26 Proceedings 
the name of Erysiphella Carestiana, as growing on the 
pileus of another fungus, viz.: Homes fomentarius, one of 
the Polyporea. This was simply P. cory/ea again. In this 
case after the re-attachment had taken place, the append- 
ages had become broken off, so that the fungus was put 
into a wrong genus. 
In Uncinula, the other genus in which the reversal of 
the perithecium takes place, no special outgrowths occur, 
for the purpose of re-attaching the perithecium, but this 
function is performed by the apices of the appendages. 
When the perithecium becomes turned over, the walls at 
the apex of some of the appendages become somewhat 
mucilaginous and finally fixed to the surface of the leaf. 
Again this phenomenon has caused disaster to system- 
atists. In 1893, an American botanist described an Unei- 
nula from the U.S. as U. Columbiana, and described it as 
growing on the leaves of a Scute//laria. The fungus was 
really only the old and well-known species, U. Sadicis, 
which grows on willows and poplars. Perithecia of this 
species had merely fallen off from some tree or shrub of 
poplar or willow near, and become affixed by its append- 
ages to the Scutellaria. 
Further, in 1899, a Swedish botanist, Vestergren, des- 
cribed as a new strange variety of the same species, U. 
Salicis, a fungus under the name of U. Sadicis var. Eptlobit, 
growing on Efpilobium angustifolium. Again, this proved 
to be founded merely on perithecia of U. Sadicis, which 
had become attached to leaves of the Zpilobium. 
Lastly, Sredinski has lately described as a great novelty 
U. Salicis, occurring on Ivy. There is little doubt that 
here also the same error has been made, that the Uncinula 
is not, as supposed, really parasitic on the Ivy. 
Now, why do the perithecia become reversed and re- 
affixed? No one knows. 
Until the explanation has been found, it may be feared 
that at some time some one will start a theory that Nature 
has planned it all for the express purpose of leading sys- 
tematists into error, and that a law exists, comparable to 
the physical one, viz.: “that Nature abhors a systematist !” 
