Jasminocereus thouarsiii is a leafless treelike cactus growing to 7 m (23 ft) tall, with green or greenish yellow branching stems made up of individual sections 10–50 cm (4–20 in) long.

The flowers, borne singly, open at night, and are up to 6 cm (2+1⁄4 in) across, with many creamy white to yellow or olive green petals and numerous stamens.

Three varieties are recognized by some sources; they are said to vary in height, flower texture and fruit colour, among other features.

His descriptions are brief and refer in part to information received from others; he also notes that neither the flowers nor the fruit of Cereus galapagensis were known.

The specific epithet thouarsii refers to Abel Aubert du Petit-Thouars, who found both species some 30 years earlier when his ship visited the Galápagos.

A classification produced in 2010 by Nyffeler and Eggli puts all three genera in a much larger tribe Phyllocacteae.

[12] Jasminocereus thouarsii is endemic to the Galápagos, where it is found on Fernandina, Floreana, Isabela, San Cristóbal, Santa Cruz and Santiago, plus some islets,[3] including Bartolomé.