-2-So far, the earliest seed plants that have been found in the fossil record are from the Devonian period, showing that seed plants have been around for at least 360 million years. The plants were gymnosperms, which include conifers and cycads, as well as the living fossil ginkgo biloba.
-3-There are about 600 different species of fungi that are known to infect seeds and use them to propagate themselves. Some can be beneficial, or at least benign to the plant, however some can cause disease, such as bunt in wheat. These fungi destroy the flowers and then spread by spores.
-4-The coco de mer is the biggest largest seed in the world. It was originally collected in the Maldives, which is why it was given the epithet of maldivica, however its' true home was eventually found to be the Seychelles. It can grow to 18 kg / 40 lbs in weight and around 30 cm / 12 in long.
The large size allows the seed to power the growth of the plant so efficiently that it can grow 10 meters in height within a few years.
-5-The largest wingspan of any seed is held by the Brazilian zebra wood tree (Centrolobium robustum). These seeds are protected by spines and have a wing up to 30 cm long!
-Bonus-Here's David Attenborough talking about the coco de mer seeds:
Silvertown, Jonathan. An Orchard Invisible: A Natural History of Seeds. Reprint edition. Chicago; London: University of Chicago Press, 2010.