Aristolochiaceae, the Birthwort Family
Flowers greenish-brown or reddish-brown, at or near the ground, with inferior 6-celled ovary.
| 1a. Leaves alternate, on the stem; flowers on a basal scaly branch (1-4 dm. high; summer) | Virginia Snakeroot, Aristolochia serpentaria. |
| 1b. Leaves a single basal pair, bearing 1 short-stalked flower between them (spring) (Wild Ginger) — 2. | |
| 2a. Lobes of the perianth ending in a tubular portion 5-8 mm. long | Wild Ginger, Asarum canadense. |
| 2b. Lobes of the perianth ending in a tubular portion over 1 cm. long | Wild Ginger, Asarum canadense var. acuminatum. |
| 2c. Lobes of the perianth triangular, not tubular at the end | Wild Ginger, Asarum canadense var. reflexum. |