72 REMARKABLE FLOWERS. [CHAP. 



latter are very sweet and juicy, and much esteemed 

 on account of their cooling nature. One species 

 (0. Tuna} attains the height of twenty feet, and as it 

 produces large numbers of stiff sharp spines is exten- 

 sively used as a hedge-plant. In Mexico this species 

 is largely cultivated to afford food for the Cochineal 

 insect (Coccus), for which purpose another species, the 

 Nopal, is also cultivated. Several species of Opuntia 

 have been introduced into Southern Europe, and so 

 successfully that Dr. Philippi in his "Vegetation of 

 Etna," tells us that " on the roughest lava thrives 

 the Indian or Prickly Pear, of which the large, cooling 

 fruits are sold at less than 2d. for thirty. This plant 

 is one of the most useful presents of the New to the 

 Old World, as it grows on the poorest and most 

 rocky soil, where nothing else will vegetate, requir- 

 ing no attention, and even its succulent-jointed stems 

 are greedily devoured by goats." 



Nature is most liberal to us in her supply of neces- 

 saries and luxuries; still one could hardly expect her 

 to supply us with such luxuries as toothpicks ! Yet 

 even these are provided ready made for us by a 

 species of Rchinocactus (E. insnaga). Some years 

 ago a specimen at Kew was estimated to bear no 

 less than fifty-one thousand of these useful articles. 

 They are as no doubt our readers have already 

 guessed the spines borne on the stems of this 

 species, and really in common use among the Mexi- 

 cans for the purpose mentioned, from which they 

 derive the specific title of Visnaga, which means a 

 toothpick. Their length is from an inch to an inch 

 and a half. 



