PLATE 54 
x, a.—Cross sections through the deeper tissues of two ammonia intumescences in 
a cauliflower leaf showing that even in the depths they preserve their hypertrophic 
character. Time, nine days. The intumescences are surrounded by the normal 
tissues of the leaf. At VB are vascular bundles. Figure i, X 160; figure 2, X 75 - 
