RUST AND MILDEW IN INDIA, 47 



Certainly does not exist in the Simla region ; it is quite possible that 

 it may have escaped my observation, though I do not think this 

 probable, especially as, to be the cause of rust here, it must be 

 common. I am more inclined to think that the life-history of P. 

 rubigo has a different course from that taken in Europe, and that 

 the subject would well repay thorough investigation, not only in 

 the interests of science, but also in those of economy. I may add 

 that I have recently found, by experiment, that the barberry 

 ^Ecidium is produced by a teleutospore on a wild grass with all the 

 characters of P. graminis ; but I have never found this teleutospore 

 on any cvltivated cereal here. Moreover, the season during which 

 the barberry /Ecidium is produced here is the summer, whilst the 

 wheat and barley crops are raised here, as in the plains, during the 

 winter months, and are reaped in April and May. 



I have figured the teleutospores obtained from specimens 

 gathered at Dumraon, Jeypore, Gujrat, Simla, and the Ghilghit 

 valley (Table II.) ; and, if these are compared with the figures I 

 have copied from Frank, it will be seen that they are typical 

 P. rubigo spores. This will be the more striking if these figures 

 are compared with Fig. 1, taken from a specimen of Jeypore 

 wheat, representing a typical P. graminis teleutospore. Moreover, 

 the teleutospore beds were in all cases (except those from which 

 Fig. 1 were taken), covered w 7 ith epidermis, and the uredospores, 

 wherever I found them (Fig. 4), presented the characters of P. 

 rubigo. It is very astonishing to find that P. graminis occurs in 

 Jeypore, and that the natives recognise the distinction, since they 

 call P. graminis " Rolli," and P. rubigo "Rolla." I am inclined, 

 however, to think that it is a mere coincidence that the specimens 



I received labelled "Rolli" and "Rolla' 1 happen to have been 

 different species, because it was stated by the zemindar that 



II Rolla" (P. rubigo) was less destructive than M Rolli" (P. graminis); 

 . whereas from a very careful inspection of the grains I myself took 



from the ears of each named specimen showed that, on the con- 

 trary, the destructive effect of P. rubigo ("Rolla ") was, as I have 

 already shown, very considerably greater than that of P. graminis 

 ("Rolli"). If P. graminis is related to no other iEcidium but 

 that on the barberry, and there is no reason to doubt it, then we 

 have here an excellent instance of the great distance the aecidio- 

 spores can be carried, since, if these spores came from the Hima- 

 layas, the nearest barberry habitat, they must have travelled about 

 300 miles. 



I should not omit to note here, that P. rubigo may apparently 

 survive from year to year without any intermediate aacidial host, as 

 the mycelium which produces rust and mildew has the power of 

 surviving in a perennial form in the roots of grasses. Such a con- 

 tinuous succession of the rust mycelium is, however, much more 

 probable in Europe, where crops, both of cereals and w T ild grasses, 

 overlap one another, than in India, where analogous conditions are 

 apparently absent or much rarer. I am not aware that a single 

 species of our summer or " kharif " crops (millets for the most part), 

 which alternate with wheat in cultivation, harbours any species of 



