ANACARDIACEAE. 117 



of Japan ; notable among the plants of temperate regions as in- 

 cluding the very poisonous poison ivy and poison sumach, the 

 former an attractive but ineradicable climber, and the latter an 

 unusually beautiful shrub. 



RHUS. Sumach. 



Deciduous shrubs or straggling small trees with aromatic 

 resinous or milky sap ; soft reddish or greenish wood with small 

 ducts, decreasingly smaller or in wavy transverse patterns in 

 the summer growth, and fine medullary rays ; usually stout 

 roundish or 3- or 5-sided twigs with large pith of similar shape ; 

 alternate somewhat raised triangular or C-shaped large leaf- 

 scars ; roundish sessile buds ; pinnate leaves with mostly toothed 

 or sometimes incised lanceolate leaflets ; small often imperfect 

 polypetalous yellowish flowers in axillary or terminal clusters ; 

 and small often dry drupe-like fruit. The true sumachs are 

 sometimes separated as Schmaltzia, and the name Toxicodendron 

 used for the poisinous group. 



1. Leaflets three. 2. 

 Leaflets 5 or more. 4. 



2. Fruit red, pubescent. R. canadensis. 

 POISONOUS. Fruit white, glabrous. 3. 



3. Prostrate or climbing by roots : leaflets thin, 



scarcely lobed. (Poison ivy). R. radicans. 



Bushy : leaflets firm, often deeply lobed. 



(Poison oak). R. Yoxicodendron. 



4. POISONOUS. Fruit white, glabrous: leaflets 



entire. (Poison sumach). R. Vernix 



Fruit red, pubescent. 5. 



5. Rachis winged between the leaflets. 6. 

 Rachis not winged. 7. 



6. Leaflets entire, glossy, glabrous beneath. R. copallina. 

 Leaflets toothed, hairy beneath R. javanica. 



7. Glabrous. 8. 

 Hairy. 9. 



8. Leaflets serrate. R. glabra. 

 Leaflets deeply cut. R. giabra laciniata. 



