htfluence of Climate on Vegetation. 439 



branches of trees (as ferns and other plants sometimes do in 

 moist situations in Britain), sending down their long fibrous 

 roots in search of moisture, and requiring no soil save what 

 may have been accidentally deposited on the' branch which 

 forms their habitation. Want of attention to this fact long 

 prevented, or at least greatly impeded, the cultivation of this 

 beautiful class of plants in stoves ; and, even so late as 1822, 

 the Berlin botanic garden, one of the richest in Europe, could 

 boast of only nineteen species : now, there are above three 

 hundred cultivated in the nursery of the Messrs. Loddiges 

 alone ; and very large private collections are to be found in 

 various parts of the kingdom. 



Islands between the tropics have a different climate from 

 that of the main land, in the same latitude. They, even in the 

 dry season, in the nights, have heavy dews. The plants from 

 these countries require less repose ; they are always in a 

 growing state ; and they should have nearly the same degree 

 of heat in the night as in the day. The temperature, gene- 

 rally, should be more moderate and less varying. Many West 

 Indian and New Zealand plants rank in this class. 



A great number of valuable and favourite plants come from 

 Africa, a country which varies very much in its climates. 

 The regions from which most of the African plants are 

 brought may be divided into three classes. In the first, the 

 neighbourhood of Senegambia, the Congo River, and settle- 

 ments on the coast of Sierra Leone, there are, alternately, wet 

 and dry seasons. During the latter, the face of the whole 

 country appears parched and withered ; but, immediately that 

 the rainy season commences, the whole vegetation of the 

 country bursts into life. The plants grow with a luxuriance 

 and rapidity scarcely to be conceived, immense leaves unfold 

 themselves, and the soil is covered with a dense mass of rich 

 verdure. 



The immense arid plains extending from the Cape of Good 

 Hope into the interior of Southern Africa, known by the name 

 of the Great Karroo, or Desert, present a scorched and barren 

 surface during the greater part of the year. The plants never 

 grow close enough together to give the appearance of a mass 

 of vegetation ; and, during all the dry season, extreme sterility 

 is the characteristic of the scene. I3ut, as soon as the rains 

 fall, the whole face of the country suddenly changes: bulbous- 

 rooted plants push up their innumerable leaves and gaudy 

 flowers, the Mesembryanthema unfold their glittering blos- 

 soms, and, for a brief month or six weeks. Flora occupies the 

 karroos in her gayest forms : but, in August, the sun over- 

 .comes the humidity of the air and earth ; leaves wither up ; 



F F 4 



