Taxonomy
The naming & classification of Pleione species has changed quite a lot in recent years, and continues to do so as new species are discovered and new data such as from DNA studies is gathered. Because of disagreements between botanists it is not even easy to say exactly how many species of Pleione are recognised. If you consult the World Checklist on Kew's website you will find that it currently lists 26 species and 9 natural hybrids. Not everyone would agree with this, but here are the ones listed:
Species: albiflora, arunachalensis, aurita, autumnalis, bulbocodioides, chunii, coronaria, dilamallata, formosana, forrestii, grandiflora, hookeriana, hui, humilis, jinhuana, kaatiae, limprichtii, maculata, microphylla, pleionoides, praecox, saxicola, scopulorum, vietnamensis, xiushanensis, yunnanensis.
Natural Hybrids: x baoshanensis, x barbarae x christianii, x confusa, x kingdonwardii, x kohlsii, x lagenaria,
x maoershanensis, x taliensis
In their respective monographs, Phillip Cribb and Gianantonio Torelli show some differences. Cribb recognised 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
Torelli recognised 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
Both these monographs are now somewhat dated and this explains some of the differences from the Kew Checklist
Species: albiflora, arunachalensis, aurita, autumnalis, bulbocodioides, chunii, coronaria, dilamallata, formosana, forrestii, grandiflora, hookeriana, hui, humilis, jinhuana, kaatiae, limprichtii, maculata, microphylla, pleionoides, praecox, saxicola, scopulorum, vietnamensis, xiushanensis, yunnanensis.
Natural Hybrids: x baoshanensis, x barbarae x christianii, x confusa, x kingdonwardii, x kohlsii, x lagenaria,
x maoershanensis, x taliensis
In their respective monographs, Phillip Cribb and Gianantonio Torelli show some differences. Cribb recognised 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
Torelli recognised 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
Both these monographs are now somewhat dated and this explains some of the differences from the Kew Checklist
What are the Differences?
The names disputed between these two authors 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. It is accepted as valid in the World Checklist.
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).
I was kindly invited to Kew by Phillip Cribb to discuss the status of P. chunii. We carefully examined his photographs of the original Type specimen of P. chunii and looked at other data too. 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. The specimens we see in cultivation have hairs on the lip, not lamellae - this is why Torelli believes that these live specimens are not true P. chunii and so calls them P. hookeriana var. sinensis. However, when I looked at the Type it was obvious it had hairs, not lamellae, so Tso made an error in his description. So the type specimen of P. chunii does seem to fit the live examples in cultivation. We should therefore keep them called as P. chunii and not as P. hookeriana var. sinensis.
In more recent times, P. chunii and P. hookeriana have also been questioned as to whether we can maintain them as separate species. They could be synonymous with P. hookeriana taking precedence, or possible with P. chunii as a variety of P. hookeriana. See Phytotaxa 350 (3): 247–258 for details
P. hubeiensis, P. voltolinii, P. pleionoides and P. speciosa : Cribb regards hubeiensis and voltolinii to be no more than variants ofpleionoides, 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". The World Checklist agrees with Cribb and has only pleionoides as valid
P. hui : Torelli recognises this as a true species; Cribb regards this as probably a Chinese form of P. formosana. The World Checklist agrees with Cribb
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. The name is accepted as valid in the World Checklist
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. The World Checklist regards vietnamensis as a valid name
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 back crosses 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. The World Checklist does not mention it as a natural hybrid but does have "Pleione barbarae" (note the missing "x") as a synonym of P. grandiflora.
There are many other 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.
The names disputed between these two authors 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. It is accepted as valid in the World Checklist.
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).
I was kindly invited to Kew by Phillip Cribb to discuss the status of P. chunii. We carefully examined his photographs of the original Type specimen of P. chunii and looked at other data too. 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. The specimens we see in cultivation have hairs on the lip, not lamellae - this is why Torelli believes that these live specimens are not true P. chunii and so calls them P. hookeriana var. sinensis. However, when I looked at the Type it was obvious it had hairs, not lamellae, so Tso made an error in his description. So the type specimen of P. chunii does seem to fit the live examples in cultivation. We should therefore keep them called as P. chunii and not as P. hookeriana var. sinensis.
In more recent times, P. chunii and P. hookeriana have also been questioned as to whether we can maintain them as separate species. They could be synonymous with P. hookeriana taking precedence, or possible with P. chunii as a variety of P. hookeriana. See Phytotaxa 350 (3): 247–258 for details
P. hubeiensis, P. voltolinii, P. pleionoides and P. speciosa : Cribb regards hubeiensis and voltolinii to be no more than variants ofpleionoides, 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". The World Checklist agrees with Cribb and has only pleionoides as valid
P. hui : Torelli recognises this as a true species; Cribb regards this as probably a Chinese form of P. formosana. The World Checklist agrees with Cribb
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. The name is accepted as valid in the World Checklist
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. The World Checklist regards vietnamensis as a valid name
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 back crosses 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. The World Checklist does not mention it as a natural hybrid but does have "Pleione barbarae" (note the missing "x") as a synonym of P. grandiflora.
There are many other 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.
Which Names Do I Use On This Website?
Of course it's difficult for us amateurs to know what to accept! I agree largely with the World Checklist with the following reservations:
1. P. autumnalis, P. microphylla and P. vietnamensis: These as far as I know are not in cultivation so I have not seen live plants of these. So I reserve judgement on whether to accept these as true species.
2. P. kaatiae: I grow several clones of this and it seems quite variable. I lean towards accepting it as a true species but also have some sympathy with Cribb who regards this as probably just a distinctive form of P. scopulorum.
3. P. x barbarae: 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 recognise one additional natural hybrid to the World Checklist.
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. I would welcome the amalgamation of these three species. But them I am a taxonomic "lumper" by nature!
Of course it's difficult for us amateurs to know what to accept! I agree largely with the World Checklist with the following reservations:
1. P. autumnalis, P. microphylla and P. vietnamensis: These as far as I know are not in cultivation so I have not seen live plants of these. So I reserve judgement on whether to accept these as true species.
2. P. kaatiae: I grow several clones of this and it seems quite variable. I lean towards accepting it as a true species but also have some sympathy with Cribb who regards this as probably just a distinctive form of P. scopulorum.
3. P. x barbarae: 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 recognise one additional natural hybrid to the World Checklist.
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. I would welcome the amalgamation of these three species. But them I am a taxonomic "lumper" by nature!