THE AMERICAN BOTANIST 43 



many years ago and is now in flourishing condition. So far 

 as is known to the writer, it is the only tree in the Hawaiian 

 Islands. The mangrove is not mentioned by Hillebrand, or 

 by any other of the many botanists who have visited and 

 written of the native and naturalized plant life of Hawaii. 

 The tree specified is not only in vigorous growth, but has pro- 

 duced many seedlings which have evidently become thoroughly 

 naturalized. The evidence strikingly corroborates the writer's 

 previous conviction as to the Hawaiian possibilities of the 

 mangrove. 



The family Rhizophoracese, of which the mangrove is 

 characteristic, comprises 15 genera and about 50 species. 

 VVeihca with 12 species, Ceriops with 2 speceies, Amsophyllea 

 with five species are all in the old world tropics, Briigueira 

 with 5 species is tropical Asia and Africa and Poga with one 

 species in Africa, Rhizophora has 3 species, mangle of tropical 

 America and West Africa, mucronata and conjiigata of tro- 

 pical Asia and East Africa. These are widely distributed on 

 the shores of tidal marshes and estuaries. The generic name 

 is from the Greek, "root-bearing," and was used by early 

 writers to designate various climbing plants with aerial roots. 



The genus is almost unique in the plant world because 

 the seeds have no true resting period, that is, they germinate 

 at once on the plant. The radicle may reach a length of 3 

 feet, although usually less ; it is club-shaped and heaviest at the 

 apex, so that when the seedling finally falls from the tree, it 

 sticks vertically in the mud, with the radicle down, ready to 

 grow. This is one of the best examples of vivipary, as the 

 embryo continues in a state of uninterrupted development from 

 the outset. This is essentially seedlessness, from the phy- 

 siological standpoint and germination in the usual sense, does 

 not take place. This habit is of obvious usefulness, facilitat- 

 ing both the wide dispersal and abundant reproduction of 

 these plants, as is testified by the extensive coastal mangrove 



