Pleurothallid alliance flasking

[coli0157]

I am interested in the Pleuro alliance and read in Kay Greisens book, Commercial Propagation of Orchids in Tissue Culture: Seed-Flasking Methods, that Masdevallia and other members of the subtribe Pleuro should not have charcoal in any of the flasking media. She says "...it is detrimental to Pleurothallids and Masdevallias." Does anyone have experience growing these plants from seed? Is this a commonly known thing for this genus? Why would this be detrimental to the plants?

[Kyle]

Ecuagenera sowed seed on media without charcoal and Hoosiers added extra charcoal. It can go either way.

Kyle