I02 British Uredinca; and Ustilaginetr. 



altogether different, for the smut is formed at the time, or 

 soon after, the cereals are in blossom, and long before 

 harvest it has been scattered by the winds, so that in the 

 harvest field one never finds a smutted ear. We know, 

 moreover, that when once the teleutospores fall on the 

 ground, or in any way become damp, they forthwith ger- 

 minate, and although they are capable of retaining their 

 power of germination for some years, it is only when they 

 are perfectly dry — a condition which never obtains with 

 them in a state of nature. There must, therefore, be some 

 means by which the interval is bridged over between the 

 ripening of the teleutospores of U. segettun, which takes 

 place in early summer, and the time when the grain itself 

 germinates, for this, under any circumstances, can only be 

 one or two months later. This may be by a metoecism, 

 but there is no proof whatever that any such occurs ; or it 

 may be by the continued reproduction of yeast-spores, as 

 Brefeld suggests taking place in manure heaps. My own 

 experiments, however, with nahrlosung containing U. sege- 

 tmn spores have all been negative. 



There is a certain point in connection with the repro- 

 duction of smut {U. segetiini) wherein it differs essentially 

 from bunt [T. tritici); it is this — that however carefully 

 wheat may be dressed with cupric sulphate, arsenic, 

 brine, lime, etc., while such dressing almost absolutely 

 protects the crop from bunt, yet it has no appreciable 

 affect upon smut. This fact is obvious to any one residing 

 in an agricultural district. The wheats are dressed for 

 bunt on every well-managed farm, but they are as much 

 affected with smut as the barley and oat crops, which 

 latter, never being affected with bunt, are never subjected 

 to protective dressing. 



In 1883, I made a series of experiments by applying the 

 teleutospores of U. segetmn to the wheat and oat plants 



