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, rarely on
conifers; 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. Photo © Gary
Emberger.

Figure 2. Zonate caps with violet coloration along the
margins. Photo © Gary Emberger.

Figure 3. The violet coloration characteristic
of Trichaptum biforme is visible on the lower surface
of these specimens. Photo © Stephanie Depew.

Figure 4. This very young specimen of violet-toothed
polypore shows vivid coloration. Photo © John Plischke III.

Figure 5. Another example of the intense coloration possible
in young specimens. Photo © Pam Kaminski.


Figure 6. The tooth-like pore surface is quite evident here
as is the overall violet coloration. Photo © Tom Volk.

Figure 7. The violet coloration of this species fades with
time. Here, the color is 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 8. The violet coloration remains longest on the
tooth-like pore surface even as the color fades on the cap
surface. Photo © Gary Emberger.

Figure 9. Much of the pore surface is brownish on these
older specimens. The violet coloration is restricted to the
margin. Photo © Larry Grand.

Figure 10. Ttiny black clubs can often be found on the
upper surface of older Trichaptum biforme fruitbodies.
The clubs are Phaeocalicium polyporaeum, a saprobic
ascomycete often associated with this polypore.
Photo © John Plischke III.

Figure 11. A closer view of Phaeocalicium
polyporaeum on Trichaptum biforme.
The two species often occur together.
Photo © John Plischke III.