530 0?i the Dispersion and 



of the Andes, in South America, we find, at a certain height, 

 vegetables corresponding to the natives of the temperate and 

 even the frigid zones. But there is a peculiar circumstance 

 respecting these plants which we must not overlook. It is a 

 remarkable fact, that though Humboldt found upon the above- 

 mentioned mountains individuals resembling others native to 

 the temperate zones, yet, though in general the same, they were 

 almost in every case specifically different. Thus they possess, 

 says Humboldt, certainly, plantains, valerians, arenarias, ranun- 

 culuses, medlars, oaks, and pines, which, from their physio- 

 logy, we might confound with those of Europe ; but they are 

 all perfectly distinct. The antarctic birch (^etula antarctica) 

 resembles, but is not identically the same with, the Betula, 

 nana of northern regions. Upon this subject we shall speak 

 more fully when v>^e come to treat of the geography of plants. 

 It has been asserted by Mr. Brown to be generally true, that 

 the native country of a genus is where the greatest number 

 of its species is found. This, though correct in some pecu- 

 liar cases, can hardly be allowed to hold universally. For 

 instance, by far the greatest number of our heaths (^ricae) are 

 met with near the Cape of Good Hope ; yet the ling ( Calluna 

 vulgaris), and the ^rica Tetralix and cinerea of our moors, 

 cannot surely be denied as indigenous to the north of Eu- 

 rope. We are ready to admit the migration of plants to a 

 certain extent, and from various causes : thus, the floras of 

 islands generally exemplify this fact. * The different groups 

 seated in the great Southern Ocean, which lies between Ame- 

 rica and Eastern Asia, serve as instances in point : the eastern- 

 most islands contain more plants of American families or 

 species ; and the western, of those tribes peculiar to the Indian 

 islands : placed in the neighbourhood of two continents, they 

 comprise the vegetation of both. Malta and Sicily have plants 

 which belong to Europe, and others of an African stock. The 

 vegetation of the Cape de Verd Islands is intermediate between 

 the floras of the Canary Islands and of the African coast. 

 {Phys, Geography, part ii. p. 49.) On the contrary to this, 

 there are some spots producing species quite peculiar: thus, 



* " On the shores of the Marianne Islands, fruits and seeds of many 

 trees were observed ; the greater part not indigenous, but wafted from 

 remote stations by the sea. The greater number of these seeds belong to 

 the arborescent or the climbing leguminous plants, which grow plentifully 

 every where between the tropics. Those of the Guilandina Bonduc are 

 very common among them ; but we only saw the plant itself once, on one 

 of the Leeward Islands.'* (Translation, in part ii. of Hooker's Botanical 

 Mncellany^ of Chamisso's notices respecting the botany of certain coun- 

 tries visited by the Russian voyage of discovery under the command of 

 Captain Kotzebue.) — J. D. 



