PHYSIOLOGY OF THE RED MANGROVE. 665 



The three species of Rhizophora are distributed over the world 

 in the following manner : R. mangle of the American tropics, West 

 Africa and the Pacific Islands ; R. miicronata in Japan to Australia 

 and East Africa, while R. conjugata is found throughout all tropical 

 Asia. In Japan, according to T. Ito/^^ there are three genera of the 

 family present, KandeUa, Bruguiera and Rhisophora with the nor- 

 thern limit of range 31° 20' N. Lat. This is the limit for any of 

 the mangroves in Japan, i. e., the forests in Satsuma, and indeed for 

 all Asia, it is of interest when a comparison is made for the northern 

 range limit in America, which in Florida is about 28° N. Lat. ; 

 exception here is made, how^ever, of the Bermudas which support 

 an Avicennia-RhicopJwra mangrove association. 



As mentioned above, Australia and the Malay Archipelago is 

 the southern limit of range in the eastern hemisphere. In South 

 America the range limits for R. mangle are for the west coast very 

 sharply defined. This is nothing but desert beach along the coasts 

 of Chili and Peru until the frontier of Ecuador is reached. The 

 Rhisophora shores begin at 4° 5' Lat. and are practically continuous 

 to the equator, except a sterile stretch north of Guyaquil, as noted 

 by Guppy. On the eastern coast of South America the mangroves 

 extend almost to the tropic of Capricorn. The stations and ranges 

 in North America have been carefully worked out by Professor 

 Harshberger.^°^ Rhhophora occurs in all the shores of the Greater 

 Antilles, Cuba and Mexico. In Guatemala there is only a strip occu- 

 pied by them along the coast. In Haiti and Santa Domingo, the 

 Virgin Islands and the Bahamas they go up into the bays and har- 

 bors, while the Florida Keys and the southern part of the Peninsula 

 are girdled with a thick mangrove formation. On the west coast of 

 the northern continent, the mangroves extend to Lower California, 

 the range limit being 24° 38' N. Lat., a little north of Matzatlan, 

 while Hawaii and Tahiti have no mangrove flora at all. Regarding 

 the presence of Rhizophora on the west coast of Africa, it is sup- 

 posed that R. mangle has reached those shores by migrating from 

 America, due to ocean currents. On the other hand, Guppy does 

 not regard the presence oi R. mangle in the Southern Pacific Islands 



^^s Ito, T., " Rhizophoreae in Japan," Annals of Botany, XHL, 465. 

 159 Harshberger, J. W., loc. cit., 145. 



