While hiking in the woods, you may have noticed bracket fungi (also called shelf fungi or conks) growing on dead trees. Bracket fungi come in many shapes, sizes and colours , but one characteristic they all share is that they produce spores in long tube-like structures (Lincoff 1981). When you look on the underside of a bracket fungus, you will see the many openings or pores to the spore chambers. Hence, their inclusion in the family Polyporaceae, meaning "many pores" (Arora 1986; Lincoff 1981). Within this family, 98 different species have been described (Hawksworth et al. 1995).
Description:
The most conspicuous parts of bracket fungi are the reproductive structures or fruiting bodies that extend out of damaged or dead wood. These fruiting bodies can be very colourful (bright yellow) and fragile, but can also be dull in colour (browns) and tough (Callan 1996). The fragile fruiting bodies are produced annually and will decay, while the perennial fruiting bodies continue to grow for decades, adding a layer of reproductive pores each year (Callan 1996; Lincoff 1981). In contrast to the fruiting body, the majority of the fungus exists within the wood as fine filamentous cells called hyphae (Evert & Eichhorn 2013).
Ecology:
Bracket fungi are usually found growing on dead trees that are either still standing or have fallen to the forest floor. But some species of bracket fungi will attack living trees that are wounded (Callan 1996). Therefore they are often associated with diseased trees. The hyphae grow through the tree and contribute to the decomposition of the wood. They do this by secreting digestive enzymes that break down chemical components such as cellulose into simpler molecules (Alexopoulos et al. 1996). These simpler molecules are then absorbed by the fungal cells and used as a source of nutrition (Alexopoulos et al. 1996). During the decomposition process, the wood becomes soft and provides a home for insects that consume the fungus. The soft insect-infested wood attracts woodpeckers that in the process of hunting for insects create cavities that other animals use for nesting. The dead trees that are still standing are often referred to as wildlife trees because of the wide variety of organisms that live within the decomposing wood (Callan 1996). In addition, the decomposition of dead organic matter is critically important for the recycling of nutrients, making them available for other plants in the forest (Callan 1996).
Reproduction and Dispersal:
As mentioned above, the conspicuous fruiting bodies are reproductive structures (Arora 1986). The underside of the bracket is riddled with pores leading to spore-producing tubes. Millions of spores are produced by each bracket fungus. The spores drop out of the bracket and are then carried by the wind to new locations (Callan 1996; Hawksworth et al. 1995).
References cited:
Alexopoulos CJ, Mims CW, Blackwell M. 1996. Introductory mycology. 4th ed. New York: John Wiley & Sons, Inc.
Arora D. 1986. Mushrooms demystified. Berkeley (CA): Ten Speed Press.
Callan BE. 1996. Bracket fungi, common forest decay conks. Canadian Forest Service. [accessed 2018 Jan 31]. http://cfs.nrcan.gc.ca/pubwarehouse/pdfs/4208.pdf.
Evert RF, Eichhorn SE. 2013. Raven biology of plants. 8th ed. New York: W.H. Freeman & Company.
Hawksworth DL, Kirk PM, Sutton BC, Pegler DN. 1995. Ainsworth & Bisby’s Dictionary of the fungi. 8th ed. Wallingford: CAB International.
Lincoff GA. 1981. National Audubon Society field guide to North American mushrooms. NY: Knopf Publishing Group.
Arora D. 1986. Mushrooms demystified. Berkeley (CA): Ten Speed Press.
Callan BE. 1996. Bracket fungi, common forest decay conks. Canadian Forest Service. [accessed 2018 Jan 31]. http://cfs.nrcan.gc.ca/pubwarehouse/pdfs/4208.pdf.
Evert RF, Eichhorn SE. 2013. Raven biology of plants. 8th ed. New York: W.H. Freeman & Company.
Hawksworth DL, Kirk PM, Sutton BC, Pegler DN. 1995. Ainsworth & Bisby’s Dictionary of the fungi. 8th ed. Wallingford: CAB International.
Lincoff GA. 1981. National Audubon Society field guide to North American mushrooms. NY: Knopf Publishing Group.