ON STEMS. 



Mrs. B. This is formed of the basis of decayed 

 leaves. A circle of leaves annually sprouts from the rim 

 of the new layer of wood ; and, when they fall in autumn, 

 leave these traces of their past existence. When a Eu- 

 ropean wood-cutter begins to fell a tree of this descrip- 

 tion, he is quite astonished at his hardness. " If I have 

 so much difficulty with the outside," says he, " how shall 

 I ever get through the heart of the wood ? " But as he 

 proceeds, he discovers that the trees of the tropical climes 

 have tender hearts, if you will allow me the expression ; 

 this circumstance renders it very easy to perforate them, 

 and makes them peculiarly appropriate for masts of ves- 

 sels, pipes for the conveyance of water, and such like 

 purposes. 



These plants have usually no branches ; but there is 

 one species of palm-tree which shoots out two or three 

 branches together. 



The family of the gramineous plants, that is to say, the 

 grasses and corn have a knot at the base of each leaf, 

 whence the shoot grows. 



Caroline. I have observed that the straw of corn is 

 hollow, but closed at certain intervals, forming externally 

 a sort of ring ; and it is from these rings that the leaves 

 and branches shoot. 



Mrs. B. The sugar-cane, which grows in this man- 

 ner, is the largest of the gramineous plants. 



Lilies are also of this description. 



The Yucca of the tropics differs from our liliaceous 

 plants only by having a longer stem ; in these temperate 

 climes vegetation has not sufficient vigor to develope all 

 the energies of the plant, and the stem grows only later- 

 ally, never shoots upwards, but lies concealed in the bulb. 

 Were it transplanted to a tropical climate, as soon as it 

 had attained its lateral growth, it would shoot upwards in 

 the manner I have described. 



190. How does Mrs. B. say this substance so much resembling bark 

 is formed'? 191. What surprises the woodcutter in felling tropical 

 trees'? 192. Why are these trees good for pipes to convey water 1 

 193. What is said of their branches'? 194. What is said of the 

 family of gramineous plants'? 195. Which is the largest of gramine- 

 ous plants'? 196. How does the Yucca of the tropics differ from our 

 liliaceous plants'? 197. What causes this difference'? 



