Description from Flora of China
Herbs, shrubs, or rarely trees. Leaves opposite or rarely alternate, whorled or basal, rosette forming; exstipulate; usually simple, rarely shallowly to deeply lobed, pinnately or rarely palmately veined. Inflorescences usually cymes, rarely racemes, axillary, often near apex and appearing terminal; usually pedunculate. Flowers perfect, zygomorphic, seldom actinomorphic. Calyx actinomorphic, rarely zygomorphic; usually (4 or)5-divided. Corolla gamopetalous, zygomorphic, rarely actinomorphic; usually 2-lipped. Fertile stamens 2 or 4, then often didynamous, rarely 5, epipetalous; anthers free or coherent, thecae 2, parallel, divergent, or divaricate; staminodes 1-3 or absent. Disc ringlike to cupular, rarely absent. Ovary superior in all Old World taxa [half inferior, or inferior], 1-loculed; gynophore seldom present; placentas (1 or)2, parietal, rarely 2-loculed, placenta 1 per locule and axile; ovules numerous, anatropous. Style 1; stigmas 1 or 2. Fruit usually capsular, loculicidal, septicidal, or circumscissile, rarely a berry, indehiscent. Seeds numerous, fusiform to ellipsoid or ovoid, minute, sometimes with appendages at 1 or both ends, with or without endosperm; embryo straight, cotyledons equal or unequal after germination.
About 133 genera and 3000 species: Africa, Central and South America, E and S Asia, S Europe, Oceania; 56 genera (25 endemic) and 442 species (354 endemic) in China.
A few foreign well-known ornamental species are cultivated in China, including the florist's gloxinia, Sinningia speciosa (Loddiges) Hiern, and African violet, Saintpaulia ionantha Wendland.
The two ovary carpels may each produce a stigma; these stigmas are fused into a single structure. Some students of Gesneriaceae have considered the stigma to be single and either simple (capitate) or 2-lobed, whereas others consider each of the two stigmas as units. We have maintained the latter usage, but a family-wide investigation of stigma development is needed. The distinction can be blurred, however, because the stigmas may be completely fused into one with a capitate apex (as in Didymocarpus) or one of the two carpels or stigmas may be aborted resulting in a single stigma that may or may not be 2-lobed.
Certain characters used in this treatment require some explanation. Disc shape is frequently described as "ringlike," "cupular," or rarely "tubular"; ringlike describes a disc that is shorter than or equalling its diameter, and cupular describes one that is longer than its diameter. Tubular describes a disc which is at least twice as long as wide. The corolla tube diameter measurement is for the widest part, usually the mouth.
Wang Wentsai, Pan Kaiyu, & Li Zhenyu. 1990. Gesneriaceae. In: Wang Wentsai, ed., Fl. Reipubl. Popularis Sin. 69: 125-581.
(Authors: Wang Wen-tsai, Pan Kai-yu, Li Zheng-yu; Anna L. Weitzman, Laurence E. Skog)