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Taxonomy |
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Taxonomy |
The answer to this question will depend on which botanist you ask! Pleione nomenclature is in a state of flux, with new species being discovered and named and some previously named species being re-named. These newly described species and changes to old names are not agreed by everyone. These differences of opinion are reflected in the two most recent major works on pleiones, the first by Phillip Cribb (with Ian Butterfield), the second by Gianantonio Torelli (see Literature).
Currently, Cribb recognises 19 species and 6 natural hybrids. His assessment is based on the examination of plants in the herbarium, field and cultivation as well as experimental studies of chromosomes and DNA. Those he recognises are:
Species: albiflora, aurita, bulbocodioides, chunii, coronaria, formosana, forrestii, grandiflora, hookeriana, humilis, limprichtii, maculata, microphylla (with reservations), pleionoides, praecox, saxicola, scopulorum, vietnamensis, yunnanensis.
Natural Hybrids: x barbarae, x christianii, x confusa, x kohlsii, x lagenaria, x taliensis
Currently, Torelli recognises 22 species and 5 natural hybrids, but with some differences, as follows:
Species: albiflora, aurita, autumnalis, bulbocodioides, chunii, coronaria, formosana, forrestii, grandiflora, hookeriana, hubeiensis, hui, humilis, limprichtii, maculata, microphylla, praecox, saxicola, scopulorum, speciosa, voltolinii, yunnanensis. He also has amoena as a questionable species.
Natural Hybrids: x christianii, x confusa, x kohlsii, x lagenaria, x taliensis
The disputed names are: autumnalis, chunii, hubeiensis, hui, microphylla, pleionoides, speciosa, vietnamensis, voltolinii and x barbarae. The differences are as follows:
P. autumnalis : Torelli recognises this as a valid species; Cribb regards it as a small-flowered form of P. maculata.
P. chunii : The name "chunii" has had the most complex history! To cut a long story short, Cribb now believes this name should be correctly applied to plants that have previously been called "hookeriana var. sinensis" (which are sometimes also called P. hookeriana var. milanii or simply P. milanii). He had previously applied the name "chunii" to a species which both he and Torelli now agree is correctly called P. aurita. Torelli still believes that "chunii" is correctly applied to certain plants not yet in cultivation and known only from herbarium sheets. If this is so, then he says that "hookeriana var. sinensis" should correctly be called P. sinensis as it is clearly a species distinct from the true P. hookeriana. (Cribb's DNA work confirms that the plants he now calls chunii are not closely related to true hookeriana but are more closely related to aurita).
P. hubeiensis, P. voltolinii, P. pleionoides and P. speciosa : Cribb regards hubeiensis and voltolinii to be no more than variants of pleionoides, which is a very variable species, whereas Torelli thinks them sufficiently distinct to warrant being separate species. Torelli prefers to continue to use "speciosa" for the species that Cribb now calls "pleionoides".
P. hui : Torelli recognises this as a true species; Cribb regards this as probably a Chinese form of P. formosana.
P. microphylla : Torelli recognises this as a true species; Cribb believes this may also be a Chinese form of P. formosana but reserves judgement until he is able to see live material.
P. vietnamensis : Cribb, with some reservations, regards this as a distinct species related to P. praecox. There is a form of P. praecox which was once described as a separate species, P. reichenbachiana, which Cribb regards as just a variant of P. praecox. Torelli regards this variant as sufficiently distinct to warrant varietal status and calls it P. praecox var. reichenbachiana. Until he is able to examine live specimens of P. vietnamensis he, for now, treats this as being the same as P. praecox var. reichenbachiana.
P. x barbarae : Cribb applies "x barbarae" to plants which were previously thought to be pink variants of P. grandiflora and so were often referred to as "pink grandiflora". Recent DNA analyses seem to confirm these plants are hybrids, with true (white) P. grandiflora as one parent and P. bulbocodioides (or a similar species) as the other. The variability and vigour of these plants suggest that they are from a hybrid swarm with both F1 and backcrosses among them. Torelli's view at present is that he is unsure whether these plants and "x barbarae" (as described originally by a botanist called Braem) are the same thing. On his website he still has these plants as pink forms of P. grandiflora.
There are many other, often older, names out there which I won't go into here. See both Cribb's and Torelli's publications for more extensive discussions of the synonyms.
Of course it's difficult for us amateurs to know what to accept! I find myself agreeing a bit with both sides. I tend to agree with Cribb about "pleionoides" so I'll be using that name and not speciosa or hubeiensis or voltolinii.
I was kindly invited to Kew by Phillip Cribb to discuss the status of the plants he calls chunii. Having carefully examined his photographs of the original Type specimen of chunii and looked at other data I have decided to accept his assessment, albeit with some reservations still. There remain some unexplained discrepancies between the written original description (done by a botanist called Tso) and both the herbarium and live specimens. It is clear that on some counts at least, Tso simply got it wrong. For example, he describes the Type specimen as having fimbriate lamellae on the lip, whereas when I looked at the Type it was obvious it had hairs, not lamellae.
I strongly agree that x barbarae is a natural hybrid. I thought these plants were hybrids the moment I first saw them and even guessed what the parents would turn out to be. So I'll be using "x barbarae".
Lacking any substantial information on "microphylla" or "hui", or "autumnalis" I'll not be using these names.
I tend to agree with Torelli about P. praecox var. reichenbachiana and the possibility that "vietnamensis" may be just a further variant on that theme, but also that judgement on this needs to be tentative until material becomes available for further examination. P. praecox exhibits quite a lot of variation and my guess is that if and when more material becomes available, it will be difficult to draw lines between the many variations. Mind you, the pictures of vietnamensis show very distinctive flowers so I can understand if these are given species status.
Species: albiflora, aurita, bulbocodioides, chunii, coronaria, formosana, forrestii, grandiflora, hookeriana, humilis, limprichtii, maculata, pleionoides, praecox, saxicola, scopulorum, yunnanensis. Some of the non-disputed species also have varieties which will crop up too, such as P. forrestii var. alba.
Natural Hybrids: x barbarae, x christianii, x confusa, x kohlsii, x lagenaria, x taliensis
Seems at present I recognise 17 species, fewer than either Cribb or Torelli. Guess that makes me a "lumper"! However, this is in part due to not having material of some things on which to make judgements.
No doubt we have not seen the end of developments in Pleione taxonomy. For example, it was suggested quite some time ago that bulbocodioides, pleionoides and limprichtii could all be regarded as one species. This idea has not been fully embraced by the botanists yet, but I wonder how long before it is? I have certainly found that the more plants I see, especially with many new ones coming into cultivation from China, the harder I find it to tell them apart as the supposed differences all seem to become less and less distinct the more specimens you examine.