Principia (alga)
| Principia | |
|---|---|
| Scientific classification | |
| Clade: | Archaeplastida |
| Division: | Rhodophyta |
| Class: | Florideophyceae |
| Stem group: | Corallinales |
| Family: | †Archaeolithophyllaceae |
| Genus: | †Principia |
Principia is a genus of alga that has been placed in the coralline stem group on the basis of its slightly differentiated thallus; it forms an "intermediate" between Hortonella, Neoprincipia and Archaeolithophyllum.