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Northern Tooth Fungus

9-22 northern tooth fungus 159Northern Tooth Fungus, Climacodon septentrionale, is an unusual combination of both a shelf (also called bracket) fungus as well as a toothed fungus. Typically a shelf fungus produces spores inside pores located on its underside. Northern Tooth Fungus, however, produces spores on pendant, spine- or tooth-like projections on its underside (see insert). This fungus usually has several tiers of “shelves” that grow in tight, thick layers, and change from white to light tan as they age.

Northern Tooth Fungus is a parasite of living trees, especially Sugar Maples, and it causes the central heartwood of the living tree to rot. The only sign that a maple has this fungal parasite is the appearance of these shelf-like fruiting bodies in late summer or fall. Often trees with this fungus become weak and are blown over by the wind. As with most shelf fungi, it is considered to be inedible. (Thanks to Jeannie Killam for photo op.)

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Slime Molds on the Move

8-21-15  431As usual, Naturally Curious readers submitted unbelievably creative ideas about the identity of yesterday’s Mystery Photo. Kudos to those of you who recognized that it was a slime mold. Slime molds look like a fungus, and reproduce with spores like fungi do, but are no longer classified as fungi. Slime molds are made up of individual organisms that form a mass called plasmodium. They can be bright orange, red, yellow, brown, black, blue, or white. These large masses act like giant amoebas, creeping slowly along and engulfing food particles (decaying vegetation, bacteria, fungi, and even other slime molds) along the way. If a slime mold is cut up into pieces, the pieces will pull themselves back together.

The most common species are in a group called plasmodial slime molds. They share one big cell wall that surrounds thousands of nuclei. Proteins called microfilaments act like tiny muscles that enable the mass to crawl at rates of about 1/25th of an inch per hour. A slime mold mass can actually navigate and avoid obstacles. If a food source is placed nearby, it seems to sense it and head unerringly for it.

As long as conditions are good, (enough food and moisture and favorable pH), the mass thrives. But when food and water are scarce, the mass transforms itself into spore-bearing fruiting structures. These typically form stalks topped by sphere-like fruiting bodies called sporangia that contain spores that are carried by the rain or wind to new locations. After they have been dispersed, each of these spores will germinate and release a tiny amoeba-like organism which, if it successfully finds and fuses with another similar organism, can then begin to feed and develop into a new plasmodium.

The pictured slime mold, Coral Slime (Ceratiomyxa fruticulosa), is one of the more common slime molds. It is unusual in that it produces its spores externally on small stalks, not in sporangia, which gives it a fuzzy appearance.

To watch a time-lapse video of slime mold moving, go to

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Pinesap Flowering

8-4-15 pinesap 378Pinesap, like its close relative Indian Pipe, is a flowering plant which lacks chlorophyll, and therefore is not green and cannot make its own food. Often found under pine trees, Pinesap’s color ranges from yellow to pink, red, orange or brown or some combination of these. Often pine sap that flowers in the summer is yellowish, while pink is more dominant in the fall. Pinesap gets its nutrients from other plants’ roots, but not directly. Mycorrhizal fungi are the middlemen, connecting the roots of Pinesap with those of the fungi’s host plant, allowing nutrients to be passed along from the host plant to the Pinesap. Being the beneficiary of a fungi-dependent relationship makes Pinesap a myco-heterotroph.

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Living Hollow Trees

12-31-14 hollow yellow birch 027Occasionally one comes across a living tree with a portion of its trunk, or its entire trunk, hollow. How is it possible for a tree to thrive even when its center, or heart, has completely decayed? It comes down to the different kinds of wood that are produced by a tree: sapwood and heartwood.

Sapwood (often light-colored) is the younger, living, outermost portion of a woody branch or tree trunk (just beneath the bark), while heartwood (often dark-colored) is the dead, inner wood. All wood in a tree is first formed as sapwood. Sapwood’s principal functions are to conduct water from the roots to the leaves (via xylem tissue) and to disperse nutrients made by the leaves to the rest of the tree (via phloem tissue). Heartwood (so called because of its central position, not because it is essential to the health of the tree) is basically non-functioning xylem tissue that has become blocked with resins, tannins, and oils. Although the dead heartwood can lend stability to a tree, it is no longer part of the transport system, and therefore, not vital to the tree.

Cavities and hollows typically result from an injury to a tree (usually caused by fire, storms, lightning, insects or birds) that exposes the heartwood. Bacteria and fungi lose no time moving in and beginning the decaying process, which can result in a hollow tree. Because the sapwood, and therefore the transport system, is still intact, the tree lives, despite the loss of its inner heartwood.

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Snowfleas Appearing

snowfleas 049A7533One rarely even thinks about snowfleas (a species of springtail, Hypogastrura nivicola) until snow falls and then starts to melt. This is when these tiny wingless arthropods that catapult themselves through the air with the aid of a fork-like structure, or furcular, seem to magically appear out of nowhere. They actually are present year round, but their dark color makes them visible against the white snow.

The great majority of snowfleas live in soil, feeding on fungi, algae, decaying plant matter and bacteria. They work their way to the surface of the snow, crawling up the trunks of trees, plant stems and side of rocks where an open channel allows their migration. Thousands can be found on melting snow, especially in tracks or other depressions. No-one is absolutely sure of why they exhibit this behavior, though some scientists feel that these migrations are triggered by overcrowding and lack of food. Eventually those that survive on top of the snow make a return trip down into the soil.

Formerly classified as insects, snowfleas are now categorized as hexapods, due to some features they have which insects do not.

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