FUNGI. 399 
and is probably injurious to health, though this 
has not been clearly determined. I have found a 
few sporules at the apex of every grain in very 
fine samples of wheat. Like Cadmus, therefore, 
the unconscious farmer sows in his fields with 
his seed the teeth of a dragon, which, if developed 
by a cold and wet season, will destroy his pro- 
spects of a harvest. 
Every farmer has painful: knowledge of the 
disease called mildew (Puccinza Gramints, Fig. 46). 
It attacks the leaves and culms of corn, as well as 
many of the grasses employed in hay-making, and 
proves most injurious when developed to a great 
extent, as is often the case when severe frost im- 
mediately succeeds copious and continuous rain in 
autumn. It appears on the diseased leaves in 
yellowish elongated pustules, which speedily burst 
into fissures filled with an orange powder, diffuse 
themselves, and become confluent, until the whole 
plant looks as if sprinkled with red ochre. These 
rusty spots, under the microscope, are found to 
consist of a number of filaments aggregated to- 
gether, on which are developed a cluster of colour- 
less globose cells, which, as they enlarge, become 
filled with an orange-coloured endochrome. A 
month or two later the red pustules assume 
a browner hue; and if examined under the 
microscope they are found to consist of a dense 
