240 SEA AND LAND 



roots in salt water and wliich have indeed developed a variety 

 of remarkable structures favoring- their life in such positions. 

 These species are commonly known by the name of mangroves. 

 Of the many thousand species of trees there are probably less 

 than a dozen which have effected this curious adaptation ena- 

 blinof them to dwell on lands below hiofh-tide mark. Thouoh 

 these forms are few, there being but two species known in this 

 country, the part which the\' pki)' in the history of the harbors 

 in the warmer parts of the continent is most important. The 

 work which the}' do in m()dif)-ing the inclosed marine waters 

 is even greater than that effected by the salt-loving grasses 

 which flourisli in colder climes. It will therefore be well for us 

 to trace, somewhat in detail, the way in which the mangrove 

 attains its peculiar development. 



The seed of the mangrove is remarkably large and is a 

 slender cxlinder, tapering at either end and about six or eight 

 inches in length. The lower extremity is armed with a number 

 of small booklets, and is so weighted that when the seed falls 

 into the water, as it normally does when it parts from the parent 

 stem, it floats beneath the surface in a nearh' vertical position. 

 As it absorbs water it settles near the bottom, so that when 

 driven around b\- the currents it is likely to become attached to 

 a bit of seaweed or other object lying on the floor of the harbor. 

 Thus fixed it quickly takes root and sends its shoot towards the 

 surface of the water. If that surface be only a foot or so away 

 at low tide it ma\- manage to obtain access to the air, subsisting 

 the while (mi the considerable store of nutriment contained in 

 the relatively large seed. Rising above the surface of the sea, 

 it soon develops its first leaves and establishes the crown or 

 point between tlie roots and stem at about high-water mark. 

 Above this level the trunk and folia'-e much resemble the India- 



