Hericium Abietis

Day 17: On October 19, I posted a photo of Hericium coralloides, a species I had probably observed on many occasions, although I never took the time to investigate its substrate. Had I done so and found it growing on hardwood, I would have known that it was not Hericium abietis (shown here), a morphologically identical species which grows only on conifer wood. Many fungi are substrate-specific, genetically encoded to release particular enzymes which will allow them to break down the substrate material into the nutrients which sustain them. In turn, the fungi may then be consumed by insects whose nutritional requirements match what the fungus has absorbed and carries in its tissues. Thus, one species of fungus may grow only on one substrate and may only be consumed by one type of insect, although in actuality the range is generally wider than 1:1:1. Mushroom rarity may be influenced by a number of different factors including plant associations, substrate availability, and so on. This specificity puts a whole new dimension on the phrase, "You are what you eat." Just ask a fungus.

Tremella Mesenterica On Hardwood

Day 61: Natural history lesson for the day: it is often helpful to identify the substrate on which a lichen or fungus is growing. Some species prefer hardwoods to soft, as is the case with Tremella mesenterica, commonly known as Witches' Butter. It has a close look-alike in Dacrymyces palmatus which, conveniently, exhibits a preference for softwood such as Doug-fir. When the wood on which the fungus grows is too badly decayed to sort out, we must resort to microscopic examination of the spore-producing basidia. Both Tremella and Dacrymyces are common in the Pacific Northwest. While identification of the substrate isn't a foolproof way of separating them because Dacrymyces also occasionally occurs on hardwood, if you observe an orangy-yellow jelly fungus similar to the one shown in this image and it is growing on rotting alder, it is undoubtedly Tremella mesenterica.