157 

 Leaves simple, etc.— Continued. 



Smooth ; bark wifhout milky juice : 

 Fruit flesh}/, or at least berry-like : 



1-seeded (a stone), globular: Cherries: 



With mostly rounded teetb 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 upper 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 verj 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- cut hlant or pm.nted lobes, 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, deex:)ly-cut teeth (occasionally with 3 to 



5 somewhat equal blunt lobes) 67 



With inlckle-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 oiyposite' 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 shcillow, rounded teeth ; fruit 



a 1-seeded keys : Ash = 57 



