1 1 8 British Uredine^ and Ustilacrinece. 



growing plants of Rnmex obtusifoliius and Ranunadtis 

 repens, germinate a quantity of the P. magmisiana in a 

 watch-glass, and then put half on a Rumex and the other 

 half on a Ranunculus ; in a week or ten days we shall find 

 the Ranunculus affected and the Rumex free. Care, of 

 course, must be taken that there is no mixture of teleuto- 

 spores in the watch-glass. In like manner the P. phrag- 

 initis may, on a subsequent occasion, be applied to the 

 other two plants, when we shall find the Rumex become 

 affected and the Ranunculus will remain free. 



The main points to be attended to in order to ensure 

 success in performing these cultures are, first and foremost, 

 to have ocular demonstration that your infecting material 

 is actually germinating at the time you use it; and, secondly, 

 to infect the young growing foliage of established plants. 



