The specific epithet regis-jubae, meaning 'King Juba's euphorbia' honours the king's contributions to natural history and his role in bringing the genus to notice.

It has light brown stems and terminal rosettes of leaves that are narrow and oblong, with a pointed or somewhat blunt apex.

The greenish-yellow floral bracts are large, not joined at the base, and persist when the fruit has formed.

[2] It has been treated as a subspecies of other Canary Island euphorbias under the names E. obtusifolia subsp.

has been used "indiscriminately" for two species found in the Canary Islands: the eastern E. regis-jubae, and the western E. lamarckii.