SPRUCE NEE OLE -RUST. 



463 



tall, with a thickened spongy stem, at first whitish, then 

 rosy-red, and eventually dark brown. 



The fungus kills silver-fir needles and causes them to fall, 

 but it is not widely spread and becomes dangerous only when 

 young thickets of silver-fir spring up among cowberry plants, 

 when the latter should be uprooted and destroyed. 



Fig. 224. Spruce twig attacked by Chj-ysomyxa Abietis, Ung., in autumn. 

 (^Natural size.") 



18. Chrysomyxa Abietis, Ung. 



(Spruce Needle-rust.) 

 a. Description and Life-history. 



This form of spruce needle-rust may be recognised by dull 

 yellow bands appearing from May to the middle of June on 

 yearling spruce needles. 



They gradually become broader and assume a brighter 

 yellow colour. Towards the end of August brownish longi- 

 tudinal stripes appear on the affected needles, which by 



