I once had the two species in bloom at the same time... the different lengths of their respective hirsutissiness (hairyness) were quite distinct. The colour of the infloresence of my "plain" hirs was lighter (more in a greenish direction); the esquirolei (this spelling is from Averyanov, Cribb et al. in their seminal monography on The Slipper Orchids of Vietnam - I guess, they should know) of a very dark colour. But I don't know, if this, too, is a distinguishing trait, or was just by coincidence.
In my experience esquiroleis have overall had the larger flowers, but Rudolf might be right about the size of the dorsal relative to the flower in total for hirsutissimum? Any input from someone with a more specialized knowledge of these varities?
This discussion of the discernability of the plants in question, by the way, I think, for once should make it crystal clear, that it here makes sense to talk of two varities of the same species, not two distinct species in their own right!
I love this species but it causes a lot of confusion, too.
