Hapalopilus croceus

Scientific name:   Hapalopilus croceus (Pers.)
Bondartsev & Singer
Derivation of name:   Hapalopilus means "with a soft,
tender pileus or cap"; croceus means "saffron yellow"
although specimens are bright orange when fresh.
Synonymy:   Polyporus croceus Pers.: Fr.; Aurantioporus
croceus.
Common names: Unknown. 
Phylum:   Basidiomycota
Order:   Polyporales
Family:   Polyporaceae
Occurrence on wood substrate:  Saprobic and parasitic;
solitary to scattered on living oak (Quercus) and chestnut
(Castanea) trees and on dead wood of these trees; June
through November.
Dimensions:  Sessile caps up to 20 cm wide, 20 cm long,
and 6 cm thick.   
Upper surface:  Bright orange at first, becoming more
brownish-orange with age; hairy to somewhat glabrous with
age.
Pore surface: Bright reddish-orange when fresh.
Comments:  The cap and pore surfaces of this polypore turn
reddish-purple with the application of KOH.

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Figure 1. Hapalopilus croceus. The dropper was used
to apply KOH to the cap. The color change is
reddish-purple. Photo © John Plischke III.

Figure 2. The striking reddish-purple coloration that
develops after application of KOH.
Photo © Gary Emberger.
    

Figure 3. Pores, too, turn reddish-purple after
application of KOH. Photo © Tom Volk.

Figure 4. The cap surfaces of two specimens displayed
on the collection table at a NAMA foray. They are soft
and watery when fresh. Photo © Gary Emberger.


Figure 5. The bright reddish-orange pore surface of the
specimen on the left compared to the cap surface on
the right. The cap surface fades with age and exposure.
Photo © Gary Emberger.

Figure 6. Can you see pores? Photo © Gary Emberger.

Figure 7. Can you see the pores now? They average
2-3 per mm. Photo © Gary Emberger.