Habit: Harrisia brookii grows erect forming a many-branched structure. The main stems are up to 5 m in height/length. Stem typically 10 ridged with deep fissures between ridges. The areoles occur along the stem approximately 2 cm apart with 6 to 12 spines some reaching 3 cm in length.
The complete, perfect, slightly zygomorphic flowers are solitary in arrangement occurring near the ends of stems/branches. The flowers open at night and are up to 25 cm in length. The perianth has numerous sepals and petals. There are numerous stamens. The ovary is inferior and has numerous seeds. The fruit is a berry bearing small tubercles and aeroles with white hairs. At maturity the fruit is yellow/white and is the size of a softball.
Habitat: Harrisia brookii grows in open rocky areas of Dry Broadleaf Evergreen Formation –Shrublands (Scrubland coppice). It has been recorded to occur in disturbed areas.
Distribution: Harrisia brookii is endemic to the Lucayan Archipelago and occurs only on Eleuthera and Long Island.
Medicinal/Cultural/Economic usage: Harrisia brookii is not known to be used medicinally in the Lucayan Archipelago. The fruit of other species in the genus are known to be edible.
Harrisia brookii is protected by CITES as an appendix II species. It is illegal to collect and transport for commercial or personal usage.