155 
may have probably been their ancestors, or at any rate are of 
common ancestry ; the two exceptions have no known immedi- 
ate American relatives living. 
The restriction of these eleven or more species to Bermuda 
(and insular floras as is well known, are often, in large part, com- 
posed of endemic species) gives text for a consideration of the 
causes which effect the modification of a plant into a species dif- 
ferent from its parents; from the experiments and observations 
of de Vries and MacDougal, we no longer need believe that the 
hange must necessarily be a very gradual one, occupying 
thousands or tens of thousands of years ; a new species may be 
evolved from an old one ina saad ion and if organized 
so as to imate ne dispute the 0 y with its parent 
species, may survive and ultimately pee nee type which gave 
it birth. The aoe cause or causés which induce this 
mutation of species are as yet obscure, but the isolation of the 
offspring species from the ancestral one is clearly not necessarily 
one of them 
Let u e up the case of the Bermuda palmetto and follow 
briefly its Saale ancient history. A hurricane uproots a fruiting 
Floridian or Bahamian palmetto (Sada/ Palmetto) and carries it 
into the sea; the Gulf Stream carries the wreck northeastward, 
the winds cause it to drift more seaward and it is ultimately cast 
up in a marshy place upon the old Bermudian shore ; its fruits 
have maintained the life of the seed within them, and one or 
more of these seeds germinate, and grow into palmettos; either 
these original palmettos of Bermuda, or some of their offspring 
mutate ; the new palmetto is better adapted to the climate, or soil 
of Bermuda, or to both the climate and soil, and it survives, 
giving us Sabal Blackburniana instead of Sabal Palmetto. As the 
Bermuda tree is more elegant than its eine loyal Bermudians 
will doubtless rejoice that mutation has taken place and produce 
one of the most interesting plants of —e oe a feature which 
does not fail to attract the attention of all observant visitors. 
The natural acu dee of Bermuda, though in general uniform, 
are charming and indeed sufficiently varied to be thoroughly 
enjoyable; the ae hills, rising in places to above 250 feet, 
