OS Botanical Geagrapry. 8 ABT 
accompanied by an evergreen kind, the general aspect of 
the forests is quite different from that of northern Europe. 
It is only in the extreme south, where the diminished tempe- __ 
-rature and the moisture which remains in the ground are 
favourable to the formation of peat, that the forests yield to. 
open moors. But the vegetation of these moors is peculiar, — 
consisting of a saxifrage and a plant allied to the lilies, as- 
sociated with cranberries, Ranunculi, and rushes. 
24. Oceanic Lslands. 
The native plants of islands often differ considerably 
from those of the nearest continent ; the aboriginal flora 
has been preserved in greater purity than elsewhere ; and it 
is to insular floras of this character that the important theory — 
of the migration of plants owes its origin. 
- The Azores, Madeira, and the Canaries, an archipelago 
_ formed of lava and volcanic rocks, possess a flora altogether 
independent, but enriched from without, and known asthe 
Atlantic Flora. That of the Azores resembles the Mediter- | 
ranean fiora; evergreen shrubs and forest trees belonging to ~ — 
the Lauracee, together with beautiful Ferns, cover the 
greater part of the islands. Madeira was, at the time of its oie, 
discovery, completely clothed with wood down to the shore. 
But the so-called cedar of the island, a timber-tree with a — 
valuable scented wood, disappeared after a great forest-fire. 
_ The vegetation has been completely altered by cultivation. 
Together with the sugar-cane, which has taken the place of 
the vine-—-the latter having been almost destroyed by the 
vine-disease since 1852—the plantain has been generally 
cultivated ; tropical fruit-trees are abundant ; but there are 
no palms. Other noteworthy native plants are the dragon- — 
tree Dracena, the luxuriant forests of laurels, the shrubby — 
heaths, magnificent Ferns, and dense underwood, which 
characterise the district of the thickets above the laurel- 
woods. The flora of the Canary Islands has an African 
