120 Scientific Intelligence. 



A considerable number of the Madeira plants belong to genera not 

 found in the adjacent continent, but in the Canaries, Azores, or Cape 

 de Verd Islands ; thus indicating a botanical affinity between these 

 groups, and confined to them. 



The evidence of this relationship is very decided, from the peculiar- 

 ity of the genera or species giving rise to it. Though comparatively 

 few in number, their characters are so prominent and so widely differ- 

 ent from the Mediterranean plants which accompany them, that the lat- 

 ter, though numerically much the greatest, seem superadded, and, as it 

 were, intruders on the former. 



The Canaries and Madeira, from their central position and various 

 other causes, are the centre of this botanical region, called by Mr. 

 Webb the " Macronesian," and exhibit more peculiarity than the Cape 

 de Verds, (as far as they are at present known,) or the Azores. There 

 can be little doubt that Madeira was even more peculiar in its vegetation 

 than now, previous to the destruction by fire of the luxuriant forests, 

 which, according to historic evidence, clothed almost all the lower parts 

 of the island. Not only would such a catastrophe destroy species, but 

 their place would be afterwards occupied by strong-growing imported 

 weeds, which would prevent the reappearance of the native plants by 

 monopolizing the soil. 



With very few exceptions, the Mediterranean are the only plants 

 found in Madeira and the Canaries besides what are confined to those 

 islands; in the Azores, on the other hand, some Northern European 

 species are associated with them. In the Cape de Verds, far to the 

 south, W. African and VV. Indian plants replace those of the Mediter- 



ranean. 



to 



The Island of Madeira participates in the flora of the W. Indies 

 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 cli- 

 mate, is clear, from the plants in question being almost entirely Ferns, 

 viz. :— Acrostichum squamosum, Sw. AspidiunTmolle, Sw. Asplenia 



monanthemum, Sw. Asplenium fureatum, Sw. Trichomanes radical* 

 Sw., species found no where on the continent of Europe, nor in N. Africa. 

 The presence of a plant belonging to the otherwise exclusively Ameri- 

 can genus, Clethra, is striking, because indicating a further relationship 

 with the Flora of the New World, but of a very different character 

 from the above. 



The Helichfysa 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 Mope plant, is a native of the 

 Azores, but of no intervening latitude on the West coast of Africa or 

 the Atlantic Islands, or indeed any where else but Abyssinia. Though 

 not a subject falling immediately within the province of the pure bot- 

 anist, it may not be amiss here to state, that the four Island-groups * n 

 question have been conceived by my friend, Professor Forbes, to be 

 the remnins of one continuous and extended tract of land, whic 

 formed the western prolongation of the European and African shores- 

 He points to the identity of species between these islands and Europe 



as affording botanical evidence of this ingenious theory, which, ho* 



