Royal Palms are used extensively in ornamental landscapes, but they grow in estuaries and coastal swamps also. They belong to the Roystonea genus of eleven species of monoecious palms, native to the Caribbean Islands, and the adjacent coasts of Florida and Central and northern South America.
The Roystonea genus contains some of the most recognizable and commonly cultivated palms in tropical and subtropical regions, such as Roystonea regia, commonly known as the Cuban royal palm or Florida royal palm, which is a very similar species native to southern Florida, Mexico and parts of Central America and the Caribbean.
Roystonea borinquena (Puerto Rico Royal Palm) Aka Mountain-cabbage Palm, Royal Palm, Palmiste, Palma Real Puertorriqueña, Manacla, Palma Caruta, Palma de Cerdos, Palma de Grana, Palma de Yagua, Palma Real, or Yagua is a species of palm which is native to Hispaniola, Puerto Rico and the Virgin Islands, commonly known as the royal palms, the genus was named for Roy Stone, a U.S. Army engineer. The ‘borinquena’ epithet refers to the Taino word for Puerto Rico.
The flowers are white unlike its cousin Roystonea regia’s (The Cuban Royal Palm) which tend to be pink. It belongs to the Arecaceae family of palms.
These are the female flowers. Both fruit and flowers are eaten by birds and bats which disperse the seeds. The flowers are white unlike Roystonea regia’s (The Cuban Royal Palm) which tend to be pink.
The fruit are spheroid to ellipsoid in shape, 8.9–15 millimetres (0.35–0.59 in) long and 7–10.9 mm (0.28–0.43 in) wide. They are green when immature, turning red and eventually purplish-black as they mature.
Here you can see a raceme of both the male and female flowers. Roystonea borinquena is a monoecious palm, bearing unisexual male and female flowers separately. The 1–1.4 m (3.3–4.6 ft) inflorescences bear creamy yellow male and female flowers; the anthers of the male flowers are bright purple.
Roystonea borinquena is large palm which usually reaches a height of 12 to 18 metres (40 to 60 ft), but individuals 26.4 m (87 ft) have been recorded. Stems are smooth and grey-brown to cinnamon-brown, and range from 25–70 centimetres (10–28 in) in diameter.
Leaves are 2.4–3.7 m (7.9–12.1 ft) long, with short petioles and leaf sheathes 1–3 m (3.3–9.8 ft) long which encircles the upper portion of the stem, forming a crownshaft, which is an elongated circumferential leaf base formation present on royal palms.
Roystonea regia, however, reaches a height of 20–30 metres (66–98 ft) tall, (with heights up to 34.5 m (113 ft) reported, according to Wikipedia) and a stem diameter of about 47 centimetres (19 in).
If you’re interested in Royal Palms, please read the following forum discussion about the differences between Roystenia borinquena and Roystenia regia: http://www.palmtalk.org/forum/index.php?/topic/46843-roystonea-regia-vs-boriquena/