306 THE VOYAGE OF H.M.8. CHALLENGER. 



ORCHIDE/E. 



As an instance of what may be effected by the agency of the sea, Moseley (Notes by a 

 Naturalist, p. 368) says : " On the shores of Little Ki Island I found on the beach, above 

 the ordinary reach of the waves, a large mass of the pseudo-bulbs of an epiphytic orchid 

 with its roots complete. It was partly buried at the foot of a tree, and seemed quite 

 lively. It had evidently been washed up in a storm." 



PAJMM. 



Cocos nucifera, Linn. 



Notwithstanding the fact that the cocoa-nut palm is essentially a littoral tree, is now 

 almost cosmopolitan in the tropics, and the further fact that its seeds or fruit will bear 

 long immersion in sea-water without detriment, it is doubtful whether oceanic currents 

 have played an active part in its diffusion. It is possible, and indeed very probable, that 

 its present wide area is partly due to this agency. For example, the Keeling or Cocos 

 Islands, in the Indian Ocean, do not appear to have been inhabited before 1827, when 

 some Europeans settled there for the express purpose of exporting the products of the 

 cocoa-nut palm, which abounded there. Darwin (Journal of Researches, ed. 18S4, pp. 

 453, 454) states that at first sight the cocoa-nut tree seems to compose the whole wood, and 

 the whole prosperity of the place depends upon it. He also mentions that young and full- 

 grown cocoa-nut trees grew intermingled ; so that there can be no doubt of its capability 

 of reproducing itself abundantly unassisted in favourable situations. Another instance 

 may be Cocos Island, off the coast of Central America, in the Pacific ; yet it is strange 

 that the cocoa-nut does not exist in the not far distant Galapagos, which lie in the course 

 of currents running from America, and where, according to Collnett, as cited by Darwin 

 (loc. cit., p. 392), various seeds and seed-vessels are washed ashore. Moseley (Notes by a 

 Naturalist) mentions in several places the paucity, or absence, of the cocoa-nut in certain 

 uninhabited islands of the Molucca Sea. And Jouan (M^m. Soc. Sci. Nat. Cherbourg, xi. 

 1805, p. 127) has the following observations on the distribution of the cocoa-nut in con- 

 nection with the vegetation of the Marquesas Islands. "Too much has been made, I 

 think, of the influence of oceanic currents in the dispersion of the cocoa-nut, or at least to 

 their unaided influence. The waves may well, as Forster says, and as may be seen every day, 

 have washed ashore cocoa-nuts, which may have germinated, as any kind of soil suits it ; 

 but, as I have explained elsewhere, the cocoa-nut tree produces itself with difficulty un- 

 assisted. The nuts fall to the ground, where the greater part of them perish without 

 germinating. It is necessary to bury them, or at least to fix them to the soil." He further 

 states, that, according to current traditions, the cocoa-nut was planted in certain islands 

 in the Pacific by the hand of man, while in others it is known to be of recent introduc- 



