Saturday, November 20, 2010

Dry Weather Fungi

Drought years make it really hard to find fungi. When we began the year with an abundance of rain, I was looking forward to an excellent fungi season. Things began well, but when the rain stopped in July, fungi numbers began to drop. Four months of drought have left us with practically no noticeable fungi. Fortunately, several species of shelf fungi persist for many years and are still easy to find.

The log that sprouted these fungi was located right on the creek bank. The extra moisture found in this location may have been responsible for the explosion of shelf fungi that formed.

This is one of the softer, leathery feeling shelf fungi. The leathery types are not as persistent as the harder types. It’s not unusual to see these whither and disappear in a comparatively short amount of time.

The woody types of shelf fungi are durable and give you the impression that they were carved from the tree wood itself. Each shelf fungi plays host to its own small ecosystem. Mosses, lichens and algaes colonize the top of the shelf. On large shelves, a thin layer of soil can form that serves to support more evolved plant life. Some specialized insects are known only to exist in association with the fungi shelves.

Like other fungi, the shelves represent reproductive parts, with the bulk of the fungus being hidden from view within the tree. Eventually, the wood will be weakened to the point where the tree will fall. Because the infected wood becomes soft and easy to dig, shelf fungi trees are often used by cavity nesting species. When I see this on the side of a tree, I always look up to see if a woodpecker hole is present.

Woody shelf fungi have specific growing seasons at which time they add a fresh reproductive layer to the underside and edge of the shelf. Most add new growth in the spring and some also have a fall growing season. The resulting growth reminds me of the formation of a volcanic island. The new growth on the edge is like the beach that is too unstable to support terrestrial life. As you move away from the edge, you find increasingly older and more stable material. Eventually, you get to the old center portion that supports plant and animal life.

The under side is perforated by hundreds of pores. Each pore is lined with cells that produce the spores that must be set adrift in order to produce new fungi. To effectively release spores, the pores must be perfectly vertical. Occasionally a shelf fungi tree will lean or fall and the new growth has to reorient itself in order to produce the vertical pores. This sometimes results in an unorthodox shaped shelf.


  1. The fungi produce their own artwork, don't they.... Great images once again.

  2. Thanks, Lois. Nature is probably the best artist I know.