Hapalopilus croceus

Scientific name:   Hapalopilus croceus (Fr.) Donk.
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:  
Phylum:   Basidiomycota
Order:   Polyporales
Family:   Hapalopilaceae
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.
Edibility: Inedible.
Comments:  The cap and pore surfaces of this polypore turn
reddish-purple with the application of KOH.


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.
    

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.


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.

Figure 6. Can you see pores?

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