50 More Urban Species #37: Carbon Balls

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Carbon balls Daldinia concentrica

What looks like a clump of old rot on a piece of dead wood is, in this case, a vibrant and relatively long-lived life form. An oddball among fungal fruiting bodies, carbon balls are perennial, persisting for years with new fertile layers growing over the old. The closely related mushroom dead man's fingers has a similar growth pattern. In cross-section, the layers of growth are visible as concentric rings, which is where the fungus gets its species name. The hard, coal-like structure conserves water, and allows the fungus to produce spores even under very dry conditions when most other fungi stay dormant. For reasons which are unclear but probably adaptive, carbon balls emit spores nocturnally. These small growths (less than 2 inches in diameter at most) can produce up to ten million spores per night.

Carbon balls are in the broad group of fungi that include cup fungi and morels, as opposed to the other main group that produce umbrella-shaped mushrooms and bracket fungi. Each group digests a different component of wood, and can therefore live in the same substrate without necessarily competing. In the photo above, a bracket fungus (possibly violet tooth polypore) shares dead wood with the carbon balls.