In all living animals, us included, our cells contain two full sets of chromosomes. This state is referred to as being Diploid. A cell that contains only one set is called Haploid, many plants and animals use this state sometime in their life cycle. Up until recently I had thought these were the only two states possible, but I was wrong!
In fact, most angiosperms (flowering plants) have a cell known as the endosperm that develops in their seeds, that is Triploid. This means that the cell contains THREE full copies of chromosomes. This feature is unique to the flowering plants and helps them with the crucial step of germinating from seed.
That's my "interesting" plant fact of the day today.