LESSON 7.3 THICKENED AND FLESHY LEAVES. 



53 



farther on, it is contracted into a tendril, enabling the plant to climb ; 

 the end of this tendril is then expanded into a pitcher, of five or 

 six inches in length, and on the end of this is a lid, which exactly 

 closes the mouth of the pitcher until after it is full grown, when the 

 lid opens by a hinge ! But the whole is only one leaf. 



128. So in the root-leaves of the Tulip or the Lily (Fig. 73), 

 while the green leaf is preparing nourishment throughout the grow- 

 ing season, its base under ground is thickened into a reservoir for 

 storing up a good part of the nourishment for next year's use. 



129. Finally, the whole leaf often serves both as foliage, to pre- 

 pare nourishment, and as a depository to store it up. This takes 

 place in all fleshy-leaved plants, such as the Houseleek, the Ice- 

 plant, and various sorts of Mesembryanthemum, in the Live-for-ever 

 of the gardens to some extent, and very strikingly in the Aloe, and 

 in the Century-plant. In the latter it is only the green surface of 

 these large and thick leaves (of three to five feet in length on a 

 strong plant, and often three to six inches thick near the base) which 

 acts as foliage ; the whole interior is white, like the interior of a 

 potato, and almost as heavily loaded with starch and other nourish- 

 ing matter. (Fig. 82 represents a young Century-plant, Agave 

 Americana.) 



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