Position in a system
| system | Vitae - living organisms |
| domain | Eukaryota Whittaker & Margulis, 1978 - lifeforms with nucletic cells |
| superregnum | Bikonta - bikonts |
| Corticata | |
| Archaeplastida | |
| kingdom | Plantae Haeckel - plants |
| divisio | Magnoliophyta Cronquist, Takht. & W.Zimm. - flowering plants |
| class | Rosopsida Batsch - eudicots |
| order | Zygophyllales Chalk. |
| family | Zygophyllaceae R. Br. |
| subfamily | Larreoideae Sheahan & Chase |
| genus | Guaiacum Plum. ex L. - lignum-vitae |
| species | Guaiacum unijugum Brandeg. |