200 FUNGI. 
4icid. berberidis seemed more than ever probable. In about ten 
days the spermogonia appeared. After a time the cut leaves 
began to decay, so that the fungus never got beyond the 
spermogonoid stage. Some three-year-old seedlings were then 
taken, and the germinating resting spores applied as before. 
The plants were kept under a bell-glass from twenty-four to 
forty-eigkt hours, and then exposed to the air like other plants. 
From the sixth to the tenth day, yellow spots appeared, with 
single spermogonia; from the ninth to the twelfth, spermogonia 
appeared in numbers on either surface; and, a few days later, 
on the under surface of the leaves, the cylindrical sporangia 
of the .Wecidium made thcir appearance, exactly as in the 
normally developed parasite, except that they were longer, 
from being protected from external agents. The younger the 
leaves, the more rapid was the development of the parasite, and 
sometimes, in the younger leaves, tke luxuriance was far greater 
than in free nature. Similar plants, to the number of two 
hundred, were observed in the nursery, and though some of them 
had A¢cidium pustules, not one fresh pustule was produced ; 
while two placed under similar circumstances, but without the 
application of any resting spores, remained all the summer free 
from Atcidium. It seems, then, indubitable so far that Aiczdium 
berberidis does spring from the spores of Puccinia graminis. 
It has, however, to be remarked that De Bary was not equally 
successful in producing the Pucecinia from the spores of the 
Aicidium. In many cases the spores do not germinate when 
placed on glass, and they do not preserve their power of germi- 
nating very long. He reverts then to the evidence of experi- 
merts instituted by agriculturists. Bénninghausen remarked, in 
1818, that wheat, rye, and barley which were sown in the neigh- 
bourhood of a berberry bush covered with A’cidium contracted 
rust immediately after the maturation of the spores of the Acidia. 
The rust was most abundant where the wind carried the spores. 
The following year the same observations were repeated; the 
spores of the Aicidium were collected, and applied to some healthy 
plants of rye. After five or six days these plants were affected 
with rust, while the remainder of the crop was sound. In 1863 
