The Cactus. 211 



pores on their surface are comparatively few, and so small as to 

 act with extreme slowness when the air is dry ; so that in pro- 

 portion to the aridity of the air and the heat to which such plants 

 are exposed, is their reluctance to part with the food they con- 

 tain. They digest and re-digest it with extreme slowness, and 

 niay be truly said to live upon themselves during all those months 

 when they cannot feed upon the soil or atmosphere. This state- 

 ment applies more particularly to the species consisting of solid 

 fleshing masses like the melon thistles, hedgehog thistles, and the 

 like; but requires to be modified with reference to the thinner 

 stemmed species, as Cactus Speciosus, Speciosissimus and Trun- 

 catus ; of them it is equally true, but in a less degree. The 

 property which the Cactuses thus possess, of living where few 

 other plants can exist, sometimes renders them of great utility to 

 man. On Mt. Etna, for instance, and its volcanic fields, it is the 

 Indian Fig which the Sicilians employ to render such desolate 

 regions susceptible of cultivation. This plant readily strikes into 

 the fissures of the lava, and soon by extending the ramifications 

 of its roots into every crevice of the stone, and bursting the 

 largest blocks asunder by their gradual increase, makes it capable 

 of being worked. We will come now to the botanical charac- 

 ters by which this interesting class of plants are known. It is 

 in the class Icosandria or Calycandria, order Monogynia ; the 

 generic name is derived from the Greek kaktus, the ancient name 

 for the prickly pear. Its characters are : — calyx superior, divided, 

 imbricate ; petals, inner ones larger than the outer, many ; stigma 

 many cleft ; berry one-celled, many seeded, hollowed in the cen- 

 tre. The Showy Cactus — Cereus Speciosus, is the one repre- 

 sented in our plate, though by no means the handsomest or 

 largest of this glorious tribe. In the flower of this species you 

 will seek in vain for a distinction between the calyx and corolla. 

 It has a cylindrical stalk, the lower part of which is hollowed 

 out for the ovary, and the upper portion covered with small scale- 

 like rose-colored bracts, which gradually pass into large thin 

 delicate leaves of the same color, unfolding tier upon tier within 

 each other, and adhering by their lower ends, till a firm fleshy 

 tube is produced. About the middle of this tube, just where it 

 swells out and ceases to be cylindrical, spring forth a multitude 

 of slender stamens, placed row upon row within the tube, and 

 forming a long white filamentous cylinder or cone. The ovary 



