104 
this vacuolated protoplasm which Brunchorst (loc. cit., Plate I, Fig. 
G) mistook for the plasmodia of his Spongospora. In the warts con¬ 
taining mature spore balls the hyphse are usually empty. The struc¬ 
ture of the spore balls was correctly understood and drawn by Brunch¬ 
orst (loc. cit., p. 221, Plate i, Figs. 4, 5), but they are not detached, being 
fastened to the surrounding liyplme of the pseudo-parenchyma. In thin 
cross sections one can easily see that this is so, and that very often, if 
not always, branches of the hyplme penetrate the interstices of the 
spore ball, fill them up, and are firmly united to the individual spores. 
According to this the development of the spore balls is quite different 
from the one stated by Brunchorst (loc. cit., p. 223). I did not meet 
with any early stages of the spore formation among my material. Ac- 
coiding to the structure of the mature spore balls it is presumable, 
hovevei, that they arise in the following way: Neighboring' hypha? de¬ 
velop upon the pseudo-parenchyma, and divide up into small cells which 
cling firmly to, and partly surround, the sporogenus hyphm. The outer 
membrane of the peripheral spores is not quite smooth, but seems 
grauulose. The size of the individual spores agrees with the statement 
made by Brunchorst. I have been as unsuccessful as Brunchorst in 
making the spore balls germinate. Until we understand their man¬ 
ner of germination it would be premature to assign the fungus to 
any definite place in the system of classification. Probably the libera¬ 
tion and germination of the spores results through the decay of the 
surrounding pseudo-parenchyma, Brunchorst mentions that the crusts 
are frequently eaten by insect larvae, and this seems to be the case here 
also. It is probable that the spores pass through these insects without 
sustaining any injury, and are distributed in this manner. It might 
prove of interest to make experiments in this line. 
In conclusion a few words may be said in regard to the correct name 
of the fungus. It seems to me that Spongospora solani Brunchorst is 
identical with a fungus long known and described by various authors. 
The name of this fungus is Erysibe subterranea Wallrotli (Linnea, 1842, 
p.332), Avhich is said to have the following synonyms: 
Protomyces tuberum-solani , Martius, Kartoffel Epid., 1842, p. 28, t n 
Figs. 9-13, t. hi, Figs. 36-38. 
Tubercinia scabies , Berkeley, Journ. Roy. Hort. Soe,, 1846, vol. i, p. 33, 
Figs. 30, 31. 
Sorosporium scabies , Fischer von Waldheim Aper. Syst. Ustil., 1877, 
p. 33. 
Unfortunately the publications of Wallrotli, Martius, and Berkeley are 
not accessible to me, which renders it impossible for me to decide this 
question. If my supposition be correct, the fungus should be called 
Spongospora subterranea (Wallr.). 
Microbiological Laboratory at Quito, June 24 , 1891 . 
