BULLETIN OF THE BUSSEY INSTITUTION, 415 
No. 22.— On the American Grape-Vine Mildew. By W. G. 
FARLOw, Assistant Professor of Botany in Harvard 
University. 
THERE are, probably, no plants in general cultivation in this country 
which are attacked by a greater number of fungi, or rather by fungi 
to which a greater number of names has been given, than the different 
species of grapes. We have under cultivation not only our native 
species of Vitis with the fungi peculiar to them, but also the imported 
varieties of Vitis vinifera, accompanied, also, by their own special mala- 
dies. In his List of the Plants of North Carolina, Curtis enumerates 
no less than eighteen species of fungi found exclusively, or almost exclu- 
sively, on species of Vitis; and to this number might be added others 
which, although common on grape-vines, are also found on other 
plants. It is a mistake to suppose, however, that the species enumer- 
ated are all really distinct from one another. On the contrary, the 
genera, Phoma, Diplodia, Septoria, and others are nothing but 
secondary forms of genera of Ascomycetous fungi, of which several 
representatives, Rhytisma Vitis, Schw., Tympanis viticola, Fr., Dia- 
trype viticola, Schw., Valsa Vitis, Schw., and others are found on our 
grape-vines ; and it may appear, in the end, that the supposed variety 
of fungi is not so great after all; but, like the bill of fare presented by 
the obliging waiter, nothing more than ram, lamb, sheep, and mutton. 
We are, as yet, in ignorance as to exactly which of the ascigerous forms, 
the secondary forms belong, and, until we have a more complete knowl- 
edge of the subject, distinct, specific names will still continue to be 
given to the latter. It is to be hoped, however, that, the time is not 
remote when we shall have such a knowledge of the development of the 
different fungi which are found on the grape, as to enable us to dis- 
pense with the superfluous specific names which represent, as it is, our 
ignorance rather than knowledge. . 
The grape disease, properly speaking, that which has proved so 
disastrous at different times to the vines in Europe and Madeira, is 
caused by a fungus to which Berkeley has given the name of Oddium 
Tuckeri. All we know of this fungus botanically is, that it is the 
conidial form of some species of Ascomycetes, probably some Erysiphe. 
The perfect fruit has never been found on the vine in Europe. The 
