64 REeporRT OF THE BOTANIST OF THD 
to the production of spores; but it is difficult to harmonize this 
idea with the statements of florists who say that the disease may 
be very destructive in dry seasons. During the extremely dry 
summer of 1899, a correspondent in Massachusetts lost, through 
this anthracnose, all field grown plants propagated from cuttings. 
It also did considerable damage to plants grown from seed. 
The basidia are very short, being scarcely distinguishable 
except in very thin sections, 
ON THE LEAVES. 
Plants attacked by anthracnose show multitudes of dead 
leaves which remain hanging on the stems a long time. 
The leaf spots are circular, slightly sunken and have a diameter 
of from three to five millimeters. They originate as yellowish- 
green spots with indefinite outline, but very soon become dirty 
white, or sometimes greenish, definitely outlined and very fre- 
quently have a narrow brown border. If the plants have good 
ventilation and are kept moderately dry neither spores nor set 
are formed and the spots retain their dirty white color; but in a 
moist chamber both spores and sete make their appearance in 
from 24 to 48 hours. Upon the appearance of spores and sete, 
the leaf spots instead of turning black (as is the case with the 
stem spots) merely become smoke colored. This is owing to the 
fact that the stromata of the acervuli are much lighter in color 
and the sete much less numerous than on the stem spots. The 
stromata are also less developed than those on the stems. 
AN EXPERIMENT ON TREATMENT. 
From the nature of the disease it was expected that it could 
be prevented by spraying. Accordingly, the following experi- 
ment was made: On May 15, 1897, 110 Antirrhinum plants, six 
to eight inches high and apparently healthy were set in two rows 
of 55 plants each. On row was sprayed once a week with Bor- 
deaux mixture, receiving in the course of the summer 17 appli- 
cations, while the other row was left unsprayed for a check. 
