10 SYLVAN ONTARIO. 



V. THE STEM OR FOOTSTALK OF THE LEAF. 



This is called the petiole, but in a leaflet it is the stalk. 



The petiole may be perfectly round, or flattened as in the Poplars, 

 or with a groove above as in the Cherries, or bordered by a- 

 narrow wing on each side as in the Sweet Viburnum, or 

 marked by conspicuous glands (See VII. below) as in the 

 High-bush Cranberry, the Cherries, or the Shining Willow. 

 The petiole is sometimes not in line with the midrib, and 

 may then becalled oblique, as in the very small leaves of the 

 Hemlock or the very large ones of the Basswood. The 

 length of the petiole often serves to distinguish a species. 

 A blade without petiole or stalk is sessile. 



VI. STIPULES are small structures growing in pairs at the base of or 



along a petiole. In many species these disappear as soon as 

 the leaves are unfolded, but in cases where they remain 

 throughout the summer they are often distinctive marks. 

 (See p. 16 27a, 27c, 27d, 26b; p. 20 37b; p. 26 67b.) 



VII. SURFACE OF LEAF OR TWIG. 



Smooth : Without hairs of any kind ; no reference to evenness of 

 surface. 



Glaucous : Covered with a bloom like a cabbage-leaf or a grape. 

 This covering is usually pale or white on the lower surface 

 of leaves. It gives the color to " blueberries " and is 

 noticeable in some cases on the upper surface of leaves, as 

 in the Juneberries. In all cases it may be rubbed off, 

 leaving a more or less shining surface. 



Downy or Pubescent : With fine, soft, short hairs. 



Woolly : With dense matted hairs. 



Hoary : With fine, short, white or greyish down. 



Rough : Applied to the " feel " of a leaf as in the Slippery Elm 

 or Red Mulberry. 



Scurfy : Covered with loose scales, usually colored or shiny. 



Resinous-dotted : With shining dots, caused by a resin-like sub- 

 stance. Such leaves are often sticky when pressed between 

 moistened finger and thumb. 



Glands : Waxy-looking bodies or raised dots found on petioles, or 

 on the midrib above as in Chokeberry, or on the points of 

 teeth as in some Willows and Cherries. (See p. 34 24c> 

 24d, 24e: p. 20 37b.) 



