664 BOWMAN— ECOLOGY AND 



Relation to other Organisms. 



The mangrove swamps of the western hemisphere are somewhat 

 different in appearance from the oriental forests according to the 

 descriptions given by writers of eastern tropical botany. The main 

 difference is seen in the absence in the western mangrove formation 

 of a large epiphytic flora, a few Tillandsias being about the only 

 plants which live on the branches of the RhisopJiora mangle (Fig. 

 3, PL VIII.), as is seen in the photographs taken in the Bahamas. 



Other plants associated with the mangrove, i. e., terrestrial, have 

 been given by Harshberger in the lists of species for the formation, 

 a great many of the species given there are rarely found in the 

 purer Rhisophora formations of the islands and mangrove keys, 

 but occur in the mangrove formation in the river hammocks. 



The animal life of the mangrove swamp is rather limited, also 

 several species of cranes, the pelicans and a few other species build 

 their nests among the low trees and thickets. The two forms most 

 closely associated with the Rhhopliora trees, however, are the crabs, 

 of which there are also several species, mostly hermit crabs, and the 

 oysters. The oysters, as mentioned in the old narratives of Labat 

 and Sloan, have always been found growing on the submerged prop 

 roots of the mangroves and their tangle of roots offers an ideal 

 place for their development, and an easily accessible means of col- 

 lecting them, a fact appreciated by the Seminoles, who use them for 

 food in considerable number. 



Distribution. 



The geographical distribution of the family, according to 

 Schimper, in Engler and Prantl,^^'^ is confined purely to the tropics, 

 and in the American tropics there as only two genera, Cassipourea and 

 Rhisophora. Of these, the former is indigenous to the West Indies, 

 Central and South America, and the latter is represented by only one 

 species, R. mangle, although, as remarked in the chapter on ecology, 

 there are other plants in the hemisphere which belong to the man- 

 grove association. 



157 Engler, A., and Prantl, K., " Die Natiirlichcn Pflanzenfamilien," III. 

 Th, 7 and 8 Abt., p. 58. 



