— eS Re ee ee Te eT ee Oe Te ce cn 
48 MISSOURI BOTANICAL GARDEN. 
4 
greenhouse lettuce, and from his description there is no 
evidence whatever that S. Libertiana was present. In the 
same year, Jones (29) in Vermont mentions a lettuce rot due 
toa Botrytis. Under the term “mildew,” Taft (57), in 1894, 
gives an account of a lettuce disease, attributing it to a species 
of the same genus. Galloway (19) states that ‘‘wet rot,” pro- 
duced by Botrytis, is the result of too much moisture. Bailey 
(2) believed that the lettuce “rot” was caused by Botrytis, 
which is at first saprophytic on decaying matter in the soil, 
but under conditions unfavorable to the plant, attacks it and 
acts as a parasite. He figures a plant infected with the fungus 
which is characteristic of the “drop.” Selby (47) mentions 
a disease as lettuce “rot,” attributing it to Botrytis. 
Stone and Smith (54), in 1897, describe a “drop” due to 
Botrytis. Their description of the disease agrees very well 
with that of Humphrey. Again, in 1898 and 1899, they refer 
to the lettuce “drop’’, still attributing it to the same fungus, 
which produced a number of small flat sclerotia on the in- 
fected plants and in the cultures. Garman (20) at this time 
refers to a “rot” of lettuce due to Botrytis and other organ- 
isms. It is interesting to note that the disease causing the so- 
called “drop” was in all cases attributed to Botrytis cinerea. 
Smith (48), in 1900, in a paper in which he brings to- 
gether a large number of observations, concludes that there 
are two distinct forms which cause the lettuce “drop.” The 
first he designates as the Botrytis type which, besides causing 
the “drop,” produces a damping-off of the young seedlings. 
The fungus growing in the cultures and on the plant pro- 
duced an abundance of conidia with but little mycelium. 
Small sclerotia were formed in large numbers, both in the 
cultures and on the infected plant. The second type he re- 
fers to as the “no-Botrytis’ type, belonging to the fungus 
S. Libertiana. This form produces a cottony mass of my- 
celium with sclerotia, but no conidia. Infection takes place 
directly by the mycelium. Smith, unable after numerous 
attempts to germinate the sclerotia, was of the opinion that 
the bulk of the disease is due to a degenerate form of this 
