Acanthus was a class L planet located on the opposite side of the space of the Romulan Star Empire away from the Federation.
History and specifics
Acanthus was somewhat near Ibex and Apandana. Geologically, the planet was compatible with the formation of dilithium. Its surface was charred with holes betraying mining activity by pirates.
In the 23rd century, the Federation starship USS Enterprise was stranded near Masaba, where they obtained a star chart showing the name and details of Acanthus. (TOS video game: 25th Anniversary)