Inonotus obliquus

Scientific name:  Inonotus obliquus (Ach. ex Pers.) Pilat.
Derivation of nameInonotus means "fibrous" (ino-) and
"ear-like" (ot-). Obliquus means "slanted" or
"oblique" in reference to the acute angle of the tubes to
the surface of the substrate. 
SynonymsBoletus obliquus Ach. ex Pers., Polyporus
(Ach. ex Pers.) Fr.; Poria obliqua (Ach. ex Pers.)
P. Karst  
Common name(s): Clinker polypore, birch conk, birch
canker polypore, chaga. 
Phylum:   Basidiomycota
Order:   Hymenochaetales
Family:   Hymenochaetaceae
Occurrence on wood substrate:  Parasitic; sterile conk
made of compacted hyphae forming almost exclusively
on trunks of living birch (Betula) species; conks found
Dimensions:  The sterile, black clinker- or cinder-like knobs
or conks can be quite large, 10-40 cm across and irregular in
Description:  Resembling charred wood or a canker-like
growth, the outer surface of the sterile conk is dark brown
to black, hard, and deeply fissured. Internally, the tissue is
corky and yellow to yellow-brown.
Edibility: Used to make a tea called chaga.
Comments:  In addition to the sterile conk, the species
forms an effused, poroid fruiting body beneath the bark or
outer layers of wood on snags or fallen trunks. This fertile
portion is not commonly found and will not be further.
described. Chaga tea is prepared from the sterile conk
and used medicinally.

More information at


Figure 1. Inonotus obliquus on paper birch (Betula
papyrifera). Photo © Greg Marley.

Figure 2. Inonotus obliquus on yellow birch (Betula
alleghaniensis). Photo © Gary Emberger.

Figure 3. A rather elongate specimen. Photo © John
Plischke III.

Figure 4. Rick Van de Poll refers to conks shaped like
this as "pig snout specials." Photo © Rick Van de Poll.

Figure 5. The dark, cracked outer surface of the sterile
conk. Photo © Gary Emberger.

Figure 6. Internally, the clinker polypore is yellowish to
yellow-brown. Photo© Gary Emberger.

Figure 7. Section throrugh Inonotus obliquus showing
attachment to the wood. Detaching the clinker polypore
often requires a hatchet or hammer.
Photo © John Plischke III.

Figure 8. Tea preparation involves breaking chaga into small
pieces. Photo © John Plischke III.

Figure 9. A coffee grinder can be used to prepare a fine
powder used to make chaga tea. Photo © John Plischke III.


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