Torreya 12: 14. 1912.
Shrubs, dense, erect, to 1 m. Stem segments dark green, flattened, elliptic, (4–) 10–17.5 × (3–) 5–7 cm, moderately tuberculate, making margins appear scalloped, glabrous; areoles 3–5 per diagonal row across midstem segment, elliptic to subcircular, 4–6 × 2.5–3 mm; wool pale tan to white, loose. Spines 2–3 (–5) per areole, spreading, yellowish, aging gray-white; major ones straight, stout, slightly flattened, commonly spirally twisted, longest to 25–60 mm. Glochids dense in crescent at adaxial edge of areole, sparser along sides of areole, yellow, turning red to brown, to 5 mm. Flowers: inner tepals yellow throughout, to 30 mm; filaments and anthers pale-yellow; style pale greenish yellow; stigma lobes pale cream. Fruits reddish at maturity, obovoid, 40 × 25 mm, fleshy, glabrous; areoles 17–21, bearing few spines to 9 mm. Seeds tan, subcircular, ± 3 mm diam.; girdle to 0.3 mm. 2n = 22 (Puerto Rico).
Phenology: Flowering year-round.
Habitat: Brushlands, coastal sands, ocean bluffs, disturbed areas
Elevation: 0 m
Fla., West Indies
Opuntia cubensis is known in the flora only on Big Pine Key, Florida.