PAPERS ON BOTANY 221 
CULTURES 
In culture the fungus produces a colony which grows very 
rapidly. There is generally abundant, white or greyish, cot- 
tony, aerial mycelium (Plate III, Fig. 2) which covers a very 
large number of spores which are produced from the internal 
mycelium. The under side of the culture is dark, with num- 
erous more or less distinct concentric rings. The colony is in- 
distinguishable from those of a large number of Alternarias. 
Considerable variation is found when the fungus is grown 
on different media. Cornmeal gave a darker colored colony 
than bean (Plate III, Figs. 2, 3), and a rather more abundant 
growth. Unfavorable conditions caused the fungus to spread 
over a greater area but was much lighter in color and less 
abundant in growth and formation of spores. 
THE CONIDIA 
The conidia vary in length from 31 to 57 microns, the 
average being 43. These measurements do not include the 
beak. The end beak in a chain may be very long, while the 
spores within the chain may have almost none. The width of 
the spores was from 9 to 22 microns, the average being 3. 
Thus the spores are about three times as long as wide, not 
including the beak, They are almost always pointed and reg- 
ular in shape when just mature (Plate I, Figs. 3, 8, 9), but 
when they are old they become wider, misshapen, the beak 
disappears, and the cells become constricted (Plate I, Fig. 11). 
The normal spores are dark in color and have from four to 
eight transverse septae. In the young or just mature spores 
there are a few longitudinal septae, but when they become old 
and constricted there are many. The spores are borne in great 
numbers and are almost without exception in chains, the 
number in the chain averaging about twelve. From one or 
more of these spores a side chain may be produced, having as 
many more (Plate 1, Fig. 8). 
CONIDIOPHORES 
The conidiophores vary in length from 100 microns or 
more to less than 10. They are invariably dark colored and 
In most cases the cell next the first spore is enlarged slightly 
