De Candolle's concept of the genus included all woody legumes with papilionoid flowers and spine-tipped leaflets which originated in the West Indies.

Beyra and Lavin designated P. obcordata the lectotype since it was, in their analysis, the species with the fewest specialised traits.

[9][10] The trans-Atlantic distribution of Pictetia and other closely related genera led Beyra and Lavin to conclude that Pictetia was likely to be an "early Tertiary vicariant"—in other words, that the ancestors of the genus where already present in its current range before South America and Africa split apart.

[6] This suggests that the presence of Pictetia in the Caribbean reflects the dispersal of its ancestral species into the region long after the islands became isolated from the mainland.

[5] P. aculeata, the species with the easternmost distribution, is found in the British and U.S. Virgin Islands and Puerto Rico.

[14] P. sulcata is found both in Hispaniola and Cuba,[15] while the remaining species (P. angustifolia,[16] P. marginata,[17] P. mucronata,[18] P. nipensis[19] and P. spinosa[20]) are Cuban endemics.