SPRUCE DISEASES 331 



other in the soil. No strands of mycelium grow through the 

 soil, however, as in the case of the shoe-string root-rot (see 

 page 78). For further details concerning the life history 

 and control of wood-rotting fungi, see page 64. 



References 



Schrenk, Hermann von. Polyporus annosus Fr. In Some diseases 

 of New England conifers. U. S. Dept. Agr. Div. Veg. Phys. 

 and Path. Bui. 25 : 49-50. 1900. (It seems probable that von 

 Schrenk also described the rot due to Fames annosus under the 

 discussion of Polyporus subacidus Pk. on pages 44-^9.) 



Hartig, R. Trametes radioiperda R. Hartig. In Wiehtige Krank- 

 heiten der Waldbaume, pp. 62-65, pi. 3. 1874. 



Hartig, R. Trametes radioiperda. In Die Zersetzungserscheinungen 

 des Holzes, etc., pp. 14r-31, pis. 1-4. 1878. 



Red-Beown Root- and Butt-Rot 



Caused by Polyporus Schweinitzii Fries 



Spruce, as well as fir, pine, larch, hemlock and arbor-vitse, 

 is commonly affected by this root-rot throughout its range. 

 This disease is second only in importance to the pecky wood- 

 rot. The sapwood is at first yellowish and cheesy but later 

 becomes red-brown and brittle. The sporophores are stalked 

 reddish-brown umbrella-like structures. For a more complete 

 description of this rot see under pine diseases, on page 294. 



Yellow Root-Rot 



Caused by Sparassis radicata Weir 



This root-rot of spruce is as important as the shoe-string and 

 brown root-rots in the Northwest. Fir, pine and larch are 

 also affected by the yellow root-rot in the same region. Lateral 

 roots even to a considerable depth in the soil are decayed and 

 killed. Yellowish fan-Uke sheets of mycelium are formed in 

 the bark. The sapwood is then affected and the medullary- 



