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, 

 plum, poplar, wil- 

 low. For 8-ranked, 



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 known 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 only 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 



D 



