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 | Rosales Perleb |
| family | Rhamnaceae Juss. |
| genus | Frangula Mill. - buckthorn |
| species | Frangula californica (Eschsch.) A.Gray - California Buckthorn |