U-* TREES AMi SHRUBS 



2. RHOEIDIUNI Greene. 



Suit, woody, widely blanching desert shrub, feet high 



and of equal diameter with stems intricately interlaced, the short 



imetimes spinescent; leaves small, generally about % inch 

 long, with about 7 elliptic leaflets borne on a winged rachis; leaf- 

 lei- acute, mostly entire, the terminal slightly larger and occasional- 

 ly having a few coarse teeth near the apex: flowers small, in 

 crowded clusters on the naked branches of the previous season in the 

 axils above the leaf scars; calyx lobes orbicular, concave, entire; 

 petals white, finely sciliate; fruit globose, about 6 mm. in diameter; 

 hispisdulous, viscid. 



A single species common in the Lower Sonoran 



Z " ne l. R- microphyllum. 



3. TOXICODENDRON Miller. Poison Oak 



Low shrub, usually about 1 toot high, with 3-foliolatt- pois 

 ous eaves having large, broadh to rhomboid, acuminate. 



coarsely few-toothed or entire leaflets; flower inconspicuous, green- 

 ish yellow, in small, several-flowered axillary panicles; fruit de- 

 pressed globose, gabrous, white and shining when mature. 



!. 7". ri/dbergii. 



4. RHUS L. Sumac 



el spreading shrubs 3 to high or more, with pin- 



nately 5-to many-foliolate leave- and axillary or terminal panicles 

 Kill, dull whitish or yellowish flowers: leaves persistent or de- 

 ciduous, the leaflets lame. 1 to 3 inches long, flowers and fruit de- 

 bed under the family. 



Leaves evergreen, thick: flowers axillary in 



small clusters: stems very hard and woody. l. Ft. virens 



Leaves deciduous, thin: flowers in dense ter- 

 minal panicles; wood of stem soft, with 

 large pith. 



Rachis winged; leaflets densely pubescent be- 

 neath, of the same color on both surfaces. 2. /?, lanceolata 

 Rachis not winged: leaflets glabrous and 



paler benea th R. glabra. 



