PINE CONE FUNGUS 



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point, therefore it continues to grow and yields very 

 eccentric sections, owing to growth being checked by 



Fig. 68. Peridermium harknessi. 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 



