22 FLOWER. 



125. Spines are sharp-pointed organs, which must be 

 looked upon as merely abortions of a bud ; the spines of 

 the Sloe tree are convertible into branches, if that tree 

 be transplanted into a rich soil. They are likewise 

 continuous with the woody tissue of a plant, and thus 

 differ from prickles. 



Floral and Reproductive Structures. 



126. The organs included under this head, are the 

 true floral envelopes, the generative organs and fruit. 



127. Floral envelopes and generative organs consti- 

 Fig. 15. tute a nower > which is composed of the 



calyx (a), the corolla (b), the stamens (c), 

 and the pistil (d), in those cases in which 

 # all the parts are fully developed. 



128. Of the floral envelopes. If we take 

 a the flowers of a cowslip we shall be able to 

 separate its foliaceous structure into two 

 portions; an outer or green covering (a), 

 the calyx, and an inner or yellow one (b), 

 the corolla ; both taken together are called the Perian- 

 Fig. 16 thium, and the flower itself is termed Z)z- 

 chlamydeous. 



129. All flowers, however, have not two 

 distinct coverings, and such are termed 

 monochlamydeous ; and when none exist at 

 all, it is achlamydeous. 



130. The calyx, or outer floral covering, 

 is generally of a green colour, and consists 

 either of one continuous foliaceous piece, 

 or else is composed of several separate 

 pieces. 



131. The pieces of which a calyx is 

 composed, are termed sepals or phylla. 



132. The calyx of the Cowslip is of one piece, and is 

 therefore termed monosepalous, and the calyx of the 

 Mustard, of many, and is termed polysepalous. All mo- 



