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Winter 2011

Urban Jungle

The changing natural world at our doorsteps | Illustration and text by Patterson Clark      

Trametes, a shelf fungus, or bracket fungus

February 22, 2011

Long-lasting shelf life

A fungus hangs tough through the winter.

Harsh February weather seems to have little effect on thick, leathery shelf fungi, which protrude from the broken branches and fallen trees brought down by storms of years past.

A single shelf fungus can release trillions of spores, some of which drift through the air and settle onto damp, exposed wood. Those fortunate spores produce tiny fungal threads that creep into the wood to digest it. A growing "white rot" will slowly soften a hardwood log, encouraging insects to enter and hasten decay of the timber.

As it exploits the wood, the fungus sends out a hard, durable structure called a conk, which has on its underside tens of thousands of pores. Each pore is the open end of a tube that can generate and drop millions of spores.

Unlike soft, perishable toadstools, conks can survive for years, producing concentric annual growth rings on the conk's top surface.

A detail of the underside of a shelf fungus, or bracket fungus

SOURCES: Canadian Journal of Botany, Macalester College,Utah State University, Palomar College