How are male and female reproductive structures distributed on Ephedra plants?

In the genus Ephedra, reproductive structures are contained within compound strobili, or cones. Most species of Ephedra are dioecious, meaning that individual plants typically produce either pollen-producing (microsporangiate) cones or seed-producing (megasporangiate) cones. However, some species may occasionally bear both male and female cones on the same plant.123

The distribution and structure of these cones are as follows:

• Microsporangiate (Male) Strobili: These cones consist of oppositely arranged bracts with short fertile shoots in their axils. Each fertile shoot terminates in a microsporangiophore that bears a cluster of microsporangia, which produce pollen grains.2
• Megasporangiate (Female) Strobili: These cones also feature oppositely paired bracts. In their axils, fertile shoots consist of paired bracteoles that enclose an ovule, which is the precursor to a seed.2

Both types of strobili share a similar basic organization, characterized by these oppositely arranged bracts and fertile shoots.2