Trying to settle a little disagreement between me and my mum!

[King_of_orchid_growing:)]

Like I said, it can be. But there are many non-specialists.

However, the fungi must be known "orchid mycorrhizae".

Taxonomy is kinda weird with these group of fungi. Not much focus was put into their classification or the taxonomic name may be kept a secret for whatever reasons.

Sometimes, they'll just be referred to by a letter and a number.

For example, there is a Dactylorrhiza mycorrhiza commonly referred to as "B1 fungus". That's it, nothing more.