These are the famous royal palms, dating back to the period of Dom João VI. These trees were originally reserved for the royal family only. All palms are originated from a single tree, the Palma Mater (that was tragically destroyed by a lightning recently). The seeds were supposed to be burned, so that they wouldn't be used by ordinary subjects. A curiosity is that slaves sometimes would hide them and smuggle them outside the gardens. Many of them purchased their freedom papers using money earned from selling these seeds.