Omphalotus illudens

Scientific name:  Omphalotus illudens (Schwein.) H.E.
Bigelow
Derivation of name:  Illudens means "deceiving" although
I'm not sure why this specific epithet is applied to this
species.
Synonyms:  Clitocybe illudens Schwein.
Common name(s):  Jack O' Lantern mushroom; False
Chanterelle
Phylum:   Basidiomycota
Order:   Agaricales
Family:   Marasmiaceae
Occurrence on wood substrate:  Saprobic; in dense
cespitose clusers at the base of deciduous trees and stumps
or on the ground from decaying underground roots; July
through November.  
Dimensions:  Caps 7.5-20 cm wide; stipes 7.5-20 cm long
and 0.5-2.3 cm thick.   
Cap:  Smooth; bright orange to yellow-orange.      
Gills: Decurrent; same color as cap.
Spore print: Creamy white.
Stipe: Yellow-orange.
Veil: Absent.
Edibility: Poisonous.
Comments:  The gills of this mushroom are bioluminescent
giving off a green glow. Care must be taken to not confuse
this poisonous mushroom with edible chanterelles.
Chanterelles are not associated with decaying wood, they
have blunt gill-like folds or ridges instead of true gills, and
they do not occur in such dense cespitose clusters.

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Figure 1. The orange coloration of Omphalotus illudensis
is striking, even when viewed from a distance.
Photo © Gary Emberger.


Figure 2. Up close, the large brilliantly orange clusters of Jack
O' Lantern are a beautiful visual treat. Photo © George C.
Gress.

Figure 3. This cluster is in a typical location at the base of a
stump. Photo © David Work.


Figure 4. Young specimens appearing in cespitose array
near the base of a tree trunk. Photo © Gary Emberger.

Figure 5. In contrast to Figures 1-4, another typical
location is on lawns where the fungus arises from dead
roots. The owner of this house indicated there was a large
pin oak tree on the front lawn which had been removed
recently. Photo © Gary Emberger.

Figure 6. Very young specimens with inrolled/incurved
margins. Photo © Gary Emberger.

Figure 7. Maturing speciemens with even margins.
Photo © Gary Emberger.

Figure 8. Quite mature specimens with uplifted and wavy
margins. Figures 6-8 illustrate the changes in shape which
so often accompany mushrooms as they develop.
Photo © Gary Emberger.

Figure 9. A typical cespitose cluster in which the stipes
arise close together but are not joined. Photo © Gary
Emberger.

Figure 10. Decurrent gills of the Jack O' Lantern
mushroom. Photo © Gary Emberger.

Figure 11. A mycology class sitting among the specimens
observed in Figure 1. Photo © Gary Emberger.