692 TKEES OF NORTH AMERICA 



febrifuge. The wood is hard, durable, and dark-colored. By means of the aerial 

 germination of its seeds and in its power 'to develop roots from trunks and branches, 

 Rhizophora is especially adapted to maintain itself on low tidal shores and is an 

 important factor in protecting and extending them into the ocean. Roots springing 

 from the stems at a considerable distance above the ground and arching outward 

 descend into the water and fix themselves in the mud beneath, while roots growing 

 down from the branches enter the ground and gradually thicken into stems. The 

 fully grown radicle ready to put forth roots and leaves, and often 10'-12' long, is 

 thicker and heavier at the root end than at the other, and in detaching itself from 

 the cotyledons and in falling the heavy end sticks in the mud, while the plumule at 

 the other end, held above the shallow surface of the water, soon unfolds its leaves. 



The generic name, from ta and Qepeiv, was used by early authors to designate 

 various climbing plants with thickened roots. 



1. Rhizophora Mangle, L. Mangrove. 



Leaves oval or elliptical, rounded or acute at the apex, gradually narrowed at the 

 base, dark green and very lustrous on the upper, paler on the lower surface, 3'-5' 

 long, 1/-2' wide, with slightly thickened margins, broad midribs, and reticulate vein- 

 lets, persistent for one or two years; their petioles ^'-1^' J n g; stipules lanceolate, 

 acute, \\' long, deciduous as the leaf unfolds. Flowers produced throughout the 

 year from the axils of young leaves, 1' in diameter, on stout 2 or 3-branched pedun- 

 cles l^'-2' long, with pale yellow petals coated on the inner surface with long pale 

 hairs, 8 stamens, and villose filaments. Fruit V long, rusty brown, slightly rough- 

 ened with minute bosses, the hard woody thick-walled tube developed from the 



cotyledons protruding |'-f' from its apex after the germination of the seeds, cov- 

 ering the plumule, and holding the dark brown radicle marked with occasional 

 orange-colored lenticels and when fully grown 10' -12' long and ^'-J' thick near the 

 apex. 



A round-topped bushy tree, with spreading branches usually 15-20 high, form- 

 ing almost impenetrable thickets with its numerous aerial roots or occasionally 70- 

 80 high, with a tall straight trunk clear of branches for more than half its length, a 

 narrow head, and stout glabrous dark red-brown branchlets, becoming lighter colored 

 in their second year and then conspicuously marked by large oval slightly elevated 



