Violet-toothed Polypores

I’m intrigued by colourful fungi and have a special fondness for purplish ones. I was thus very happy to come across these Violet-toothed Polypores (Trichaptum biforme) in western PEI.

Photo: Violet-toothed Polypores on PEI.

Violet-toothed Polypores are among the most commonly recorded fungi on the Island, likely a combination of both their ease of identification and abundance. As polypores (sometimes called bracket or shelf fungi), they grow on the sides of standing or fallen dead wood – hardwood in this case – and are covered in tiny pores underneath.

Like the related Turkey Tail (Trametes versicolor) that I’ve posted about before (https://www.pei-untamed.com/post/turkey-tails), Violet-toothed Polypores grow in overlapping groups with bands of colour on their caps. Unlike Turkey Tail, Violet-toothed Polypores’ bands are generally pale or drab except at the margin where they sport their eye-catching, namesake colour. It takes a look underneath to get the full violet effect, though: those pores are beautifully coloured in fresh specimens (Photo). As the mushrooms age, the colour fades and the pores become more tooth-like, hence the common name.

Polypores are decomposers, breaking down deadwood and recycling the stored nutrients. Different types of decomposers promote different types of recycling. Violet-toothed Polypores are white-rot fungi, breaking down lignin and leaving behind lots of cellulose (a carbohydrate) which supports a host of organisms including nitrogen-fixing bacteria and wood-eating invertebrates. In this way, they contribute to healthy forest soils, available nitrogen, and forest biodiversity.

White rot fungi generally, and Violet-toothed Polypores specifically, also create the beautiful patterns of spalted wood, coveted by woodworkers. They do this in two ways. First, because lignin is pigmented, when the fungi digest lignin they remove those pigments and create spots of lighter colour in the wood.

Second, these are territorial fungi. When one colony meets another each forms a barrier to keep the foreign colony out and protect their own resources. This barrier shows up as lines in the wood which can be black, brown, green, blue, red, or – in the case of our Violet-toothed Polypores – pink! Under the right conditions, Violet-toothed Polypores create the most amazing spalting, especially on White Birch.

Violet-toothed Polypores have been recorded in every province and territory in Canada except Nunavut, but are especially common here in the east. Keep your eye out for this beautiful and helpful fungus as you explore the woodlands of PEI Untamed!