Southern Extension of North American Flora. 333 
these figures will have to be considerably altered because of a large number of 
new species of West Indian affınity found there. The close relationship of the 
flora of the Florida hammocks, or everglade keys to that of the West Indies is 
now established by the fact that considerably more than one half of the species 
found on the islands south of Miami are also native in Cuba and the Bahamas. 
It is interesting to note that some of the genera cited above, as marking 
the transition from tropic to sub-tropic United States, also extend into extra 
tropic South America, namely to Argentine. Those cited by ENGLER') are 
Arnithamnia, Bignonia, Lippia, Chaptalia and Galphimia, to which may be 
added many amaranths and others. 
We have given by MOHR?) some accurate statistic data as to the relation- 
ship of the flora of Alabama to those of the West Indies, Mexico and South 
America. Not less than 290 genera containing nearly 40 per cent of the 
plants indigenous to the Alabama flora are represented in the West Indian 
islands, Mexico, Central America and more rarely in South America, as far 
south, as Argentina. On the western coast of the continent, but a few genera 
occur which also occur in Alabama. About 140 species are common to 
Central America, Mexico and the West Indian islands. This relationship is 
most evident between the coastal plain flora and the flora ofthe more elevated 
regions of tropic America with climatic conditions somewhat similar to those 
prevailing in southeastern North America. The flora of the sub-tropic regions 
of Alabama exhibits, according to Mohr, the features of the vegetation of the 
neighboring tropics by the presence of a few genera of epiphytes, Tillandsia, 
Epidendrum, Polypodium. A stronger tropic character in this flora is afforded 
by the presence of the dwarf palmettos, Sabal, Serenoa, while the deciduous-leaved 
trees are represented by ten genera common to both regions. The slash pine or 
Cuban pine Pinus heterophylla (= P. caribaea, P. bahamensis, etc.) extends from 
the West Indian islands to Honduras; Tarodium inhabits Mexico and the savin, 
Juniperus barbadensis the West Indies with other species of Funiperus in Mexico. 
The following plants common to the southern United States and Venezuela 
have been listed by A. ERNST?) of Caracas. The enumeration of the species 
IS derived from the observations of Ernst compared with CHAarMan’s Flora 
(New York 1860) 
BER Number of species t 
Divisions u Carus Mor In Venezuela | Per cen 
 Apopetalae .. ... 768 81 10.55 
Gamopetalae .. 935 90 9.63 
Apetalae ...... 236 36 15-25 
ymnospermae... 20 AS 2 
Monocotyledoneae . 655 60 9.16 
Cryptogamae .... 70 16 22.85 
Totals 2684 283 10.54 
1) ENGLER, A.: Entwickelungsgeschichte ı1: 189. 
2) MoHR, CuarLes: Plant Life of Alabama. P. 41. la. Journal 
“ B Ernst, A.: On the Plants common to the southern United States and Venezuela. 
otany British and Foreign V: 200-296. 1867. 
