726 



RHIZOPHORACE/E. 



[Epigynous Exogens. 



Order CCLXXIX. RHIZOPHORACEjE.— Mangroves. 



Rhizophorese, R. Brown Gen. Rem. in Flinders, p. 17. (1814) ; in Congo, p. 18. (1818) ; DC. Prodr. 3. 

 31. (1828) ; Barll. Ord. Nat. 320. (1S30) ; Endl. Gen. cclxiii. ; Meim. p. 119 ; Wight Illustr. 1. 207 ; 

 Arnott in Ann. Nat. Hist. 1. 359. — Valetuviers, Savigny in Lam. Vict. 4. 696. (1796). 



Diagnosis. — Myrtal Exogens, with a plurilocular ovary, polypetalous flowers, valvate calyx, 

 indefinite stamens, and flat cotyledons much shorter than the radicle, which germinates 

 before the fruit falls. 



Coast trees or shrubs. Leaves simple, opposite, occasionally dotted, entire or toothed, 

 ■with convolute deciduous stipules between 

 the petioles. Peduncles axillary or ter- 

 minal. Calyx adherent, often surrounded 

 at the base by a cup-shaped bract, with 

 the lobes valvate and varying in number 

 from 4 to 12, occasionally all cohering in 

 a calyptra. Petals arising from the calyx, 

 alternate with the lobes, and equal to them 

 in number. Stamens arising from the 

 same point as the petals, and twice or 

 thrice their number, or in Kandelia indefi- 

 nite ; filaments distinct ; anthers erect, 

 innate. Ovary 2-3-4-celled, each cell con- 

 taining 2 or more ovules hanging from 

 the apex of the central angle, anatropal. 

 Fruit indehiscent, crowned by the calyx, 

 1-celled, 1-seeded. Seed pendulous, without 

 albumen ; radicle very long, piercing the 

 fruit and rapidly extending downwards in 

 germination ; cotyledons 2, flat. 



Mangroves are readily known from 

 every Order to which they can be usefully 

 compared, by their very curious habit of 

 germinating while the seeds are still at- 

 tached to the branch that bears the fruit. 

 The radicle and club-shaped crown of 

 the root gradually lengthen until they 

 enter the soft muddy soil, or if too high, 

 drop, and fixing themselves in the muddy 

 bottom, immediately strike root at one 

 end, while leaves unfold at the other. — 

 Wight. In Carallia, however, the seeds 

 do not germinate in the pericarp. That 

 the species belong to the Myrtal Alliance 

 there can be no doubt ; as indeed is indi- 

 cated, not only by their structure but by the leaves of some species 

 of Carallia having pellucid dots. At the same time they seem to be 

 connected with the Gentianal Alliance through Cassipourea, which 

 comes very close to Loganiads. The Order also agrees with Cuno- 

 niads in its opposite leaves and intermediate stipules, and with great 

 part of them in the aestivation of its calyx, and in the structure and 

 cohesion of ovary. De Candolle points out its relation to Vochyads 

 and Myrobalans, and even to Melastomads, through the genus Olisbea. 

 The genera were comprehended in Loranths by Jussieu. Mr. Griffith 

 has explained with his usual skill the nature of the anther in Rhizo- 

 phora. In the plants belonging to that genus the anther is alveolar, 

 the sockets being filled with pollen, and in this circumstance it 

 resembles Viscum ; but in its younger state the anther is oblong, 

 compressed laterally, and uninterrupted on its surface ; when it is 

 mature its two faces fall away, and leave behind a solid centre, in 

 cavities of which the pollen lias been generated. See Transactions 

 of Med. and Phys. See, Calcutta. 





Fig. CCCCLXXXVI. 



Fig. CCCCLXXXVI. — 1. Kandelia Rheedii ( Wight) ; 2. its flower spread open ; 3. a perpendicular 

 section of its ovary ; 4. the geruiiiiatsig seed ; 5. the anther of Khizophora macrorhiza. {Griffith.) 



