallales, especially Phallus and Dictyophora are considered a delicacy in China! As you might guess (especially if you're familiar with the doctrine of signatures, where the ailment cured by an organism is related to its shape), you won't be surprised that both of these are considered aphrodisiacs! Sometimes they are eaten in the egg stage, and sometimes they are eaten after maturity, after the spore mass is removed. They are even cultivated and sold in stores in China, either fresh or dried. I've had them, and they're actually pretty good. I get at least 5 emails per week from people asking how to get rid of the stinkhorns, slime molds, cannonball fungus, and other fungi in their mulch. You can read about this on my mulch page. I will not answer any further emails about how to get rid of fungi in your yard. THERE IS NOTHING YOU CAN DO ABOUT THEM short of paving over your yard, so you might as well find some way to enjoy it. :) I hope this page helps your enjoyment. And just when you thought you'd seen everything, here's another bizarre member of the Phallales, Clathrus columnatus, the stinky squid stinkhorn. The image shows one mature fruiting body with the slimy spore mass on the inside of the radiating arms. next to it are two "eggs" from which more fruiting bodies will emerge. This fungus is uncommon, but with a widespread distribution in the southeastern United States, and probably other subtropical areas. I hope you enjoyed learning something about Dictyophora and other members of the Phallales. They're very interesting fungi to find. But don't spend a lot of time smelling them-- and don't collect them in your mushroom basket and leave them in a hot car-- you'll be very sorry! If you have anything to add, or if you have corrections or comments, please write to me at volk.thom@uwlax.edu This page and other pages are © Copyright 1999 by Thomas J. Volk, University of Wisconsin-La Crosse. Return to Tom Volk's Fungi Home Page -- http://TomVolkFungi.net
The two fruiting bodies here are members of the genus Mutinus, often called the "dog stinkhorns." (If you don't know the reason for this I don't think you're ready for me to explain it to you...). To the left is the red/orange Mutinus elegans and to the right is the white and more slender Mutinus caninus. On each of them you can see the saclike structure at the base from which the rest of the fruiting body emerged. Mutinus species lack a cap at the top of the stalk. The slimy spore mass is borne directly on the pointed apex. I get at least seven or eight emails per year from people who have one of these Mutinus species growing in their yard, especially in bark mulch. I have also found them in very rich soils in wet areas. They're actually kind of fun to fund. Usually when you find one stinkhorn fruiting you can find more. If you look around you can sometimes find the egg stage, before the stalk emerges. I collect these and put them in a high humidity chamber (like a glass jar) and use them for my mycology class. Under the right circumstances, we can watch the fruiting body emerge from the egg within a few hours. It's certainly an interesting class activity, one that students will remember for a very long time.
I hope you enjoyed learning something about Dictyophora and other members of the Phallales. They're very interesting fungi to find. But don't spend a lot of time smelling them-- and don't collect them in your mushroom basket and leave them in a hot car-- you'll be very sorry!
