﻿Trees of New York State 285 



ANACARDIACEAE 



Ehus Vernix L. [Toxicodendron Vernix (L.) Shafer; Rhus venenata DC] 



Poison Sumach 



Habit — A shrub or small tree 20-25 feet in height with a trunk 5-6 inches in 

 diameter which generally divides near the ground into a number of stout, 

 spreading limbs to form an open, rounded, bushy crown of coarse branches. 



Leaves — Alternate, odd-pinnately compound, 7-14 inches long, consisting of 

 7-13 leaflets arranged suboppositely along a smooth, greenish red rachis. 

 Leaflets obovate- oblong, 3-4 inches long, acute at the apex, cuneate and 

 inequilateral at the base, entire, revolute margined, short-petiolate aside 

 from the terminal leaflet, at maturity coriaceous, dark green and lustrous 

 above with scarlet midribs, paler and glabrous below. 



Flowers — Appearing in June and July before the leaves have attained full 

 size, dioecious, yellowish green, borne in rather narrow, drooping, axillary 

 panicles 2^-8 inches long clustered near the tips of the twigs. Calyx 

 5-lobed, ovate, acute, glabrous. Disk prominent. Petals ovate-lanceolate, 

 acute, erect. Stamens 5, exserted, with slender filaments and orange-col- 

 ored anthers. Pistil consisting of an ovoid-globose, glabrous ovary sur- 

 mounted by 3 short, thick, spreading styles terminated by proximate, capi- 

 tate stigmas. Vestigial organs occur in flowers of both sexes. 



Fruit — A globose, slightly compressed, thin-fleshed, lustrous, ivory-white or 

 taA^Tiy white, somewhat striated drupe, tipped with the style remnants, 

 about Vs of an inch in diameter, borne in loose, pendant clusters, ripen- 

 ing in September but persisting on the trees far into the mnter. Pit pale 

 yellow, thin-shelled, prominently grooved. 



Winter characters — Twigs stout, glabrous, brown to orange-broA\-n, marked 

 by numerous, minute, raised lenticels, exuding a watery, poisonous juice 

 when broken, at length light gray. Pith large, yellowsh brown, homo- 

 geneous. Terminal bud conical, acute, purplish, finely pubescent, 1/5-% 

 of an inch long. Lateral buds similar but much smaller. Mature bark 

 thin, pale light gray, smooth or somewhat striate, marked with prominent, 

 horizontally elongated lenticels. 



Habitat — In old peat bogs and cold, wet swamps which are often inundated 

 for a portion of the year. 



Range — Northern New England westward through southern Ontario to Min- 

 nesota, southward into the Gulf States. Zones A, B, and C. 



XJses — A poisonous species to be shunned by people susceptible to its poison- 

 ous properties. The active principle is a non-volatile oil similar to and 

 causing the same reaction as that from Poison Ivy. The symptoms are 

 acute irritation of the skin including itching, swelling and the formation 

 of blisters which exude a hyaline, somewhat viscid fluid when ruptured. 

 It is recommended that the parts be scrubbed vigorously with alcohol or 

 a saturated solution of lead acetate as soon after exposure as possible. In 

 lieu of this, use soap and water. ISIore advanced stages may be relieved 

 with an aqueous solution of baking soda, applied directly to the affected 

 parts. The species has no economic value. 



