Stereum ostrea

Scientific name:  Stereum ostrea (Blume & T. Nees) Fr.
Derivation of name: Ster- means "tough, firm, solid."
Ostre- means "oyster" in reference to their shape.
Synonyms: Thelephora ostrea Blume & T. Nees  
Common name(s):  False turkey tail.
Phylum:   Basidiomycota
Order:   Russulales
Family:   Stereaceae
Occurrence on wood substrate: Saprobic; clustered on
decaying logs, stumps, and branches of deciduous trees; June
through December.  
Dimensions: Petal to fan-shaped or semicircular caps are 1-
7 cm wide.  
Sterile upper surface:  Covered with silky hairs; zonate with
orange, gray, reddish-brown, and other colored zones; often
whitish at the margin.
Fertile lower surface: Smooth (small bumps may be
present), buff to cinnamon-buff to reddish-brown.     
Edibility: Inedible.
Comments:  This is our largest and most colorful Stereum
species. It is sometimes confused with turkey tail, a species of
polypore. Use a hand lens to make sure pores are absent.

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Figure 1. Stereum ostrea clustered on a log.
Photo © Gary Emberger.

Figure 2. False turkey tail is sometimes confused with
turkey tail, Trametes versicolor, a species with a poroid
fertile surface. A hand lens will confirm the absence of
pores in false turkey tail. Photo © Gary Emberger.

Figure 3. Overlapping clusters of false turkey tail. Sterium
ostrea fruit bodies do not tend to fuse together as much as
some other Stereum species. Photo © Gary Emberger.

Figure 4. The colorful, zonate upper surfaces of Stereum
ostrea. Photo © Gary Emberger.

Figure 5. Some of these false turkey tails are almost fused
in such a way as to form funnels. I have collected some
specimens that are actually in the form of a funnel.
Photo © William Roody.

Figure 6. The specimen on the right in the foreground was
placed upside down in order to show the fertile surface.
Note the white margin. Photo © Gary Emberger.


Figure 7. The smooth, fertile, basidia-bearing lower
surface (left) compared to the sterile silky, zonate upper
surface on the right. Photo © Gary Emberger.