PINE-SHOOT FUNGUS. 459 



11. Cenaiu/iuvi Abictis, Duby. 



(Pine-shoot -Fangus.) 

 a. Description and Mode of AilarJc. 



This fungus causes the death of isolated shoots of young 

 pines. As a rule, only yearling shoots are attacked, but some- 

 times 2 to 3 years old shoots also, chiefly at their tips. The 

 shoots die from April till June, from the top downwards. 

 Mycelia are found in the dead shoots, including their buds. 

 The cells of the cortex turn brown and become filled 

 with resin, the tissues are rent. The inner tissues down. to 

 the giith also turn brown. The mycelium is most abundant 

 in the Imds. The needles die from the base, contrary to those 

 attacked in the pine needle-cast (p. 465). They turn yellowish 

 green, yellowish brown, and eventually brown. 



This is not a wound-parasite. The sporocarps are dark 

 brown roundish cushions, breaking out from the mid-nerves 

 of the needles or from the base of yearling shoots, but cliiefly 

 from those 2 — 5 j'ears old dead shoots. The spores germinate 

 only after the dead shoots have fallen to the ground, where 

 they obtain sufficient moisture. 



If the number of infected shoots is sufficiently numerous, 

 the trees attacked may die, otherwise the damage consists in 

 loss of increment only. 



/'. Subjects of Attack, and Distribution. 



This fungus specially attacks Scots pine, of any age, but 

 chiefly 12 — 20 years old thickets and polewoods. Also black 

 and Weymouth pines. Until 1883, it was considered as 

 saprophytic only on dead spruce and silver-fir branches. 

 Then F. von Thiimen suggested that it is parasitic on Scots 

 pine. This was proved to be the case in 1892 by Frank., the 

 fungi having appeared in 184 Prussian forest districts. The 

 exceptional nature of the weather in 1892 certainly assisted 

 in its spread. The fungus occurs in France and Sweden, as 

 well as in Germany. ^ 



Ilartig considers that the damage done in 1892 was due 

 to the intense insolation in February and March, while the 



