All of the pictures are beauty endlessly - glory over glory!
And they are all equally interesting - the close up for the details on the flowers and their immediate growth conditions; the wider ones for presenting more of the actual habitat and growth habit. If a book is on its way, please, remember to provide us with both sorts of photos/information!
And before we jump to conclusion in respect to culture from the fact that the plants grow on limestone, we must take into consideration what they are growing in: are they growing as humus epiphytes on limestone or with the roots directly on the cliff? What is the pH-value of (rain)water running from the growth place (Averyanov et al. had some interesting measure of that concerning, I think, it was P. henryanum - as far as I remember a tiny wee bit to the more acidic side, not alkaline, as one intuitively would have expected...I will look it up when I get back to my books!), etc.
Kind regards,
Jens