130 BOTANY. 



gence of the leaves. In Fig. 393 the angle of divergence 

 is I the circumference of the stem ; in Fig. 394 it is -J-, and 

 in Fig. 396 it is f its circumference. 



In studying some of your specimens, the string may 

 pass three times round the stem in its spiral course before 

 you come to a leaf placed over the first, and this leaf may 

 be the ninth in the upward succession, eight leaves being 

 required to complete the cycle. Here you have eight per- 



FIG. 397. 



pendicular rows of leaves, with an angular divergence of 

 f the circumference of the stem ; it is, therefore, called 

 the f arrangement. 



In some plants the leaf-cycle includes five turns of the 

 spiral and thirteen leaves, so that the fourteenth is placed 



