394 TREES IN" WINTER 



POISON SUMACH 



Poison Dogwood, Poison Elder, Swamp Sumach. 



Rhus Vernix L. 



R. venenata DC. 



HABIT — A shrub or small tree 5-20 ft. in height with a trunk 

 diameter reaching 8-10 inches; trunk generally forking near the ground 

 producing an open, rounded, bushy head. 



BARK — Thin, light gray, smooth or slightly roughened with more or 

 less conspicuous horizontally elongated lenticels. 



TWIGS — Stout, brown to orange brown, older growth light gray, 

 smooth with watery resinous juice turning black on exposure. LEN- 

 TICELS — numerous, minute, raised dots. PITH — yellowish-brown. 



LEAF-SCARS — Alternate, more than 2-ranked, comparatively large, 

 conspicuous, inversely triangular, raised, upper margin straight, 

 slightly depressed or elevated, pointed and projecting. STIPULE-SCARS 

 — absent. BUNDLE-SCARS — conspicuous, irregularly scattered in % 

 closed ring or a single curved line. 



BUDS — Terminal buds present, small but larger than laterals; short- 

 conical, 3-20 mm. long, purplish. BUD-SCALES — finely downy on the 

 back and margins. 



FRUIT — A globular, slightly compressed, striate drupe about 5 mm. 

 in diameter, very shiny, ivory white or yellowish-white, generally per- 

 sistent through the winter in long pendant clusters. The species is 

 dioecious, however, and therefore some trees do not fruit. 



COMPARISONS — From the other Sumachs the Poison Sumach is dis- 

 tinguished by the presence of a terminal bud, its broad leaf-scars not 

 encircling the bud, with conspicuous generally scattered bundle-scars. 

 The loose clusters of white fruit are distinctive when present. The 

 Poison Sumach is almost entirely confined to swamps or wet places 

 while the other Sumachs grow for the mo^t part in dryer situations. 

 The Poison Sumach resembles its climbing relative the Poison Ivy \_Rhus 

 Toxicodendron L.] in that all parts of the plant at all times of the year 

 contain an oil poisonous to the touch, only more actively so. Some 

 individuals are more and others less susceptible. A preventive 

 against the poison is thoroughly to wash as soon as possible in strong 

 alcohol or strong soap suds the parts of the body that have come in 

 contact with the plant. 



DISTRIBUTION — Low grounds and swamps; occasional on the moist 

 slopes of hills. Infrequent in Ontario; south to northern Florida; west 

 to Minnesota and Louisiana. 



IN NEW ENGLAND — Maine — local and apparently restricted to the 

 southwestern sections; as far north as Chesterville, Franklin county; 

 Vermont — infrequent; common throughout the other New England 

 states, especially near the seacoast. 



\%^OOD — Light, soft, coarse-grained, light yellow, streaked with 

 brown, with lighter colored sapwood. The juice can be used as a 

 black lustrous durable varnish. 



