CHAP, xiii.] Fungoid Diseases of Trees 283 



II. ON STEMS AND BRANCHES (in the bark or in 

 the wood). 



The cankerous diseases which belong to this section may be 

 divided into two main groups. In the first of these are 

 comprised all such diseases of the bark and the cambium as 

 cannot be healed without human interference, because of their 

 influence annually extending, so that when it has encircled the 

 stem all above this zone dries and dies off. And in the second 

 group are comprised disorders which only, as a rule, spread 

 through the bark during a single period of vegetation ; but if 

 within that time the disease has not completed its circuit round 

 the stem the infected place becomes cicatrized and heals over. 

 Unfortunately the only one of the chief cankerous diseases 

 below mentioned which belongs to this latter group is Nectria 

 cucurbitula. 



A. Of Conifers : 



1. Trametes pini. Pine fungus. Mainly attacking Scots Pine, 

 Spruce, Larch, Silver Fir. 



2. Aeddium pint, Pers. var. corticola^ Pine-canker or bark- 

 fungus. Mainly attacking Pines. 



3. Caeoma pinitorquum, Pine-shoot fungus. Mainly attack- 

 ing Pines *. 



4. Aeddium elatinum, Silver Fir fungus. Mainly attacking 

 Silver Fir. 



5. Nectria cucurbitula. Spruce-bark fungus. Mainly attack- 

 ing Spruce. 



6. Peziza Willkommii, Larch canker. Mainly attacking 

 Larch. 



Minor disorders are occasioned by Cladosporium entoxylinum 

 and C.penidllioides on Scots Pine, and Pestalozzia Hartigii on 

 Spruce and Silver Fir (seedlings in nurseries). 



1 See foot-note on opposite page. 



