- 
6 Rhodora JANUARY 
is the case for most florae. I think that this source of probable error 
may be discounted without any considerable concern. Of these 551 
species, etc., 136 are credited only to the north of Cape Cod, 113 only 
to the south of it, while 302 are credited to both sides of it. In other 
words, species, etc., exclusively north amount to about 24.5 per cent. 
of the whole number, those exclusively south to about 20.5 per cent., 
and those passing the Cape in one direction or the other to nearly 55 
per cent. 
The first interest naturally centers in the 302 species, or approxi- 
mately 55 per cent. of the whole number of species concerning whose 
exact nature as to whether they may belong more normally with the 
northern or with the southern group it is desirable to have farther 
information. Careful examination into the details of occurrence of 
these species enables one to separate them into their respective 
groups, only 12 being clearly uncertain and needing more careful 
study from this point of view to determine their exact status. By 
removing from the 290 species remaining, those which occur south only 
in colder waters or which appear or fruit only in the colder seasons, we 
are able to feel certain that 132, or about 43 per cent. of those generally 
distributed, are normally northern species. Adding these 132 to the 
136 species found only north of Cape Cod, there result 268 which may 
perhaps seem normally northern. On the other hand, if, in a similar 
way there are removed from the 302 generally distributed species, the 
12 doubtful ones and then those which occur north only in the warm 
spots or warmer situations, there are found to be 158 of these and this 
number added to the 113 which are credited only to the south of Cape 
Cod gives 271 as presumably normally southern. These figures seem 
to indicate that the number of species, varieties, etc., is approximately 
the same for each flora. 
It might seem that the figures given above were sufficiently accurate 
and explicit to indicate the exact nature of the situation on the coast 
of New England, but a careful consideration of the details of the 
conditions under which the species accredited only to the north exist 
there, shows that 37 of them occur in warm localities and are presum- 
ably to be considered as normally southern. ‘Probably they will be 
found south of the cape at some future date. As to why they have 
not as yet been found south may be due to several reasons, viz. in- 
complete exploration, lack of suitable habitat, scarcity, ete. It must 
be borne in mind that the shores south of Cape Cod are more largely 
