PREFACE. 
IX 
thirty years ago, and before I bad the pleasure of examining the 
Island in company with Captain J. B. Oliver, It. A., a few years ago, 
w h° subsequently published a pamphlet on the subject; audit is 
extiemely satisfactory to me to find that in the main points we are 
all unanimous in opinion as to the geological constraction of the 
Island. 
Mr. Andrew Murray, F.L.S., in a very interesting paper, recently 
published,* on the geographical relations of the chief Coleopterous 
launa, taking as a basis the theory of " continuity of soil at some 
former period,” to explain the present geographical distribution of 
plants and animals over the globe, expresses his conviction “ that 
tlieie has been one, possibly two, great continental routes of com- 
munication between the Northern and Southern Hemispheres, both 
7* ^ in ocean, the one at the bottom of the 
tl antic, the other in the depths of the Pacific and points to St. 
e ^ entl us a crucial test to the hypothesis of a communication 
etween the Northern and Southern Hemispheres by an Atlantic con- 
tinent. Mr. Poland Trimen, F.L.S., F.Z.S., having himself visited 
some of the Atlantic islands, shows in a subsequent paper, f with some 
odd notes, a disinclination to favour this theory of dispersal, and 
refers^ to the opinion of Mr. Darwin (Orig. of Spec., 4th edit. 
P' 427) as being also unfavourable to such an hypothesis. As regards 
le O ceai hc Islands, of which St. Helena forms a type, it seems to 
ine that the hypothesis is not in any way borne out by an inves- 
tigation of the geological structure of the Island, but, on the 
contraiy, e\ery characteristic of that volcanic mass seems to point 
0 an en th*ely insular land of vast antiquity. 
branch of Natural History is perhaps so calculated to 
convey a correct idea of a place as its Botany, and a careful and 
ull account of even its exotic plants and flowers, with the par- 
iculars and peculiarities which surround them, would in this respect 
not be without some value. I have therefore endeavoured to make 
my list include every plant that is found in the Island; and in 
Uoing so I have had the aid of Dr. Roxburgh’s Catalogue, and 
a so been fortunate enough, through the kindness of Dr. Hooker, to 
ave my own collection examined and identified at the Kew Her- 
barium, where I have received much kind and ready assistance from 
* Journal Linn. Soc., vol. xi. No. 49, 1870. 
t Ibid. No. 52, 1871. 1 
J 
