Echinocereus barthelowianus is a species of cactus native to Mexico.[1]
Echinocereus barthelowianus often forms clusters up to in diameter. Its cylindrical, upright shoots grow up to long and in diameter, mostly covered by dense thorns. It has eight to ten slightly tuberous ribs with large areoles. The thorns, pink to red when young, darken to black with age. The five to nine strong, straight central spines can reach up to long, and the 18 marginal spines are long.
The broad, funnel-shaped flowers are lavender and appear from the shoot tips to the base. They grow up to long and in diameter.[2]
Echinocereus barthelowianus is widespread in Baja California Sur, particularly around Isla Magdalena and neighboring islands growing on rocky hillsides at elevations of . Plants grow among Cochemiea halei, Cochemiea poselgeri, Cochemiea dioica, Cochemiea schumannii, Stenocereus eruca, Stenocereus gummosus, Cylindropuntia molesta, Cylindropuntia cholla, Cylindropuntia tesajo, Opuntia pycnantha, Opuntia invicta, Pachycereus pringlei, Stenocereus thurberi, and Lophocereus schottii.[3]
Nathaniel Lord Britton and Joseph Nelson Rose first described this species in 1922 in the third volume of The Cactaceae.[4] The specific epithet "barthelowanus" honors Captain Benjamin Barthelow, who accompanied Rose in exploring the Lower California coast on the US steamship Albatross.