209 



SOUR-WOOD. 



Oxydendrum arboreum, (Linnaeus) De Candolle. 



GENUS DESCRIPTION The Sour-wood is the sole representative of the genus Oxydendrum. 

 The word Oxydendrum means acid tree, in allusion to the acid foliage. 



FORM A medium-sized tree which may reach a height of 50-60 ft. with a diameter of 20 inches, 

 but usually is about 25 ft. in height with a diameter of 8 inches. Trunk usually straight, tall, 

 slender, and bears a narrow round-topped crown. 



BARK Rather thick, roughened by fissures which separate rounded ridges covered with 

 thick scales. On old trunks grayish often tinged with red; on young branches reddish-brown. 



TWIGS Rather slender, at first yellowish-green, later orange-colored and reddish-brown. 

 Marked with numerous, oblong, elevated lenticels. 



BUDS Alternate, axillary; terminal buds absent; small, partly imbedded in the bark, acute 

 at apex, covered with several opposite dark red scales. 



LEAVES Alternate, simple, oblong, stalked, acute at apex, wedge-shaped at base, serrate 

 on margin, very smooth, 5-7 inches long, l$-2i inches wide. 



LEAF-SCARS Alternate, elevated, nearly triangular, with a single compounded bundle-scar. 



FLOWERS Appear about July. White, perfect, with cylindrical corolla, and borne in 

 racemes often 6-8 inches long. 



FRUIT A 5-sided, ruvalved capsule terminated by a persistent style. Matures in September 

 only a month or six weeks after the flowers. Capsules often persist in clusters. 



WOOD Diffuse-porous; hard, heavy, compact, reddish-brown with lighter sapwood. Medullary 

 rays are numerous but narrow. Weighs 46.48 Ibs. per cubic foot. Used locally for runners 

 of the Appalachian tanbark sleds, and for tool handles. 



DISTINGUISHING CHARACTERISTICS The Sour-wood, also known as Sorrel-tree and Sour 

 Gum, can be distinguished in summer by its white bell-shaped flowers which are arranged 

 in racemes resembling the lily-of-the-valley. The alternate bitter leaves which resemble the 

 peach leaf are also characteristic. The bark on older trees resembles that of the Black Gum. 

 The winter buds, which are dark red, alternate, very small, often partly inbedded by bark, are 

 also characteristic. 



RANGE Pennsylvania and Indiana south to Florida and western Louisiana. 



DISTRIBUTION IN PENNSYLVANIA Found only sparsely in the southeastern part of the 

 State. 



HABITAT Usually frequents well-drained soils. Commonly found on hillsides, seldom along 

 streams. 



IMPORTANCE OF THE SPECIES The Sour-wood is native only to a very small portion 

 of southern Pennsylvania. Its small size and limited distribution in this State prevent it from 

 being recommended for fores-trj purposes. It is, however, an attractive ornamental tree on 

 account of its form, ia*e flowering, beautiful and attractive autumnal foliage. 



14 



