XVII ENTADA SCANDENS 179 



caprae, that are found all round the tropics, have performed the 

 circuit of the globe with America as their home. 



One may remark in passing that the double home of the genus 

 in America and the Old World, though offering a serious difficulty 

 in plant geography, has no immediate bearing on the present mode 

 of distribution of Entada scandens. Questions relating to the dis- 

 tribution of tropical shore-plants that are dispersed by the currents 

 at first resolve themselves into considerations of the arrangement 

 of the currents. Entada is not alone amongst the genera contain- 

 ing littoral species in having a home both in the Old and in the 

 New World. Carapa is another instance, ana additional cases 

 might be cited. 



The next peculiarity in the geographical range of this species is 

 concerned with its irregular distribution in the archipelagoes of the 

 tropical Pacific. Notwithstanding its great capacity for dispersal 

 by the currents, although it occurs in all the groups of the Western 

 Pacific as well as in the Cook Islands, it has not been recorded 

 from the Society Islands, the Paumotus, the Marquesas, and 

 Hawaii. Since, however, its seeds have been gathered by 

 Mr. Arundel on the beaches of Flint Island, lying about six 

 degrees north of Tahiti {Bot. Chall. iv, 302), it is not unlikely that 

 it will be found growing in other parts of Eastern Polynesia south 

 of the equator. One might have looked for an explanation of its 

 rarity in Eastern Polynesia to the absence of mangrove swamps, in 

 which, as in Fiji, it is sometimes most at home ; but this is nega- 

 tived by its abundance in Rarotonga, where mangrove swamps do 

 not exist. 



The dispersal of Entada scandens by the curre?its. — This 

 plant offers one of the most conspicuous examples of the transport 

 of seeds across oceans through the agency of the currents. In the 

 pages of many botanical works, from the close of the 17th century 

 onward, reference is made to the transport of its beans (often in 

 association with those of Mucuna urens and Caesalpinia bondu- 

 cella) by the Gulf Stream or other currents across the Atlantic to 

 St. Helena, the Azores, the west coast of Ireland, the Hebrides, the 

 Orkney Islands, the coasts of Scandinavia, and even as far north as 

 Nova Zembla (see Hemsley's Bot. Chall. Exped. ; Sernander's 

 Skand. Veg. Spridningsbiologi, Sic). That the seeds of Entada 

 scandens retain their germinating capacity after this ocean-trans- 

 port has been demonstrated not only by the germination of 

 stranded seeds on the shores of St. Helena, but also by the 

 germination when sown at Kew of seeds drifted to the Azores, as 



N 2 



