The successful interspecific cross is reported for the first time between kenaf (Hibiscus cannabinus L .), a diploid species (2n = 36) and roselle (Hibiscus sabdariffa L.), a tetraploid species (2n = 72) . Kenaf, grown for its bast fiber and also under investigation as a source of paper pulp, is fast-growing and well adapted to mechanical harvesting, but susceptible to root-knot nematodes . Roselle, also grown for its bast fiber, is slower growing, not well adapted to mechanical harvesting, but certain varieties are resistant to root-knot nematodes . Five hybrid plants were produced from the pollination of 4,445 flowers of kenaf with pollen from roselle ; no hybrid plants were produced from 2,655 pollinations made in the reciprocal direction . One line of roselle was the parent of 3 of the 5 hybrids ; one line of kenaf was the parent of 2 of these 3 . The Fl hybrids were triploid, and varied in vigor, growth habit and vegetative morphology, but had similar flowers . Two of the Fl hybrids showed high pollen fertility, apparently as a result of restitution at first meiotic division leading to unreduced spores . These two hybrids each produced a small amount of seed, which gave rise to an F 2 population of 22 plants . The F2 plants vary in vigor but are morphologically uniform, have thick leaves with mosaic sectors, and are presumably spontaneous allohexaploids . The theoretical possibilities of increasing the percentage of recovery of the Fl interspecific hybrids and of developing a synthesized hybrid variety useful for bast fiber and paper pulp are discussed .