Inonotus dryadeus

Scientific name:   Inonotus dryadeus (Pers.) Murrill
Derivation of name:   Inonotus means "fibrous" (ino-) and
"ear-like" (ot-); dryadeus means "oak" (dryad-) and
"belonging or pertaining to" (-eus) in reference to the primary
host of this species.
Synonymy: Pseudoinonotus dryadeus (Pers.) T. Wagner
& M. Fisch; Polyporus dryadeus Pers.: Fr.
Common names:   Warted oak polypore.
Phylum:   Basidiomycota
Order:   Hymenochaetales
Family:   Hymenochaetaceae
Occurrence on wood substrate: Parasitic, somewhat
saprobic; at the base of living oaks or recent stumps;
September through October, overwinters. 
Dimensions:  Caps up to 40 cm wide, 23 cm long, and 15
cm thick.  Caps may fuse together.
Upper surface:  Buff to grayish-brown to yellowish-brown
to reddish-brown to blackish; finely hairy at first, becoming
glabrous; uneven to warty or bumpy; cracked in age; margin
thick, rounded, same color as cap or sometimes ivory in
color; cap and margin exuding amber-colored droplets when
Pore surface: Whitish to gray-brown, becoming dark;
exuding amber-colored droplets when young; 4-6 pores per
Edibility: Inedible.
Comments: Inonotus dryadeus causes a white rot of the
butt and roots of living oaks.

Figure 1. White oak infected by Inonotus dryadeus with the
fruiting body appearing at the base of the tree. The tree was
alive when the picture was taken in September, 2004.
Photo © Gary Emberger.

Figure 2. As a result of infection by Inonotus dryadeus, the
beautiful mature white oak tree (Quercus alba) shown in
Figure 1 had to be removed in April of 2006. The tree was
not dead but was judged hazardous to people and
property. Photo © Gary Emberger.

Figure 3. Note the uneven surface and ivory-colored margin.
Fruitbodies may also appear some distance from the trunk
growing from roots of infected trees. Photo © Gary

Figure 4. Inonotus dryadeus completely surrounds this
dead oak tree. Photo © John Dawson.

Figure 5. Immature fruit bodies at the base of an oak tree.
Photo © Gary Emberger.

Figure 6. The growing margin of Inonotus dryadeus is
often spotted and may exude droplets of liquid.
Photo © John Dawson.

Figure 7. Amber-colored droplets of liquid exuding from the
young, growing margin. Photo © Gary Emberger.

Figure 8. Caught in the sun's rays, the marginal droplets of
Inonotus dryadeus are quite striking.
Photo © Gary Emberger.

Figure 9. Older marginal areas of Inonotus dryadeus, no
longer with droplets, are pock-marked like the surface
of the moon. Photo © Gary Emberger.

Figure 10. This section through the cap reveals the rust brown
context, streaked with differently colored tissues. At the
bottom is the layer of tubes. Photo © Gary Emberger.

Figure 11. Pore surface of Inonotus dryadeus.
Photo © Gary Emberger.


Home | Shape key | Glossary

This page © 2008 by Gary Emberger, Messiah College