Iris Cohen schreef
Well it was you who used the abbreviation,
Not I. You have to watch those successive quotes. Somebody else wrote in
that 'Shimpaku' is a cultivar in J. chinensis s. l.

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If we are splitting hairs: You did use it. You just did not introduce it.
However you were the first to use it in a sentence which depended on its
meaning being known :-)
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I am not at all sure if adding new cultivars adds anything to a
species concept, or the "sense" of a species.
In this case it just indicates that eliminating J. xmedia moves the
boundaries of J. chinensis back to where they used to be.

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That is the question. Eliminating the name Juniperus x media by itself is a
matter of a name (nomenclatural), while the boundaries of Juniperus
chinensis are a matter of the plants belonging to it (taxonomic).
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Here's something else. Apparently Larix xmarschlinsii is the correct
technical name for Dunkeld larch. (decidua x kaempferi)
Iris,

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Apparently so. Has been for a while, too. A quick scan shows a 1980
publication on the matter, but unfortunately in an out of the way journal.
Not easy to check.
PvR