PHYLLOTAXY 



49 



111. Every plant has its own arrangement of leaves. 

 For opposite leaves, see maple, box-elder, ash, lilac, 

 honeysuckle, mint, fuchsia. For 2-ranked arrangement, 

 see all grasses, Indian corn, basswood, elm. For 3 -ranked 

 arrangement, see all sedges. For 5-ranked (which is 

 one of the commonest), see apple, cherry, pear, peach, 

 pluir. poplar, wil- 

 low. For 8- ranked, ,^4^ 

 see holly, osage 

 orange. More com- 

 plicated arrange- 

 ments occur in 

 bulbs, house leeks, 

 and other condensed 

 parts. The arrange- 

 ment of leaves on the 

 stem is Icnown as 

 phyllotaxy (literally 

 "leaf - arrange- 

 ment".) Make out 

 the phyllotaxy on 

 any plant. 



112. In some 

 plants, several leaves 

 occur at one level, 

 being arranged in a 

 circle around the stem. 

 ticillate or whorled. 

 usually narrow. 



113. Although a definite arrangement of leaves is the 

 rule in most plants, it is subject to modification. On 

 shoots which receive the light onl}^ from one side or which 

 grow in difficult positions, the arrangement may not be 

 definite. Examine shoots which grow on the under side 

 of dense tree -tops or in other partially lighted positions. 



79. Rhubarb grown in the light. 



Such leaves are said to be ver- 

 Leaves arranged in this way are 



