Niveoporofomes spraguei

Scientific name: Niveoporofomes spraguei (Berk. & M.A.
Curtis) B.K. Cui, M.L. Han & Y.C. Dai
Derivation of name: Spraguei indicates this fungus species
was named after C. J. Sprague. 
Synonyms: Fomitopsis spraguei (Berk. & M.A.
Curtis) Gilb. & Ryvarden; Polyporus spraguei Berk. &
M.A. Curtis; Tyromyces spraguei (Berk. & M.A. Curtis)
Murrill  
Common name(s): Unknown. 
Phylum:   Basidiomycota
Order:   Polyporales
Family:   Fomitopsidaceae
Occurrence on wood substrate: Saprobic and parasitic;
sessile to effused-reflexed on dead wood and at the bases of
living hardwoods, particularly oak; year-round.  
Dimensions: Caps up to 15 cm wide.   
Upper surface:  Caps white to ochraceous to gray; margin
may be somewhat reddish on fresh, growing specimens;
margins of young specimens develop a green color upon
handling; azonate; smooth or slightly grooved, glabrous to
appressed-tomentose.       
Pore surface: White to cream-colored to pale brown; pores
3-6 per mm.
Comments: Young specimens exude watery drops from the
margin and upper surface. The green discoloration of the
margins is a useful marker for this species, helping to
distinguish it from similar species otherwise differentiated
only by microscopic characters.  

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Figure 1. The grayish cap of this young Niveoporofomes
spraguei specimen is exuding drops of water. Photo
© Cathy Cholmeley-Jones.

Figure 2. Water drops exuding from the pore surfaces as
well as the upper surfaces of these young specimens. Note
the pale reddish coloration at the margin. Photo © Rick
Van de Poll.

Figure 3. The cap of Niveoporofomes spraguei is
sometimes described as having the appearance of stone
or marble.
Photo © Gary Emberger.

Figure 4. Top surface of a specimen collected during a
NEMF foray. Photo © Gary Emberger.

Figure 5. Bottom surface of specimen in Figure 4.
Photo © Gary Emberger.


Figure 6. Pores (3-6 per mm) visible on the white pore
surface of Niveoporofomes spraguei. Photo © Gary
Emberger.


Figure 7. This sectioned cap reveals that the thick context
(flesh) above the pore layer has the same marble-like
appearence as the cap. Photo © Gary Emberger.

Figure 8. The margins on these fresh specimens have
discolored green where they were handled.
Photo © Gary Emberger.


Figure 9. Young speciemen collected at a NEMF foray.
Note the green discoloration where handled.
Photo © Gary Emberger.