Trichaptum biforme

Scientific name:   Trichaptum biforme (Fr. in Kl.)
Ryvarden
Derivation of name:  Trichaptum means "with clinging
hairs"; biforme means "with two forms or stages" in reference
to the pore surface which can be either poroid or toothlike.
Synonymy:   Polyporus biformis Fr. in Kl., Polyporus
pergamenus Fr.; Trichaptum pargamenum (Fr.) G. Cunn.;
Hirschioporus pergamenus (Fr.) Bondartsev & Singer
Common names:   Violet-toothed polypore.
Phylum:   Basidiomycota
Order:  Polyporales
Family:   Polyporaceae
Occurrence on wood substrate:  Saprobic; solitary to
overlapping clusters on dead deciduous wood; year-round. 
Dimensions:  Caps 1-7.5 cm wide and up to 3 mm thick.  
Upper surface: White to grayish or brownish, greenish if
covered by algae; margin often purplish; zonate; hairy.
Pore surface: Purplish at first, fading to buff or brownish but
usually retaining violet tints near margin; poroid at first with
pores 2-5 per mm, becoming toothlike in age.
Edibility: Inedible.
Comments: A very colorful polypore when young. It can
occur in great numbers on the substrate. Compare to Trichaptum
abietinum which occurs mostly on conifer wood and is generally
smaller.

More information at MushroomExpert.com:   

Figure 1. This birch (Betula) tree is covered with
fruiting bodies of Trichaptum biforme.

Figure 2. The violet coloration characteristic
of Trichaptum biforme is visible on the lower surface
of these specimens. Photo © Stephanie Depew.


Figure 3. The violet color is often restricted to just the
margin of the caps. On older specimens, the upper cap
surface may have no violet color at all.
Photo © Tom Volk.

Figure 4. The tooth-like pore surface is quite evident here as
is the overall violet coloration. Photo © Tom Volk.

Figure 5. This very young specimen of Violet-toothed
polypore shows vivid coloration. Photo © John Plischke III.

Figure 6. Another example of the intense coloration possible
in young specimens. Photo © Pam Kaminski.

Figure 7. The violet coloration of the tooth-like pore
surface fades on older specimens.

Figure 8. On these older specimens much of the pore
surface is brownish whereas the violet coloration
is restricted to the margin. Photo © Larry Grand.

Figure 9. The tiny black clubs on the upper surface of
Trichaptum biforme are Phaeocalicium polyporaeum, a
saprobic ascomycete often associated with this polypore.
Photo © John Plischke III.

Figure 10. A closer view of Phaeocalicium
polyporaeum on Trichaptum biforme.
The two species often occur together.
Photo © John Plischke III.