Where are sporangia located on lycophyte leaves?

In lycophytes, the location of sporangia relative to the leaves varies by genus:

• Lycopodium: The sporangia are closely associated with the leaves, which are referred to as sporophylls when they bear sporangia. These sporophylls may be found in zones among vegetative leaves or aggregated into specialized, compressed structures called strobili.12
• Selaginella: The sporophylls are localized in strobili. These leaves bear sporangia, with megasporophylls containing megasporangia and microsporophylls containing microsporangia.32
• Isoetes: Most leaves are fertile and function as sporophylls. Each sporangium (either a microsporangium or a megasporangium) is embedded in the expanded, concave base of the leaf on its adaxial (inner) side.132