WAYSIDE WEEDS. 163 



among the cells, so do they likewise exist amid the 

 vessel or vascular tissue. There are vessels which 

 are simply tubes, or it may be long cells with taper- 

 ing ends J others are like series of shorter cells 

 placed end to end, some are plain, others are dotted 

 and marked. But the most remarkable and inte- 

 resting to a beginner, as well ^.s the most easily 



FiO. 101.— Eoae leaf torn aennder to show a, a, spiral vesaels. 



observed, are the spiral vessels of plants. Take 

 almost any leaf, a strawberry or rose leaf if you can, 

 and tear it very gently across the leaf-veins. Ob- 

 serve as you do so, that you draw out some extreniely 

 fine, cobweb-like filaments, a few of which stretch 

 entirely across the rent (Fig. 101) ; these are the 



