122 THE WONDERS OF VE&ETATION. 



" It is to the New World," says Humboldt, " that 

 the cactus-form exclusively belongs; they appear 

 sometimes jointed, sometimes spherical, and some- 

 times like fluted columns, or organ tubes." This group 

 forms the most striking contrast with the lily-tribe 

 and the bananas. It belongs to that class of plants 

 which Saint Pierre named the "vegetable springs of 

 the desert." In the arid plains of South America, 

 the animals, tormented with thirst, dig under the sand 

 for the melo-cactus, the watery pith of which is pro- 

 tected by formidable thorns. The cacti, which take 

 the form of pillars, reach a height of 27 or 30 feet. 

 Divided into branches like candelabra, and often cov- 

 ered with lichens, they present an appearance like 

 that of some of the euphorbias of Africa. These 

 plants form vast oases in the midst of deserts bare of 

 all vegetation. 



The flowers of the night-blooming cacti have ev- 

 erywhere been regarded as symbolical. The cereus 

 obtained its name from the torches with which Ceres 

 is said to have searched for Proserpine. The superb 

 cactus, which is called the torch-thistle in Mexico, is 

 called the steppe-light in Russia. Our own Indians, 

 and those of South America, seem to have observed the 

 phenomena of sleeping and night-blooming plants, 

 and it has been thought that they had to some extent 

 anticipated the famous floral clock of Linnaeus. 



ASCLEPJAS GIG ANTE A. 



In the aspect of its trees, Eastern Africa presents 

 to us forms not less strange than the names which 



