Stinkhorns are mushrooms. We received a sample in late September at the U of I Plant Clinic. When searching for information on the stinkhorn, I found that the Purdue Plant Clinic had received a similar sample and posted pictures on their Web page. It may still be at http://www.ppdl.purdue.edu/ppdl/weeklypics/10-10-05.html. If not, a wonderful site can be found on a University of Wisconsin Web page by mycologist Tom Volk: http://botit.botany.wisc.edu/toms_fungi/july99.html.
Stinkhorns are members of the Phallaceae family of fungi. When fresh, they smell terrible, thus the name stinkhorn. Mushrooms are the fruiting bodies of fungi. The vegetative stage of the fungus is the threadlike mycelium that grows in its food source, some type of organic matter. You may recognize mycelium as the mold growing on leftover food in the refrigerator or the white growth that spreads across rotting logs in the forest. Stinkhorns are saprophytic fungi, meaning they live off dead plant material. They do not parasitize healthy plants. The mycelial phase of the fungus is beneath the finger-shaped fruiting structure and grows throughout wood chips, rotting roots, or any other organic matter in the soil, helping with decomposition. Stinkhorns are often found in parks, wood chip areas, field crops, and composted soil. They usually appear in wet conditions on fertile soil. Students working in corn or soybeans at the U of I usually find these between rows in periods of wet weather. We also have reports of the stinkhorns growing in lawns.
The stinkhorn we received at the Plant Clinic was one of the Phallus species. Identification is based on the location of the spore-forming area and the lack of a veil. Those details can be seen on Volk’s page, referenced above. Stinkhorns are fingerlike, with an egg stage (gleba) at the base and mycelium below that, growing in the organic matter. Often the horn is red or white but varies with species.
Probably the most asked question is, “How do I get rid of these things?” There is nothing you can do to eradicate these foul-smelling fungi. You can remove the egg stage, but more will form from the mycelium present in the organic matter. If there were no organic matter, there would be no stinkhorns; but then your landscape would be unattractive, as plants need organic matter to thrive. Dr. Volk’s advice is to try to enjoy these wonders of nature.