Page 73 - The Miracle In The Seed

Seed Dispersal

ful traveling plant. Thanks to the air chambers in
the seeds, they do not sink in the water. 36
The seeds of sea heart (Entada gigas), a tropical
African sea-bean, have an interesting heart shape.
The seeds grow inside the seedpod, which is of
Gray nicker
great dimensions. Violent rain can carry seeds of seed
this plant, which grows on the banks of rivers, as
far as the Atlantic Ocean, where they go on jour-
neys lasting for years and reach places as far as
Europe, the Gulf of Mexico or Florida.
The seeds of gray nickers (Caesalpinia
bonduc) can also travel long distances on sea
currents. This small, round gray seed does not Coco-de-mer
seed
sink, thanks to an air chamber under its thick coat.
It can stay at sea for years without losing its ability to germi-
nate.
Another plant whose seeds are dispersed by water is
the sea daffodil (Pancratium maritimum). This plant, found
on sandy Mediterranean and Atlantic shores, is distribu-
ted by means of its angular black and incredibly light se-
eds, which are enclosed in a seaweed-like casing. 37
The tiny seeds of plants like nasturtium (Tropaeo-
lum majus) are covered in a hydrophobic polish that
lets them make use of surface tension to keep from
Sea heart
sinking. By this means, the seeds are able to tra- seedpod
vel by floating along rivers. 38

Some plants with quite large seeds need water to reproduce, but contain every-
thing they need, containing a store of nutrients sufficient to last for the journey,
corky floats to keep them on the surface of the water, and an oily surface.
Coco-de-mer, also known as double coconut, produces nuts weighing up to 20
kilos (44 pounds), the largest seed in the world. The seed can float thanks to a
kind of air compartment. Water-repellent oils and chemicals in the seed help to
increase its resistance to moisture. (center)