48 LETTER XXX. 



into every crevice of the stone, and l)ursting the 

 largest blocks asunder by their gradual increase, makes 

 it capable of being worked. 



You will now be curious to know by what botanical 

 characters these interesting plants are certainly known. 

 To the tufted spines that are scattered over the stem, 

 instead of leaves, I have already adverted. The 

 flowers are the next part for us to study ; and here 

 you are at last introduced to the most highly developed, 

 the most complicated, the largest, and the most richly 

 coloured, or purely colourless, of all the blossoms in 

 the Vegetable Kingdom. The Showy Cactus (Cereus 

 speciosus) is at hand ; by no means the handsomest or 

 the largest of this glorious tribe, but one that shews 

 as well as any other the nature of its organization 

 {Plate XXX.). In the flower of this species, you will 

 seek in vain for a distinction between the calyx and 

 corolla. It has a cylindrical stalk {Jig. !.)» the lower 

 part of which {a.) is hollowed out for the ovary, and 

 the upper portion covered with small scale-like rose- 

 coloured bracts (a. «.), which gradually pass into large, 

 thin, delicate leaves of the same colour, unfolding tier 

 upon tier from within each other, and adhering by 

 their lower ends, till a fleshy firm tube {fig. 4. b. & 

 fig. Q. a.) is produced. About the middle of this 

 tube, just where it swells out and ceases to be cylin- 

 drical {fig. 4. c), springs forth a multitude of slen- 

 der stamens {fig. 2. b.), placed row within row upon 

 the tube, and forming a long, white, filamentous cylin- 

 der or cone. The ovary is, as you have already been 

 told, a cavity in the bottom of the apparent stalk of 



