OEIGIN AND PEESENT DISTRIBUTION OF THE BRITISH FLORA. 423 



92, and Kerguelen's Land, 8 ; while Auckland and Campbell Islands 

 possess 6. A curious fact worth notice is that in South-eastern Australia 

 European species form ^-th. nearly of the whole flora ; but in South- 

 western Australia they constitute , ,V () th only ; while in Tasmania they 

 amount to i l 5 th. In Tasmania the following British plants occur, which 

 are not found in Australia : — Banunculus aquatiUs, Montia fontanel, 

 Hierochloc borealis. On the other hand, the Victoria Alps of Australia 

 contain fifteen European species not found in Tasmania, and all but one 

 are British plants. 



II. With regard to the extension of British plants from Europe to the 

 Cape, commencing with Morocco we find 344 present there, while in 

 northern Africa generally, which is largely "Mediterranean" in character, 

 there are 420 British plants. North-east Africa and Abyssinia appear to 

 yield about 90 British species. On the west coast of Africa the little 

 island of Fernando Po in the Gulf of Guinea was found to contain, on 

 "Clarence Peak," at above 5,000 feet elevation, 76 species of plants, of 

 which number 56 species of 45 genera belong to a temperate flora. Their 

 affinity is curiously much more with the plants of Abyssinia and of the 

 Mauritius than with those of the adjacent west coast of Africa. Of the 

 temperate flora a large proportion are European, and the following seven 

 are British : — Oxalis comiculata, Sanicula europaea, Galium Aparine, 

 Limosella aquatica, Luzula campestris, Aira caespitosa, Brachypodium 

 sylvaticum. Of the South African flora, including the portion of land 

 from the Tropic of Capricorn to the Cape, 27 species are British. 



Here, as elsewhere in our colonies, weeds of cultivation are continually 

 being introduced. 



III. In the third great extension of land, Greenland contains 210 (Ice- 

 land has 335), while British plants abound in arctic British America, as in 

 Siberia, even Parry's Island (76° north latitude) containing 32. The 

 number decreases as the warmer regions are reached ; thus Mr. 

 Drummond * records only 40 British plants in the Western States. In 

 tropical America (including the temperate and alpine regions of the 

 Cordillera from Mexico to Peru) there are 35 British plants, of which the 

 following eight are common with tropical Asia : — Cardamine hirsuta, 

 Stellaria nemorum, S. media, Ccratophyllum demerstim, Polygonum 

 Persicaria, Juncus bufonius, Scirpus lacustris, Phragmites communis. 

 In extra-tropical South America, however, there are no less than 64 

 British species, while in Fuegia and the Falkland Islands there are 24. 

 Of the British plants common to these three greatest extensions of land 

 there are common to Australia, &c, and Africa 17 ; common to Australia 

 and South America, 35 ; common to South Africa and South America, 

 19 ; common to all three extensions, 15. Lastly there have been found a 

 few British plants in islands of the Pacific Ocean. Thus, the Society 

 Islands contain 3 ; the Sandwich, 5 ; and Fiji, 16 species. 



If now we attempt to find an explanation of the fact of so many 

 plants thoroughly establishing themselves in foreign countries, there are 

 two features which strike us as worthy of observance. One peculiarity is 

 that plants do not always flourish best where nature has, so to say, made 

 their home, but in consequence of the struggle for existence they hold 

 * Hooker' Journal of Botany, vol. i. p. 185. 



