590 Went. — Notes on Sugar-cane Diseases . 
macro- and microconidia. The macroconidia are situated in 
apical chains at the end of short branches of the mycelium 
(Fig. 13). Their cell-walls are of a dark olive-green colour. 
Their contents are generally not to be seen, owing to the 
colouration of the cell-walls and to the number of large oil- 
drops in the interior (Fig. 14). Only where these oil-drops 
are very small and where the colouration of the cell-wall is 
lighter, as in Fig. 1 5, the protoplasm with the vacuoles may 
be visible. The conidium at the top of the chain very often— 
but not always — is almost spherical, as in Figs. 13 and 14, the 
other conidia being more elongated. In Fig. 1 6 the formation 
of such a chain is to be seen ; a is the beginning, one conidium 
has been formed. Under the microscope I was able to 
observe that the top of the hypha under the conidium 
formed a new transverse septum, and thus a new conidium 
was made : b was drawn one and a half hour after a ; the top 
conidium had become larger and more spherical : three hours 
afterwards, in c, the apical conidium had become still larger 
and shows a commencing colour of the cell-wall ; two new 
septa had been formed, being the beginning of the develop- 
ment of a third and a fourth conidium. It results from this 
that the macroconidia are formed in a basipetal manner. 
The microconidia are also produced in chains, but they 
arise partly in the interior of the conidia-bearing-cell. Fig. 17 
shows in a the very first beginning of a conidia-bearing 
hypha, which is a thick somewhat curved branch of the 
mycelium. This curve remains in the adult hyphae, as is 
to be seen in Fig. 17 b or Fig. 18. The number of conidia 
in a chain may be three or four, but generally is very great, 
Fig. 18 not being an extreme case at all. Fig. 19, much 
more magnified, may give an idea of the manner in which 
these microconidia are formed at the top of a hypha, from 
which they are afterwards extruded. Three of the conidia 
are quite free; one is just escaping from the cell-wall ( a ) 
of the hypha ; another has just been formed, but its basal 
wall (b) still forms a part of the hypha ; another one has its 
basal wall not yet quite developed (c). These microconidia 
