A study of the floral nectaries of Polygonum s.l. and related genera revealed that all nectaries are of a receptacular nature (persistent, axial nectaries). Two nectary types, in which the nectariferous zones are in close positional relationship with the stamens, could be distinguished. The Persicarieae have conspicuous nectar-secreting emergences which can be free or variously fused; trichomes or papillae are usually present. Most Polygoneae possess nectarial zones which are not well developed externally; trichomes or papillae are absent or range from few to many.