PINE CONE FUNGUS 



265 



point, therefore it continues to grow and yields very 

 excentric sections, owing to growth being checked by 



r 



Fig. 68. Peridermium harkncssi. i, young stem of Pinus 

 ponderosa, three years old, showing the Peridermium, two-thirds 

 nat. size ; 2, appearance of a stem eight years old, attacked by the 

 fungus, the swollen portion being thickly studded with aecidia, 

 two-thirds nat. size; 3, section through No. 2, the shaded portion 

 indicates the darkened portion of wood containing mycelium of 

 the fungus, two-thirds nat. size. 



destruction of the cambium on different sides at different 

 levels. Cells attacked by haustoria lose their contents 



