Mangroves have one of the most unique reproduction techniques in all of the plant kingdom. Rather than producing dormant resting seeds like most flowering plants, mangroves are viviparous, and they grow propagules!
When mangrove reproduction is in season, the mangroves release their propagules and disperse them via water. But you may be asking yourself, how can a single propagule serve as the foundation of a whole new mangrove ecosystem?
While the propagule is attached to the parent tree, it has varying degrees of vivipary or embryonic development based on the type of mangrove: red, black or white. Once the propagule drops from the parent tree, there is a dispersal period in which each species’ propagule must remain in the water. During this period, embryonic development continues.
For the red mangrove this dispersal period is the longest, sometimes reaching up to 40 days. The black mangrove’s propagule must drift for at least 14 days. The white mangrove’s dispersal period is the shortest at 5 days, which also includes germination.
Finally, if the propagule drifts and strands in a “favorable” area, there is an obligate stranding period before the primary roots and cotyledons (primary leaves) emerge. The propagule may be lying horizontally on the sediment or vertically “standing up” during this time, and it may even be covered by water!
Mangroves are truly incredible plants, with such a unique reproduction process.