STEM APPENDAGES. 



105 



the Post Oak grape leaf the lobes 1 and 5 o\ erlap the leaf- 

 stalk, and these portions which do this are called alae, or 

 wings; some of the other lobes in this leaf overlap, but no 



I 



Fig. 8_'. THE 



distinctive name is applied to them. The spaces between 

 the lobes, as well as the depression at the base of the leaf 

 where the petiole is attached, are called sinuses, and the 

 Bhape and depth of these afford distinguishing characters. 

 These are the principal terms used in describing the shape 

 of grape leaves, and the strikingly different forms can be 

 described so that they may be recognized ; but it is often 

 the case that the difference in foliage in distinct varieties 

 is so slight that, although it is readily perceived by a prac- 

 tical eye, it is not possible to express these distinctions in 

 words. 



5* 



