Dec. 3, 1917 
Podblight of Lima Bean 
479 
The writer collected a quantity of Lima beans (pods and stems) at 
Vineland, N. J., in October, 1914, and January, 1915, which bore an 
abundance of pycnidia of the podblight fungus, generally known as 
Phoma subcircinata E. and E. After isolating the causal fungus the ma¬ 
terial was wintered out at Washington, D. C., and covered with leaves and 
dirt. On June 2 perithecia of the genus Diaporthe were found to be 
abundant on stems and pods of this material. The perithecia were 
scattered and buried in the tissue of the host except the beaks which 
were long and projecting and somewhat bent as shown by Plate 43, D. 
A pycnidial fungus was isolated from single ascospores which was iden¬ 
tical with the one isolated from the material before it was wintered out. 
Subcultures of this strain were used in inoculation experiments and pro¬ 
duced infections identical with that produced by subcultures from iso¬ 
lations of single pycnospores. This strain (known as 598), as well as 
others isolated directly from pycnospores, produced stylospores. The 
perithecial stage has never developed in culture. 
The perithecia produced on the wintered-out material varied in size 
from 158.0 to 355.5 /x, average 251.9 jt z; the asci 28.0 to 46.2 fx by 5.2 to 
8.0 fx t average 37.4 by 6.73 /z; the ascospores 6.4 to 12.0 /z by 2.3 to 4.0 fx, 
average 9.5 by 2.93 /z. The perithecia of type material varied in size 
from 158.0 to 237.0 fx, average 215.6 tx\ the asci 28.0 to 44.0 fx by 4.8 to 
8.0 average 33.6 by 7.0 /z; the ascospores 8.0 to 12.0 by 2.4 to 4.0 /z, 
average 10.0 by 3.3 fx. From the fact that the ascospores, asci, and peri¬ 
thecia together with other morphological characters of the two organisms 
are practically identical, it is concluded that they are the same fungus and 
should be known as Diaporthe phaseolorum (C. and E.) Sacc. 
MORPHOLOGY 
PYCNIDIAL STAGE 
From the point of infection the hyphae grow in all directions, invading 
practically all classes of cells except the bast, a layer of which (fig. 1, 
A, B, d) is found just below the epidermis. Figure 1, A and B, c , shows 
parenchyma cells traversed by the hyphae. Soon after the death of the 
cells the pycnidia begin to form, and develop very rapidly thereafter. 
The hyphal growth increases in the cavities below the stomata or in the 
intercellular spaces. From here it passes up between the bast cells which 
are often somewhat separated beneath the stomata. As growth increases, 
gnarls of hyphae accumulate under the stomata and between the 
epidermis and the bast cells (fig. 1, A, B, 6). From this point the fungus 
spreads out just beneath the epidermis and develops a more or less 
circular plate, the base of which rests on the bast cells. Figure 1, A, shows 
an early stage in the development of the pycnidial plate. As the fungus 
growth continues, the epidermis is gradually elevated (fig. 1, B, a) as the 
