37o 



DISEASES OF CULTIVATED PLANTS 



of yellow mycelium, which occur round the root, and appearing 

 between chinks in the bark. It is suspected that the mycelium 

 migrates from one tree to another underground, as in 

 P. schweinitzii . 



Effused, separable, tough, pores minute, often oblique, 

 whitish, then becoming tinged yellow. 



Schrenk, E. von, U.S. Dept. Agric, Div. Veg. Phys. and 

 Pathol., Bull. No. 25 (1900). 



Porta Laestadii (Fr. and Berk.). I once found this rare 



.!'.-, If 



- 









f 



I IG. 113. Porta vaporaria. 1, portion of fungus, nat. 

 size; 2, section of same. 



fungus growing in abundance on deal boards in a hothouse in 

 kew Gardens. It proved most destructive, causing the wood 

 to break up into cubes and gradually crumble to piect 



Very thin and easily separable from the matrix, tuberculose 



