BUR OAK 



acteristic cross-shape, while on a Post Oak just beside it the 

 leaves are irregular and varied in shape, with here and there 

 one of typical form. 



BUR OAK. MOSSY-CUP OAK 



Qiu'rnis Diacrocdrpa. 



Macrocarpa refers to the large size of the acorn. 



The average height is eighty feet, but in the»valley of the lower 

 Ohio it has been known to reach one hundred and sixty. Is tolerant 

 of many soils and grows rapidly. Ranges from Nova Scotia to Mani- 

 toba, south to Massachusetts, Pennsylvania, Kansas and Texas. 

 Forms the " Oak Openings " of Minnesota. 



Bark. — Light gray brown, deeply furrowed, scaly. Branches 

 with corky ridges. Branchlets stout, at first greenish, very pubes- 

 cent, afterwards light orange yellow, later ashy gray or light brown, 

 finally dark brown. 



Wood. — Brown with paler sapwood, heavy, strong, close-grained, 

 durable in contact with the ground, valuable. Used in ship and 

 boat building, all sorts of construction, interior finish of houses, cab- 

 inet-making, cooperage, carriages, agricultural implements, railway 

 ties, fencing. Sp. gr., 0.7453 5 weight of cu. ft., 46.45 lbs. 



Winter Btids. — Light reddish brown, broadly ovate or acute or 

 obtuse, pubescent, one-eighth to one-fourth of an inch long. 



Leaves. — Alternate, six to twelve inches long, three to six inches 

 wide, obovateor oblong, lyrately pinnatifid or deeply sinuately-lobed 

 or divided. Base usually long wedge-shaped, sinuses round, some- 

 times deep, sometimes shallow, lobes five to seven ; the terminal lobe 

 is largest, oval or obovate in outline, and crenately lobed ; or smal- 

 ler and three-lobed ; the lateral lobes are larger than the basal lobes. 

 A second form is broadly ovate and deeply or slightly crenately-lobed. 

 A third form is pinnatifidly cut into five or seven pairs of lateral 

 lobes with a three-lobed terminal. They come out of the bud con- 

 volute, downy, yellow green above and silvery white below. When 

 full grown are thick, leathery, bright green, shining above, pale 

 green or silvery and coated with pale or rusty pubescence below ; 

 midrib stout, pale, often pubescent below, primary veins conspicuous. 

 In autumn they turn dull yellow or yellowish brown. Petioles short, 

 stout, flattened and grooved, enlarged at the base. Stipules varying 

 in form, usually an inch in length, sometimes persistent. 



Flowers. — May, when leaves are one-third grown. Staminate 

 flowers borne in slender hairy aments from four to six inches long; 

 calyx yellow green, four to six-lobed, downy ; stamens four to six ; fil- 



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