242 PROCEEDINGS OF THE AMERICAN ACADEMY. 
flora of the archipelago. Altogether there have been 72 families! of 
flowering plants and ferns found on the islands. Of these families 39 
include endemic forms, and 33 contain only plants common to other 
regions. Excluding some indeterminate forms, there are 232 genera 
of pteridophytes and spermatophytes upon the islands. 
Notwithstanding the uncertainty with which some plants are here 
reckoned as species, and others as varieties or forms, the following figures 
regarding the plants of the Galapagos Islands will have an interest : 
Species. Varieties. Forms. Indeterminate. Total. 
Ferns 52 2 0 1 55 
Fern-allies 2 0 0 2 4 
Pteridophytes 54 2 0 3 59 
Spermatophytes 445 17 19 50 531 
Vascular plants 499 19 19 53 590. 
(>. 4 4 
Of endemic ferns there are only 3, that is, but 5 per cent. Of endemic 
spermatophytes there are 202 species, 15 varieties, and 19 forms, —a 
total of 236, that is, 44.4 per cent of the whole flowering flora. The 
total number of vascular plants which are endemic is 239, or 40.5 per 
cent. Of these endemic plants 130, that is, more than half, are con- 
fined to a single island. 
The ratio of (determined) species to genera is as 2.16: 1. 
The ratio of species, varieties, and forms to genera is as 2.55 : 1. 
It is noteworthy that, although there is such a high percentage of 
peculiar forms, varieties, and species, there is no corresponding peculiarity 
among the genera of these islands. Of the several genera which have 
from time to time been characterized as exclusively Galapageian, only 
two, Scalesia and Lecocarpus, are now maintained, while all the others 
have been reduced to genera of continental America, with the single ex- 
ception of Macraea, which falls into a genus of the Hawaiian Islands. 
Even Scalesia is not a strong genus, as it is not easy to show very sharp 
generic distinctions between it and some allied Helianthoideae in Mexico 
and Central America. 
1 This does not include the Rosaceae and Bignoniaceae, which rest, so far as their 
Galapageian occurrence is concerned, upon single and doubtful determinations. 
2 The statement of Darwin (2), 165, regarding the genera of Compositae, is, a8 
pointed out by Mr. Hemsley, quite erroneous, and must have rested upon some 
misapprehension of data furnished him. 
