36 ON STEMS. 



. .., .-.' 



The duration of roots is either annual, biennial, or 

 perennial. To the first belong plants whose existence 

 is limited to one summer, such as barley, and a vast 

 number of garden and field flowers. The biennial root 

 produces the first season only herbage, and the following 

 summer flowers and fruit, or seed ; after which it perish- 

 es. The perennial belong to plants which live to an in- 

 definite period, such as trees and shrubs. 



A root consists of a collection of fibres composed of 

 vascular and cellular tissue, but without trachas or vessels 

 destined for the transmission of air; but there is so 

 great an analogy between the structure of the root and 

 that of the stem, that I shall reserve what observations I 

 have to make on this subject till our next meeting, when 

 I propose to examine the nature of the stem. 



CONVERSATION III. 



ON STEMS. 



Mrs. B. Every plant has a stem. 



Caroline. That is to say, trees and shrubs ; for there 

 are many plants, such as violets, anemones, fern, and a 

 variety of others, which have large bunches of leaves 

 growing from the roots out of the ground : the flowers, it 

 is true, have each a stem, but the plant itself seems to 

 have none. 



Mrs. B. I must repeat my assertion : every plant 

 has a stem, through which the sap circulates, and from 

 which the leaves and flowers spring. This stem, it is 

 true, is not always apparent : it is sometimes concealed 

 under ground, sometimes disguised under an extraordi- 

 nary form. The stem of the tulip is contained within 

 the bulb or onion, which is commonly, but improperly, 

 called its root ; that of the fern is subterraneous. A very 

 curious plant grows in some of the valleys of the Alps, 



f 150. What is the duration of roots'? 151. What are the annual 

 the biennial and perennial! 152. Of what do roots consist! 

 153. Through what part of every plant does the sap circulate"? 154. 

 Is the stem always apparent 1 ? 155. Where is it in the tulip; and 

 in the fern! 156. What curious plant is mentioned by Mrs. B. that 

 grows in the valleys of the Alps! 



