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POISON SUMACH. 



Rhus Vernix, Linnaeus. 



FORM A shrub to small tree, usually 5-10 ft. high but may reach a height of 20 ft. with a 

 diameter of 8 inches. Usually branches near ground. Crown wide, deep, and usually rounded. 



BARK Smooth, somewhat streaked, thin, light to dark gray, roughened with horizontally- 

 elongated lenticels. 



TWIGS Stout, orange-brown, later light gray, smooth, often glossy, covered with numerous 

 raised lenticels, contain yellowish -brown pith; if punctured or cut, exude watery juice which 

 turns yellow upon exposure. 



BUDS Alternate; terminal bud present and larger than lateral ones; purplish, conical, acute, 

 about 1/5-3/5 of an inch long, covered with a few scales which are downy on back and margin. 



LEAVES Alternate, compound, 7-14 inches long, with wingless petiole, and with 7-13 leaflets, 

 obovate, 3-4 inches long, acute at apex, wedge-shaped at base, entire-margined, dark green and 

 shiny above, pale below. 



LEAF-SCARS Alternate, large, broad, conspicuous, do not encircle buds, upper margin straight 

 or nearly BO, contain numerous bundle-scars which are scattered or arranged in a curved line. 



FLOWERS Appear about June or July. Staminate and pistillate flowers borne on different 

 plants. The small yellowish-green flowers are arranged in long, drooping, rather narrow panicles. 



FRTJIT A small, spherical, glossy, ivory-white to yellowish-white drupe arranged in loose, 

 drooping, grape-like clusters. It is about 1/5 of an inch in diameter, slightly compressed and often 

 persists far into winter. Ripens about September. Pistillate trees alone bear fruit. 



WOOD Ring-porous; brittle, soft, coarse-grained, light yellow in color. Weighs 27.31 Ibs. per 

 cubic foot. 



DISTINGUISHING CHARACTERISTICS The Poison Sumach, also known as Poison Oak, Poison 

 Dogwood, Poison Elder, and Swamp Sumach, can be recognized in winter by its alternate buds 

 with the terminal bud present, its broad leaf-scars which do not encircle the bud and its smooth 

 and rather stout branchlets. The white berry-like fruit arranged in drooping clusters often per- 

 sists far into winter. The leaves are compound, without winged petioles and have from 7-13 shiny 

 leaflets with entire margin which turn to a brilliant scarlet or orange in autumn. This species 

 is usually found in swamps. 



RANGE Ontario, south to Florida, west to Minnesota and Louisiana. 



DISTRIBUTION IN PENNSYLVANIA Occasional and local in the eastern, southern and central 

 parts. Rarer in other parts. 



HABITAT Prefers low grounds and swamps. Occasionally found on moist slopes. 



IMPORTANCE OF THE SPECIES This shrub or small tree is one of our most poisonous 

 plants. The wood which it produces is of no commercial importance. Some people are entirely 

 immune to its poisonous principles, while others are affected by it upon handling it while a few 

 need only to walk by it. It is claimed all traces of the poison can be removed by washing the 

 parts thoroughly with a saturated alcoholic solution of acetate of lead immediately or a few 

 hours after the contact. Pure alcohol is also valuable as a wash if applied shortly after contact. 



