Synchronization of male and female flowering behavior was recorded between C. equisetifolia and C. cunninghamiana. Among the five species of Casuarina, C. equisetifolia have monoecious as well as dioecious while others C. obesa, C. glauca and C. cristata were strictly dioecious with female genders. However, C. cunninghamiana was separate genders. Phenotypic variability of male and female floral traits was significantly higher in dioecy than the monoecy in Casuarina equisetifolia. It was observed that hand pollination registered lower seed set than the open pollination in all these species and were able to flower twice in a year (fourth week of January to end of May and third week of July to end of October). Fruit maturity duration was short (18 weeks) in both C. equisetifolia and C. cunninghamiana than other three species of Casuarina (20 weeks). Fruit reproductive biology revealed that open pollination was the dominant reproductive system over controlled pollination in natural populations.