242 



THE MONTHLY BULLETIN. 



ing effect, and the clean white appearance of the affected parts is as 

 characteristic as any form of injury could be, whether due to disease, 

 insect pests or other agencies. Alfalfa and other leguminous plants 



Fig. 44. — Alfalfa plant t.vpical of a great many in a field injured by smelter 



fumes. ( Original. ) 



that the writer has observed are always whitened by sulphur dioxide 

 gas, and a very characteristic marginal burning often takes place so that 

 the center of the leaf will be its normal green color, while the margin 



Fig. 45. — Bur clover showing characterifctic bleaching effect 

 of sulphur dioxide gas. (Original.) 



will be white. Figs. 43, 44 and 45 of alfalfa and bur clover illustrate 

 this injury very clearly. Wild peas, Laihyrus sp., have been collected, 

 which showed exactly the same kind of burning. Grains and various 



