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.