BUDS AND LEAVES. 



23 



the stem; it is then denominated perfoliate. In other cases a pair of 

 leaves have their bases united about the stem ; such leaves are termed 

 connate. 



FlG. 33. Leaf of tulip-tree with deciduous 

 stipules. 



FlG. 34. Leaf of rose with permanent foli- 

 aceous stipules. 



The petiole is often furnished at its base with a pair of foliaceous or 

 membranous appendages, termed stipules. Very often these serve as 

 bud-scales and fall away after the leaf expands (Fig. 33) ; sometimes, how- 



FIG. 36. Vertical section through a breath- 

 ing-pore of a leaf, showing the arrangement of 

 the epidermal cells. Magnified. 



FIG. 35. Vertical section of a leaf, showing cells 

 of epidermis and parenchyma, and intercellular 

 spaces. Magnified. 



ever, they form a conspicuous part of the leaf and remain until it falls 

 (Figs. 32 and 34). 



