SPRUCE NEEDLE- RUST. 468 



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. 



''ig. 224. — Spruce twig attacked by Chrysomyxa ylhietis, Ung., in autumn. 

 {Natural size.) 



18. Ckrijsomyxa Ahietis, 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 aflected needles, which by 



