The development of ovule, seed and seed coat in a few representatives of the Marantaceae was studied. A subdermally initiated outer integument was found in a monocotyledon for the first time. The seed, which belongs to the most complex among the monocotyledons, is campylotropous and, furthermore, characterised by a so-called perisperm channel, an operculum, micropylar collar and aril, the latter having a function in fruit dehiscence. The mature seed coat consists mainly of a silicified endotesta covered by tanniniferous cells, derived from the inner and the middle layers of the outer integument, respectively.