578 
Transactions of the Society. 
belonging to the following genera — Convallaria , Smilacina, Smilax, 
Polygonatum , and Maianthemum. 
In common with many parasites, the fungus does not appear on 
the surface until the leaf becomes more or less dry and discoloured, 
and on this account its presence has been considered by some as the 
result rather than the cause of the disease ; but in reality the vegeta- 
tive mycelium is present in the tissues of the leaf for some time before 
there are any external signs of its presence. 
In Smilacina stellata, as in other host-plants of the fungus, the 
tip of the leaf has a slight oblique twist that retains a small quantity 
of moisture, and it is at this point that the parasite very frequently 
first shows itself ; the secondary spores being caught, and their 
germination favoured by the film of water present ; nevertheless, it 
may be stated that a yellow patch is often present at the point 
indicated, in which no trace of mycelium can be detected, and which 
appears to be entirely due to the action of water. 
In other instances one or more yellow patches, caused by the 
mycelium of the fungus, appear at different points on the surface of 
the leaf. 
The mycelium is not perennial in the host, never extending beyond 
the leaf in any species that I have examined, but the leaves are 
attacked and much disfigured while still in their prime, or in many 
instances even before they are full-grown. 
Experiments show that the secondary spores are transported by 
some external agent — probably wind — on to the surface of the leaves, 
and that they are retained at those points that happen to be moist. 
During a dry period certain leaves of Smilacina were moistened at 
particular points with water containing a trace of glycerin to prevent 
rapid desiccation ; at the end of six days several of the moistened spots 
became yellow, and an examination revealed the presence of mycelium ; 
in about fourteen days the fasciculate sporophores of the fungus 
showed themselves at the surface. The above experiment was con- 
ducted with plants that were growing on ground covered with the 
fallen leaves of the previous season, and these furnished the secondary 
spores in abundance. The disease was also produced by direct appli- 
cation of the secondary spores to damp portions of the surface of the 
leaves, and although morphologically there appears to be but one 
species of the fungus under consideration, yet there are what may be 
termed distinct biological forms of this species ; the secondary spores 
produced by the fungus developed on one species of host-plant rarely 
cause the disease when sown on the leaves of a host belonging to a 
different genus, although both species of host have their own form of 
the fungus. 
The secondary spores, which will be described in detail later on, 
usually germinate within twelve hours of being placed in water, and 
emit from one end a single, unbranched, very sparsely septate tube 
