The genus Lagenaria (Cucurbitaceae) members are underutilised, neglected and on the verge of being threatened to extinction. An investigation of their reproductive biology will serve as the basis for effective strategic planning towards their conservation. The plant materials used for this study were collected from Osun, Ekiti and Niger States in Nigeria. Reproductive parameters, including seed germination, phenology and pollination mechanism, were documented. The highest seed germination rate was observed in the accession of Lagenaria siceraria from Ekiti Bowl. The male flowers appeared first, followed by female flowers’ emergence 14–28 days later, on the secondary shoots. The female flowers of each accession had unique inferior ovary shapes, which developed into different fruit shapes with distinct seed morphology. This study showed that the members of Lagenaria performed better as climbers than as trailers, and the number of fruits produced per accession depends on the size or weight of the fruit. Chrysomelidae and Coryna apicicornis beetles were the primary pollinators observed. Furthermore, the pollens were predominantly monad, spheroidal and tricolporate, and pollen stainability ranged between 81% and 91% in all the accessions studied. Therefore, the fruit and seed morphology were diagnostic for each accession, and the flowers were pollinated mainly by beetles