ANACARDIACE^E 605 



the shores of the Atlantic to those of the Pacific -Ocean, with sixteen or seventeen 

 species within the territory of the United States. Of these, four attain the habit of 

 small trees. The acrid poisonous juice of Rhus vernicifera, DC., of China, furnishes 

 the black varnish used in China and Japan in the manufacture of lacquer, and other 

 species are valued for the tannin contained in their leaves or for the wax obtained 

 from the fruit. 



The name of the genus is from 'Povs, the classical name of the European Sumach. 



CONSPECTUS OF NORTH AMERICAN ARBORESCENT SPECIES. 



Flowers in terminal thyrsoidal panicles ; fruit globular, clothed with acrid hairs ; leaves 

 unequally pinnate, deciduous ; branchlets without terminal buds. SUMACHS. 



Branches and leaf -stalks densely velvety hairy; leaflets 11-31, pale on the lower sur- 

 face ; fruit covered with long hairs ; buds inclosed in the enlarged bases of the 

 petioles; juice milky. 1. R. hirta (A, C). 



Branches and leaf -stalks pubescent ; rachis winged ; leaflets 9-21, green on the lower 

 surface ; fruit pilose ; buds not inclosed by the petioles ; juice watery. 



2. R. copallina (A, C). 



Flowers in axillary slender panicles ; fruit glabrous, white ; leaves unequally pinnate, decidu- 

 ous; leaflets 7-13 ; branchlets with terminal buds.. 3. R. Vernix (A, C). 

 Flowers in short compact terminal panicled racemes ; fruit pubescent ; leaves ovate, entire 

 or serrate, simple or rarely trifoliolate, persistent. 4. R. integrifolia (G). 



1. Rhus hirta, Sudw. Staghorn Sumach. 



Leaves 16'-24' long, with stout petioles usually red on the upper side and covered 

 with soft pale hairs, enlarged at the base and surrounding and inclosing the buds 

 developed in their axils, and 1131 oblong often falcate rather remotely and sharply 

 serrate or rarely laciniate long-pointed nearly sessile or short-stalked leaflets rounded 



or slightly heart-shaped at the base, at first covered above like the petioles and young 

 shoots with red caducous hairs, bright yellow-green until half grown, and at maturity 

 dark green and rather opaque on the upper surface, pale or often nearly white on the 

 lower surface, glabrous with the exception of the short fine hairs on the under side of 

 the stout midribs, and primary veins forked near the margins, opposite, or the lower 

 ones slightly alternate, those of the 3 or 4 middle pairs considerably longer than 



