4 
228 Part III. Chapter 3. 
the present Bahama group of islands is of very recent geologic history, the 
last uplift being placed not earlier than the late Tertiary by BRITTON') and 
others. The flora clearly of the Bahamas and that of Florida is of southern 
derivation, a large number of the known indigenous species, as before shown, 
being common to the near by and older islands of Cuba and Haiti, while 
many of the species are closely related to plants from these islands. The 
chief agents in the introduction and distribution of the plant populations of 
the Bahamas and Florida being migratory birds, supplemented by winds and 
ocean currents. Notwithstanding the geologically short period that the Baha- 
mas have been above the sea, they have witnessed the evolution by mutation 
or otherwise of numerous species, there being many endemic plants known 
and many more will be made known, as the result of the recent explorations. 
Many of these, it is believed, will prove to be examples of rapid evolution. 
The tropic flora of southern Florida then is represented by species that mig- 
rated into Florida since the last upheaval of the present Bahama chain of is- 
lands. The modern flora of southern tropic Florida essentially consists of the 
recent introductions which have undergone mutation into new forms. Emp- 
hasis should at this point be made of the fact that the agencies enumerated 
above were at all times, whether in the Eocene, or Pleistocene, instrumental 
in the migration and intermingling of plants, although the land bridges also 
afforded an easy means of access into an area connected by such a bridge 
with another land mass possessing a richer flora. Of the 492 plants common 
to the Bahamas and the United States, there are 40 previously enumerated 
that are only found in these two regions. Such plants as Myrıca cerifera, 
Vitis rotundifolia, Rhus Blodgeti, Eragrostis Elliotii and Baccharis angusti- 
Jolia have in all probability migrated from the mainland to the Bahamas. 
Dividing these islands into two groups, the first or northeastern, according t0 
COKER, comprises Andros, New Providence, Abaco, Great Bahama, Berry 
islands and surrounding cays, and the second, or southwestern group, consist- 
ing of Eleuthera and all the islands south of it”). It will be seen from the 
above list that all, except eight of the plants confined to the United States 
and the Bahamas are found only on the northwestern group. Analyzing the 
figure 492, we find that 322 species are common to the Bahama islands and 
southern Florida and 170 species are common to the Bahamas and the southern 
United States. Selecting a representative number of plants the following 
species found in southern Florida also occur in the Bahamas. Those 
marked by an asterisk(*) occur in Cuba; those with two asterisks(**) in the 
Greater Antilles; those with a cross (F) in Mexico and Central America, while A 
those with a paragraph ($) in South America. 
ı) Brırton, N. L.: A botanical Cruise in the Bahamas. Science new ser. XXI: 628. April 21 
1905. 
2) CoKER, WıLLlam C.: Vegetation of the Bahama Islands. 1905: 194—198. Extracted from 
publication The Bahama Islands of the geographical Society of Baltimore. i 
