336 
land is not equally distributed; the combi- 
nation or insulation of the groupes in the 
different stations that intervene between 
the shore and the mountain-tops, depend- 
ing considerably on the configuration of 
the ground, and the altitude of the moun- 
tains. In order to explain these changes, 
we will first give a general idea of the ve- 
getation in the Western part of the Archi- 
pelago, and state how it is diffused over 
the soil, noting the transitions of form 
through which it passes, the different cha- 
racters that it affects, and the aspect which 
it gives to the landscape. Taking Tene- 
riffe, the most central and at the same time 
the most elevated island of the groupe, 
for a type of that geographical topogra- 
phy which is repeated, so to speak, to 
a greater or less extent on the adjacent 
islands, we will point out those analogies 
and those differences, which to ourselves 
have appeared most worthy of observa- 
n. 
The coast of Teneriffe, like that of Ca- 
naria, Palma, Gomera, and the Isle de Fer, 
rises like a bulwark of cliffs, in sheer 
steeps, nearly from the water’s edges, ex- 
hibiting in all directions, a wall of basalt 
edged by a very narrow strand. Th 
plants of this maritime region take root in 
the cliffs, clothing their sides and the small 
platforms which surmount them. They 
are mostly fleshy-leaved species, which de- 
rive their chief nourishment from the at- 
mospheric vapors, and the emanations of 
the sea-breeze. Such a soil, indeed, can 
only produce those succulent plants which 
inhabit the sea-coast. The species vary 
according to the sites which they occupy, 
some growing on the blocks of the cliff, 
and belonging to the Chenopodee, Ficoi- 
dee, Euphorbie, and Crassulacee, &c. ; 
while others, as Zygophyllum Fontanesii, 
(nob.), Picridium Tingitanum, Astydamia 
Canariensis, Crithmum maritimum, Con- 
 yza sericea, Statice imbricata, (nob.) and 
WS. pectinata, Frankenia pulverulenta, 
&c., &c., may be seen on the very strand, 
where they are frequently washed by the 
waves. 
The plants of the flat shores are some- 
times diffused over the slopes of the val- 
[n] 
VEGETATION OF THE CANARY ISLANDS. 
lies and in the interior of the ravines. Ex- 
posure frequently accounts for these anom- 
alies; the air being charged with saline 
emanations, may, according to the forma- 
tion of the coast, which offers a free pas- 
sage to the sea-breeze, give birth, even at 
some distance from the shores, to those 
plants which require carbonate of soda. 
Still these plants cannot exist very far from 
the sea, their organization demanding a 
warm temperature where evaporation goes 
on quickly, for which reason they are only 
seen in low situations. Higher again, 
where frequent rain dispels the saline prin- 
ciples of the soil, a different tribe of vege- 
tables appears, and though their structure 
may be succulent, as the Semperviva, still 
chemical analysis will prove that it is car- 
bonate of potass, and not carbonate of 
soda, that they afford. Being endowed 
with strong powers of absorption, the 
Semperviva, a very numerous family in 
the Canary Isles, grow upon old walls, in 
the interstices of rocks, upon the most pre- 
cipitous cliffs, and wherever the surface is 
such as that humidity lodges, without re- 
maining there long. 
bove these cliffs, the ground spreads 
out into a kind of primary platform, rising 
again towards the centre of the island into 
eminences, which are rent by ravines, and 
separated by intervening vallies. The vene : 
tation that is disseminated over these 
slopes assumes an African character, and 
is remarkable for the prevalence of bare 
and tortuous trunks, and fleshy glaucous 
foliage. Here the Canary Island Euphor- 
bia prevails, its large bushes frequently 
sheltering the lesser vegetables that ae 5 
thinly scattered over the volcanic soil; the 
flowery branches of Kleinias, Plocame, 
and Echium arborescens waving over the 
while Periplocas and | 
massy Euphorlias, 
Rubias twine into an impenetrabl 
work. The glaucous verdure of th 
ferent plants produces no effect except 
ies whose 
green, 
e trellis- 
ever, the plants are little seen, com 
with the masses of tufa and o 
ese di | 
ive 
2 — 
FER ERII RANE 
ER 
