18 MR. BUNBT7ET ON THE BOTANY OF MADEIRA. 



ravine of Santa Luzia ; and S. glutinosum, the more general of the 

 two, is frequent in various places on the southern coast. 



The flora of Madeira seems to be made up of three principal 

 elements : the first, and numerically much the greatest, portion 

 consisting of South-European, or Mediterranean plants ; the second, 

 of plants characteristic of the Macaronesian region (as Mr. Webb 

 has named it), that is to say, plants either peculiar to Madeira, or 

 common to it and the Canaries or Azores, but not natives of any 

 of the continents. The third division consists of tropical or sub- 

 tropical species, American or Indian, or, in some few cases, African, 

 but not European ; most, if not all of these, are probably intro- 

 duced plants. 



1. The large proportion of South-European plants in Madeira. — 

 480 out of less than 700 phaenogamous species* — is very striking ; 

 and the space they occupy is not less remarkable than the number 

 of generic and specific forms. In the lower region of the southern 

 side especially, although the climate and the cultivated vegetation 

 are nearly tropical, the general aspect of the wild plants constantly 

 reminds one of the Mediterranean. A large proportion of these 

 South-European species, it is true, are plants of cultivated ground, 

 or of road-sides, and may have been introduced accidentally since 

 the island has been colonized by Europeans. But there are others, 

 such as Cotyledon Umbilicus, Lavandula Stoechas, Salvia clandestina, 

 Psoralea bituminosa, Ruta angustifolia, Phagnalon saxatile, DC, 

 the sea-side variety of JPlantago Coronopus, and many more, to 

 which this supposition is less applicable ; and the number alto- 

 gether seems too great to be explained by mere accidental trans- 

 port through the agency of cultivation. One is rather tempted to 

 speculate on the operation of some greater and more extensive 

 cause, and to think of the bold hypothesis of Bory de St. Vincent 

 and Edward Eorbes, concerning the former existence of an Atlantic 

 Continent , by which the three Macaronesian groups f might have 

 been connected with western Europe and north-western Africa. 

 Supposing the existence of such a continent, the presence of so 

 great a proportion of plants common to Europe and the three 

 groups aforesaid would be easily and simply explained, as they 

 might have migrated by degrees, in the course of ages, by this 

 overland route ; whereas, in many cases, it is difficult to understand, 

 how they could have crossed the great breadth of sea at present 



* J. D. Hooker, in * London Journal of Botany,' vol. vi. p. 126. 

 f Namely, Madeira and Porto Santo, the Canaries, and the Azores. 



