Tricholomopsis decora

Scientific name:  Tricholomopsis decora (Fr.) Singer
Derivation of name: Trich- means "hair" and lom refers to
a "fringe" or "hem." opsis means the species "looks like" a
member of the genus Tricoloma.  Decor- means "beautiful"
or "elegant."
Synonyms:  Tricholoma decorum (Fr.) Quel.
Common name(s):  Decorated mop.
Phylum:   Basidiomycota
Order:   Agaricales
Family:   Tricholomataceae
Occurrence on wood substrate:  Saprobic; Solitary or in
small groups on decaying conifer wood; June through
October.  
Dimensions:  Caps 2.5-6 cm wide; stipes 3-6 cm long and
0.3-1 cm thick.   
Cap:  Yellowish surface covered by gray to gray-brown to
blackish, fibrous scales; darker in center.
Gills: Attached; yellow.
Spore print: White.
Stipe: Yellow; dotted with tiny black scales.
Veil: Absent.
Comments: An article (page 28) in the Spring, 2006 issue
of Mushroom, the Journal implicates Tricholomopsis decora
in a life-threatening mushroom poisoning event. At his website
below, Michael Kuo discusses T. decora as a likely member
of a species cluster.
   
More information at MushroomExpert.com:  
 

Figure 1. Yellow cap, stalk, and gills with just a hint of the
dark fibers covering the cap surface. Photo © Larry Grand.

Figure 2. Tricholomopsis decora. Photo © John
Plischke III.

Figure 3. When young, the yellow surface is not readily
visible beneath the dark, fibrous sclaes. Photo © William
Roody.

Figure 4. Note how the expansion of the cap separates the
dark fibers, revealing the underlying yellow flesh.
Photo © Larry Grand.

Figure 5. The dark fibrous scales are readily seen against the
yellow background color of Tricholomopsis decora.
Photo © Gary Emberger.

Figure 6. A display of Tricholomopsis decora at the
NAMA meetings in Canada in 2003. Photo © Gary
Emberger.