ORIGINAL VEGETATION OE THE GLOBE. 67l 



Dionaea muscipula is limited to a small area in Carolina ; Cephalotus 

 foUicularis is found in tlie bogs near King George's Sound, Australia ; 

 Lodoicea SeycheUarum is found only in the rocky islets of Seychelles ; 

 Disa grandiflora is a rare orchid pecidiar to Table Mountain at the Cape 

 of Good Hope ; Pringlea antiseorbutica is peculiar to Kerguelen's Land, 

 and a few other antarctic islands ; and Phyliea arborea is peculiar to the 

 Tristan d'Acunha group of islands. It is said that Origanum Tourne- 

 fortii is found only in a small island in the Grecian Archipelago. The 

 vegetation of islands removed from continents presents often peculiar 

 features, the ocean acting as a barrier to the dissemination of plants. 

 The island of St. Helena was originally inhabited by a most peculiar 

 vegetation, although its productions now are completely changed by 

 the destruction occasioned by goats, and by the introduction of Euro- 

 pean and other plants, especially fruit trees. Such may also be said 

 of the plants found in the Sandwich Islands, the Society Islands, and 

 the Canaries. The island of Madeira has 672 Phanerogamous plants, 

 of which 85 are peculiar to it. 



3. — Conjectures as to the Mode in which the Earth was 



ORiaiNALLT DlOTHED WITH PLANTS. 



It is an interesting question to determine the mode in which 

 the various species and tribes of plants were originally scattered over 

 the globe. Various hypotheses have been advanced on the subject. 

 Linnaeus entertained the opinion that there was at first only one 

 primitive centre of vegetation, from which plants were distributed 

 over the globe. Some, avoiding all discussions and difficulties, sup- 

 pose that plants were produced at first in the localities where they 

 are now seen vegetating. Others think that each species of plant 

 originated in, and was diffused from, a single primitive centre, and 

 that there were numerous such centres situated in different parts of 

 the world, each centre being the seat of a particular number of species ; 

 they thus admit great vegetable migrations, similar to those of the 

 human races. Those who adopt the latter view, recognise in the dis- 

 tribution of plants some of the last revolutions of our planet, and the 

 action of numerous and varied forces which impede or favour the dis- 

 semination of vegetables at the present day. They endeavour to 

 ascertain the primitive floras of countries, and to trace the vegetable 

 migrations which have taken place. Daubeny says that analogy 

 favours the supposition that each species of plant was originally 

 formed in some particular locality, whence it spread itself gradually 

 over a certain area, rather than that the earth was at once, by the 

 fiat of the Almighty, covered with vegetation ui the manner we at 

 present behold it. The human race arose from a single pair, and the 

 distribution of plants and animals over a certain definite area would 



