MANGROVE FAMILIES, RED AND WHITE 157 



mangrove, Rhizophora Mangle, forms impenetrable bar- 

 riers of arching stilt-roots below, and interlaced branches 

 above from which hangs the extraordinary fruit. The dull 

 yellow leathery flowers, of four sepals and four petals, 

 are not conspicuous, but the fruit is remarkable in that 

 the seed germinates several months before it falls from 

 the tree. From this strange fruit the stout radicle pro- 

 trudes downward in such a position that, when the fruit 

 falls, it sinks into the mud and thus sets out the young 

 plant in the most favorable conditions for continued 

 growth. Spreading in this way year after year around 

 the parent trees, mangroves reach water too deep for 

 growth, and then the fallen fruit floats away to other 

 shores, and new colonies are started. The leathery oppo- 

 site leaves are two to six inches long. 



The white mangrove, Laguncularia racemosa, a tree 

 with opposite leaves, one to two inches long, has flowers 

 of five sepals, five tiny petals, and ten stamens. The 

 leathery fruit is not quite an inch in length. Narrow 

 upright growths from the roots, which are believed to 

 aerate them, aid in land-formation by holding, as do the 

 roots of other mangroves, all manner of debris that is 

 washed in by the tides or out by the rains. 



The button-mangrove, or buttonwood, Conocarpus 

 &recia, has alternate leaves, one to two inches long, 

 pointed at each end, and minute flowers in short racemes, 

 which later form a cone-like fruiting-head barely half an 



inch long. 



Mangroves of three different families grow on our 

 shores, often intermixed, and often in large areas of but 

 one species. The black mangrove, whose petals are united, 

 is described in the verbena family. 



The name mangrove is sometimes restricted to species 

 of Rhizophora, the true mangroves, which are not related 

 botanically to the other trees and shrubs of similar habitats 

 that are locally known by that name. 



