The mycelial barrier was the intersection of mycelial space and normal space.
Starfleet's spore drive utilized a reaction cube, which was the only place on the ship where it was safe to contact the mycelial barrier. Crew touching the barrier elsewhere would find themselves twisted around the axes of both environments. An accident of this nature killed the crew of the USS Glenn. (DIS: "Saints of Imperfection")
|Displacement-activated spore hub drive|
|basidiosac rupture • black alert • bloom failure • excess energy cavitation • Hawking radiation firewall • mycelial network • mycelial plane • mycelial barrier • mycelium spore • prototaxites stellaviatori • reaction cube • speirin • spore chamber|