442 
B. B. HIGGINS 
Cultures obtained from single ascospores were grown on steamed green 
bean pods, bean agar, steamed Irish potato plugs, steamed sweet potato 
plugs, and corn meal mush, in comparison with cultures obtained from the 
Cercospora conidia. The resultant colonies were similar in every particular 
of shape, size, coloration, and general development, and neither produced 
spores of any sort. 
The facts that no spores were obtained in cultures and that the old 
mycelium from cultures failed to produce infection made inoculation with 
pure cultures very difficult. Infection with the production of spots and 
Cercospora spores was obtained several times by crushing perithecia, con- 
taining mature ascospores, in a drop of water which was placed on the under 
surfaces of fig leaves in the greenhouse, the plants being kept under bell 
jars for a few days; but one could not be positive with this method that 
some conidia had not been included with the perithecia. It was therefore 
necessary to devise some method for inoculating with ascospores of known 
purity. For this purpose the idea of isolating in agar single spores or single 
asci containing germinating spores was hit upon. 
On March i6, 1916, perithecia containing mature ascospores were 
crushed and plated out in agar. The next day ascospores and asci contain- 
ing spores were located with a microscope and their position was marked. 
The spore or ascus, with a surrounding block of agar, was then lifted out 
with a sterile scalpel and transferred to the surface of sterile agar in another 
plate. These transferred blocks were examined under the microscope at 
intervals for two days, and only those blocks which showed no contaminating 
organism were used in making inoculations. Eight such blocks were then 
transferred to the under surfaces of leaves of fig plants grown in the green- 
house from potted roots. Two typical spots resulted, and at the end of two 
months Cercospora spores were abundant on these spots. The experiment 
was repeated on April 10, and four spots developed in a similar manner. 
While the percentage of infection was small, there can be little doubt 
that the infections were produced by the ascospores, since there was no 
possibility of Cercospora spores being present on the leaves and the checks 
receiving blocks of sterile agar developed no spots at all. The agar prob- 
ably held the spores so far from the leaf surface that the germ tubes had 
in many cases lost their power of entering the tissue before reaching the 
leaf surface. Abundant infection always resulted when the ascospores 
were placed directly on the leaf surface. 
Systematic. The structure of the perithecia, together with the eight- 
spored asci lacking the apical pore and the two-celled, hyaline spores, 
places the fungus unquestionably in the genus Sphaerella Ces. et de Not. 
So far as the writer has been able to find, no similar Ascomycete has been 
described as occurring on the leaves of the fig; and since — from the nature 
and sequence of development of the stages of the fungus — it is not likely 
to occur except on leaves parasitized by the conidial or Cercospora stage, 
describing it as a new species seems justified. 
