form the southern barrier of the saw grass, but they straddle a 

 most interesting transition zone where the water alternates 

 between fresh for half the year and salt for the other half, and 

 where a certain kind of palm (Paurotisj alone is found or can 

 thrive. Beyond the red mangroves comes a belt of the so-called 

 black mangroves, and then finally the white mangroves, which 

 march boldly out into the shallow, muddy sea waters and cover 

 all the offshore islands and some of the cays. The amazing thing 

 is that the distribution of the three species is determined by dif- 

 ferences of as little as four inches in the land level, for all of 

 them can grow in saline waters. 



Down at the southern tip of the United States, out on the sea 

 side of the mainland mangrove-stands, there are two quite 

 distinct and unique minor vegetational belts, caused respectively 

 by perpetual salt spray, and by occasional huracanes (the old 

 Spanish spelling of the Arawak name for these winds). The salt- 

 spray marshes are open areas covered with short, succulent 

 plants and various herbs, often with small bright flowers like 

 the sea daisy, and with some Sabal Palmetto. Behind this may 

 be seen from the seashore itself a rampart of most odd appear- 

 ance. This is a tangled mass of dead and starkly silver-gray, 

 gnarled and twisted trunks intermingled with masses of bil- 

 lowing bright green. These are the buttonwood trees that always 

 persist in growing right into the face of prevailing salt-filled 

 ocean winds but which always succumb to every hurricane that 

 comes along (about every forty years in each small locality) and 

 to being blown landward in a tangled mass by winds and waves. 

 Most of the big ones are thus killed, but the small ones and the 

 seeds survive and go right back to work, growing seaward again. 

 Under the buttonwoods are some hardy grasses that like saline 

 soil and the cactuses that so puzzle everybody. Here, however, 

 we are in the Northern Scrub Zone, so that only the slightest 

 elevation of this land would exterminate the mangroves and 

 bring in not northern growth or even saw grass but chaparral. 



But even here the hummocks continue, for they are but 

 ancient islands and the first pieces of land to have come up out 

 of the sea. They have a different plant growth. Inland, there 

 used to be quite a lot of a species of mahogany, but it has been 

 now mostly cut out, and the Park naturalists think that it is 

 dying out in any case because of changes in the land surface and 

 possibly the climate. On the more southern hummocks grow the 

 small soapberry trees, the leaves of which when crushed actually 

 form a thick lather; the gumbo-limbo, with a copper-colored 

 bark from which the essential ingredient of the original "gumbo" 

 soup was made; many strangler figs; and some old Caribbean 

 favorites like cocoplum and pigeon plum. Also flourishing is the 

 really deadly Cherokee-bean tree, with sparse, ordinary-looking 

 leaves, red flowers, and beanlike fruits that are a violent neuro- 

 toxin. In fact, one should not even brush against or place a hand 

 upon the trunk of this tree. This is not by any means the only 

 dangerous plant in the area, as we may see when we turn to 

 another just as deadly — the mangrove 



VEGETABLE MANTRAP 



Mangroves cover untold millions of square miles all over the 

 lower and flatter coasts of the tropics and subtropics wherever 

 continental alluvial silt exists. They do not do well on sandy or 

 other oceanic and sea-deposited coasts. While the mangroves of 



This impressive sight is the configuration of the bottom of 

 shallow seas covered by water almost as clear as the air. 



