PLANT BACTERIA, VOL. 2. 



PLATE 20 



AJiOEN A CO BALTIMORE VD 



YELLOW DISEASE OF HYACINTHS. 



(1) Cross-section of bulb, showing every scale infected except two in center. Haarlem, 1906. (2) Check-tube of litmus mfllt. 

 (3) Bacterium hyacinthi 10 days in litmus milk at 15 to 20 C. (4) Harterium hyafinthi 22 days in litmus milk at 23 C 

 (5) Plant 79, variety blue Baron van Tuyll, inoculated through the flowers. Painted after 1 7 days. (6) Cross-section of infected 

 bulb-scale. The cells of the parenchyma contain starch grains, but only a few are indicated. The xylem and adjacent parenchyma 

 are disorganized ; the phloem is uninjured. After Wakker. (7) Cross-section of a bulb, showing secondary infection. The center 

 is invaded by a soft white rot and by mites. Haarlem, August, 1906. (8) Outer face of a badly diseased" scale. (9) Inner face of 

 badly diseased bulb-scale. (10) Inner face of badly diseased bulb-scale. (II) Vertical section of a bulb, showing a secondary 

 infection ; the base is occupied by fruiting hyphae of a Fenicillium. All from Haarlem, 1906. 



