ACERACEAE 



Sugar Maple 

 Acer saccharum Marsh. {Acer saccharophorum K. Koch) 



HABIT. A handsome tree 60-80 feet high and 2-3 feet in 

 diameter (max. 135 by 5Vi feet); dense, broad, rounded crown. 



LEAVES. Simple; orbicular; palmately 5-lobed (rarely 3- 

 lobed); 3-5 inches long; lobe margins entire or sparingly wavy- 

 toothed; thin and firm; glabrous; bright green above, paler 

 below; turning bright red or yellow in autumn. 



FLOWERS. Polygamous; in crowded corymbs; apetalous; 

 yellow-green; appearing with the leaves. 



FRUIT. Key U-shaped, with nearly parallel wings about 

 1 inch long; red-brown; glabrous; maturing in autumn. 



TWIGS. Slender; smooth; red-brown; shiny. Winter buds: 

 terminal Va-Yq inch long, acute, red-brown; nearly glabrous, 

 with 4—8 pairs of visible scales. 



BARK. Smooth and gray on young stems; becoming dark 

 gray, thick, and deeply furrowed; often with long, scaly plates. 



WOOD. Very important; hard, heavy and strong; flooring, 

 furniture, etc. 



SILVICAL CHARACTERS. Tolerant; rather slow-growing; 

 long-lived; wide-spreading, lateral roots; important as an orna- 

 mental and as a source of maple syrup and sugar. The form 

 growing on the Edwards Plateau of Texas has been designated 

 the variety sinuosum Rous. 



Black Maple 



Acer nigrum Michx. 



This species very closely resembles the sugar maple and by 

 many authors is considered to be a variety of it. It is distin- 

 guished from the sugar maple by the following characters: 

 leaves mostly 3-lobed and lower leaf surface and petioles downy, 

 leaf blades thicker and drooping at sides; twigs orange-brown; 

 buds hoary-pubescent; bark often nearly black and more deeply 

 and sharply furrowea. 



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