158 



PHARMACEUTICAL BOTANY 



inflexed or reclinate vernation; if doubled on the midrib so that 

 the two halves are brought together as in the Oak or Peach, it is 

 conduplicate; when rolled inward from one margin to the other, as 

 in the Wild Cherry, it is convolute; when rolled from apex to base, 

 as in Ferns, it is circinate; when folded or plaited, like a fan as in 

 Ricinus, Maples, Aralias, etc., it is plicate; if rolled inward from each 

 margin toward the midrib on the upper side, as the leaves of the 

 Apple or Violet, involute; when rolled outward from each margin as 



FIG. 82. Stereogram of leaf structure. Part of a veinlet is shown on the right. 

 Intercellular spaces are shaded. (From Stevens.) 



Dock or Willow leaves, revolute. The inner surface is always that 

 which will form the upper surface when expanded. 



TJie Complete Leaf. The leaf when complete consists of three 

 parts, lamina, petiole, and stipules. The lamina or blade is the ex- 

 pansion of the stem into a more or less delicate framework, made up 

 of the branching vessels of the petiole. 



The petiole is the leaf stalk. The stipules are leaf -like appendages 

 appearing at the base of the petiole. 



