CHAPTER XXXI 



A CHAPTER ON VIVIPARY 



The significance of vivipary. The scale of germinative capacity. A lost habit 

 with many inland plants. The views of Goebel. The shrinking in the 

 course of ages of tropical swamp areas. The variation in the structures 

 concerned with vivipary. Abnormal vivipary. Summary. 



IT was remarked in Chapter IX that the study of the 

 germination of the floating seed carried us to the borderland 

 of vivipary ; and we may now observe that our study of the 

 mangroves, Rhizophora and Bruguiera, in the previous chapter, 

 has brought us into contact with vivipary in its most complete 

 development in the tropical swamps of our age. There is a great 

 gap between the two extremes, represented by the occasional 

 germination of a seed in a capsule or in a berry on the plant, 

 and by the elaborate process of vivipary exemplified by Rhizo- 

 phora ; but most of the intermediate stages can be illustrated by 

 known examples of vivipary. There is, however, no pretension 

 to deal with this subject here in anything but a cursory fashion ; 

 but it will, I venture to think, add completeness to a work in which 

 germination on and off the plant has been such a frequent theme 

 if I endeavour to connect together some of the various sets of 

 facts known to us concerning germination from the standpoint of 

 vivipary. 



The principal argument here followed has been already out- 

 lined in Chapter IX, where I have remarked that it is possible 

 to construct a scale of the germinative capacities of plants, pre- 

 senting a continuous series beginning with the mangroves, where 

 germination takes place on the tree, and ending with those 

 numerous inland plants where seeds are liberated in an immature 

 condition. It is suggested that vivipary was the rule under the 



