Roystonea regia, commonly known as the Royal Palm, Cuban royal palm, or Florida royal palm, is a palm species native to Mexico, the Caribbean, Florida, and parts of Central America. This large and attractive palm has been cultivated throughout tropical and subtropical regions as an ornamental tree. Although sometimes called R. elata, the conserved name R. regia is now the correct name for the species. The Royal Palm reaches a height of 15–24 m (50–80 ft). Populations in Cuba and Florida have long been considered separate species but are now treated as a single species. Widely planted as an ornamental plant, R. regia is also used for thatching, construction timber, and in some forms of traditional medicine, although currently there is no valid scientific evidence to support the efficacy or use of any palm species for medicinal purposes. Its fruit is eaten by birds and bats (which disperse its seeds) and is fed to livestock. Its flowers are visited by birds and bats, and it serves as a roost and food source for various animals.

Outdoors, the King Palm requires well-drained soil, protection from strong winds, and partial shade to prevent sunburn. Indoors, they need bright indirect light and consistent humidity to keep their foliage green and lush. Choosing the right spot ensures your palm remains fresh, strong, and an elegant addition to your room. Royal Palms grow best in full sun, but can also grow in partial shade. Choose a location that receives plenty of sunlight throughout the day for optimal growth. This palm prefers well-drained soil with a pH between 6.0 and 7.0. Avoid planting in areas with standing water, as this can lead to root rot. Royal Palms thrive in warm climates with temperatures between 18–24°C (65–75°F). The plant is suitable for USDA zones 10–12 and can tolerate a range of temperatures, but prefers consistent warmth.

• Trunk/Stem: The large trunk of the Royal Palm reaches a height of 20–30 meters (66–98 feet) (with heights up to 34.5 m (113 ft) reported) and a trunk diameter of about 47 centimeters (19 inches) (K.F. Connor reported a maximum trunk diameter of 61 cm (24 inches)). The trunk is sturdy, very smooth, and grayish-white with a distinctive bulge below the characteristic green crown shaft.

• Leaves: Has about 15 leaves that can reach a length of 4 m (13 feet).

• Flower: White with pink anthers.

• Fruit: Round to elliptical shape, 8.9–15 millimeters (0.35–0.59 inches) long and 7–10.9 mm (0.28–0.43 inches) wide. The fruit is green when unripe, turning red and finally purplish-black when mature.

• Root Nodules: Root nodules containing Rhizobium bacteria have been found on R. regia trees in India. The presence of rhizobia-containing root nodules is typically associated with nitrogen fixation in legumes; this is the first record of root nodules on a monocot tree. Further evidence of nitrogen fixation is provided by the presence of nitrogenase (the enzyme used in nitrogen fixation) and leghemoglobin, a compound that allows nitrogenase to function by reducing the oxygen concentration in the root nodules. In addition to evidence of nitrogen fixation, the nodules were also found to produce indole acetic acid, an important plant hormone.

• Propagation: Done generatively (seeds).

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