Description from Flora of China
Herbs, annual or perennial. Roots sometimes tuberous. Stems ± succulent, often climbing. Stipules sometimes present especially in seedlings. Leaves alternate; petiole long; leaf blade peltate or palmately lobed or divided. Inflorescences indeterminate, racemose, elongate, and stemlike or condensed and umbellate, with each flower subtended by a single leaf. Flowers bisexual, solitary, zygomorphic, large, on a long axillary pedicel. Sepals 5, imbricate, adaxial 1(or 3) extended into a long slender nectariferous spur. Petals 5 or some aborted, yellow, orange, blue, or purple, clawed, imbricate, 2 upper petals larger and connate with spur, others usually smaller and inserted in opening of spur. Stamens 8, 2-verticillate, distinct, unequal; anthers 2-celled, dehiscent by longitudinal slits. Ovary superior, 3-loculed, placentation axile; ovule 1 per locule, pendulous from axile apex, anatropous; style 1, apical; stigma linear, 3-lobed. Fruits separating into 3 1-seeded mericarps, fleshy or dry. Seed without endosperm; embryo straight.
Huang Chengchiu, Huang Baoxian & Xu Langran. 1998. Tropaeolaceae. In: Xu Langran & Huang Chengchiu, eds., Fl. Reipubl. Popularis Sin. 43(1): 90-92.
Three genera and ca. 90 species: Central and South America; one species (introduced) in China.
(Authors: Liu Quanru (刘全儒); Lihua Zhou (周丽华))