420 A NATURALIST IN THE PACIFIC chap. 



dispersal are very limited. If one places in sea-water a number of 

 well-dried fruits, most of them will sink within a week, and all will 

 be at the bottom in a fortnight. 



The seeds stranded on a beach are often found cracked. This 

 I think arises from long exposure to the scorching rays of the sun. 

 On account of the hardness of the shell it is very difficult to obtain 

 the kernel entire ; but the Mangaians get over this difficulty, as we 

 learn from the Rev. Wyatt Gill, by slightly baking the seeds ; 

 whilst the Fijians, according to Mr. Home, effect the same object 

 by throwing the heated seeds into cold water. On one occasion I 

 placed an empty seed on a tin plate kept at a temperature 115" to 

 120° F., a temperature near that which the seed would acquire 

 when lying exposed to the sun on a tropical beach. After five 

 days I found it had reproduced the cracks noticed in another 

 empty seed from the Keeling beach. 



Facts are not wanting with regard to the dispersal of the seeds 

 by birds ; but since the kernel alone is sought for by birds, and 

 as there is no means of cracking the shell in their stomachs, such 

 an agency is only available for local distribution. The Messrs. 

 Layard inform us that in New Caledonia a small crow (Physocorax 

 moneduloides) and a parrot (Nymphicus cornutus) are very partial 

 to these seeds {^Ibis, 1882). They were told that the crow cracked 

 them by carrying them to a considerable height and letting them 

 fall on a stone. We are not told how the parrot cracks the seed, 

 which has a shell so hard that the Malays, I may remark, term 

 the seed "bua kras," or "the hard seed," whilst a hammer is 

 required to break it. However, since Indian parrots, according to 

 Mr. J. Scott, are able to split open with their beaks the hard beans 

 of Adenanthera pavonina {More Letters of Charles DarwtJi, ii, 

 349), they evidently possess ingenuity in seed-cracking. 



My general conclusion with reference to this tree in Polynesia 

 is that it could not have been distributed, except locally, by birds 

 and currents ; and that it owes its dispersion there principally to 

 man. A contrary indication seems to be offered by the occurrence 

 of the tree in the uninhabited Kermadec group ; but since 

 Cordyline terminalis also exists there, a cultivated plant widely 

 dispersed by the Polynesians, it would appear that these islanders 

 have formerly visited the group. It is also contended by Canon 

 Walsh that the Cordyline of the Maoris was introduced into New 

 Zealand by that race. (See Checseman in vols, xx and xxxiii, 

 Trans. N.Z. Inst., for papers on the Kermadec flora and on the 

 food-plants of the Polynesians.) 



