Dear student,
Flowerless plants producing naked seeds belong to Gymnosperm category
In gymnosperms, spores are produced in sporangia of sporophyll.
Monoecious: When male and female cones are present on same plant,
Diecious: When male and female cones are present on different plants
The statement explains that a plant has two different sex organs for both male and female,the male part of the plant generates the male gametes whereas the female part generates the female gamete.
Regards