54 NORTHERN POLYPORES 



known to cause root-rot in aspen and is doubtless destructive 

 to the roots of other trees. The immense sporophores are often 

 used by amateur artists for etching. The presence of conidia 

 has recently been questioned. 



38. GANODERMA P. Karst. 



Hymenophore large, sessile or stipitate, perennial or annual, 

 epixylous; surface sulcate, covered with reddish-brown varnish; 

 context punky, brown or pallid; tubes cylindric, concolorous; 

 spores ovoid, brown. 



Sporophore annual. 



Species confined to Tsuga. i. G. Tsugae. 



Species not found on Tsuga; usually on deciduous wood. 2. G. sessile. 



Sporophore perennial, very truncate on the margin when mature. 3. G. Curtisii. 



1. ' GANODERMA TSUGAE Murrill 



Pileus corky to woody, fan-shaped, convex above, concave 

 below, 4-20 X 5-25 X 1-4 cm.; surface glabrous, uneven, con- 

 centrically sulcate, laccate, lustrous, yellowish-red to mahogany- 

 colored, at length black; margin light-yellow, acute, becoming 

 concolorous, truncate, and marked with many shallow furrows, 

 often undulate and at times more or less lobed; context soft- 

 corky, radiate-fibrous, white or nearly so, 1-3 cm. thick; tubes 

 annual, 0.5-0.75 cm. long, 4-6 to a mm., brown within, mouths 

 circular or polygonal, white to light-cinnamon, edges obtuse, 

 becoming acute; spores ovoid, obtuse at the base, attenuate and 

 truncate at the apex, yellowish-brown, 9-11 X 6-8 /z; stipe 

 lateral, ascending, frequently forked, cylindric, equal, 2-20 X 

 1-4 cm., resembling the pileus in color, surface, and context. 



Common throughout on decaying trunks, stumps, and roots 

 of Tsuga canadensis. 



2. GANODERMA SESSILE Murrill 



Pileus corky to woody, dimidiate, sessile or stipitate, imbricate 

 or connate at times, conchate to fan-shaped, thickest behind, 

 thin at the margin, 5-15 X 7-25 X 1-3 cm.; surface glabrous, 

 laccate, shining, radiate-rugose, concentrically sulcate, yellow to 

 reddish-chestnut, at length opaque-dark-brown, usually marked 

 near the margin with alternating bay and tawny zones; margin 

 usually very thin and acute, often curved downward and undu- 

 late, rarely becoming truncate, white, at length concolorous; 

 context soft-corky or woody, radiate-fibrous, concentrically 

 banded, ochraceous-f ulvous ; tubes 0.5-2 cm. long, 3-5 to a mm., 



