1920] 



BURT THELEPHORACEAE OF NORTH AMERICA. XII 



187 



Fig. 28. S. abietinum. Section X 

 68; crust-like zone, z; hymenium con- 

 taining colored cystidia, h; cystidium, c, 

 and spores, s, X 488. 



layer becoming z on a teand con- 

 taining numerous colored cys- 

 tidia having more or less the 

 appearance of colored conduct- 

 ing organs; cystidia colored, 

 cylindric, obtuse, even, rough- 

 walled or more or less incrusted, 

 90-1 50 X 6-8 fx, protruding up to 

 60 fj.; spores hyaline, even, flat- 

 tened on one side, 9-13X4-5 n. 



Resupinate specimens 2-8 X 

 2-5 cm., reflexed margin 3-8 

 mm. broad. 



On wood and logs of Abies 

 and Pinus. New Hampshire 

 to Washington and in Europe. 

 June to October. Rare. 



S. abietinum usually occurs resupinate, but its thick, separable, 

 felty fructifications are suggestive of a resupinate Stereum, and 

 this view is confirmed by the presence of the intermediate layer 

 when radial, vertical sections are examined. The cinereous, 

 pruinose surface of the hymenium due, however, to whitish, 

 cobwebby filaments rather than powdery grains, is highly char- 

 acteristic and shared only by the western S. rugisporum, as 

 are also the colored cylindric cystidia. S. rugisporum is sepa- 

 rated by its odor of anise, much thicker and more broadly 

 reflexed pilei, and presence in occasional collections of colored 

 spores imbedded in the deeper zones of the hymenium. 



I have included Hymenochaete fimbriata among the synonyms 

 of S. abietinum, but it may prove to belong with S. rugisporum 

 instead. 



Specimens examined: 

 Exsiccati: de Thumen, Myc. Univ., 1107. 

 Norway: Christiania, M. N. Blytt, type of Stereum glaucescens 



(in Herb. Fries). 

 Sweden: Stockholm, L. Romell, 29; Upsala, C. G. Lloyd, 08521 



(in Lloyd Herb, and Mo. Bot. Gard. Herb., 55497). 

 Finland: Mustiala, P. A.Karsten, in de Thumen, Myc. Univ., 

 1107. 



