Rhus. 



ANACARDIACE.E. 25 



and ridges ; reaching its greatest development in southern Arkansas and 

 eastern Texas ; running into various forms (var. lanceolata, Gray ; var. 

 leucautha, DC). 



Wood light, soft, not strong, coarse-grained, compact, satiny, suscep- 

 tible of a good polish ; layers of annual growth clearly marked by several 

 rows of large open ducts ; medullary rays thin, not prominent ; color 

 light brown, streaked with green, or often tinged with red ; the sap-wood 

 lighter. 



Leaves and bark astringent, rich in tannin ; the leaves largely collected, 

 principally in Maryland, Virginia, West Virginia, and Tennessee, and 

 ground for tanning and dyeing. 



72. Rhus venenata, DC. 

 Poison Sumach. Poison Elder. 



Northern New England, south to northern Georgia, Alabama, and 

 western Louisiana, west to northern Minnesota, Missouri, and Arkansas. 



A small tree, G to 8 metres in height, with a trunk sometimes 0.15 to 

 0.20 metre in diameter, or more often a tall shrub ; low, wet swamps, or 

 more rarely on higher ground. 



Wood light, soft, coarse-grained, moderately compact ; layers of annual 

 growth clearly marked by three or four rows of large open ducts ; medul- 

 lary rays thin, very obscure ; color light yellow streaked with brown, the 

 sap-wood lighter. 



The whole plant, as well as the allied R. Toxicodendron, is exceedingly 

 poisonous to most persons, owing to the presence of a volatile principle, 

 Toxicodendric acid ; the white milky sap, turning black in drying, yields 

 a valuable lacquer. 



73. Rhus Metopium, L. 



Poison-wood. Coral Sumach. Mountain Manchineel. Bum-wood. 

 Hog Plum. Doctor-c/um. 



Semi-tropical Florida, — Bay Biscayne to the southern keys ; in the 

 West Indies. 



A tree 12 to 15 metres in height, with a trunk sometimes 0.60 metre 

 in diameter, reaching, in the United States, its greatest development on 

 the shores of Bay Biscayne, near Miami ; one of the most common trees 

 of the region, the large specimens generally decayed. 



Wood heavy, hard, not strong, close-grained, checking badly in drying, 

 containing many evenly distributed open ducts ; medullary rays numerous, 

 thin ; color rich dark brown streaked with red, the sap-wood light brown 

 or yellow. 



A resinous gum, emetic, purgative, and diuretic, is obtained from incis- 

 ions made in the bark of this species. 



