I'm not interested in the terminology however, only in the health of this little tree.
It is not really about the terminology. This forum is not about plants, it is about bonsai, which your plant is not.
I think the fungus is not a big problem. The plant looks healthy, the fungus (if I see it right) is only there at the drainage hole at the bottom?
It will probably not damage the plant. As it is at the bottom, soil there may stay too wet giving the fungus a chance. Repotting in a shallower container with a better draining substrate would help.