62 MISSOURI BOTANICAL GARDEN. 
and agrees with the observations of the disease on poin- 
settias. As was stated, this infection is due to the sapro- 
phytic nourishment afforded to the germinating spores by the 
stigmatic secretions. Kissling assumes that a cellulose dis- 
solving enzyme is the sole cause of the destruction of the cell 
walls and the transformation of the cell contents into avail- 
able food. 
On the other hand, Ward (66) found that direct infection 
was possible in the form of Botrytis investigated by him. 
However, he observed that the infection was more virulent 
if the fungus was first saprophytically nourished. Like the 
others, he attributes the disorganization of the tissue to a 
cellulose enzyme secreted by the fungus. He further observed 
that this was accomplished by a marked swelling of the middle 
lamella, which preceded the breaking down of the cell walls. 
Nordhausen (37), investigating the biology of Botrytis 
cinerea, was unable to make out this swelling of the middle 
lamella. He found that the non-cuticularized, etiolated and 
injured plants were much more susceptible to infection. 
Smith (49) believes that too much importance has been 
given to this cellulose dissolving enzyme. He finds that we 
have two stages in the process of the breaking down of the 
living tissues; first, a poisoning and killing of the cells, due 
probably to oxalic acid; second, their disintegration and 
utilization by the fungus. The work of Brooks (11) can be 
summed up in his statetmesit att, Whatever thay : ‘be! the 
causes at work in thé isite” ‘ells whith ‘confer ‘imintinit> or 
predisposition on the specie§:of the,host play jis}or which con- 
fer virulence or impotence ‘ont ‘the’ spore? they’ tie deeper than 
nutrition.” We may safely say that: Botrytis varies greatly 
in its ability to be a true parasite, ‘dnd that in most cases it 
is at first saprophytic. 
Tissues infected by Botrytis become soft and decay is very 
rapid. Sections of the diseased tissues show a darkening, loss 
of turgidity, breaking down of the cell contents, separation of 
the cells from one another and final disintegration of the 
whole tissue into a slimy mass. As was observed by Smith 
