206 



BLACK GUM. 

 Nyssa sylvatica, Marshall. 



GENUS DESCRIPTION The genus Nyssa is rather limited in its distribution being confined 

 to the eastern United States and southern Asia. It comprises 7 species in the world 5 of which 

 are native to North America and 1 to Pennsylvania. All the representatives produce wood which 

 is very tough on account of its twisted and contorted grain. 



FORM Usually a medium-sized tree with a Leight of 15-40 ft., but may reach a height 

 of 106 ft. with a diameter of 5 feet. Trunk straight and rather continuous. Many lateral 

 branches are horizontal; some of the lower are drooping and the upper ascending. Old trees 

 often have a low Hat crown but have their middle and lower trunk covered with small 

 horizontal branches. 



BARK Grayish, smooth to scaly on young trunks; reddish-brown to grayish-black, very 

 rough and scaly on older trunks. Forms what is known as alligator bark on very old trunks 

 characterized by quadrangular and hexagonal blocks. See Fig. 100. 



TWIGS Smooth, with few lenticels, grayish to reddish-brown; pith rather large, white, 

 separated by layers of stone cells which may be seen with magnifying glass. 



BUDS Alternate, ovate, reddish-brown, J of an inch long, usually smooth, covered by 3-5 

 visible, ovate, closely overlapping scales. Lateral buds sometimes superposed, smaller than 

 terminal one. Buds originate close to leaf-scar and occasionally protrude into it. 



LEAVES Alternate, simple, oval, 2-5 inches long, acute at apex, wedge-shaped at base, 

 entire and slightly thickened on margin, dark green and shiny above, often hairy below, 

 turning to a gorgeous red in fall. 



LEAF-SCARS Alternate, conspicuous, rather large, broadly crescent-shaped, with three 

 single or 3 groups of bundle scars, which are conspicuous on account of size; brownish in 

 color, contrasting with lighter surface of the leaf-scar. 



FLOWERS Appear in May or June. Borne on long slender somewhat downy stalks. Sta- 

 minate And pistillate flowers separate. Slaminate occur in dense many-flowered heads; 

 pistillate in open few-flowered clusters. 



FRUIT A small, dark blue, fleshy berry or drupe, ovoid, of an inch long, 1-3 in a 

 cluster, often with a few remnants of undeveloped pistillate flowers at base. Borne on 

 long stalks. Ripens in Octobei. 



WOOD Diffuse-porous; rays indistinct; growth-rings usually indistinct; pores numerous, 

 small, uniform in si/e and distribution; wood cross-grained, tough to split, diflicult to work, 

 not hard, moderately strong and stiff, not durable, light yellow. Weighs 36.91 Ibs. per cubic 

 foot. Used for hubs of wheels, boxes, ironing boards, rolling pins, chopping bowls, excelsior, 

 broom handles, baskets, and berry crates. 



DISTINGUISHING CHARACTERISTICS The Black Gum, also known as Sour Gum, Tupelo, 

 and Pepperidgn, can be distinguished by its alligator bark when old, grayish to reddisli-brcnvu 

 smooth clear twigs when young which are marked with conspicuous leaf-scars with three 

 bundle-scars. The buds diverge very much from the twigs and may be superposed. Lateral 

 branches on young trees often take a horizontal position. The separation of the pith by stone 

 cells, the gorgeous red color of the autumnal foliage, and the bluish berries also aid in 

 recognizing it. 



RANGE Maine to .Tampa Bay, Florida; west to southern Ontario and Michigan, southward 

 to Texas. 



DISTRIBUTION IN PENNSYLVANIA Very common in the eastern, central, and southern 

 parts, local in western part, rarer in northern part. Reaches large size in swamps of Adams 

 and Franklin counties. 



HABITAT Found in variable habitats. Very c-omnion on burnt-over areas, on dry mountain 

 slopes, abandoned fields, abandoned charcoal hearths; but reaches its best development along 

 streams and in low wet situations. While it lias preferences it is not a chooser of habitats. 



IMPORTANCE OF THE SPECIES The Black Gum has been despised since the early farmers 

 tried to split it for fence rails. It is slowly gaining favor, but is not of suflicient importance 

 to be recommended for forest planting. Its autumnal foliage is beautiful and in winter the 

 form of young trees is very attractive. 



