PHYLLOTAXY 



8. Continue this numbering, beginning with any numbered 



scale, until the majority of the scales of the cone are 

 numbered. 



9. Take the scale next above scale number i in a vertical 



line, subtract i from the number upon this scale, and 

 the result will be the number of leaves passed through 

 in going from one leaf to the one directly above the 

 one from which we started. This, of course, will be 

 the denominator of the fraction. 



10. Verify this number several times, taking other numbered 



scales for starting-points. (The accuracy of this 

 method may be proven upon cones with few scales 

 such as those of the American Larch.) 



11. The numerator will be the smaller number of secondary 



spirals. 



XII. Examine all the cones of different kinds you can get, 

 and determine the phyllotaxy of each. In this way, arrange- 

 ments represented by the fractions |, ^, and ^ may be 

 found, and sometimes || and |4 may be made out. 



Compare these fractions in the same way as in X. 



XIII. Examine an erect branch of some species of Maple 

 and notice : 



1 . The regularly opposite leaves. 



2. That the pairs of leaves upon adjacent nodes are decus- 



sate, i.e. are at right angles to one another. 



3. The petioles of both leaves in each pair are equal or very 



nearly so. 



4. Look down upon the top of the stem and notice the 



four regular vertical ranks. 



5. Make sketches to show these points. 



