1897.] The Origin of the Galapagos Islands. 665 
From this paper I quote the following: “It is well known 
not only that the archipelago possesses a peculiar and remark- 
able vegetation, but that the different islands exhibit in their 
floras a striking individuality.” “While upon some of the 
smaller islands Dr. Baur collected only a few species, enough 
material is at hand not merely to confirm strongly the view 
that almost every island has its peculiar species and varieties, 
but to show clearly that even plants, which must pass as the 
same species, often exhibit, when found upon several islands, 
more or less striking racial differences. These facts, while in 
other respects noteworthy, derive a special interest from their 
relation to the probable origin of the flora of the group. Re- 
garding the fauna Dr. Baur has in several recent articles called 
attention to peculiar harmonic relations existing between the 
forms of the different islands, and has argued from zoological 
grounds that the islands must at one time been united, not only 
with each other but with the mainland near Central America.” 
“ This view has been severely criticised by several writers, but 
no one has attempted to account for the peculiar distribution 
of differing, yet closely related forms upon the islands, and as 
the subject is one which merits further attention, it seems 
worth while to present the botanical data in some detail. 
Perhaps no species to be found upon the different islands 
better illustrates the noteworthy racial divergence in related 
forms than Euphorbia viminia Hook. fil. This species differs 
markedly in foliage from any other known member of this 
large genus, and is characteristic of the Galapagos Archipelago. 
Being essentially a desert plant, it can subsist even upon those 
islands of the group which are of low altitude and do not attain 
the upper regions of moister atmosphere. It was first collected 
by Macrae upon Albemarle, rediscovered by Anderson on 
Charles, and has now been collected by Dr. Baur on the fol- 
lowing islands: Barrington, Chatham, Southern and Eastern 
Albemarle, James, Jervis, Bindloe, Tower and Abingdon. 
Even the most cursory inspection of the forms from these dif- 
ferent islands discloses marked variation in the contour, size, 
thickness, rigidity, and color of the leaves, as well as in the 
length of the intenodes, color of the stem, etc., while more 
