S 8 A NATURALIST IN THE PACIFIC CHAP. 



in great part of these plants ; and a sorry spectacle is presented by 

 a beach possessing such plants as Gossypium tomentosum, Helio- 

 tropium anomalum and H. curassavicum, Lipochaeta integrifolia, 

 Tephrosia piscatoria, Tribulus cistoides, &c. Yet to the student of 

 plant-distribution such a motley collection would be full of 

 suggestiveness. From the circumstance that species of Cuscuta, 

 Jacquemontia, and Lipochaeta, that are peculiar to the Hawaiian 

 Islands, have made their homes on the beach, he would infer that 

 since Nature has been compelled to borrow from the endemic 

 inland flora, there has been some difficulty in stocking the beaches 

 with their plants. The occurrence of endemic species amongst the 

 strand-plants would be viewed by him as especially indicating 

 incapacity on the part of the ocean currents. 



Yet in the quantities of drift timber, showing evidence of many 

 months and probably even of years of ocean-transport, to be seen 

 stranded on the weather coasts of these islands, the observer discerns 

 undoubted evidence of the efficacy of the ocean currents. But 

 what he finds are huge stranded pine logs of "red- cedar" and 

 " white-cedar " from the north-west coasts of America. He may 

 search the drift for days together, as I have done, and discover no 

 tropical fruits or seeds except such as could be supplied by the 

 present Hawaiian flora. The subject of this drift is especially 

 discussed in Note 30 ; and it need only be mentioned here that it 

 is not improbable that, as shown in the next chapter, some drift may 

 reach Hawaii from tropical America under exceptional conditions, 

 and that its presence is masked by the Oregon drift. 



The agency of the drifting log in carrying small seeds in its 

 crevices would be effectual in the instance of plants from the 

 temperate coasts of North America. For example, the nutlets of 

 Heliotropium curassavicum, which have no buoyancy, might easily 

 be washed, together with sand, into the cracks of a pine log stranded 

 temporarily on the Oregon coast where this plant occurs. The 

 modus operandi was brought home to me when examining the 

 drift brought down by the Chancay River on the coast of Peru. 

 Here I found this species of Heliotropium growing on the margin 

 of a swamp near some stranded logs, that would probably be 

 carried out to sea when the river was next in flood. 



It is probable, I may add, that the seeds or fruits of some of 

 the plants of the non-buoyant group of the Hawaiian littoral flora 

 may be dispersed in birds' plumage. For instance, the spiny 

 fruits of Tribulus cistoides sink in sea-water ; but they are well 

 suited for entangling themselves in birds' feathers. 



