STEREUM. 



431 



!^**l^» 

 ^^1 



The very characteristic destruction of oak-wood caused by 

 this fungus was investigated by E. Hartig. The diseased wood 

 has a uniform dark-brown colour, broken at intervals by white 

 rounded spots or hollow cavities ; 

 hence it receives the name of 

 " partridge-wood." In the white spots 

 the wood has by the action of the 

 mycelium become transformed into 

 cellulose, the middle lamellae and 

 starch-grains being dissolved out. In 

 the neighbourhood of old eaten-out 

 cavities the process of decomposition 

 is slightly changed, so that the cell- 

 walls disappear without previous trans- 

 formation into cellulose. 



CLAVARIEAE. 



Tj^jhula. 



Sporophores filamentous, and, as 

 a rule, developed from sclerotia. 

 Basidia, with four colourless smooth- 

 coated spores. 



Typhula graminam Karst.^ This 

 appeared on wheat plants in Sweden, 

 killing them and forming yellow 

 sclerotia (Sclerotium fulvum, Fr.). 



Fig. 261. — Stereum frustulosum. 

 Later stages of Oak-wood destruc- 

 tion. LoD^tudinal section showing 

 holes in the timber, (v. Tubenf 

 phot.) 



HYDNEAE. 



Hydnum. 



Sporophores very variable in form and structure. The 

 hymenial layers are spread over teeth-like projections. The 

 basidia bear four white spores. 



Hydnum diversidens Fr.^ (Britain). The sporophores form 

 yellowish-white crusts or brackets, with spiny outgrowths on 

 the lower side. The hymenial layer consists at first of basidia 

 only, later, however, hyphae grow up through it and build 



^Eriksson, Landtbr. Alcad. Hand, v. Tidshr., 1879. 

 '^R. Hartig, Zersetzungsersche'mmirjen. 



