xxxi A CHAPTER ON VIVIPARY 



47i 



to all appearances quite at home in a mangrove-swamp. Others 

 again, like Carapa, Lagunculana, and Nipa, whilst displaying 

 vivipary in a varying degree, in some cases as a general rule, in 

 others only occasionally, exhibit no special structures connected 

 with it. This point is well brought out by Schimper in his work 

 on the Indo-Malayan strand-flora (p. 43), and no further mention 

 need be made of it here. 



The structures connected with vivipary vary greatly in their 

 degree of specialisation. At the one end of the scale we have 

 highly complex structures, such as are described in the preceding 

 chapter. At the other end we have those cases of occasional 

 germination on the parent plant where there is seemingly no 

 special structure of any sort. That the complex arrangements 

 concerned with the vivipary of Rhizophora, Bruguiera, /Egiceras, 

 and Avicennia are adaptations is argued by Haberlandt and 

 Schimper, both of whom devoted much attention to the study 

 of these plants. This is seemingly indicated by the circumstance 

 that complex structures concerned with vivipary are found in 

 plants so divergent in their characters (the four genera above- 

 named representing three orders, Rhizophoreae, Myrsinaceas, and 

 Verbenaceae) that they only possess their stations in common. It 

 does not, however, follow that all mangroves that exhibit a complex 

 form of vivipary are of the same antiquity. I should be inclined 

 to regard those of the Rhizophoreae as the more primitive types, 

 whilst it is possible that plants of other orders, though ancient 

 denizens of a mangrove-swamp, may be more recent intruders 

 into the mangrove-formation after the differentiation of a dry-land 



flora. 



Of particular interest in this connection are the cases of 

 abnormal vivipary, or of " precocious germination," that have been 

 recorded from time to time respecting a number of plants not 

 denizens of a mangrove swamp, none of which would appear, accord- 

 ing to Schimper's views, to present anything of the nature of an 

 adaptation. Goebel mentions a number of instances, such as that 

 of wheat-grains germinating on the stalk in a wet summer, and that 

 of Dryobalanops camphora, the Borneo camphor-tree, when during 

 a prolonged wet season in Java the seed germinates in the fruit on 

 the parent tree. Amongst other examples he cites the Cacti, 

 Epilobium, Agrostemma, and Juncus, the last case coming also 

 under my observation in a wet season in England. One may here 

 notice the instance of Dracaena, of which Mr. Hemsley, in April, 

 1902, exhibited at a meeting of the Linnean Society of London a 



