O52 Emerson: MACROPHOMA AND DIPLODIA 
ning. In spite of such good growth pycnidia develop slowly and 
sparingly on potato but very freely on cocoanut pith. It was not 
possible to obtain young healthy cocoanut plants which could be 
inoculated with pure Macrophoma in order to prove whether it 
was parasitic or simply saprophytic. When fresh leaves from a 
greenhouse were used for inoculation, moulds and other fungi 
which were already established quite prevented the Macrophoma 
from growing at all. 
In the development of the fungus, first a white film of my- 
celium spreads quickly over most of the medium ; in about a 
week parts become dark green and gradually black, and in ten 
days to two weeks from the sowing the pycnidia are formed. 
On cocoanut pith, bread or potato cultures these were often 
quite above the substratum, even as early as eight or nine days 
from the sowing, when they looked like tiny green bubbles cov- 
ered with hyphae. Even in this immature condition the Macro- 
phoma spores were abundant; being pale green, granular and 
often containing what appeared to be oil-drops, and seeming to 
have more abundant contents than those from maturer pycnidia. 
In a damp atmosphere the Macrophoma spores are apt to come 
out of the mouth of the pycnidia and form a white mass. No 
spores which resembled conidiospores were noticed, but there were 
several other forms which seemed to be sclerotial or resting in 
their function. Soon after the green color came in a culture, om 
examining the mycelium it would be seen that a few cells or as 
many as eight in a hypha had become round or oblong, thick- 
walled, brown, sometimes quite rough, 25-294 x 8-18 /. They 
germinate very readily, putting out several tubes from one Spore 
(FIGURE 4). Sometimes two of these will cling together and the 
two might easily be mistaken for a Diplodia spore. Around the 
outside of the pycnidium there is apt to be a mass of empty tWO- 
celled bodies, one cell being slightly smaller than the other, a5 in 
a Puccinia teleutospore. Possibly they are merely short, swollen 
hyphae similar to the cells which make the outside wall of the 
pycnidium. 
From the time the cultures were first obtained pure it was evi- 
dent that the growths of Macrophoma and Diplodia were very much 
alike, as had been suspected from their close association and the 
