jan. 37,1923 Production of Conidia in Philippine Sclerosporas 247 
dered it necessary to secure inoculating material early in the morning 
(around 9 o’clock) when the leaves were moist. Miyake (75) however, 
in his investigation of 5 . sacchari Miy., of sugar cane in Formosa, learned 
that conditions obtaining at night were in some way involved in inducing 
conidiophore production. In an endeavor to secure material suitable 
for germination experiments he placed infected cane leaves in glass jars 
which were inverted over shallow dishes of water. Under these con¬ 
ditions he found that deposition of spores always took place at night 
and never in the day time, no matter at what time these cultures were 
started. To observe the procedure more carefully he prepared similar 
moist chamber cultures which he examined hourly from 5 p. m. De¬ 
position of conidia began at 1.30 a. m. and continued until 2.30 a. m. 
He concluded that during the day time the fungus prepares for conidi¬ 
ophore and spore formation which takes place during the night, but he 
believed his investigations needed repetition. Miyake realized that 
conidia were deposited at night under these laboratory conditions and 
inferred that this was true in the field also, but apparently he did not 
appreciate that this occurs repeatedly night after night on infected 
plants, nor did he attempt to determine whether moisture, darkness, or 
other night conditions are responsible. 
DEVELOPMENT OE THE CONIDIOPHORES 
Whenever and wherever it may occur, however, the development of 
the conidiophores and conidia follows the same general procedure. As 
has been said above, it is apparently the covering of the surface of the 
maize plant with moisture which influences the Sclerospora mycelium 
within the tissues of the host to produce conidiophores and conidia. 
After the host surface is thus covered, the stout mycelial branches which 
are located in the intercellular spaces and in the air chambers beneath 
the stomata (PI. 7, G, H) begin to send out prolongations, several of 
which push through each partly closed stomatal pore (PI. 7, B, C, D) 
and give rise to a compact group of several simple or branched knob¬ 
like processes (PI. 7, E) which are closely appressed to the outer leaf 
surface, covering the stoma. From each of these knobs develops a cla- 
vate hypha (PI. 8, B, C), the main axis of the conidiophore, which in¬ 
creases rapidly in size (PI. 8, D, E) and finally forms at its apex the 
papillate buds (Pi. 8, J), which grow into the stout primary branches 
(PI. 8, K, M). As these extend they, in turn, form at their apices the 
paired protrusions which become the secondary branches (PI. 8, N); 
and in like manner the tertiary or even quarternary series of branches 
are developed (PI. 8, O) until finally from the ultimate tips arise the 
sterigmata. From the apex of each sterigma buds out a conidium (PI. 8, 
Q) which grows rapidly, beginning as a small, globular protrusion (PI. 
8, R, S) and passing successively in its development through globular 
pyriform, oval or ellipsoidal stages (PI. 9, A-I), until finally it attains 
the size and shape, usually rounded cylindric, of maturity, and is cut 
off from the sterigma by a wall (PI. 9, J, K, W). 
These successive stages of conidiophore development require several 
hours for their completion. The formation of the group of knoblike 
conidiophore initials is not completed until the surface of the plant has 
been covered with moisture for two to four hours; and the development 
of the conidiophore and conidia to maturity consumes about three hours 
