Stinkhorn Eggs

I could hear my roasted root vegetables sizzling in the oven when I saw their car pull into my driveway. Eric and Nanette stepped out, carrying a big basket of food. A whole watermelon, can of spaghetti sauce, two fresh tomatoes—these were things they didn’t want to leave in their cabin for the winter or haul home to Madison.

One of the items in their basket was a little weirder, though. On a walk through the woods, they’d found a small, dirty white globe on the ground. Figuring it was fungal; they brought it to me for identification, and so we could exclaim over it together. I like this kind of hostess gift at least as much as wine!

I’d never seen something quite like this before, and I certainly wasn’t ready for the texture when I picked it up. First of all, it was heavy. This was no puffball. The thin outside coating was cool and dry, but a squishy consistency beneath that hinted at something a little more moist. It reminded me of a water balloon filled with pudding. The bottom was slightly flattened, with a limp little stem-like appendage.

We enjoyed our dinner with the mystery as our centerpiece, but I didn’t get around to slicing it open until the next day at work. A quick photo/question to my favorite mushroom expert produced a reliable identification: common stinkhorn.

Stinkhorns are either amazing or disgusting, depending on your perspective. They begin their reproductive life as an “egg,” just like the one Eric and Nanette found. A universal veil on the outside protects the developing fruiting body. Slicing through the egg, I found the compact features of a mushroom just waiting to expand.

The thin, white, elastic “eggshell” covered a layer of tan-colored jelly. The gleba, as this second layer is known, contains both the spores and the offensive smell that earns stinkhorns their name. Inside the jelly is a C-shaped, dark-brown mass that will become the mushroom cap, and then the pure white, firm-but-hollow stalk in the center. In some countries, the gleba is removed, and the inner mass of the egg is sliced and eaten. (I think my garden-fresh green beans probably tasted better at dinner.)

Bursting forth from the egg, stinkhorns mature extremely rapidly. Their growth rate has been measured at ten to fifteen centimeters per hour, and an individual may take anywhere only an hour or two to “hatch.” One mathematical model even predicts that the common stinkhorn can exert enough force to emerge through asphalt. By those calculations, three mushrooms emerging together could lift almost 900 pounds.

Once grown, a common stinkhorn bears a dark cap at the top of a white stalk. The cap is covered with the slime at first, but as that wears off, a morel-like texture and yellowish color emerge. Stinkhorns can be quite phallic, and the scientific name “Phallus impudicus” means shameless or immodest. In the Victorian era, embarrassed citizens (including Charles Darwin’s granddaughter) would collect and destroy stinkhorns each morning so as to protect the purity of any nearby maids.

Even more offensive than the shape of a stinkhorn is its smell. Once mature, the gelatinous gleba on the outside of the cap produces a strong odor of carrion that can be smelled from a fair distance away. This attracts flies, beetles, and other insects. In Austria, blow-flies even feed on the slime. When the insects fly off, spore-filled goop sticks to their legs and they become agents of mushroom dispersal. While disgusting, this is a more advanced method of spore dispersal than waiting for a gentle breeze.

Around the world, stinkhorns come in an amazing variety of shapes and colors. From red stars to hot pink whiffle balls, and white bridal veils, they erupt from their eggs in fountains of color and stench. As saprophytic mushrooms that decompose wood, stinkhorns are an important as well as interesting part of the forest…but perhaps, not an important part of dinner.

Stinkhorn eggs open to reveal the compact form of a developing mushroom. Photo by Emily Stone