Description from Flora of China
Herbs, perennial [or annual], terrestrial [epilithic or epiphytic], rhizomatous, without rhizoids, stolons, or traps. Roots fibrous. Leaves in a basal rosette, simple, petiolate or sessile, soft and fleshy; leaf blade adaxially usually with numerous viscid glands, veins pinnate, margin entire and usually involute. Inflorescences with a solitary flower, rarely a 2- or 3-flowered raceme, without scales, bracts, or bracteoles. Calyx 2-lipped; lower lip 2-lobed; upper lip 3-lobed. Corolla open at throat, palate of lower lip not raised; lower lip larger than upper lip, spurred, 3-lobed, middle lobe larger; upper lip 2-lobed. Capsule loculicidal, opening by 2 valves. Seeds many per capsule.
About 55 species; N temperate regions, most diverse in Central America, extending S to Patagonia; two species in China.