US sheet cited (as isotype, not lectotype!) by G.J. Breckon in G.L. Webster & M.J. Huft, 1988, Ann. Missouri Bot. Gard. 75: 1114. Annotated by B. Dehgan (2002) as "Cnidoscolus sp."; US sheet variously annotated as "holotype", "lectoholotype" but no publication of lectotypification found.