Helminthosphaeria

It’s Mushroom Monday, and this week you get two fungi for the price of one! This smoky-looking individual is a White Coral Fungus (Clavulina coralloides) being infected by the parasitic Helminthosphaeria clavariarum fungus.

Unlike typical cap-and-stem mushrooms, Coral Fungi are club-shaped or branched, and many resemble their namesake marine invertebrates. Coral Fungi can be white, black, or brightly coloured (such as the Violet Coral I showed you earlier this fall), but none have the distinctive blue-black hue and two-toned appearance seen here. That’s because this Coral Fungus isn’t really that colour.

Without the presence of Helminthosphaeria, White Coral Fungus is – you guessed it – white. The parasite infects the Coral Fugus from the ground up, turning it dark and reducing branching at the tips (you can see this in fully-infected arms of the Coral Fungus shown here). If you look at an infected Coral Fungus under a magnifying glass, you’ll find it’s covered in tiny black dots; these are ‘perithecia’, the spore-producing (reproductive) parts of Helminthosphaeria. The presence of those dots is a good way to confirm that what you are seeing is Helminthosphaeria rather than some new type of Coral Fungus.

Mycoparasites – fungi that parasitize other fungi – are not uncommon. For example, last week we looked at Shrimp of the Woods (the result of a Honey Mushroom being parasitized by an Entoloma), I’ve posted before about Lobster Mushrooms (formed when Hypomyces lactiflorum parasitizes a Brittlegill or Milkcap), and this year Bolete Mould (Hypomyces chrysospermus) was abundant in my area, including on King Boletes.

While some mycoparasites kill their hosts, scientists aren’t yet sure what impact Helminthosphaeria has on the Clavulina species it infects. Remember, the Coral Fungus we see is just a fruiting body, like an apple on a tree; the fungus itself lives as thread-like mycelia in the soil. Helminthosphaeria may just alter the appearance of the Coral – like scabs on apples – or it may infect the underground mycelia and have longer-lasting effects.

Although the word ‘parasite’ has a negative connotation to many people, parasitic plants, animals, and fungi are natural parts of PEI Untamed!