Ch. IV, 11] SPECIAL FUNCTIONS OF STEMS 



193 



single spine of the Cactus-lilve Eupliorljias is a stem, really 



the persistent and hardened flo^-er-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, nocleless, and leaf- 

 less, though sometimes 

 the}^ bear bracts (page 

 73). An elongated stem 

 ending in a single flower 

 or small cluster, espe- 

 cially if starting directly 

 from the ground, as with Adder's-tongue or Molcts, 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 tj'pical flower 

 stalk consists really of one 

 internode, bearing at its 

 top several nodes merged 

 together in one enlarged 

 RECEPTACLE wliich Sup- 

 ports the floral parts (page 

 271). 



The most striking of the 

 new functions assumed by 

 stems is found in the re- 

 placement of leaves as 

 foUage. In the simplest 



Fig. 1.37. — Spine, a branch 

 developed from an axillary bud, 

 in Honey Locust ; X 



Fig. L3S. — Euhus sqiiarrosu>i, a 

 shrub in which the foliage function i,5 

 assumed by the stems and petioles; 

 much reduced. (From Wiesner.) 



