Climacodon septentrionale

Scientific name:   Climacodon septentrionale (Fr.) Karsten
Derivation of name:   Septentrional- means "northern."
Synonyms:  Steccherinum septentrionale (Fr.) Banker;
Hydnum septentrionale Fr.
Common name(s):  Northern tooth.
Phylum:   Basidiomycota
Order:   Polyporales
Family:   Meruliaceae
Occurrence on wood substrate:  Parasitic; in dense
overlapping clusters on trunks of living deciduous trees,
particularly maple (Acer) and beech (Fagus); July through
October.  
Dimensions:  Individual caps up to 30 cm wide and from
2.5-5 cm thick at the base. Overlapping clusters of shelving
caps may be up to 80 cm high.  
Description:  Upper cap surfaces are whitish to creamy
yellow when young and become yellow-brown in age. Cap
surfaces are hairy to rough. Odor and taste when young are
not distinctive but the odor of old specimens is described as
like old, spoiled ham and the taste becomes bitter. The
crowded, whitish spines on the underside of the caps are 0.5-
2 cm long and have lacerated or ragged tips. Like the cap
surfaces, the spines become yellowish in age.       
Edibility: Inedible.
Comments:  This fungus looks like a polypore until the
spines are noticed. It causes a heart rot of trees in urban
areas, parks, and in forests.

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Figure 1. The overlapping clusters of shelving caps tend to
occur vertically. Photo © George Barron.
    

Figure 2. Climacodon septentrionale looks like a polypore
until you see the teeth. Photo © William Roody.

Figure 3. Older specimen of Northern tooth with
yellow-brown coloration. Photo © Fred Habegger.

Figure 4. Ragged spine tips. Photo © William Roody
(enlargement of Figure 2).