422 BOTANICAL GAZETTE [JUNE 
stated, the usual conditions under which this organism may 
affect living plants are as follows: excessive moisture, stagnant 
air (these two especially when combined with high temperature), 
low vitality of the host plant, and upon young or delicate parts 
of plants. While not covering all cases, the parasitic attacks of 
Botrytis may almost always be ascribed to one or a combination 
of these conditions. (A number of typical cases of Botrytis 
attacks are described or referred to in the writer’s previous 
article.) All degrees of parasitic activity occur under these 
favorable conditions, from growth upon ripe fruit, where the 
_ fungus is scarcely more than a saprophyte, to vigorous develop- 
ment upon live growing tissue. 
Generally stated, this species is disseminated by means of its 
conidia, which germinate upon parts of plants and send germ 
tubes into the living tissue, where they spread about, causing 
: death and disintegration. Kissling found that, unless germina- 
a tion started with saprophytic nourishment at hand, no infection 
ae es eae a peculiarity previously discovered by De Bary in 
ae has been found by the writer to be a constant : 
h 
one. W; I some material direct infection could be produced in ae 
moist chamber, while at other times such attempts were unsuc- 
cessful. In all cases much more active infection took place 
| saprophytic nourishment was used as a starter. The con- 
refore seems justified that Botrytis varies in the ability 
° ones lia to produce directly parasitic germ tubes, but —_ ae 
1 ry to require a saprophytic start. ae 
infection has taken place, the affected tissue becomes 
d dead and rapidly disintegrates. ee the case of : 
ances, such as turnips | and carrots, it is noticeable _ 
as no other coernes become abundant, no be 
ert 8 by he fungus. In fee ri cf «shown the 
