Roystonea borinquena O.F.
Abstract
Roystonea borinquena is a rapidly growing tree with an average height of 12-2018 m but it can reach up to 26.4 m. Young trees can average 1 m height growth annually. Diameters range from 25 to 70 cm; maximum age is 80-110 yrs. The tree has a smooth, gray trunk with a swollen base and gracefully drooping fronds. It is native to Puerto Rico, the Puerto Rican island of Vieques, St. Croix in the U.S. Virgin Islands, and possibly Tortola in the British Virgin Islands. A widely planted ornamental, R. borinquena may have naturalized in the British Virgin Islands, and in St. Thomas and St. John, U.S. Virgin Islands. Because of its ability to withstand high, hurricane-force winds, it sometimes dominates the forest canopy despite its short stature. It is also a common sight in the island cities. The species’ ability to withstand a polluted atmosphere and to grow well on either moist, well-drained soils or partially compacted fill dirt enhances its value as a landscape plant. Roots will not damage sidewalks or curbs even when the trees are planted in constricted spaces. Palm lumber was once widely used in rural construction and the leaves were used as a roof thatch. Flowering can begin as early as the seventh year, and trees can bloom throughout the year. The length of the inflorescence reaches up to 1 m. The whitish male and female flowers form on the same panicle, with male flowers of each tree opening and falling before the female flowers to prevent self fertilization. The stalkless male flowers measure 13 mm across, while the smaller female flowers measure 3.2 mm across. The flowers are an important nectar source for honey bees, and the fruits a fat-rich food for birds. The greenish-yellow fruit are 13 mm long and about 10 mm in diameter. Fruits ripen to a brownish-purple color and contain one light brown elliptic seed that is 8 mm long, hard, and oily. On a suitable site, natural regeneration may be so abundant that the one- or two-leafed plants may be mistaken for grass.