Agrocybe spp.

Scientific names:  Agrocybe acericola (Peck) Singer;
A. praecox (Pers.) Fayod; Agrocybe sororia (Peck)
Singer.
Derivation of names: Agr- means "field" and cyb-
means "head." Acer- refers to "maple," a common
substrate for this fungus, praecox - means
"early" in reference to its appearence in spring,
soror- means "sister" in reference to specimens
growing near each other as in a "sorority."  
Common names: Maple Agrocybe; Spring Agrocybe.
Phylum:   Basidiomycota
Order:   Agaricales
Family:  Strophariaceae
Occurrence on wood substrate:  Saprobic; solitary to
scattered or growing in groups on decaying deciduous
logs and stumps in forest environments and on wood
chips and composted materials in urban areas; April
through September.
Dimensions:  Depending on the species, caps are 3-15
cm wide; stalks are 5-10 cm long and 0.5-1.5 cm thick.   
Cap:  Cap yellow-brown to tan, fading to pale
yellow-brown; smooth, cracked or fissured with age
in some species.
Gills: Attached; off-white when young, becoming
brownish at maturity.
Spore print: Brown to dark brown.
Stipe: Same color as cap or whitish at first, becoming
brownish with age at least in the basal portions; cordlike
white rhizomorphs often present at base of stipe.
Veil: Present or absent dependent on species:
A. acericola with white membranous ring at first, staining
brown by spore deposition, persistent as large, pendant
ring; A. praecox with fragile thin membranous ring
persistent or not on stalk or leaving remnants on cap
margin.
Edibility: Not recommended.
Comments: The taxonomy of the genus is unsettled.
Identification may require microscopic analysis in
addition to macroscopic characters and habitat
information. For additional information on the genus
and a key to species, see:

More information at MushroomExpert.com

Consult the following websites for more information
about A. acericola and A. praecox.

More information at MushroomExpert.com   
More information at MushroomExpert.com
More information at TomVolkFungi.net

Figure 1. Agrocybe acericola. Note the close gills and
persistent ring stained the color of the spores. Unlike
the next two species, A. acericola is typically found
in forest settings on logs and woody debris.
Photo © John Plischke III.

Figure 2. Agrocybe acericola with large, persistent,
pendant superior ring. Photo © Steve Nelsen.


Figure 3. Agrocybe acericola collected at a foray.
The partial veil is collapsed about the stem and is the
color of the spores deposited on it.
Photo © Gary Emberger.


Figure 4. Agocybe praecox growing on wood chip mulch.
Note the presence of the ring on only one of the stipes and
the white rhizomorphs at the base of the stipes.
Photo © Gary Emberger.


Figure 5. For Agocybe praecox, the veil may persist only
as remnants on the cap margin.
Photo © Gary Emberger.

Figure 6. The presence of a cracked or fissured cap is quite
common in certain Agrocybe species including Agrocybe
praecox. Despite the fissuring, the fruit bodies are unusually
long-lasting.
Photo © Gary Emberger.

Figure 7. I believe this mushroom is Agrocybe sororia
although I did not have an opportunity to confirm
microscopic features. Like A. praecox, which it closely
resembles, A. sororia is often found on hardwood wood chip
mulch in the spring. Photographs 8-13 are also of this
species.
Photo © Gary Emberger.


Figure 8. The strongly zonate cap of this species is due to its
hygrophanous nature. Hygrophanous refers to the change in
color that occurs as the cap tissue loses moisture.
Agrocybe is a genus that includes many hygrophanous
species. Photo © Gary Emberger.

Figure 9. The hygrophanous nature of the cap is evident in
the color differences in the central and marginal areas of
the cap. A dark brown spore print was deposited on the
right side of the large mushroom cap. The overtopping
cap was removed in order to reveal the spore print.
Photo © Gary Emberger.


Figure 10. White rizomorphs are present at the base of the
stipe. Photo © Gary Emberger.


Figure 11. Young specimens of A. sororia show no
evidence of a partial veil covering the gills. A. sororia
does not have a partial veil. The immature gills are whitish.
Photo © Gary Emberger.


Figure 12. Agrocybe species have attached gills.
Photo © Gary Emberger.


Figure 13. The flesh of Agrocybe species is whitish and
does not discolor after cutting.
Photo © Gary Emberger.