Sporangia produce spores. Microsporangia and megasporangia may be distinguished if different spore types are produced. In the Ferns s. str., the sporangia are mostly located on the lower leaf surface of the sporophylls. In the Horsetails, the sporangia are located on the lower surface of table-shaped sporophylls at the apices of the stems. In the Clubmosses, the sporangia are located on the upper surface of foliole sporophylls which are mostly arranged in terminal strobili (which are homologous to flowers). In the Spermatophytes the pollen sac corresponds to the microsporangium and the nucellus to a megasporangium.