The oldest viable seed is that of:

The oldest viable seed is that of a lupine, Lupinus arcticus excavated from Arctic Tundra. The seed germinated and flowered after an estimated record of 10,000 years of dormancy.

A recent record of 2000 years old viable seed is of the date palm, Phoenix dactylifera discovered during the archeological excavation at King Herod’s palace near the Dead Sea.

Rhizophora is a mangrove and it exhibits vivipary. In them embryos begin to develop before the seeds detach from the parent.