The letter H. It completes the list of letters that are vertically symmetrical. In other words, you can fold the top half of the letter over the bottom half and everything lines up.
King Ferdinand has no immediate living relatives and decides to hold a contest to find a worthy successor when he dies. He gives a seed to every contestant and explains that the person with the healthiest and most beautiful plant will win the throne.
When the final day of the contest arrives, the king finds hundreds of plants of all shapes and sizes. However, he ignores them and awards the throne to a girl holding a pot with only moist dirt.
King Ferdinand was a kind and trusting man and wanted to be sure he found an honest heir. He gave small pebbles to all the contestants, claiming they were seeds. Therefore, any contestant with a plant had switched their “seed” in order to win. Everyone but the girl had been dishonest.
I am, in truth, a yellow fork From tables in the sky By inadvertent fingers dropped The awful cutlery. Of mansions never quite disclosed And never quite concealed The apparatus of the dark To ignorance revealed.