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 | Monilophyta Cantino et Donoghue - ferns and horsetails |
| class | Psilotopsida D. H. Scott |
| order | Ophioglossales Link |
| family | Ophioglossaceae (R. Br.) Agardh |
| genus | Ophioglossum L. - adderstongue |
| species | Ophioglossum lusitanicum L. - Least Adder's-tongue |