Pad -are numerous succulent nidine| especially Euphorbiaceae’ 
S “t ‘ As 
%: 
of the vine-disease ; and the Opuntias, which serve for the © 
_ rays of the sun that it is impossible for the aqueous vapour 
_ was ascarcity of wood, when the goats were taken away and - 
refreshed by a steady trade-wind and two rainy seasons, iS 
~ native flora. “ena 
Wey os’ 
458 “s ie | we Ph lysiological Botany. 
or 
> 
Me 
iardettr in its Bes districts ; - the prevalent foe ete” 
the date-palm, and tamarisks. ‘These districts are general 
arid, especially since the change introduced in consequence — 
nourishment of the mochineae aphis, have become one of. the 
most important objects of cultivation. The remaining - dis- 
tricts, characterised by laurel-woods, thickets, pines, and 
Genistas, indicate an Atlantic flora, although the evergreen” 
woods have been to a large extent destroyed. cari 
wa he Cape- -de-Verde Islands differ from those already 
mentioned in their more tropical climate. The rocks — 
and loose stones, uncovered by wood or even by the least — 
stratum of soil, are heated to so high a temperature by the | 
brought by the trade-wind to become condensed ; and since ~ 
there is sometimes no rainy period the vepelian of the 
islands 1s sparse. Four-fifths of the surface is said to be en- - 
tirely unproductive ; the only cultivated plants are a few 
introduced cocoa-nut and date-palms, coffee-bushes and a 
fruit-trees. The native flora is generally similar to the: ke a 
Atlantic, while the introduced plants indicate the proximity | 
of Africa. one 
The volcanic island of St. Helena was, at the time of its | 
discovery at the commencement of the sixteenth century, — 
--covered with wood, but the young branches were so com-- Ri: 
pletely destroyed by introduced herds of goats, which in-~ 
creased with great rapidity, that three centuries later there | 
trees introduced from all parts of the globe. The climate, 
Searle fertile ; but the introduced plants, ands es- 3 
_ Madagascar, penetrated by ere chains of granite mou 
