The Testimony of the Endemic Species of the Canary 
Islands in Favour of the Age and Area Theory of 
Dr. Willis. 
BV 
H. B. GUPPY. 
M ANY botanists of eminence have interested themselves in the 
Canarian flora, and much has been written about it. An abundance 
ol materials is, therefore, at our disposal, enabling us to appreciate the 
methods followed in dealing with the endemic species and the standpoints 
adopted with regard to the problem of their origin. It is to these two 
subjects that the following remarks will be entirely devoted. 
Like most archipelagos that with other adjacent groups of islands go 
to form a separate floral region, the Canary Islands display a double 
endemism, the endemis‘m peculiar to the group and the endemism that it 
shares as a member of the floral region. There are the endemic species 
peculiar to the archipelago, the Canarian proper, and there are the endemic 
species which it holds in common with the other groups of the Macaro- 
nesian floral region, the Azores, the Madeiras, and the Cape Verde Islands. 
The true Canarian endemic species number about 400, whilst the 
Macaronesian species, which occur in other Macaronesian groups but' are 
not known from any other floral region, number about fifty. As far as 
my researches indicate, this disproportion is typical of insular floral 
regions. 
The Macaronesian endemics are far more generally distributed over 
the Canary Islands than are the Canarian proper. From the materials 
supplied by Christ and by Pitard and Proust it appears that wdiilst only 
8 per cent, or 10 per cent, of the Macaronesian endemic species have been 
recorded from one island only, between 60 per cent, and 65 per cent, of the 
Canarian endemics are only known from single islands. On the average 
the Macaronesian endemics occur in three or four islands (3*5), but the 
Canarian are found in only one or two (1*7). 
The following tables have been prepared by the writer from the work 
of Pitard and Proust : 
[Annals of Botany, Vol. XXXV. No. CXL. October, 1921.] 
