MILDEW AND BEAND. 51 



fig. 141)^ and the yellow bodies_, now termed sijores 

 (whetlier correctly so_, we do not at present inquire), 

 break from their short pedicels and escape, to the 

 naked eye presenting the appearance of an orange 

 or rust-coloured powder. In this stage the spores 

 are globose, or nearly so, and consist of but one 

 cell (plate VII. figs. 142, 144). It will afi'ord much 

 instructive amusement to examine one of these 

 ruptured pustules as an opaque object under a low 

 power, and afterwards the spores may be viewed 

 with a higher power as a transparent object. The 

 difference in depth of tint, the nearly colourless and 

 smaller immature spores, and the tendency in some 

 of the fully matured ones to elongate, are all facts 

 worthy of notice, as will be seen hereafter. 



A month or two later in the season, and we will 

 make another trip to the cornfield. Rusty leaves, 

 and leaf- sheaths, have become even more common 

 than before. A little careful examination, and, here 

 and there, we shall find a leaf or two with decidedly 

 brown pustules intermixed with the rusty ones, or, 

 as we have observed several times during the past 

 autumn, the pustules towards the base of the leaf 

 orange, and those towards the apex reddish brown. 

 If we remove from the browner spots a little of the 

 powder, by means of a sharp-pointed knife, and 

 place it in a drop of water or alcohol on a glass 

 slide, and after covering with a square of thin glass, 

 submit it to examination under a quarter-inch 

 objective, a different series of forms will be 



E 2 



