STEM APPENDAGES. 



107 



they are called pubescent — woolly, or hairy, according to 

 the degree of roughness. When the leaves are merely 

 smooth, they are called glabrous, but if they have a polished 



Fig. S4.— The Post Oak. 



surface, then they are called shining. When the leaves ar 

 covered with a whitish bloom, or waxy substance that 

 readily rubs off, they are called glaucous. 



There is also a great difference in the texture of leaves, 

 some are very thick and tough, while others are brittle, 

 But the thinness or thickness of the leaf does not indicate 



