Some Tomato Diseases. F. T. Brooks and G. O. Searle. 187 
PYCNOSPORES. 
SHAPE, 
SEPTATION. 
GUTTULATION. 
SIZE. 
PYCNOSPORES. 
SHAPE. 
SEPTATION. 
GUTTULATION. 
SIZE. 
PYCNOSPORES, 
SHAPE. 
SEPTATION. 
GUTTULATION. 
SIZE. 
PYCNOSPORES. 
SHAPE. 
SEPTATION,. 
GUTTULATION. 
SIZE. 
Form M. 
Issue in coils through ostiolum, hyaline. 
Ovate to sub-cylindrical, rounded ends, very varied in size 
and shape. 
Usually non-septate, about 20 % 1-septate and generally 
constricted at the septum. Occasionally 2-septate. 
No guttules. 
4°5¢-I2uxX2pu-4m non-septate. Qmué—-I7 wx 2°5 w-5 wo I-SEp- 
tate. 15 x 3°5m (20 measurements). 
Form P. 
Issue in coils through ostiolum, hyaline. 
Ovate to sub-cylindrical with rounded ends, occasionally 
slightly curved. 
Usually non-septate, about Io % 1-septate, not constricted 
at the septum. Percentage of septate spores rapidly increases 
with age. 
Very occasionally a single guttule. 
3°5 M-I0 uw xX2u-4 u non-septate. 8 u—-14 uw x 3 u—-4 uw I-Septate 
(20 measurements). 
Form Q. 
Issue in coils through ostiolum, hyaline. 
Ovate to cylindrical, one end usually and sometimes both 
ends pointed. 
Non-septate. 
Generally bi-guttulate. 
4 w-8 wh x 2°5 u-3°5 wm (20 measurements). 
Form T. 
This was a specimen of Ascochyta Pisi Lib. 
Issue in coils through ostiolum, the coil often attaining a 
length of two or three millimetres. Hyaline, often very 
vacuolate, but non-vacuolate in perfectly fresh spores. 
Cylindrical with rounded ends, often slightly curved. 
95 % I-septate, occasionally 2 or 3-septate, not constricted 
at the septum, except in perfectly fresh spores which were 
slightly constricted. 
Indefinite. 
10°5 u—-I7'5 u xX 2°5 u—-4'5 mw I-Septate. 14°5 u x 3°5 u 2-septate. 
24"@x4°5m 3-Sseptate. 8ux3, non-septate (20 measure- 
ments). 
The systematic position of species of the genera Phoma, 
Ascochyta, and Diplodina is difficult to determine. 
The chief difference between the genera Phoma and Diplodina 
is that, according to systematists, the spores of Phoma are 
non-septate and those of Diplodina I-septate. 
A study of the herbarium specimens does not tend to make 
matters easier as will be seen by the following descriptions: 
