of the Galapagos Archipelago. 237 
between south and east. A failure of this, the trade-wind, caused the extra- 
ordinary rise of the thermometer mentioned above. 
The nature of the coasts and surface of the islands is in some measure 
indicated by the plants contained in the various collections, some of the more 
generally diffused of which may thus be classified with reference to locality. 
The genera Avicennia and Rhizophora, species of both of which bear the 
name of Mangrove in different parts of the world, prove that in some of the 
islands at least (Charles and Chatham) there is a phenogamic vegetation 
below high-water mark. On the other hand, from the steepness of the coasts 
and dryness of the soil near the ocean, there appear to be few maritime plants. 
Those which I presume to be more strictly’ such are Cissampelos Pareira, 
Tephrosia littoralis, Sceevola Plumieri, Convolvulus maritimus, Calystegia 
Soldanella, Vi Verbena littoralis and Heliotropium Curassavicum, all natives of 
the South American coast, and to which may probably be added some of the 
peculiar 4maranthacee. 
The lower parts of the island are very arid and rocky, presenting thickets 
of starved shrubs and leafless trees, and to these situations are assigned * the 
weeds of the Flora, such as herbaceous or suffrutescent Malvacee and Euphor- 
biacece, many species of Borreria, some Composite, various Lycopersica, Fer- 
bene, Galapagoa, Boerhaavia and some grasses ; to which may be added some 
larger shrubs, as small trees of Acacia, Castela, Cactus and Opuntia. Where 
marshy land occurs, and this is not uncommon on the summits, several species 
of Cyperus and Mariscus appear; and to a salt lake, which is beautifully 
fringed with succulent plants, belong Portulaca, some Amaranthacee, Pleu- 
ropetalum, and probably Sesuvium. 
On ascending the hills the climate and vegetation both suddenly change, 
the sea-vapours are condensed on the higher parts of the islands, and a com- 
paratively luxuriant flora isthe consequence. From these more favoured loca- 
 lities are brought the greater number of the very peculiar vegetable forms of 
the island ; curious arborescent Composite, which have no near allies in other 
parts of the globe, and of which there are eight species in this group, all 
* In thus assigning localities to the species, I have been guided in many cases by notes attached to 
the specimens, in some by the plant growing in islands of a uniform surface and character, and in not 
a few instances by a knowledge of the situations which the species affect in other parts of the world, 
212 
