Bahaman Region: Insular Area. 689 
trees, which are found as a scrubby coppice growth. The arid condi- 
tions, which generally prevail, are due to the porous rock which prohibits 
the appearance of living streams of water and to occasional periods of ex- 
cessive drought. Salt lakes and marshes abound and mangrove swamps lend 
variety to an otherwise monotonous landscape. There is little or no soil, 
but the eolian rocks are fairly honeycombed with holes, pits and cavities of 
all sizes; often sharp, jagged points project, making walking difficult. 
Such environmental conditions, however, have occasioned corresponding 
adaptations of habit and structure in the plants of the region. The plants of 
the sand dunes, salt marshes, mangrove swamps, rock surfaces pos- 
sess many interesting and peculiar adaptations. According to COKER, for 
example, the old leaves of Rhisophora mangle become much thicker and 
change their function from photosynthesis to water storage. 
a) Insular Area. 
This corresponds territorially with the archipelago of islands and cays. 
Our knowledge of the flora of these islands has been extended recently by 
the expeditions under the auspices of the New York Botanical Garden and 
the Geographical Society of Baltimore‘), The author visited the group for 
botanic purposes at Great Inagua in the summer of ı901. The following for- 
mations have been recognized and may be described in the pages that follow. 
Beginning seaward with the Strand Formation of the several islands 
and cays, the following associations may be recognized: Ipomoea pes-caprae 
Association. On the south side of New Providence, /fomoea pes-caprae is 
by no means abundant and where it does not occur its place is taken by 
grasses: Paspalum : vaginatum and Sporobolus virginicus. This grass strip, 
according to COKER, varies from ı to 10 feet, beginning at high-water mark 
and running back. Ä 
The Uniola-Tournefortia Association in New Providence occupies 
the gently sloping, or in some places quite level, sandy strip that extends to 
the scrubby coppice behind. Uniola paniculata is scattered at intervals with 
large clumps of Tournefortia gnaphaloides, Scaevola Plumieri, together with. 
Suriana maritima, Salmea petrochioides, Strumpfia maritima, Borrichia glabra, 
Ambrosia hispida (in open spots), Seswvium portulacastrum. On the eastern 
beach of Eleuthera there are dunes go feet high. The beach at the foot of 
the dunes is covered at high-tide mark by Uniola, Tournefortia, Iva imbri- 
‚eata, Cakile aegualis, behind which is a fringe of tall Suriana with which is 
mixed Salmea and Cenchrus tribuloides. Scattered individuals of Agave rı- 
1) NORTHROP, AuıcE: Flora of New Providence and Andros. Memoirs BE N 
Club XII No. I, pages I—98 Dec. 1902; BRITToN, N. L.: Report.on Exploration of the DABEIDER: 
Journal New York Botanical Garden V: 201, Nov. 1904; Nast, Geo. V.: Botanical N 
the Inagua Islands, Bahamas, do VI: 1. Jan. 1905; CoKErR, W. C.: Vegetation of Bahama Islands. 
The Bahama Islands 1905: 185—270 see Bibliogr. pp. 87—92. 
Harshberger, Survey N.- America, a 
