Entoloma abortivum

Scientific name:  Entoloma abortivum (Berk. & M.A. Curtis) Donk
Derivation of name:  Abortivum refers to the misshapen
structures often found in association with this species.
Synonyms:   Clitopilus abortivus Berk. & M.A. Curtis
Common name(s): The mushroom's traditional common
name is the "aborted entoloma." However, given the nature of
the aborted forms (see comments below), a better name is
"aborting entoloma."
Phylum:   Basidiomycota
Order:   Agaricales
Family:   Entolomataceae
Occurrence on wood substrate:  Saprobic on wood:
solitary to clustered on or near decaying deciduous wood
such as stumps, logs, or buried wood; August through
November.  
Dimensions:  Caps are 5-10 cm wide; stalks are
2.5-10 cm long and 5-15 mm thick.  
Cap: Dry; gray to grayish-brown.       
Gills:  Decurrent; pale gray when young and pinkish at maturity.
Spore print: Salmon-pink.
Stipe: Colored like the cap.
Veil: Absent.
Aborted structures: The presence of misshapen fruitbodies,
described as "aborted," is actually what most people use to
identify this Entoloma species. These aborted structures
may be found with or without the gilled Entoloma
abortivum nearby. The aborted structures are 2.5-5 cm tall
and 2.5-10 cm wide; whitish masses with pinkish marbling
within a spongy white flesh.
Edibility: Edible with caution, see below.
Comments: For years, field guides indicated that the
aborted forms of Entoloma developed in response to being
parasitized by Armillaria spp. such as Armillaria mellea.
Recent work indicates that the relationship is the other way
around, that is, Entoloma is the parasite and the aborted
structures are Armillaria spp. Both the aborted Armillaria
structures and Entoloma abortivum are edible but care
must be taken not to eat other members of the Entoloma
genus, some of which are poisonous.

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Figure 1. Entoloma abortivum and aborted structures.
Photo © William Roody.


Figure 2. Mature pinkish gills and immature white gills of
Entoloma abortivum. Photo © Gary Emberger.

Figure 3. Typical gray-capped Aborted Entoloma. Aborted
Entoloma is no longer a very appropriate common name
because we now better understand the true identity of the
aborted structures. Photo © Larry Grand.

Figure 4. Closeup of aborted Armillaria spp. The aborted
forms are described as whitish, chalky, bumpy, or streaked
with a firm to spongy texture. Photo © Gary Emberger.


Figure 5. Three aborted forms. The inside flesh of these
specimens is shown in Figure 6. Photo © Gary Emberger.

Figure 6. The typical marbled, streaked flesh of aborted
Armillaria structures. These sections are of the aborted
forms shown in Figure 5. Photo © Gary Emberger.


Figure 7. In view from left to right is Armillaria mellea,
aborted Armillaria mellea, and Entoloma abortivum,
the players in our drama of parasitism and mistaken
identity. Photo © John Plischke III.