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Fic. 15. Cultures of the fungus in sterilized and living chestnut branches. The central 
figure shows a large mass of yellow mycelium grown on the moist, cut surface of a living branch. 
The figure to the right shows fruiting pustules arising from mycelium introduced beneath the 
bark of a living branch. On the left is an enlarged view of numerous pustules grown on steri- 
lized chestnut. 
