The Mangroves 



forming almost impassable stretches of arching roots, accum.u- 

 lating rubbish of all sorts that finally lifts the level above the 

 tide and makes solid ground that is soon covered with the char- 

 acteristic vegetation of the tropics. Mangrove islands of varying 

 sizes now dot the surface of shallow bays which a few years ago 

 were quite destitute of islands. 



The tree reaches its greatest height on dry ground back 

 from the coast. Here the trees grow tall and bare of limbs for 

 two-thirds of their height, and almost abandon the habit of 

 throwing down aerial roots. The wood is used for fuel and built 

 into wharfs. It is not counted a valuable tree. 



The White Mangrove, or Buttonwood (Laguncularia race- 

 mosa, Gaertn.), is not a true mangrove at all; it belongs in a 

 different botanical family, and is related to the aralias. It 

 mingles with the mangroves, but lacks the aerial roots character- 

 istic of the latter. The foliage is red when it unfolds, becoming 

 dark green and glossy. The flowers are small, in axillary spikes. 

 The fruit is a flask-shaped, i -seeded drupe with corky flesh and 

 leathery skin. The wood is hard and dark brown, except for the 

 wide white sap wood. The bark is rich in tannic acid, and were 

 the trees located in less miasmic regions they would soon be cut 

 down for the bark alone. 



The buttonwood the Floridian esteems as a fuel tree is 

 Conocarpus ereda, Linn., whose flowers and fruits are button-like. 

 It is also esteemed for its bark which yields tannin and a tonic 

 drug. 



The Black Mangrove {Avicennia niiida, Jacq.) is an ever- 

 blooming tree, with inconspicuous white flowers and a dry, i- 

 seeded capsule, i to i J inches long. The leaves resemble those of 

 the true mangrove in form, but have a grey-green colour. The 

 tree's habit enables it to make soil in much the same way. The 

 seeds germinate before they fall, and are ready to root as soon 

 as they lodge in the mud. The roots of the adult trees extend far 

 out and, branching, send up a grove of leafless projections a foot 

 or two above the tide level, thus forming a network that holds 

 the soil, and soon makes land out of what was a tide-swept marsh. 

 No aerial roots strike downward from the branches of this tree. 



The bark of the black mangrove exceeds that of Laguncularia 

 racemosa in value to tanners. It is certain that were the trees 

 located in more accessible regions, on solid ground instead of 



402 



