157 



Leaves simple, etc.— Coutinued. 



Smooth; bark -svithout milky juice: 

 Fruit Jieshy, or at least berry-like : 



l-seedecl (a stone), globular: Cherries: 



With mostly rounded teeth on the margin of leaf 45 



With sharp teeth on the margin of the leaf: 

 Dull green on upper surface of leaf; commonly 



downy below; teeth straight 47 



Shiny green on upx^er surface ; not downy below ; 

 teeth more or less incurved : 



Green on the under surface 44 



Pale on the under surface : 



Margin often with teeth of two sizes 48 



Margin with teeth of only one size 46 



3-seeded, pear-shaped : Buckthorns : 

 Margin of leaf wavy, sometimes with vcv'/ small teeth, 



or nearly entire 30 



Margin of leaf always toothed and somewhat downy 



on the under surface 31 



Fruit not fleshy nor berry-like— a catkin with persistent 

 woody scales : Alders : 



Base of the leaf wedge-shaped 75 



Base of the leaf rounded or heart-shaped 77 



b. With coarse (not bristle or prickle pointed) teeth : 



Leaves equal-sided ; teeth of one size or of two sizes and glandular- 

 pointed : 



Broadly triangle-shaped, not glandular-toothed ; bark bitter : 

 Poplars : 



Teeth hairy, close, and much incurved 85 



Teeth not hairy, rather distant, and but slightly incurved 86 



Ovate or lance-shaped, glandular-toothed ; bark not bitter : Alder 76 

 Leaves unequal-sided; teeth of two sizes, but not glandular- 

 pointed: Elm 62 



c. With deeply-cul hlunt or iwinted lohes, distant-undulate, prickle or 



bristle pointed teeth : 

 Circular in outline, with 3 to 7 (mostly 5) deep, sharp-pointed 



lobes; fruit a ball" : Sycamore 65 



Ovate, etc., in outline ; fruit an acorn : Oaks : 

 Leaves very large, 4 to 10 inches in length, with 3 to 6 pairs of 



deep blunt lobes 68 



Leaves smaller, mostly less than 3 inches long: 

 With bristle-pointed, deeply-cut teeth (occasionally with 3 to 



5 somewhat equal blunt lobes) 67 



With prickle-pointed shallow teeth (sometimes with wavy, but 

 not lobed margin) : 

 Halberd- shaped ; mature leaves usually glossy green on both 



sides 71 



Ovate or elliptic ; mature leaves usually downy on the under 



side 70 



B. — Leaves set opposite- on the branches: 



Margin deeply cut with 3-pointed lobes; fruit (seed) a 2- winged key'': 

 Maples : 



Lobes mostly entire, or only occasionally with coarse teeth 35 



Lobes always with rather fine sharp teeth - 34 



Margin entire, or only slightly indented with shallow, rounded teeth ; fruit 



a 1-seeded key5 : Ash „ 57 



