360 REPORT OF THE COMMISSIONER OF AGRICULTURE. 
tf the diseased spots are examined after a week or ten days of dry 
weather an abundance of the minute globules above referred to will 
be seen. Ifa rain follows, the substance which cements the spores 
together is quickly dissolved and the latter are set free. A micro- 
scopic examination of the drops of water which collect on the canes 
and leaves after a rain will show numerous spores floating about, 
and many will be seen to have germinated by sending out delicate 
colorless filaments or germ tubes. 
Spores (Fig. 3) sown in a drop of water germinate at the expiration 
of about twenty-four hours, so that if the water which sets the spores 
free evaporates shortly after the gummy substance is dissolved, the 
former are in such condition that the slightest breath of air is suffi- 
cient to carry them from place to place. If they fall upon healthy 
leaves or canes, and the proper conditions of moisture and heat are 
present, they will germinate, and itis very probable that the slender 
filaments produced will penetrate the cuticle of the plant and ulti- 
mately produce new diseased spots and give rise to the same fungus 
development from which they were derived. : 
Early in June of the present year (1887) numerous sowings of the 
spores were made in various solutions prepared by macerating the 
green and ripe fruit in water, and juices made in a similar manner 
‘from the leaves and young canes were also used. It was found that 
spores sown in pure water germinated much more readily than any 
sowninthesolutions. It was also discovered that if the spores which 
had germinated in pure water were removed to the prepared solu- 
tions, the filaments therefrom grew with greater vigor than when 
left in pure water. From these experiments it would seem reasonable 
to believe that pure water is required, if not absolutely necessary, for 
the germinations of the spores, and that the germinating filaments, 
after they have entered the tissue, find in the juices of the plant all 
that is necessary for their future development. Another fact which 
would further warrant us in this belief is that the disease rarely 
spreads during dry weather. It spreads rapidly, however, during 
damp weather and at times when moisture collects in drops on the 
canes. Although no new spots are formed during a dry season the 
old spots continue to enlarge, and frequently the leaves wilt, owing, 
no doubt, to the fact that the injured cane can not supply the neces- 
sary amount of moisture. It is not known how long the mycelium 
is capable of retaining its vitality; nor do we know of any other 
mode of propagation excepting by the spores above described. Pos- 
sibly the fungus lives in the old canes through the winter, and is 
capable of developing a new series of spores the following spring. 
Thismay or may not bethecase. One fact, however, inthis connection 
is worthy of note, and that is, that spores taken from old spots after 
the canes have been kept for several months in an herbarium will 
germinate. Hath 
The fungus under discussion is only known in its active or injuri- 
ous form; other stages may occur, but they have never been satis- 
factorily made out. A Phoma which develops an immense number 
of minute, oval, colorless spores is frequently found on the old spots 
made by the Glwosporiwm. In this Phoma the spores are produced 
within minute dark-colored sacs, called pycnidia, which appear to the 
naked eye as minute black specks. Another fungus, very similar to 
the above, but which should be referred to the genus Phyllosticta, 
has been found associated with the Glwosporiwm, but whether either 
