I did a little research for you and this is what I found:
seeds can be used to grow more Poincianas. They are an inch long and are gray brown in color. Because the
seed covering is very hard, it takes a long time for the
seed to get started. A method that I have used is to carefully look at the
seed to locate the embryo end - look for a small spot at the tip - the
seed scar. Using a pair of pliers, carefully break off the smallest possible piece of the OPPOSITE end. This helps the
seeds to absorb moisture and start germination.