PLATE I 
Pythiacystis gummosis on lemon trees, from inoculation with diseased bark tissue. 
A.—Tree inoculated on February 27, 1912, the gum formation showing the develop¬ 
ment of disease on August 2, 1912.0 
' B.—^alne tree, September 19, 1912, over 6 months after inoculation; 
C. —Same tree about i year later, view at right angles to B. Only 5 cm. of live 
bark then prevented complete girdling. 
D. —Same view as A and B, on May 24, 1913, 15 months after inoculation. The 
gum first formed has been dissolved away by winter rains and the dead bark has 
drie^ and shrunk. Gum was exuding farther around, as in C, at this time. 
B;-^Lemon tree inoculated with diseased bark tissue, September 21, 1912, lowing 
excessive exudation of gum 2 months later. 
F.—^^mon tree inoculated with diseased bark under a glass slide held with putty, 
September 21, 1912, showing gum formation 2 months later. 
o A majority of the trees in this same orchard had the same overgrowths” at the union of stodc and 
scion as observed in this illustration. 
(236) 
