108 
THE PRINCIPLES OF BOTANY. 
crop is in flower, will show us that some of the young ears 
are black, as though they had been immersed in a bag of 
soot, the appearance being due to the exudation of the dark 
granules of the smut grains as they exude in masses from the 
ruptured epidermis of the flowers and their envelopes ; and 
as the whole of these are destroyed by the fungus, the pro- 
duction of grain in the affected ears of corn is rendered im- 
possible. These black ears are more common in the barley 
crop, but wheat, oats, and even some of our pasture grasses, 
are not free from it. 
Two years since we calculated that we lost at the rate of a 
sack of barley per acre from this cause, and last year a field of 
Talavera wheat was estimated to have lost as much as two 
bushels per acre. 
It causes little mischief besides the loss, as a shower of 
rain washes away most of the smut grains. But sometimes, 
in a dry season, the epidermis does not fully burst up, and, 
consequently, the agglomerated masses of smut, kept to- 
gether by the slightly broken epidermis of the grain, will 
find their way into the sample, in which case such barley 
will be totally unfit for the finer ales, and can only be used 
for commoner high-coloured beer or porter. 
Under the microscope, the fungus appears as small, glo- 
bose, smooth granules, each containing one or more smaller 
granules or spores, which, with a quarter-inch object-glass, 
are about the size of the letter o in the type of this article ; 
and these granules are sometimes so numerous, and so easily 
displaced, that a walk through a corn crop is sufficient to 
smut one not unlike a sweep. Its smell and taste are in- 
nocuous. 
2. The Uredo caries. — The carious smut or bunt is so 
called from its highly stinking properties. This especially 
affects the wheat grains, the testae of which, instead of being 
filled with flour, are wholly occupied by a black stinking or 
foetid powder, which is resolved under the microscope into 
rough, warty granules, of a spherical outline, in each of 
which are from one to three spherical spores. The stinking 
nature of this fungus renders it a great pest to the farmer, as 
it imparts not only a bad smell, but a most disagreeable 
flavour to the sample in which it is found ; and so powerful 
are these qualities that a little of it is sufficient to depreciate 
the produce. It must, however, be stated that now the evil 
arising from bunt is by no means so great as formerly, as 
machines called smutters have been invented, which effectu- 
ally removes this pest, though, of course, not without a 
trifling additional outlay. 
