226 HELMINTHOSPORIUM SPP. ON CEREALS AND SUGARCANE IN INDIA 
of corrosive sublimate in water (1 in 1000 c.c.) and then in distilled water. 
The washed piece of diseased leaf was transferred to an agar tube. This gave 
rise to an aerial growth in the tube from which a subculture was taken giving 
rise to pure culture. 
In the beginning spores are produced laterally on the mycelium in a large 
number. When young they appear to be sessile but after four or five hours’ 
growth they are distinctly seen on a stalk which grows in length and bears many 
more conidia. Very often the conidia are borne at the tip of the hyphe but 
after some time each of them becomes stalked, the stalk increages in size and 
forms two conidiophores. 
On some media gemme-like bodies are formed and on some irregular 
stromatic masses, but no sclerotia or pycnidia have ever been observed. 
Growth on different culture media. A large number of media were 
inoculated in duplicated with pure culture of Helminthosporium. All the media 
were inoculated on the same day and from the same tube. On some of the 
media the fungus was grown repeatedly to mark variations, if any. Tubes were 
kept for more than six months and in some cases for almost a year but no 
perfect stage of the fungus was obtained. 
The following is a detailed account of the growth on various media :— 
(1) Nutrient plain agar (+4 Fuller’s scale). 
(2) Dextrose agar (+2 33 >. 
(3) Glycerine ugar (-+6 = Se: 
(4) French bean agar (+8 Bs » )» The growth is poor in all these media 
with very little aerial growth. Spore formation is scanty and spores are smaller than those 
formed on other media. 
(5) Litmus lactose agar (4-6 Fuller’s scale). The growth is submerged and creeping in 
the beginning but lateron a woolly aerial growth appears. After a few days the pinkish 
medium gradually turns blue. There is a good deal of spore formation, but the size of spores 
is smaller as on last medium. Spores are as small as 15 in length and septation is reduced 
very much in most cases and in some cases spores are formed without any septum. Average 
spores are 45°6 to 95 by 15:2 to 22°8y in diamater. Mycelium becomes gemmate in old 
cultures, 
(6 & 7) Nutrient glucose agar (+-5 Fuller’s scale) and nutrient saccharose agar. Fairly good 
growth of a greyish green colour. Spore formation is copious. The medium gradually becomes 
greenish, then dark green on account of the submerged growth, and after some days still darker. 
Spore formation is more copious at 20-22°C. than at 30-32°C., and at the later temperature 
sometimes spores of abnormal size are formed. At low temperatures growth is slow and the 
colour is dark greenish grey instead of light greenish grey as at 30°C. It takes about four 
days to fill the tube completely at 30°C., but spore formation decreases gradually with the 
increase of temperature, 7.e., when growth is increased, spore formation is less and vice versa. 
In old cultures the mycelium swells up irregularly forming gemmate. 
(8) Thaxter’s hard potato agar (+6 Fuller’s scale). Copious aerial growth, the medium 
becomes greyish green. The growth is light green at 32°C., and dark at 22°C. In 5 or 6 days 
the tube is quite full and the mycelium is seen spreading on the walls of the tube. Spore 
formation is very free and spores are greenish brown in colour. Hyphe light greenish brown 
