118 British Uredinee and Ustilaginee. 
growing plants of Rumex obtusifoliius and Ranunculus 
repens, germinate a quantity of the P. maguusiana 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- 
mitis 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. 
