312 Wormald. — Further Studies of the ‘ Brown Rot ’ Fungi. I. 
appear that most of the conidia had been washed down towards the base of 
the lamina, for they had been placed near the middle of each leaf. 
In series (a) the punctures showed brown margins in every case on 
May 8, and on some leaves the punctures were connected by brown cells ; 
in three leaves the discoloration had extended from the punctures to the 
edge of the leaf on that side of the midrib. Later, further extension of the 
browning occurred, usually accompanied by a yellowing of the tissues in 
advance of the browning and by a distortion of the leaf as a result of 
a check in its development on the inoculated side. Finally, in four leaves 
the diseased portions dropped out and the rest of the leaf did not become 
affected ; in each of the other two, however, the whole leaf was killed, and 
in one of them the disease extended into the axis of the shoot, causing the 
wilting of all the other leaves on the shoot, and then into the twig to form 
a canker (Plate XIV, Fig. 24). As these are features which have not 
previously been recorded, details of observation are here tabulated. 
Results on six plum leaves punctured and inoculated on May y 
May 24. 
Leaf withered and brown 
to base of petiole. 
The infected portion has 
fallen away. 
The diseased area, 5x6 
mm., is now breaking 
away. [A few days later 
it had fallen out.] 
Diseased portion fallen out. 
Infected portion fallen out. 
Infected leaf withered to 
base of petiole ; other 
leaves of the shoot are 
wilting ; the lower end of 
the petiole of one leaf is 
brown for 6 mm. 
Later observations on leaves No. i and No. 6 , the two which were 
killed outright, were as follows : 
No. i. On May 31 the tip of the shoot was dead but the lower leaves 
were alive ; by June 10 no further development had occurred except that 
the infected leaf bore pustules of Monilia cinerea. 
May 11. 
1. A browning of the 
tissues extends from the 
punctures to the margin 
of the leaf. 
A browning extends 
from the punctures to the 
edge of the leaf. 
3. There is a brown mar- 
gin to the punctures. 
May 16. 
The browning extends from the midrib 
to the margin of the leaf on the punc- 
tured side and for a distance of 2 cm. 
along the edge ; there is also a yellow- 
ing of the infected side accompanied 
by distortion. 
The discoloration is now .extending 
towards the midrib ; there is a slight 
yellowing and distortion of the leaf 
between the punctures and the base of 
the leaf. 
The browning extends for 2 mm. from 
the punctures ; there is a slight yellow- 
ing and distortion on the infected side. 
4. Tissues brown between, 
and round the margins 
of, the punctures. 
5. The punctures have 
brown margins ; two are 
connected by brown 
cells ; leaf slightly dis- 
torted. 
6. Punctures connected by 
brown cells ; browning 
extending to the margin 
of the leaf. 
That portion of the leaf from the punc- 
tures to the margin is yellowish-green 
and there is some distortion. 
Punctures all connected by brown 
tissues, leaf distorted, and yellowish 
between the punctures and the base. 
The browning extends as far as the 
margin of the leaf and to the midrib, 
and for 1.5 cm. along the edge; leaf 
distorted. 
