Xylaria: What, where, how?

This post was originally published in The Journal of Wild Mushrooming, and is modified slightly for this format.


What: recognition and classification

Any avid mushroom hunter will likely have seen them, reaching blackly (and vaguely ominously) upward from twisted, rotting wood on the forest floor. Maybe you’ve ignored them—‘there’s no way that can be edible’, you might have said to yourself—or maybe you’ve pulled a few from the log they were growing on for closer examination later, noting their reluctance to separate from the decaying but surprisingly hard wood. They might have been hard, brittle, black, like charred twigs, or maybe they were a little cartilaginous, black below, but with pale, powdery tips, releasing a small puff of white, dusty spores to the air as you pulled them from their wooden home. Arora’s Mushrooms Demystified takes you to Xylaria hypoxylon (Fig. 1), the candlesnuff fungus (“much too tough to be of value”), or maybe Xylaria polymorpha, with the morbid sounding common name of dead man’s fingers (“much too tough and rough to be edible”). The notes here hint at a hidden diversity, but the descriptions in this and similar mushrooming guides leaves the reader wondering, holding a small, black fruiting body, with a name that may or may not be correct, and more questions than answers.

Xylaria hypoxylon

Xylaria hypoxylon, photo by Alan Rockefeller (MO 225661). This is a young fruiting body: note the pale surface at the upper end (from which it gets the name candlesnuff fungus) and the flattened branching tips, characteristic of this species and close relatives. Perithecia have not developed yet, but will swell from beneath the outer white coating, which will eventually slough off, leaving the black carbonized layer exposed.

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