210 



VEGETABLE PHYSIOLOGY 



their hosts. The most easily observed of these is the 

 Dodder (Cuscuta), which often attacks the cow- wheat or the 



Fro. 102. SECTION OF STEM OF DICOTYLEDONOUS PLANT ATTACKED BY 

 HATJSTOEIA OF Cuscuta. 



clover (fig. 101). The seed when germinating puts out an 

 embryo which has no cotyledons. Germination takes 



