The Stinkhorn: Standing Tall and Proud

This, friends, is a stinkhorn.

And what, you may be wondering, is a stinkhorn?

Simply put, it's a fungus, and, depending on your point of view (and your maturity level), it might be one of the strangest, funniest, most fascinating, and/or most offensive organisms you’ll come across in the woods. Whenever I encounter one, I can’t help but chuckle, but I once had a person on a guided hike feel so offended by the stinkhorn’s appearance that they let out a gasp and averted their eyes.

These fungi belong to Phallaceae, a family found worldwide, but especially in the tropics. Many of its members display fetid, sticky spore masses on the end of a phallic stalk. Several are native to North America, and some bear a startling resemblance to an erect, human penis. I recently came across one in the genus Mutinus, and members of this genus look more like a canine phallus. The species I found is commonly called the Dog Stinkhorn (Mutinus spp.**). Like many fungi, it can grow very quickly (some appear overnight), and the one I encountered emerged in the middle of a trail that I had walked just two days prior. It’s possible I hadn’t noticed it, but I’m betting it grew the night before.

Like many of its relatives, this species emerges from a spherical “egg” half-buried in leaf litter. This structure splits open, and the fruiting stalk expands to its full height of 10-12 centimeters, sometimes within a matter of hours. The stalk’s tip is covered in a dark-brown slime that is the spore-bearing matrix (properly called gleba). It gives off an odor similar to animal feces, attracting invertebrates, including flies (often members of the Calliphoridae genus, such as blow flies) and beetles. These insects move around the tip and remove the slime, unwittingly carrying the spores away as they depart and disperse them elsewhere in the surrounding habitat.

However you react to the stinkhorns, it’s tough to deny that their striking appearance and distinctive odor make any encounter with this species a memorable one.

*I encourage you to look into other members of the Phallales order. Besides the phallic members of the Phallaceae family discussed here, relatives in other stinkhorn families take on striking and beautiful forms; some resemble sea anemones and others develop cage-like structures that look nothing like what most of us think of when we hear the word “mushroom”.

Further reading:

1. Real Monstrosities: Mushrooms From Hell: http://www.realmonstrosities.com/2012/09/mushrooms-from-hell-stinkhorns.html 

2. Kibby, Geoffrey. "The weird, wonderful and smelly world of stinkhorns and clathroid fungi." Field Mycology 16.2 (2015): 58-69. Preview at: http://www.sciencedirect.com/science/article/pii/S1468164115000262/part/first-page-pdf

**Some members of the Mutinus genus are difficult to distinguish. The specimen I found was likely either Mutinus caninus or Mutinus ravenelii (both are often referred to as Dog Stinkhorn). I’m leaning towards the latter because most records I found indicated that M. ravenelii has a more pinkish hue and larger pits on the stalk than M. caninus. Mushroomexpert.com has a page that offers a good breakdown of the three Mutinus species that look similar (http://www.mushroomexpert.com/mutinus_elegans.html), but they also say that, “European and North American concepts of Mutinus elegans, Mutinus caninus, and Mutinus ravenelii appear to differ somewhat, and some authors (e.g. McNeil, 2006) suggest that Mutinus caninus and Mutinus ravenelii are synonyms.”