PLATE io 
A. —(i) Dwarfed Irish Cobbler plant. (2) Unmottled curly-dwarf Green Mountain 
hill diseased as result of aphid inoculation in preceding season from parent of 
plant (A, 1). 
B. —(1) Healthy plant and corresponding tuber progeny. (2) Plant and cor¬ 
responding tuber progeny infected with spindling tuber. Healthy and diseased 
plants from Rose 4 variety. 
C. —Parts of the same Green Mountain strain. In left center, spindling-tuber seed 
potatoes planted. On right, all-mosaic seed potatoes planted. August 20, 1918. 
