Flowers destitute of corolla, and sometimes also of calyx.

Order LXXIII. Aristolochiaceae. (Birthwort F.)

Herbs with perfect flowers, the tube of the 3-lobed calyx adherent to the 6-celled many-seeded ovary. Leaves heart-shaped or kidney-shaped, on long petioles from a thick rootstock. Stamens 12 or 6. Flowers solitary. Calyx dull-coloured, the lobes valvate in the bud.

As'arum

Tourn. Wild Ginger. A. Canaden'se, L. Radiating stigmas 6. Leaves only a single pair, kidney-shaped, and rather velvety, the peduncle in the fork between the petioles, close to the ground. Root-stock aromatic. Calyx brown-purple inside, the spreading lobes pointed. - Rich woods.