108 MANUAL OF BOTANY 



as the secondary axes, a", and their divisions as the tertiary 

 axes, a"', &c. 



Kinds of Peduncle. — Under certain circumstances pedun- 

 cles and pedicels have received special names. Thus, when a 

 peduncle is elongated, and gives off from its sides sessile flowers 

 (figs. 212 and 213), or branches bearing flowers (figs. 210 and 

 211), it is called the rachis; but if, instead of being elongated, 

 it becomes more or less dilated, and bears nmnerous flowers, 

 it is termed the receptacle. The receptacle varies very much 

 in form ; thus, it is flattened in the Cotton Thistle (fig. 224), 

 conical in the Chamomile (fig. 202), concave and fleshy in 

 the Dorstenia (fig. 205), pear-shaped and hollowed out in the 

 Fig (fig. 204) ; or it assumes a variety of other intermediate 

 forms. 



It should be observed that the term receptacle is also applied 

 to the extremity of the peduncle or pedicel upon which the parts 

 of the flower are placed. This is, however, better called the 

 thalamus. 



When plants which have no aerial stem bear flowers, the 

 peduncle necessarily arises at, or under, the ground, in which 

 case it is called a scape or radical peduncle (fig. 200), as in the 

 Spring Snowflake, Tulip, Hyacinth, Primrose, and Cowslip. 

 The scape may bear either one flower as in the Tulip, or several 

 flowers as in the Hyacinth. 



Forms of Peduncle. — In form the peduncle is generally more 

 or less cylindrical, but besides the departvire from this ordinary 

 appearance exhibited by the receptacle just described, and 

 its modifications, it frequently assumes other shapes. It may 

 become more or less compressed, or grooved in various ways, or 

 excessively enlarged during the ripening of the fruit, as in the 

 Cashew-nut ; or it may assume a spiral character, as in the 

 ValUsneria (fig. 206) ; other modifications also may occur. 



Sometimes the peduncle, or several peduncles united, may 

 assume an irregular flattened appearance, somewhat resem- 

 bling the fasciated branch already described, and may bear 

 numerous flowers in a sort of crest, as in the Cockscomb, 

 and in the Cauliflower, where the united fleshy branches of 

 the peduncle form a rounded mass bearing on its upper part 

 abortive flowers. 



Insertion. — In speaking of the branches of a stem, we found 

 that in some cases, instead of arising in the axil of leaves, they 

 become extra-axillary in consequence of adhesions of various 

 kinds taking place between them and the stem and other parts. 



