ON STEMS. 41 



Emily. The stem then does not begin to rise until it 

 is as large in circumference as at full growth. How I 

 should like to see one of these broad flat stems ! 



Mrs. B. You may see them growing in hothouses ; 

 and though we have none in the open air in these cli- 

 mates, we have many smaller plants of the same descrip- 

 tion. Corn and all gramineous plants, the liliaceous tribe 

 of flowers and bulbous roots, are all endogenous. 



Caroline. But lilies, tulips, and all flowers which 

 spring from bulbous roots have long stems, thick at the 

 lower end, and tapering towards the flower. 



Mrs. B. You again confound the stalk of the flower 

 with the general stem of the plant. Both flowers and 

 leaves, with but few exceptions, have each a separate 

 stem or foot-stalk : that of the flower is called by bota- 

 nists a peduncle or pedicel ; that of leaves a petiole. 

 These are perfectly distinct from, and independent of, the 

 general stem of the plant. The stems of bulbous plants 

 are contained within the bulbs as I have already inform- 

 ed you. 



Caroline. This mode of growing puts me in mind of 

 the pushing out of an opera glass, the sliding cylinders 

 of which are contained one within the other. 



Mrs. B. The leaves and fruit of this class of plants 

 grow from the centre of the last shoot, and form a sort 

 of cabbage at the top of the tree, which, if you cut off, 

 the tree perishes. 



Emily. But what becomes of the bark of these trees ? 

 How does that resist the pressure of so many successive 

 layers of wood ? 



Mrs. B. Endogenous plants have no real bark, the 

 external coats of wood are so much hardened as to ren- 

 der such a preservation unnecessary. 



Emily. But the palm and cocoa-nut tree, which I 

 have seen at Mr. Loddiges's hothouse, have a very rough 

 external coat, greatly resembling bark. 



182. Where are these broad flat stems to be seen! 183. What 

 gmall ones of the same description grow in the open air of our own cli- 

 mate! 184. What mistake does Caroline make concerning flowers 

 which spring from bulbous roots'? 185. How does Mrs. B. correct 

 this mistake! 186. Of what does Caroline say this mode of growing 

 reminds herl 187. What is said of the leaves and fruit of this class 

 of plants'? 188. What is said of endogenous plants as to bark! 

 What trees has Emily seen of this class which she thinks have barkl 

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