Dogtoberfest beer!Mutinus caninus, the dog stinkhorn, in honor of Dogtoberfest

Tom Volk's Fungus of the Month for October 2006

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Mutinus caninus, the dog stinkhorn After 117 (One hundred seventeen!) Fungus of the Month pages and nine years' worth of October fungi, it's getting more difficult to come up with a good October fungus. I've done all the obvious ones already, including the Halloween fungi: Jack-O-Lantern Mushroom, Omphalotus olearius or O. illudens; Claviceps purpurea, cause of the plant disease ergot and likely factor in the Salem Witch Trials; Tremella mesenterica, witch's butter; Hygrocybe conica, the witch's hat mushroom; Monotropa uniflora, the ghost plant, aka Indian Pipe; Hydnum umbilicatum, the sweet tooth mushroom; and Lactarius rubidus, candy caps. I have also had a fungus for Oktoberfest, Hemitrichia serpula, the pretzel slime mold. So, what should I choose for this October's fungus?

La Crosse, Wisconsin is the home of one of the largest and best Oktoberfest celebrations in America. However, in many parts of the country they celebrate something called Dogtoberfest. Somewhere I had heard the word "Dogtoberfest" in conversation, so I decided to google "Dogtoberfest" and found over 12,000 entries! Wow! I'm on to something here I guess. Most of the Dogtoberfest pages describe festivals for people and their dogs-- or in many cases, a kind of beer. You can do the search on your own. So I knew I had to come up with a dog-related fungus for this month. I had already had the dog turd fungus, Pisolithus tinctorius, as fungus of the month, so I decided to make the dog stinkhorn, Mutinus caninus, this month's fungus.

I probably get more email about stinkhorns in people's yards than about any other fungi. Most people don't seem to like them-- something about the smell. Go figure. I already have a page about Dictyophora duplicata, the netted stinkhorn. This page also includes information about other stinkhorns, but I decided to make a page just for Mutinus, the dog stinkhorn.

Here's a typical email:

Mutinus in mulch

"Hi Tom, I have beauty bark that has the white webbed fungis under the top layer of beauty bark. It has some disgusting mushroom fruit that looks like a dog d*ck with the tip dipped in sh*t. I am entirely serious. It's growing in the beauty bark of the home I just bought. What kind of shroom is that? I imagine that I will need to remove all the bark to eliminate the spidering fungis.

I've been stepping on the shrooms, but in researching shrooms, I've decided to start pulling them up in a garbage bag and throwing them away.

/signed/ Mushroom hater

I wrote back: "There's no way to get rid of them." I also referred him to my page on stinkhorns.

He wrote back: "How can there be no way to be rid of them????? I sprayed the fruit with poison. Then chanted Die Die Die!"

cross section and whole eggs of Mutinus caninus, the dog stinkhornThe common name stinkhorn is very appropriate. The fruiting body begins as an "egg" stage (shown to the right), 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 as the black spore mass in the picture. Instead the flies get a meager portion of spore mass, presumably not as delicious as real rotting meat. 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.

As I've said before, there's really not much you can do to get rid of these fungi once they start to grow in your mulch, short of taking out all the mulch and paving over everything. Adding more mulch just gives them more food. Many gardeners spend lots of time and money looking for something new and unusual for their yards, something to show off to their friends and make the neighbors envious. Something fun like stinkhorns show up in their mulch, and many want to just kill it. My recommendation is that you find a way to enjoy them. Call all the neighbors over. Call all your friends. They will marvel at your gardening skills.

However some people do not appreciate fungi, no matter what. Here's another email:

fairy ring of MutinusSorry, but recommending that one sit back and enjoy one's stinkhorns is a tough one for me. The smell and the flies really do rather overpower what I will concede is a fascinating organism. I do agree that it's interesting, mind you---particularly the "egg" aspect----but I will say that I have had some success in diminishing the infestation by 1. assiduous "egg" collection, 2. removing fine particles of mulch that seem conducive to spore production and 3. application of copper-based fungicide to the most overwhelmed areas. I would say that it is rather easier to enjoy them in the abstract, than it is to enjoy having them densely populating a small urban front yard just below one's living room windows, with their distinctively retch-worthy odor wafting in the breeze. Additionally, after having glanced through your site, I should mention that if I did have something called "dog-vomit slime mold", I don't think I could bring myself to enjoy its presence in my yard either. Perhaps those of us who are unable to enjoy these reeking slimy fungi could send them your way, since you are so partial to them. No offense meant. I doubt your house smells like mutinus elegans and if it did, your enthusiasm for it might be diminished, if not your social life. Try to be a bit more sympathetic. /unsigned/

hmmm. I hope that this is the worst thing this person has to worry about in their life. There are so many things that are a lot more important (e.g. health) than whether there's a smell in your yard. Good Luck to you.

many Phallales species-- stinkhorns-- A=Clathrus??, photo by Jim Cerullo B=Lysurus mokusin, photo by Ian Heidt, C=Clathrus, photo by Diane Derouen, D=Phallus impudicus E=Mutinus, F=<i>Protubera</i>, a stinkhorn that never opens, G=Phallus rubicundusDictyophora cinnabarina from HawaiiMutinus is related to Dictyophora, but probably not very closely. The spore-bearing portion of the fruiting body is not a separate structure in Mutinus as it is in Dictyophora or Phallus. There are quite a few other kinds of stinkhorns in various shapes and sizes. If you are in the tropics or subtropics the variety becomes even more astounding.

In the picture to the left you can see Dictyophora cinnabarina from Hawaii. In the picture to the right, A=Clathrus??, B=Lysurus mokusin, C=Clathrus, D=Phallus impudicus E=Mutinus, F=Protubera, a stinkhorn that never opens, G=Phallus rubicundus. Note that Mutinus comes in various colors. It is confusing to me which color actually corresponds to the name Mutinus caninus. Is it the orange one pictured at top of this page? The white one in E? Or the is it the white and pink ones in the fairy ring shown above? I do not know the answers to those questions, but I'm sure someone will write to me with the correct answer. I have found conflicting information, and I have not seen molecular data that might help sort this out.

The stinkhorns are all Gasteromycetes (literally "stomach fungi"), an artificial group of Basidiomycota whose spores mature after the fruiting body is mature. Can you find all the other Gasteromycetes that have been Fungus of the Month?

I hope you enjoyed learning about the dog stinkhorn. It's a very common mulch fungus, but I have also seen it in the woods. There's not need to write to me anymore about how to get rid of it, since THERE'S NO WAY TO GET RID OF IT WITHOUT PAVING OVER YOUR MULCH. Just enjoy the new and unusual thing you have in your yard. I hope you are having a happy Dogtoberfest.

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 my email address

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