450 



BASIDIOMYCETES. 



The two species are held by many authors to be identical. 

 It occurs chiefly on stems of beech, also on oak and birch. 

 In regard to its parasitism nothing further is known. 



Polyporus (Fomes) annosus Fr. (Trametes radiciperda 

 Hartig 1 ) (]>ritain and U.S. America). The sporophores vary 

 much in form, according as they occur more above or more 

 below ground on tree stems, or on timber in mines. The 

 upper surface is brown and marked in zones, the margin being- 

 lighter. The section through the woody sporophore is white. 

 The hymenial layer is also white. Spores ovoid and colourless, 

 germinating easily in water. In artificial cultures, Brefeld 

 states 2 that they produce only conidia. 



fcsSSBT m 



FIG. 231. Polypoi-ust annosus Fr. (Ti-ametfs radiciperda Havtig). Stool of ;i 

 forty-year Spruce, which has been dead for two or three years. The sporophore 

 is several years old. </, a, White open-pored layer forming over the dead basidial 

 layer, b, b; at c a narrow strip of wood still remains firm, the remainder is 

 completely destroyed and rotten. (After R. Hartig.) 



This species was first investigated in detail by Ii. Hartig, 1 

 and is described by him as the most dangerous of all parasites 

 in the conifer forest. It is most frequent on Conifers, e.fj. pine, 

 Weymouth pine, spruce, silver fir, Douglas fir, balsam fir. 

 juniper, and Thuja ; it also occurs on various broad-leafed trees, 

 '//. beech 3 and hawthorn. 



1 R. Hartig, Zersetzungserscheinungen, PI. I.-IV. \Vichtige Krankheiten, PL 

 III. Zeitx<'hr(ti /". l'\tr*t-inid Jagd-wesen, 1889, p. 428. Botan. Centralblatt, 

 XL.II., 1890. 



-Brefeld, Schimm<'l)>il:.<>, Heft 8, 1889. 



3 Rostrup, Afbildning or/ Beskrivelse af de farlii/ste Snylten-ampe, 1889. 



