CH. IV, 11] SPECIAL FUNCTIONS OF STEMS 



193 



single spine of the Cactus-like Euphorbias is a stem, really 



the persistent and hardened flower-bearing branch. As in 



case of leaves, however, 



the significance of these 



spines is uncertain (page 



79). 



Support of the flowers, 

 which mostly stand out 

 in the light, is another of 

 the special functions of 

 stems. Flower stalks 

 are usually slender-cylin- 

 drical, nodeless, and leaf- 

 less, though sometimes 

 they bear bracts (page 

 73). An elongated stem 

 ending in a single flower /' '/ FlG - 137. Spine,, a branch 



/ rf developed from an axillary bud, 

 Or small cluster, espe- Q// in Honey Locust ; 



cially if starting directly 

 from the ground, as with Adder' s-tongue or Violets, is called 

 a SCAPE; a flower stalk from the axil of a leaf is called a 



PEDUNCLE, and in clusters 

 each separate stalk is a 

 PEDICEL. A typical flower 

 stalk consists really of one 

 internode, bearing at its 

 top several nodes merged 

 together in one enlarged 



RECEPTACLE which SUp- 



ports the floral parts (page 

 271). 



The most striking of the 

 new functions assumed by 



FIG. 138. Rubus australis, a shrub stems is found in the re- 

 in which the foliage function is assumed n lr,p PTnpT1 t n f Ipflvpc! flq 

 by the stems and petioles; much reduced. P lacement ol 



(From Wiesner.) foliage. In the simplest 



