Description from Flora of China
Herbs, shrubs, rarely lianas, subshrubs, or trees; root, stems, and leaves with oil cells. Leaves alternate; stipules absent; petiole usually present and well defined; leaf blade simple, usually pinnately veined, sometimes palmately 3-5-veined, margin usually entire, rarely 3-5-lobed. Inflorescences terminal or axillary, racemes, cymes, or corymbs, or flowers solitary. Flowers bisexual, zygomorphic or actinomorphic. Perianth usually with 1 petaloid whorl (in Saruma with 2 whorls: outer one sepaloid, inner one petaloid), mostly connate into distinct tube, cylindric to campanulate or subglobose; limb rotate, urceolate, cylindric, or ligulate, 1-3-lobed; lobes valvate. Stamens 6-12 (in China), in 1 or 2 series; filaments adnate to ovary (in Asarum) or style column (in Thottea) with anthers free, or filaments and anthers fully adnate to style column to form gynostemium (in Aristolochia); anthers 2-loculed, dehiscence longitudinal. Ovary inferior to superior, 6-loculed (in Thottea 4-loculed); carpels connate only at base or fully fused; ovules numerous, anatropous, usually in 1 or 2 series; placentation parietal. Styles free or connate, column 3- or 6-lobed (in Thottea 5-20-lobed). Fruit a fleshy or dry capsule, rarely siliquiform or follicular. Seeds many; testa somewhat hard or crustaceous; endosperm copious, fleshy; embryo minute.
About eight genera and 450–600 species: primarily in tropical and subtropical regions; four genera (one endemic) and 86 species (69 endemic) in China.
(Authors: Huang Shumei (黄淑美 Hwang Shu-mei) ; Lawrence M. Kelly , Michael G. Gilbert)
Cheng Ching-yung, Yang Chun-shu & Hwang Shu-mei. 1988. Aristolochiaceae. In: Kiu Hua-shing & Ling Yeou-ruenn, eds., Fl. Reipubl. Popularis Sin. 24: 159–245.