670 GENERAL AND ENDEMIC DISTRIBUTION OF PLANTS. 



2. — General and Endemic Distribution of Plants. 



While some plants are generally diffused, it is found that the 

 different quarters of the globe are each characterised by more or less 

 distinct floras. Europe, Asia, Africa, North America, South America, 

 and Australia, may be regarded as separate provinces of the vege- 

 table kingdom, possessing species, genera, and families of plants, 

 which give to each division its distinctive features. Humboldt and 

 Bonpland, in their travels in equinoctial America, did not see an 

 exogenous plant which was found equally in the New and the Old 

 World ; the only plants which they discovered common to both being 

 some grasses and sedges. Among 4160 species met with in New 

 Holland by Brown, 166 only were to be found in Europe. 



Some plants live in society, occupying exclusively large tracts of 

 ground, from which they banish all other vegetables. These are 

 called by Humboldt Social plants. They give a peculiar feature to 

 the countries and districts in which they grow. To this class belong 

 many species of Seaweed in the ocean ; Oladonias and Mosses in the 

 waste levels of Northern Asia ; Grasses (Bamboos), and some Cactuses, 

 Mangroves, and Avicennias in tropical countries ; Perns in the South 

 Sea Islands ; Banksia speciosa in Australia ; Cinchonas in certain 

 parts of South America ; Coniferous trees and Birches in the Baltic 

 and Siberian plains. 



Some plants are very much restricted in their distribution over 

 the globe ; a few are confined to single localities, while others have 

 a limited latitudinal range. The species of the genus Erica, Heath, 

 which extend from northern regions to the Cape of Good Hope, are 

 scattered over a surface very narrow compared to its length ; in other 

 words, while their latitudinal range is great, their longitudinal range 

 is very much restricted. Calceolarias occur chiefly on the western 

 side of the CordUleras of Chili. Lobelia Dortmanna is found princi- 

 pally in the western countries of Europe. Camellias are also limited 

 in longitudinal direction, so also Phalangium bicolor and ' Eaymondia 

 pyrenaica. Arbutus Unedo, Erica mediterranea, and Dabeocia poli- 

 folia, whose chief seat is in the Pyrenees and the mountains of 

 Asturias, migrate in a north-westerly direction, and appear in Ireland. 

 It is said that Azaleas, Ehododendrons, Magnolias, Vacciniums, 

 Actseas, and Oaks, which form prevailing genera on the east of the 

 Eocky Mountains, scarcely appear on the western side. Epacridace^ 

 are confined to Australia; Cinnamon, Cloves, and Nutmeg, are the 

 produce of the Indian Archipelago ; Gentians and Saxifrages form a 

 characteristic feature of the European Alps j Bejarias and Cinchonas 

 of the Peruvian CordiUeras ; Schizanthuses of Chili ; Polemoniacese of 

 California and Oregon ; yellow and brown Papilionacese of Australia ; 



