2298 LIFE OF A TREE. 
ing of very minute fungous plants. ‘The disease 
called by the farmers the “ Rust” in wheat is of 
this nature. It attacks the corn-fields in Spring, 
particularly in wet seasons ; and soon causes the 
heart of the agriculturist to tremble for his crops, 
as with sorrow he contemplates their drooping, 
yellow, sickly aspect. While the wet weather 
lasts, the fungus grows rapidly, the corn-plant 
suffering in proportion; but if the rain is stayed, 
if the sun again sheds his warm influence on the 
fields, and the moisture thus becomes dispersed, 
the fungus soon withers away, and the drooping 
blades stand fresh, green, and erect, as though 
they had never been the victims of disease. An- 
other is called the wheat-mildew, and is also 
most liable to attack the corn in moist seasons. 
The little seeds, or more properly speaking 
‘“‘sporules,” from which these fungi are deve- 
loped, are infinite In number, and of extreme 
minuteness in size. ‘They are supposed to rise 
like thin smoke into the air by evaporation, and 
are then scattered about in every direction by 
the winds. An author who has paid much at- 
tention to these matters, has calculated that in 
one plant there were at least ten millions of these 
