Well, for starters, I am definitely in favor of checking relationships of particular plant individuals at the DNA level. When I say individuals, I really do mean individual clones, since the extent of natural genetic variation within what looks 'the same' or similar could be rather low or rather high. Populations of plants are notorious in this aspect, and understanding individual variation within populations -- AND between them -- is very important in my view. In narrow endemics like most Paphs and Phrags, the situation of ALLOPATRY (geographically distinctness) often leads to both genetic and morphological divergence. Allopatric SPECIATION can occur if gene flow, e.g., is largely cut off between populations, leaving them to go their own way further still. This said, in plants, the definition of species is more clouded than simple lumping vs. splitting, because real reproductive isolation may not be enforced at all if 'species' come into contact. Although botanists have found many, many more examples of cryptic reproductive isolation through, e.g., partial fertility barriers than previously supposed, there are NOWHERE NEAR as many examples of gene flow between recognized species of animals -- vertebrates, say. Plants extend their promiscuousness by having the tendency to form polyploids along with hybridization events. Angiosperms go crazy with polyploidization, and it's surprising that so few natural slipper tetraploids have been identified. Polyploidy is a way out of any reproductive barrier between 'species' (or distinct populations of 'species') that might come into contact.
Going on to the issue of when a new species, subspecies, or variety might be named, this does indeed involve quite a bit of hand waving. Some (like me) would like to see biodiversity given concrete description, and the best way to preserve the intent of describing biodiversity is at the species level, since species names NEVER DIE -- they can simply be ignored if one wants. So maybe it's A-OK to name a Phrag. dalessandroi and then have most of the world consider the plant Phrag. besseae var. or subspecies dalessandroi. I don't know which of the latter names have been validly published, or which are in most common use -- the fact remains that the Latin binomial Phrag. dalessandroi is always there as a formally described entity. Subsuming Phrag. dalessandroi into besseae is merely a decision you or I could make -- nobody can rid themselves of the existence of the name Phrag. dalessandroi since it was validly described. So use it if you like, or any other valid name that might apply to a given individual plant with features that fit.
As for Phrag. schlimii vs. fischeri vs. manzurii, I guess I'd support their DESCRIPTION as species in order to get the Latin binomial on record. Of course, one could validly describe manzurii as a variety of schlimii -- accept what you want -- the same packages of biodiversity are there even if one less 'species' is on the Phrag. list.
New species especially, but also new subspecies or hybrids, create a lot of excitement in the orchid world -- folks gotta have 'em. So, any new names create markets, no matter how small the morphological differences.
Many examples of new species are dead clear -- like when Phrag. besseae or Paph. malipoense were discovered. But then the subtlties creeped in when natural variation led some to accept the species Phrag. dalessandroi and Phrag. jackii. Well, the latter two are different from the former 2, and do appear to form distinct populations, and are probably a little distinct at the DNA level. I'm glad that Phrag. dalessandroi and Paph. jackii exist as names recognizing diversity, but it just doesn't matter taxonomically if they are referred to as varieties. If one is interested in various aspects of evolutionary biology beyond taxonomy, such as population genetics, pollination interactions, or ecology, one might care more than I would.
These are my 2 cents -- rambling a bit, sorry for that. And I may change my mind on some things I wrote!
All best,
Vic.
