Cyathus stercoreus

Scientific name:  Cyathus stercoreus (Schweinitz) de Toni
Derivation of nameCyath- means "cup." Stercor-
means "dung" or "manure" and refers to the common
substrate of this fungus.
SynonymsNidularia stercorea Schwein.  
Common name(s):  Dung loving bird's nest.
Phylum:   Basidiomycota
Order:   Agaricales
Family:   Agaricaceae
Occurrence on wood substrate:  Saprobic; solitary or
mostly clustered on the dung of herbivores, manured soil, and
wood chips; July through October. 
Dimensions: The cone-shaped nests are up to 1.5 cm tall
and 4-8 mm wide.    
Sterile nest surfaces: The outer surfaces are quite shaggy
or wooly (at least when young) and yellow-brown in color,
becoming smoother and darker (blackish) in age. The inside
surface is lead-gray to black and smooth.        
Fertile tissue:  Peridioles are dark gray to black and 1-2
mm in diameter.  
Edibility: Inedible.
Comments:  Although listed in most field guides as inhabiting
dung, the pictures I took on this page are of a specimen
growing on pine bark mulch that was not manured. Visit the
following website for a key to the many bird's nest fungi of
North America

More information at

Figure 1. Large cluster of Cyathus stercoreus fruit bodies.
Photo © John Dawson.

Figure 2. Cyathus stercoreus growing on pine bark mulch
just outside my patio door. Photo © Gary Emberger.

Figure 3. The small, dark peridioles are initially covered by a
white membrane. Photo © Gary Emberger.

Figure 4. The nongrooved, nonfurrowed inside nest surface
of Cyathus stercoreus is an important identification
character. Compare this species with Cyathus striatus which
is also wooly outside and has dark peridioles but the inside
nest surface is furrowed. Photo © John Dawson.

Figure 5. The peridioles of Cyathus stercoreus are 1-2 mm
wide. A similar species, Cyathus olla, has peridioles up to
3.5 mm wide. Photo © Gary Emberger.

Figure 6. The outside surfaces of the conical fruit bodies are
quite wooly. Photo © Gary Emberger.

Figure 7. This nest was split open to better show three
peridioles remaining in the nest. Each peridiole is attached to
the nest wall (peridium) by a funiculus. When the peridiole is
splashed out, the sticky base of the funiculus is released from
the nest allowing it to adhere to objects it strikes. The
remainder of the funiculus uncoils as the peridiole continues
on its trajectory. The peridiole may end up either dangling at
the end of the funiculus or the funiculus may wrap around the
object. Photo © Gary Emberger.

Figure 8. Two peridioles are attached to grass blades. If the
nest is on herbiviore dung, it is to the advantage of the
fungus to have its peridioles ejected away from the dung and
onto grass that might be eaten by another herbivore.
Basidiospores of bird's nest fungi can travel through the
digestive tract of herbivores unharmed and eventually form
fruit bodies on a new dung pile. Photo © Larry Grand.


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This page © 2008 by Gary Emberger, Messiah University