Cornell Mushroom Blog

The “I” in this post is Kathie Hodge, who lives on the outskirts of Ithaca in upstate New York.

I know of only three fungal species named for Ithaca: Cordyceps ithacensis, Humaria ithacaensis, and voila! our fungus of the day, Furia ithacensis. They’re all named for Ithaca, New York, not the arguably more famous Greek Island (remember The Odyssey? Odysseus came from Ithaca).

I’ve already met C. ithacensis and had the sad duty of relegating it to synonymy with Cordyceps variabilis.¹ I’m still looking for Neotiella ithacaensis (=Humaria ithacaensis), a small cup fungus that grows on liverworts (I’ll keep you posted). This week’s find was the spectacular Furia ithacensis, which I encountered for the first time, ever, right here at my home.

So here’s Furia ithacensis doing its thing, which is killing snipe flies.² Snipe flies are true flies in the family Rhagionidae. They spend much of their life being nasty, bristly, wriggly maggots in wet places, then transform into elegant big-eyed flies. They’re sometimes called down-looking flies. I hear that out west they look down on you, then fly over and bite you. Our eastern flies are tamer.

I’d stumbled onto a devastating epidemic among snipe flies. I found them on the undersides of witch hazel leaves, wings outstretched, bound to the leaf by a hundred hyphal ties. Not just ordinary hyphae, either, but specialized hyphae called rhizoids that grab the leaf via a serious sucker-like holdfast. I found perhaps a few dozen victims on the hazels along a small stream. The cadavers were in various states of disrepair–some actively discharging fungal spores (left), others long-dead and salted with granular resting spores that have peculiar wrinkled coats.

You can easily learn to recognize entomophthoralean fungi. Victims typically die while clinging to something–in this case the undersides of leaves. For a brief time, often early in the morning, the unfortunate host swells up and fungus erupts from the softer membranes to discharge a distinctive halo of shot spores. If you find your cadaver after that, identification can be difficult because these fungi quickly subside after discharging all their spores. If you have a good hand lens, you’ll come to recognize their distinctive glassy or waxy appearance–more translucent than “normal” molds.

Recognizing these fungi is one thing; identifying them can be tricky. If you are a good entomologist, identifying the host will help in narrowing down the identification, because each of these species is pretty finicky about which insects it will kill. Furia ithacensis, for example, is known only from flies in the family Rhagionidae. Otherwise, you’ll need a microscope to look at spore shape, sporophore branching, rhizoids, and stuff. The spores in the photo are stained with a special dye called aceto-orcein (derived from lichens!), which stains the condensed chromatin in the nuclei red. This dye can help determine which of the five families of the Entomophthorales is home to your specimen, and help you count the numbers of nuclei per spore (family Entomophthoraceae, and one, in this case).

If I were a birder, I’d call this fungus a “good bird,” because it is not commonly reported, has a personally relevant name, and is uber-cool. If I were a birder, I would be keeping track of my “good birds” on my “life list.” If I were a birder, I’d be able to download a list of all birds known from North America. For fungi, we aren’t even close to comprehending North American biodiversity, and we’re discovering new species and genera all the time. For me, that makes mycology all the more exciting. Go ahead, start a life list. Maybe yours will include something that is brand new.

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