The deficiency of specialized bibliography had caused great difficulties and changes
in the identification of the species, in the procedures of a Seed Testing Laboratory. Therefore,
through the morphological characteristics of Convolvulaceae weed seed species, which occur in
Brazil and in other tropical and temperate regions, it was elaborated a taxonomical key and drawings
in order to help the seed identification of 36 species. It was also presented the main synonyms and
some considerations about the species, as identification problems and others. The taxonomical
key were based mainly on the colour and pilosity of the seed coat (surface) and the hilum area, the
size and the outline of the hilum, which are very stable characteristics. It was used also the size
(length, wideness and thickness) of the seeds. The shape of the Convolvulaceae seeds, vary with
the amount of seeds developed in the fruit and is not a consistent characteristic that can be used in
identification.