228 HELMINTHOSPORIUM SPP. ON CEREALS AND SUGARCANE IN INDIA 
EFFECT OF REACTION OF CULTURE MEDIA. 
This experiment was run in duplicate on glucose medium. Twenty tubes 
were inoculated, two of each reaction and ranging from—15 to +30 Fuller’s 
scale. After three days there was found to be no growth at +25 and+30 
Fuller’s scale ; very poor at +20, and poor at +15 and—15. It was little 
at 10 and +10, good at +-5 and best at 0 Fuller’s scale. In eight day-old 
culture the growth increased at -+-10 and +5 but comparatively little took 
place at0. From the above data it is observed that this fungus prefers reaction 
from a neutral to an acid media ranging from 0 to +10 Fuller’s scale and is 
best at +-5 Fuller’s scale though growth is more rapid at 0 in the beginning. 
LONGEVITY OF THE SPORES OF MAIZE HELMINTHOSPORIUM. 
Large numbers of diseased spots of maize Helminthosporium were cut and 
put in a stoppered bottle and kept for more than a year. It was noticed that 
up to four months ninety per cent. of the spores germinated when placed in a 
drop of water and incubated in a moist chamber, and up to eight months fifty 
per cent ; after eight months the spores rapidly lost their power of germina- 
tion, and after a year they were incapable of germinating. This shows that 
spores can survive long enough to infect the next crop. It is quite probable 
that this fungus occurs on some wild grasses also and asearchfor them is being 
made. 
RELATION OF PARASITE TO HOST. INFECTION AND CONIDIOPHORE 
PRODUCTION. 
The penetration of the fungus takes place either through stomata or by 
directly piercing an epidermal cell (Plate IIT, figs. 1, 2 and 3). It can penetrate 
any epidermal cell, but generally it enters through subsidiary cells. The 
hypha from a germinating spore comes in contact with the cuticle, swells up 
and then sends out a narrow tube. This pierces the cuticle and may travel 
for a distance inside the cuticle, parallel to the outer wall of the epidermis, and 
atter some time either enters an epidermal cell or passes threugh the side walls 
of two epidermal cells into the cells below. Sometimes it surrounds an epider- 
mal cell, sending in branches which fill the cavity. When penetration is 
through a cell in contact with a guard cell, it enters the sub-stomatal space, 
branching freely, and becomes septate. It passes to other cells directly or 
through two adjacent cell-walls, 7.e., it is both intra- and inter-cellular. The 
mycelium branches and sometimes forms a net work below the epidermal 
layer. Afew hyphe may enter an epidermal cell to forma stromatic mass from 
which conidiophores arise. The development of fructifications depends upon 
————— as 
