The plant is a colonizer of lava fields – hence its common name – where it forms spiny clumps up to 60 cm (24 in) tall.

The lava cactus is a leafless clump-forming species, with cylindrical stems typically up to 50–60 cm (20–24 in) tall in formations that can be as much as 2 m (6 ft 7 in) across.

The remains of the flower stay attached to the fruit, which is a berry, red to brown in colour, covered with yellow spines and filled with many black seeds.

[2][3] The species was first described in 1902 as Cereus nesioticus by Karl Moritz Schumann in an account of the flora of Galápagos authored by Benjamin Lincoln Robinson.

[11] The lava cactus is endemic to the Galápagos, where it is found on Fernandina, Genovesa, Isabela, Pinta, Santa Cruz, and Santiago,[12] as well as some smaller islands,[2] including Bartolomé.