I've written and spoken for some time now about the particular problem with those plants currently labeled as P. "rosettifolia" and/or P. sp. 'G25KC00'. (Honestly, in my opinion, the label 'G25KC00' is probably the most responsible labeling we could apply to this group of plants right now.) Over time, I have collected at least four different individuals (clones) with these labels. These plants all show similar, but individual characteristics. In my opinion, after growing them all side by side, and conducting a little research of my own, I feel they are all seperate individuals of the same species. Now, I have yet another plant that I would like to add to this grouping - Petrocosmea "menglianensis".
A young, flowering plant that I acquired as P. "menglingensis" (there is no such species with that spelling, I feel it was supposed to have been labeled P. menglianensis (the published spelling of a species). I now feel this plant is NOT P. menglianensis either, but another clone of the grouping currently knows as P. "rosettifolia".
The flower of P. "menglianensis" is almost identical to the flowers of the four individuals that I have acquired as P. "rosettifolia". The flower on this plant is a bit more lavender in color, but morphologically is identical to P. "rosettifolia" flowers. 
A side view of a flower of P. menglianensis shows the upper lip, which is the fused upper two petals. The upper lip of the flower is roughly one-half the length of the lower petals, a trait that likely puts this species in Section - Anisochilus of the genus Petrocosmea. 
A flowering plant of P. "rosettifolia" #2, the plant is almost identical to the plant labeled P. "menglingensis" when I acquired the former. The plants have near identical flowers and the leaves are identical except that the leaves of the plant labeled P. "menglingensis" are nearly twice the size of the leaves of P. "rosettifolia" #2. I feel they are two seperate clones of the same species. 
A flower of P. "rosettifolia" #1, again, nearly identical to the flowers of P. "menglianensis". This form of "rosettifolia" is the smallest of the now five forms of the species that I have. The cymes on this form are darker purple in color, shorter, and tend to curve, causing the flowers to "nod". I realize this is all very confusing. Here's the breakdown of what I am attempting to say here:
#1 There are at least four different individuals of the same species all labeled as P. "rosettifolia". I feel that this new plant, which I acquired as P. "menglingensis" is yet another form of the same species.
#2 All four (now five) plants in this grouping all likely NOT the true P. rosettifolia. None of them match the published description of that species in the Flora of China.
#3 The plant which is the subject of this post originally came to me, and is still being sold and distributed as P. "menglingensis"...which is an erroneous spelling of P. menglianensis (the published species name). I feel that this plant is NOT P. menglianensis, and is yet another different clone of the plants all now being grown as P. rosettifolia. It is NOT P. rosettifolia either, but is almost identical to all of the other plants being grown under the erroneous labeling of P. rosettifolia.
#4 If my hunch is true, there are now at least five different individual clones of this same species, which is not yet properly identified.
#5 If you have this plant, I would recommend continuing to keep it labeled as it is, in order to identify it seperately from the other "P. rosettifolia" clones....BUT with the knowledge that it is likely not either P. menglianensis OR P. rosettifolia....we simply don't have a proper identification on any of these plants at present.
WHEW!!! I hope this is all as clear as mud, at least. Either way, the plant is still lovely, and a welcome addition to the genus in my plantroom. It does grow much larger than any of the other forms of the species (whatever species that is?) and should be grown in for no other reason than to preserve it's genetics. The leaves on this form get quite large on a mature plant and with maturity, in it's third of fourth year, it can bloom quite heavily.
