Viviparous seedlings

The seeds of mangroves are especially remarkable because they commonly germinate within their fruit while still attached to the parent plant, a condition known as "viviparous seeds."

Having their embryonic root (hypocotyl) already elongated gives them a better chance of establishing themselves in soft mud during low tide. Called "sea pencils," the cigar-shaped seedlings (disseminules) of red mangrove may have an elongate taproot up to 10 inches long when they drop from the parent tree.

The unusual, top-shaped fruit of tea mangrove contains one of the largest seeds in the world (excluding palms).

It floats with the elongate, embryonic root pointing downward, and readily becomes implanted in soft mud.

Germinated seedlings and sprouted fruits of the black mangrove and white mangrove are also dispersed by ocean currents.

Red mangrove (Rhizophora mangle) with a viviparous (germinated) seedling still attached to the fruit on the parent shrub.

The seedling drops into the water where it is automatically planted in the soft mud or floats away.