80 THE VOYAGE OF H.M.S. CHALLENGER. 



We have expressed an opinion in another part of this work that the seeds of Ipomcea biloba, 

 or pes-caprce as it is more commonly called, are carried by the waves of the sea from one 

 place to another, and often germinate when cast ashore ; and we find this opinion supported 

 by a memorandum in Burchell's manuscript. It runs thus : " Statio : In littore, ventum 

 versus, Sandy Bay, ubi scepe inveniuntur semina Acacia? scanclentis et Dolichos. Semina 

 super undas longe feruntur, ah aqua marina nullium detrimenti, et variis in littoribus 

 hosjtitalitcr recipientia: planta hcecce vere nautica." 



The " Acacia scandens " mentioned by Burchell is more familiarly known under its 

 modern appellation, Entada scandens. It is widely dispersed in tropical countries, and 

 its seeds are surpassed by few in size. Among other places, they are frequently thrown 

 up on the Azores, where, however, the conditions are not favourable to their germination, 

 though they retain their vitality, as has been proved by plants having been reared in the 

 hothouses at Kew from seeds picked up on the shores of the Azores. From the direction 

 of the prevailing oceanic currents, it is evident that these seeds are carried from the West 

 Indies to the Azores, a distance of about 3000 miles. 



Burchell does not say whether the seeds of Entada scandens ever begin to germinate 

 on the coast of St Helena ; it is obvious, however, that this plant could not establish itself 

 there. Melliss states that the seeds are often cast ashore on the windward side of the island, 

 and that they have been known to germinate and grow into plants of considerable size ; 

 yet he doubted the existence of a single plant in the island at the time he wrote. He also 

 mentions that the hard slate-coloured seeds of Gkiilandina bonduc are frequently washed 

 ashore on the beach at Sandy Bay, the same locality given by Burchell, though no instance 

 of their having germinated had come under his observation. 



NYCTAGINE^E. 



Boerhaavia verticillata, Poir. 



Boerhaavia verticillata, Poir. in Lam. Encycl., v. p. 56; DC, Prodr., xiii. 2, p. 454; Melliss, St 



lie]., p. 312. 

 Boerhaavia repanda, Roxb. in Beatson's St Helena Tracts, p. 302, non Willi 

 Boerhaavia helerue, Roem. et Schult., Syst. Veg., i. Mant, p. 73. 



St Helena. — Indigenous ? Ladder Hill, and various other localities — Burchell, 1 ; 

 Rupert's Hill, &c. — Melliss. 



" Hogweed." 



This plant is widely diffused in Tropical Africa, and Melliss thinks it is probably indi- 

 genous in St Helena: but it is more likely to be an introduced plant, because all the 

 known indigenous plants have a peculiar facies. It would seem, however, to have been 

 commoner in Roxburgh's time than it is now, for he says " common amongst the rocks in 

 James's Valley, &c." 



