122 Picture of Vegetation on the Surface qfthe Globe, 



" The cactuses are almost exclusively peculiar to America. 

 Their form is sometimes spherical, ,sometimes articulate ; some- 

 times it rises like the pipes of an organ, into long channelled co- 

 lumns. This group forms in its exterior the most striking con- 

 trast with that of the liliacea? and bananas ; it belongs to those 

 plants which Bemardin de St Pierre has so happily named the 

 Vegetable Springs of the Desert. In the parched plains of 

 South America, the animals, tormented by thirst, look out for 

 the melocactus, a spherical plant, half concealed in the sand, en- 

 veloped in formidable prickles, and whose interior abounds in 

 refreshing juices. The stems of the columnar cactus rise to the 

 height of thirty feet, and form a sort of candelabra ; their phy- 

 siognomy has a striking affinity to that of some African Eu- 

 phorbia?. 



" While the cactuses form vases dispersed through leafless de- 

 serts, and the orchideae, under the torrid zone, animate the As- 

 sures of the wildest rocks, and the trunks of trees blackened by 

 excess of heat, the form of the vanillas is brought into notice, by 

 their pale-green leaves, filled with juice, and their variegated 

 flowers, so singular in structure. These flowers resemble a 

 winged insect, or the small bird which feeds upon the perfume 

 of the nectaries. A whole hfe would not suffice an artist to 

 paint all those magnificent orchideae which adorn the deeply 

 furrowed valleys of the Andes of Peru. 



" The CasuarinacecB, which occur only in India, and the 

 islands of the great ocean, are denuded of leaves, like the greater 

 part of the cacti : they are trees whose branches are jointed like 

 the stems of equisetum. We find, however, traces of this type in 

 other parts of the world. The pines, the thuyae, and cypresses, 

 belong to a northern form, which is of rare occurrence in the 

 torrid zone. Their continual and always fresh verdure, enlivens 

 the landscape saddened by winter, and announces at the same 

 time to the nations bordering upon the poles, that even when the 

 earth is covered with snow and frost, the internal life of plants, 

 like the fire of Prometheus, is never extinguished upon our 

 planet. 



" The mosses and lichens in our northern climates, the aroideoi 



imder the tropics, are parasites as well as the orchidea, and clothe 



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