Re. the entry Rosa Yakachinensis, this is probably what is known as R. yakushimaensis. It is an alpine form of Rosa onoei collected on Yakushima island off the south coast of Kyushu, Japan. It was first named R. yakualpina. It is or has been in the bonsai trade in California as Yakushimaibara (the rose from Yaku island). It should probably be called Rosa 'Yakushima' or R. onei 'Yakushima'. Small, white, delicate single flowers about 12.5 mm in diameter. Leaves with narrow leaflets and in scale with the small flowers. The stems larger and not in scale with the tiny flowers and leaves. Eventually forms a 1 to 2 meter high tangle. Very painful prickles which break off in the skin. Has been used as a parent
It is my impression that Rosa yakualpina while belonging to R. onoei is considerably smaller than typical R. onoei var. onoei and is worthy of recognitions as a clonal cultivar selection, which it is. At least in California it is not a variable group of R. onoei seedlings, it is clonally propagated descendants of the original collection made on the peak of Yakushima island. So while the IOPI determination putting it as a synonym of R. onoei var onoei may be botanicly correct it ignores the horticultural importance of this particular clone. It would be similar to saying 'Old Blush' is a synonym of Rosa chinensis. Old Blush is a form of R. chinensis but is not typical of the original R. chinensis.
Do I understand you correctly...akin to R. omeiensis 'Pteracantha'?
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#4 posted
19 JUN 07 by
Unregistered Guest
Hello Cass: How did R. omeiensis 'Pteracantha' enter into this? It is not related to R. yakualpina, or R. onoei 'Yakushima'. This rose is a natural miniature member of the Synstylae related to R. wichurana and R. luciae and more distantly to R. multiflora.
Hi, Fred. Excuse me for being obscure. I want to make sure I understand your point about R. yakushimaensis. You said, "[it] is worthy of recognitions as a clonal cultivar selection."
Yes, I see that it is a variant of the species, georgraphically isolated. I see that it was used by Louis Lens in breeding. I see that it is in trade in California for bonsai, presumably vegetatively propagated.
My question is for your confirmation whether you think such species cultivar selections should be listed separately from the species. I mention R. omeiensis 'Pteracantha' as an analogous species cultivar selection (although I believe several forms may actually by in commerce.)
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#6 posted
20 JUN 07 by
Unregistered Guest
Cass: Oh, I see. . I believe cultivar selections should be both listed separately from the species and also under the species not just lumped into a species, implying that the cultivar is just such and such species. So the rose in question would have an entry under each of its various published names and cultivar names with notes that it is a clonal selection of R. onoei var. onoei. And the species name would also lead you to the cultivar: R. onoei var. onoei 'Yakushima'. I seem to recall that Modern Roses doesn't list species clones under their respective species. My suggestion may cause confusion as to which is the correct name to use at a rose show 'Yakushima' or Rosa onoei var. onoei 'Yakushima'. Don't know the ARS rules on that.
My start of this rose, as 'Yakushimaibara' came from Western Hills Nursery years ago.
