a  vailing direction of the winds. — It may t 
128 BOTANY OF THE 
W. Indies to a much greater degree than does any part of 
the adjacent continent :—that this is in a great measure due to 
the dampness of its insular climate, is clear, from the plants 
in question being almost entirely Ferns, viz. :— 
Acrostichum squamosum, Sw. 
Aspidium molle, Sw. 
Asplenium monanthemum, Sw. 
» furcatum, Sw. 
Trichomanes radicans, Sw. 
species found nowhere on the continent of Europe, or in 
N. Africa. The presence of a plant belonging to the other- 
wise exclusively American genus, Clethra, is striking, be- T 
cause indicating a further relationship with the Flora of — > 
the New World, but of a very different character from the — — 
above. 
The Helichrysa of Madeira are allied in rather a remarkable | 
degree to the S. African species of that genus; a fact which > 
reminds us that the Myrsine Africana, a Cape of Good | 
Hope plant, is a native of the Azores, but of no intervening 
latitude on the West coast of Africa or the Atlantic Islands, 
nor indeed anywhere else but Abyssinia. Though not a 
subject falling immediately within the province of the pure 
Botanist, it may not be amiss here to state, that the four 
Island-groups in question have been conceived by my friend, 
_ Professor Forbes, to be the exposed remains of one continuous 
and extended tract of land, which formed the western prolon- : 
gation of the Europ san and African shores. He points t 
+ specific identity of these islands and Europe, as afford 
. Botanical evidence of this i ingenious theory, which, however. 
he chiefly rests on geological grounds. Regarded in this 
light, the question will resolve itself, in the opinion of most 
.. Botanists, into one, concerning the power of migration, 2 and 
~ the probability of migration having taken place, to a | 
. great extent, over the Atlantic Ocean, and against the mS 
such a pieno would eve — t ies d a nd:  solel 
"- S 
