ORDER RHIZOPHOREJ2, OR MANGROVE TRIBE. 431 



joining figure. The calyx in this order is formed of from 4 to 

 13 adherent sepals ; and the petals are equal in number to the 

 sepals, and are inserted upon them. The number of the stamens 

 is double or triple that of the petals. The ovarium is two-celled, 



being formed by the union of 

 two carpels, which have sepa- 

 rate cells ; and each cell con- 

 tains several ovules. But in 

 the ripe fruit, we find but one 

 cell and one seed, this having 

 been developed at the expense 

 of the others. These seeds are 

 peculiar on account of their 

 power of germinating whilst 



FrfG. 157- PARTS OF THE FLOWBR OF MAN- . . . . . 



GROVE. A, the fruit, seated upon a calyx of 7 et Wlthm the Seed-VCSSel. 



four sepals, and surmounted by two styles. phe final CaUSC Or purpose of 

 U, a 'flower cut open, showing four petals ... ... 



alternating with four sepals, (the latter being this Singular provision IS CV1- 



**, when the circumstances 

 under which the tree grows 

 are considered. "Were they to be shed as seeds usually are, they 

 would fall into the water, and be carried by the waves of the 

 sea, or by the currents of the rivers, on the margins of which 

 they live, far from any place that is fitted for their growth. But 

 by the long radicle perforating the seed-vessel, the seedling plant, 

 when dropped, becomes fixed in the swamp ; and thus forests of 

 Mangroves are formed of vast extent, unsafe to be trodden by 

 human foot, but over which the savage natives pass, leaping or 

 climbing from root to root for many miles, without once daring 

 to trust their weight upon the treacherous marshy ground. 

 These swamps continually encroach on rivers, lakes, and seas ; 

 for the network of roots intercepts and collects all the solid matter 

 brought down by the rivers ; and, as a large part of this consists 

 of decomposing vegetable matter, the Mangrove swamps are 

 peculiarly unhealthy to human beings, who are very liable to 

 suffer from pestilental fevers, if too long exposed to their emana- 

 tions. "When the roots of the Mangroves in such places are left 

 bare by the ebb of the tide, they are seen to be covered with 



