a. Cross section of a portion of the twig of a quince bush, showing spiral fibers, which appear to be fungoid. This section is the outside layer of wood, in the portion of the limb at the line of demarkation, between the dead and living tissues.

b. Cross section of a portion of the same twig, at the point where the blight first attacked it, and at the time of examination perfectly dead and dry. The limb was cut off and examined on the 14th of July, 1862. The blight struck the bush about the 15th of June. In the open spaces in the cellular tissue, are seen fungoid growths; also outside, at c and d, are seen similar growths. From the boundary walls of the interstices, are seen numerous fungoid vegetating points. On the plant at d, is seen something like sporangia. This appears different from the growth in the interstices.