FOKM OF LEAVES 



93 



130. Digitately parted leaves of begonia. 



same is said of flowers and fruits. The blade of a sessile 

 leaf may partly or wholly surround the stem, when it is 

 said to be clasping (Fig. 

 132). In some cases the 

 leaf runs down the stem, 

 forming a wing : such 

 leaves are said to be de- 

 current (Fig. 133) . When 

 opposite sessile leaves are 

 joined by their bases, they 

 are said to be connate 

 (Fig. 134). 



196. Leaflets may have 

 one or all of these three 

 parts, but the stalks of leaflets are called petiolules and 

 the stipules of leaflets are called stipels. The leaf of the 

 garden bean has leaflets, petiolules, and stipels. 



197. The blade is usually attached to 

 the petiole by its lower edge. In pinnate - 

 veined leaves, the petiole seems to continue 

 through the leaf as a midrib (Fig. 124). 

 In some plants, however, the 

 petiole joins the blade inside 

 or beyond the margin (Figs. 

 126, 135). Such leaves are 

 said to be peltate or shield - 

 shaped. This mode of attach- 

 ment is particularly common 

 in floating leaves (e. g., the 

 water lilies). Peltate leaves 

 are usually digitate -veined. 

 198. SHAPE. Leaves and leaflets are infinitely variable 

 in shape. Names have been given to some of the more 

 definite or regular shapes. These names are a part of the 

 language of botany. These names represent ideal or typi- 



131. Complete leaves 

 of willow. 



132. Clasping leaf 

 of wild aster. 



