Anacardiaceae, the Cashew Family
Shrubs or small trees, with milky or resinous juice, alternate compound leaves sometimes poisonous to the touch, and small clustered greenish or yellowish flowers.
| 1a. Leaflets 7 to many (1-5 m. high) (Sumach) — 2. | |
| 1b. Leaflets 3-5. | |
| 2a. Axis of the leaves wing-margined between the leaflets | Sumach, Rhus copallina. |
| 2b. Axis of the leaves not margined — 3. | |
| 3a. Leaflets entire | Poison Sumach, Rhus vernix. |
| 3b. Leaflets serrate — 4. | |
| 4a. Bark of the older stems glabrous | Sumach, Rhus glabra. |
| 4b. Bark of the older stems densely velvety-hairy | Sumach, Rhus typhina. |
| 5a. Terminal leaflet narrowed to a sessile base (5-20 dm. high) | Sumach, Rhus canadensis. |
| 5b. Terminal leaflet on a definite stalk, round or acute at base (3-8 dm. high, or climbing by hold-fast roots) | Poison Ivy, Rhus toxicodendron. |