60 



THE VOYAGE OF H.M.S. CHALLENGER. 



arboreous Composite of the same tribe as the St Helena, for instance, are no longer found 

 in South Africa, whatever their earlier distribution may have been. But the American 

 affinity of some of them does not necessarily involve an American origin, for, as we shall 

 show in our general introduction, the present distribution of arboreous Composite presents 

 many anomalies. It should be borne in mind, too, that these Composites differ little in 

 floral structure from the Cape shrubby Felicice. The flora of the Tristan da Cunha group 

 exhibits similar, yet closer, affinities with the American flora on the one hand, and the 

 .Mascarene on the other; and associated with the plants of these affinities is a modern 

 element comprising apparently endemic species of such genera as Chenopodium, Atriplex, 

 Rumex, &c. 



The following tabular view of the distribution and affinities of the genera of the 

 endemic flowering plants of the island illustrates the peculiarities of the composition of 

 the flora, and enables us at the same time to appreciate the difficulties to be encountered 

 in an attempt to trace its origin to one source. 



Table Showi?ig the Affinities of the Species and Genera and Distribution of the Genera of the 

 Endemic Flowering Plants of St Helena. 



