14 SILVA OF NORTH AMERICA. RHIZOPHORACES. 
conjugata,' is Indian ; and the third, Rhizophora mucronata, is found on the west and east coasts of 
Africa, on Madagascar, in southern Asia from Arabia to the Malay peninsula, in the East Indies, New 
Guinea, Australia, and the South Sea Islands. 
Rhizophora possesses astringent properties ; the bark of all the species has been used in tanning 
leather, in dyeing, and as a febrifuge ;° and the wood is hard, durable, and dark-colored. Rhizophora 
is especially adapted to maintain itself on low muddy tidal shores, and plays an important part im 
protecting and in extending them into the ocean ; this it is able to do by the aerial germination of the 
seeds and by the power to develop roots from the trunks and branches. Of these some spring 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 other roots growing down from the branches enter the 
ground and gradually thicken into stems, the whole forming a barrier which prevents the mud washed 
up by rising tides from being swept away again, and gradually consolidates it. The structure and 
character of the seed are wonderfully adapted to aid in this extension of the land into the water. The 
aerial germination protects it from the salt water, into which, without such a provision, it would fall, 
probably to be washed away or destroyed. The radicle, when fully grown and ready to put forth roots 
and leaves, is often ten or twelve inches long; the root-end is thicker and heavier than the other, so 
that when it detaches itself from the cotyledons and falls, the heavy end sticks into the mud; here 
being kept in position, it puts forth roots, while the plumule at the other end is held up above the 
surface of the shallow water and is thus enabled to unfold its leaves. 
The generic name, from pi~a and @épev, used by early authors to designate various climbing 
plants with thickened roots, like Dioscorea,* was adopted for the Mangrove by Linnzus, who discarded 
the earlier Mangles of Plumier.? 
1 Linneus, Spec. 443 (1753).— De Candolle, Prodr. iii. 33.— Fi. Trop. Afr. ii. 407. — Brandis, 1. c. 217. — Kurz, I. c. — Hooker 
Walker-Arnott, Ann. Nat. Hist. i. 363. — Blume, Mus. Bot. Lugd.  f.1.c. — Baker, Fl. Maur. & Seych. 109. 
Bat. i. 134. — Brandis, Forest Fl. Brit. Ind. 218.— Hooker f. Fi. Rhizophora Mangle, Roxburgh, Fl. Ind. ii. 459 (not Linnzus) 
Brit. Ind. ii. 436. (1824). — Blume, Enum. Pl. Jav. 91. 
Rhizophora candelaria, De Candolle, 7. c. 32 (1828). Rhizophora macrorrhiza, Griffith, Trans. Med. § Phys. Soc. Calc. 
Rhizophora apiculata, Blume, Enum. Pl. Jav. 91 (1827). — viii. 8 (1836). . 
Wight, Ill. i. 209. — Kurz, Forest Fl. Brit. Burm. i. 447. Rhizophora candelaria, Wight & Walker-Arnott, Prodr. Fl. 
Rhizophora Mangle, Blanco, Fl. Filip. 397 (not Linnzus) (1837). Ind. 310 (not de Candolle) (1834). 
2 Poiret, Lam. Dict. vi. 189 (1804). — Lamarck, Jil. ii. 517, t. 8 Howison, Trans. Soc. of Arts, xxii. 201. — Hamilton, Pharm. 
396, f. 2. — De Candolle, 1. c. — Decaisne, Ann. Sci. Nat. sér. 2,iv. Jour. vi. 11.—Baillon, Hist. Pl. vi. 298. — Procter, T'ext Book of 
75. — Wight, 1. c.; Icon. t. 238. — Walker-Arnott, 1. c. 362.— Tanning, 55.— Trimble, Contrib. Bot. Lab. Univ. Penn. i. 50. 
Blume, Mus. Bot. Ludg. Bat. i. 132. — Tulasne, Ann. Sci. Nat. sér. 4 Hermann, Parad. Bat. 217. 
4, vi. 109.— Gray, Bot. Wilkes Explor. Exped. i. 613. — Harvey & 5 Nov. Pl. Am. Gen. 13. 
Sonder, Fl. Cap. ii. 513. — Bentham, F7. Austral. ii. 493. — Oliver, 
