Rain in the late summer and early fall can bring out a dazzling array of mushrooms in our northeastern forests. All sizes, shapes and colors of mushrooms scatter about on the forest floor without obvious design. But there actually is a plan. Many mushrooms form more or less specific associations with roots of certain kinds of trees, either hardwoods or conifers and are essential for the health of those trees. Other mushrooms grow on decaying logs or on leaf litter without any obvious specificity as to their substrate. Along with bacteria, insects and a host of microbes the fungi recycle rotting wood and fallen leaves and contribute to nutrient recycling of the forest. These recycling fungi are called ‘saprobes’ which means that they live on dead plant material. One would not think of saprobes as requiring specific substrates, but two apparently saprobic mushrooms that we see in the litter of our forests actually are specific as to what they grow on.
Cantharellula umbonata, also known as the grayling, grows among hair cap mosses (Polytchum species) and is native to eastern North America. The mushroom clearly rises from the mass of mosses but does not appear to cause them any harm. It is not a big mushroom. Its cap is only an inch or so in diameter and its stalk is up to 4” long and slender. The cap is gray (hence ‘grayling’) and the gills below the cap are off white, but the cap and gills stain red when bruised. Because the gills under the cap tend to run down the stalk, similar to what is seen in the chanterelle mushroom, the grayling was once classified as a chanterelle. Unlike chanterelles, the gills of the grayling are sharp-edged, not rounded as in the chanterelle. I have not seen research into why the grayling grows only on or with the moss. The moss appears unaffected, so it is not a question of parasitism. Is there any exchange between the mushroom and the moss? An interesting subject for research! I found the grayling that we see here on the trail to High Five.
The second ‘host’ specific saprobic mushroom that is common in hemlock and pine forest in and around Deering is Micromphale perforans. This mushroom is very small, the cap no more than ¼” in diameter and is perched atop a very fine, black stalk that is no more than 1” long. This fungus is so small that it does not have a common name. We see it frequently here hemlock and pine forests, where you see it on the ground as tiny white spots. If you carefully pick up one of those little mushrooms and pull apart the debris you will see that the Micromphale is growing out from old hemlock, leaves or infrequently pine needles. Actually, fungi live in the roots, leaves and trunks of trees and leaves of most plants without causing any ill effects. These fungi, called endophytes, can be beneficial to the plant in several ways. It is a case of mutualism where both the fungus and the plant benefit. We do not know whether the Micromphale is an endophyte. How does it get there? Is the fungus waiting in the ground for the leaves to fall before invading them, or is it present in the leaves, only producing the little mushroom and completing its life cycle once the leaves have fallen?
The life styles of both of these mushrooms are curious and little known. Both interesting subjects for research! We know so very little about how our planet functions. It is these little interactions that, taken together, are critical for ecosystem functioning. So, yes, it is worth knowing the answers to these questions!