Shrubs, sprawling or erect, to 2 m. Stem segments not disarticulating, green, flattened, narrowly elliptic or obovate, 10–25(–40) × 7.5–15(–25) cm, tuberculate, making margins appear scalloped between raised areoles, glabrous; areoles 3–5 per diagonal row across midstem segment, oval, 3–6.5 × 3.5 mm; wool dense, tan. Spines 0–11 per areole, in nearly all areoles to only in some marginal areoles or absent, spreading in all directions, yellow, aging brown, straight or curving, the longest stout, oval in cross section, 12–40(–60) mm, not markedly barbed. Glochids inconspicuous, few to many in crescent at adaxial edge of areole, yellow, aging brown, often incurved, subequal to increasing in length toward adaxial edge of areole, to 4 mm. Flowers: inner tepals light yellow throughout, 25–30 mm; filaments yellow; anthers yellow; style and stigma lobes yellowish. Fruits purplish throughout, stipitate, ellipsoid or barrel-shaped, 40–60 × 25–30(–40) mm, juicy, spineless; areoles 6–10. Seeds tan, subcircular, 4–5 × 4–4.5 mm, with slightly irregular surface; girdle protruding to 1 mm. 2n = 44 (cultivated), 66.
Phenology: Flowering spring–summer (Feb–Jul).
Habitat: Coastal sand dunes, hammocks, edges of maritime forests, shell middens
Elevation: 0 m
Ala., Fla., Ga., S.C., Tex., Mexico, West Indies, Central America, South Africa (introduced), Australia (introduced).
Opuntia stricta hybridizes with O. engelmannii (apparently var. lindheimeri) forming O. ×alta Griffiths (as species) along the coast of southeastern Texas and adjacent Louisiana. The hexaploid hybrid is arborescent to 3 m; it has stem segments subcircular to oblong-ovate, with a glochid pattern intermediate of the putative parents, all yellow spines, and light green stigma lobes.