103 



BLACK WALNUT. 

 Juglans nigra, Linnaeus. 



FORM A large tree, usually attaining a height of 80-100 ft. with a diameter of 2-3 ft., but 

 may reach a height of 150 ft. with a diameter of 6-8 feet. Trunk usually straight, clean, 

 slightly tapering, bearing a round-topped crown. 



BARK Semi-fibrous, thick, rough, longitudinally and occasionally diagonally fissured. Outer 

 bark dark brown to grayish-black. Inner bark light, but turns yellow upon exposure. See 

 Fig. 81. 



TWIGS At first hairy, later smooth, orange-brown to dark brown, stout, covered with 

 rather inconspicuous, somewhate raised lenticels; pith light brown, chambered. 



BUDS Alternate, covered with thick, pubescent scales. Terminal buds usually less' than 

 J of an inch long, flattened, ovate, blunt-pointed. Lateral buds usually less than 1/6 of an 

 inch long, obtuse at apex, often superposed. 



LEAVES Alternate, compound with 13-23 leaflets. Leaflets 3-4 inches long, oblique at base, 

 acute at apex, serrate on margin, almost sessile and arranged opposite or alternate to each 

 other. 



LEAF-SCARS Alternate, large, 3-lobed, often heart-shaped, raised; upper margin notched 

 in which an axillary bud is often located. Bundle-scars grouped in three clusters, arranged 

 in a U-shaped line. 



FLOWE3.S Appear in May when the leaves are about half developed. Staminate and 

 pistillate flowers separate, but occar on same tree and usually on same branch. Staminate 

 arranged in unbranched catkins. Pistillate produced in 2-5-flowered spikes. 



FRUIT A sculptured nut with a fleshy indehiscent covering. Nut round, very rough, 1-2 

 inches in diameter, occurs solitary, in pairs, sometimes in 3s; contains an edible somewhat 

 oily kernel. 



WOOD Diffuse-porous with a ring-porous tendency; medullary rays inconspicuous; rich dark 

 brown, very durable, hard, strong, splits easily, takes glue well. Weighs 38.11 Ibs. per 

 cubic foot. Used in furniture, interior finishings, musical instruments, automobiles, sewing 

 machines, fire-arms. 



DISTINGUISHING CHARACTERISTICS The Black Walnut, also known as Walnut, some- 

 what resembles the Butternut or White Walnut but bears little resemblance to other trees. 

 It may be distinguished from the Butternut by its light brown chambered pith, shorter and 

 less flattened terminal buds, darker bark, larger size, more globose nut, notched upper margins 

 of leaf -scars, and the absence of a hairy fringe above the leaf-scar. 



RANGE New England and New York to Minnesota, and south to Florida. 



DISTRIBUTION IN PENNSYLVANIA Local throughout the State in rich bottomlands and 

 on fertile hillsides. 



HABITAT Prefers rich moist soil. Requires plenty of light and deep soil since it is 

 evidently tap-rooted. 



IMPORTANCE OF THE SPECIES The Black Walnut is one of the most valuable timber trees 

 native to this State. It reaches a large size, is attractive ornamentally, and produces wood 

 valuable for its color, figure, and the fine polish which it takes. The nuts are highly prized. 

 Forest grown trees rarely produce much fruit. Open grown trees produce abundant fruit 

 and often highly figured wood. 



