; 
a 
; 
i 
: 
! 
1887. | BOTANICAL GAZETTE. 183 
flora has been most thoroughly studied, we find few species 
of Phanogams which are not already known to be attacked 
by some special parasite, while the majority of species serve 
as hosts for a considerable number of species of fungi. 
few figures will show this point clearly. In his treatise on 
the fungi which attack the species of Vitis, published in 1879, 
Pirotta enumerates one hundred and four species of parasites. 
Between ten and twenty of these are fungi not found on Vitis 
alone, but this number is more than counterbalanced by spe- 
cies peculiar to Vitis which have been described since 1879. 
It may be objected that some of the forms called species by 
Pirotta are probably merely stages of some of the other spe- 
cies enumerated. Admitting that this is possible, and even 
probable, if we deduct half, or even two-thirds, which is lib- 
eral to the last degree, we still have thirty to fifty species 
of fungi, at the lowest estimate, which are peculiar to six 
species of Vitis, the number of species of the genus included 
in Pirotta’s observations. I have little doubt that the real 
number of species of fungi peculiar to the genus Vitis is much 
larger than the estimate I have just given. If the relative 
number of species known to occur on Vitis is greater than 
that of those known on most other enera, it is due rather to 
the fact that, from their importance in horticulture, they have 
been more carefully studied than because other genera are 
less frequented by special fungi. ; ; 
€ province of Venetia is probably no richer in fungi 
than other parts of the world; but, as it is of small size and 
is the residence of a considerable number of mycologists, its 
flora has been more thoroughly studied than that of this coun- 
try, and we can obtain a more accurate view if we examine 
Statistics of the Venetian flora. Cuboni and Mancini enumer- 
ate sixty-five species of fungi which occur on the chestnut, 
and over three hundred species on Quercus, including three 
native species of that genus. If we deduct a large number 
or species which are not found exclusively on these two 
senera or which are merely secondary forms of other species, 
We still have a considerable number of fungi to a small num~- 
er of Pheenogams. Turning to the American flora, we find 
that the species of a genus as erratic as Sarracenia are not 
without their proper parasites ; for on four species 0 Sarra- 
cenia we already know four species of fungi, three of which 
are peculiar to the genus. The list of fungi which grow on 
Saks in the United States includes between five hundred and 
‘ix hundred species. The greater part, however, are not 
