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known. It grows slowly in culture on agar making a very characteristic 
growth. Examine the plate-cultures provided. OBSERVE:— _ ; 
‘21. The form and color of the colonies. The fungus is readily 
obtained in culture by planting in agar bits of diseased tissue from within 
the corm. 
Mount some of the mycelium from the edge of the culture. Study and 
pRaw to show its form and structure. This may possibly be the form in 
which it persists in the soil. 
Secondary cycles. Pycnospores from the primary lesions, blown 
during the summer, fall upon healthy leaves where, under proper conditions 
of temperature and moisture, they germinate and produce secondary 
infection. From the large percentage of diseased corms formed by plants 
growing from seed and cormels, the foliage of which was attacked by 
Septoria Gladioli Passer., it appears that secondary infections also occur 
from spores washed by rain down into the soil, where they germinate and 
infect the corm. 
So far as known the secondary cycles duplicate in details the primary 
cycle. 
Pathological Histology. The lesions of this disease are strictly necrotic. 
The pathogene promptly kills the protoplasts of the invaded tissues. ~ 
Study prepared sections through a lesion on the leaf. OBSERVE:— 
22. The collapsed and shriveled cells in the diseased portion. 
Compare with the cells in the healthy region. What tissues are affected? 
23. The effects on the cell-organs, i. e. nucleus and chloroplasts. 
‘ 24. The mycelium of the pathogene; its relation to the host- 
cells. 
25. Position and relation of the pycnidia to the host-tissues. 
DRAW to show conditions and structures of the fungus in the diseased 
leaf. 
Study sections through a lesion in a corm. OBSERVE:— 
26. The absence or the small amount of starch in the diseased 
as compared with that in the healthy tissue. 
27. That many cells in the diseased area are collapsed; due 
to what? 
28. The layer of cork-cambium laid down between healthy and 
diseased tissue. May this be associated with the fact that the diseased 
tissue can be chipped out with the finger-nail? 
29. The presence of intercellular mycelium. 
2 DRAW to bring out these points, showing both healthy and diseased 
issue. 
REPORT 
1. A grower plants annually over one hundred acres of gladioli. 
About fifty per cent of his corms are diseased. Outline a scheme, bringing 
in the principles af eradication and protection, whereby he can gradually 
work from diseased to healthy stock, probably requiring ten years or 
oe Indicate the difficulties to be encountered in carrying out such a 
scheme. 
